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Nonword repetition and phoneme elision in adults who do and do not stutter: Vocal versus nonvocal performance differences
Abstract
The purpose of the present study was to enhance our understanding of phonological working memory in adults who stutter through the comparison of nonvocal versus vocal nonword repetition and phoneme elision task performance differences.
For the vocal nonword repetition condition, participants repeated sets of 4- and 7-syllable nonwords (n=12 per set). For the nonvocal nonword repetition condition, participants silently identified each target nonword from a subsequent set of three nonwords. For the vocal phoneme elision condition, participants repeated nonwords with a target phoneme eliminated. For the nonvocal phoneme elision condition, participants silently identified the nonword with the designated target phoneme eliminated from a subsequent set of three nonwords.
Adults who stutter produced significantly fewer accurate initial productions of 7-syllable nonwords compared to adults who do not stutter. There were no talker group differences for the silent identification of nonwords, but both talker groups required significantly more mean number of attempts to accurately silently identify 7-syllable as compared to 4-syllable nonwords. For the vocal phoneme elision condition, adults who stutter were significantly less accurate than adults who do not stutter in their initial production and required a significantly higher mean number of attempts to accurately produce 7-syllable nonwords with a phoneme eliminated. This talker group difference was also significant for the nonvocal phoneme elision condition for both 4- and 7-syllable nonwords.
Present findings suggest phonological working memory may contribute to the difficulties persons who stutter have establishing and/or maintaining fluent speech. Educational Objectives: (a) Readers can describe the role of phonological working memory in planning for and execution of speech; (b) readers can describe two experimental tasks for exploring the phonological working memory: nonword repetition and phoneme elision; (c) readers can describe how the nonword repetition and phoneme elision skills of adults who stutter differ from their typically fluent peers.
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... Numerous studies have examined working memory in AWS with tasks, such as N-back tasks, word repetition, rhyme judgment, and word list recall focusing on the phonological loop. The results indicated that AWS performed worse than those without stuttering in the variability of accuracy and reaction time [16][17][18]. Another group of studies that used both verbal and non-verbal tasks showed that when the task was not taxing enough, no difference was observed between the performance of AWS and the adult who did not stutter (AWNS) in accuracy and reaction time [19][20][21]. ...
... Regarding working memory skills, the results of the current study showed a difference between AWS and AWNS groups. These results are consistent with the results of Byrd et al. [16] who used a word repetition task, and inconsistent with the Gkalitsiou et al. [21] results who used an N-back task and reported no significant difference between AWS and AWNS. In Byrd's study, this was interpreted as AWS having distinct difficulty maintaining and simultaneously manipulating novel phonological strings in the phonological loop [16]. ...
... These results are consistent with the results of Byrd et al. [16] who used a word repetition task, and inconsistent with the Gkalitsiou et al. [21] results who used an N-back task and reported no significant difference between AWS and AWNS. In Byrd's study, this was interpreted as AWS having distinct difficulty maintaining and simultaneously manipulating novel phonological strings in the phonological loop [16]. The differences between Gkalitsiou et al. study and the present study were the type of assessment tests and the non-verbal assessment of working memory. ...
Introduction: Fluent speech requires executive functions to identify, inhibit, and modify speech interruptions to continuously regulate the speech process. The current study aims to examine the executive functions in adults who stutter (AWS) and adults who do not stutter (AWNS). We also examined the relationship between executive functions and stuttering severity. Materials and Methods: This research is a cross-sectional descriptive-analytic study. The participants included 32 AWS (Mean±SD of age=28±6.79) divided into three groups of mild, moderate, and severe severity and 32 AWNS (Mean±SD of age=28.57±6.53). Selected tests from the Delis-Kaplan executive function system (D-KEFS) were used to assess executive function domains. Results: The results of this study showed that AWS performed significantly lower than AWNS in working memory (P=0.009), problem-solving and planning (P<0.001), verbal cognitive flexibility (shifting) (P<0.001), and verbal inhibitory control (P<0.001). The results also showed no difference between AWS and AWNS in non-verbal inhibition, shifting, and reasoning. Furthermore, a significant relationship was observed between stuttering severity and executive function domains. Conclusion: This study showed that executive function skills are affected in AWS and should be considered in the rehabilitation programs of AWS.
... Different profiles of stuttering may emerge over the course of the life span and include overt difficulties with fluent speech production, negative feelings and thoughts, and work and social situation avoidance (e.g., Bloodstein et al., 2021;Yaruss, 2007;Yaruss & Quesal, 2004). Specific to linguistic factors thought to influence stuttering onset or persistence, many investigations have suggested that adults who stutter (AWS) have weaker language skills than adults who do not stutter (AWNS) in areas including lexical access and retrieval (e.g., McGill et al., 2016;Newman & Bernstein Ratner, 2007;Pellowski, 2011;Wingate, 1988), syntax (e.g., Cuadrado & Weber-Fox, 2003;Kleinow & Smith, 2000;Spencer et al., 2009;Tsiamtsiouris & Cairns, 2013), and phonological processing (e.g., Byrd et al., 2012Byrd et al., , 2015Castro et al., 2017;McGill et al., 2016). ...
... A growing amount of work has suggested that phonological processing and working memory are areas of deficit in AWS (Byrd et al., 2012(Byrd et al., , 2015Pelczarski et al., 2019). Thus, the letter fluency task may be of particular interest to evaluate in AWS. ...
... Furthermore, other tasks that have measured aspects of language skill through oral and manual modalities have produced contrasting results. For example, Byrd et al. (2015) used both oral and non-oral nonword repetition and phoneme elision tasks to measure phonological working memory ability in AWS and AWNS. They found no group differences on the nonword identification task; however, AWS needed more repetition attempts for the sevensyllable nonwords. ...
Purpose
Language abilities have long been thought to be weaker in adults who stutter (AWS) compared to adults who do not stutter (AWNS). However, it is unknown whether modality affects language performance by AWS in time pressure situations. This study aimed to examine lexical access and retrieval abilities of AWS in oral and typed modes.
Method
Fifteen AWS and 15 well-matched AWNS completed computer-administered letter fluency tasks. Adults were asked to orally produce words that began with one of two letter targets and type words that began with one of two alternate letters. Conditions were counterbalanced across participants.
Results
Generalized linear mixed-effects models were evaluated to determine the effects of group (AWS/AWNS), mode (oral/typed), and expressive vocabulary on letter fluency performance. Group predicted letter fluency such that AWS generated fewer items on both the oral and typed letter fluency tasks. Mode did not impact letter fluency results. Expressive Vocabulary Test scores predicted letter fluency similarly in both AWS and AWNS.
Conclusions
AWS were not penalized by oral task demands. AWS generated fewer items on the letter fluency tasks regardless of response mode, suggesting that they have weaker lexical access abilities. Furthermore, better expressive vocabulary skills were associated with better letter fluency performance in both groups.
... Several factors contribute to its development and persistence including genetic predisposition (e.g., Drayna & Kang, 2011), neurophysiological differences (e.g., Giraud et al., 2008;Watkins et al., 2008), differences in emotional reactivity and regulation (e.g., Jones et al., 2014;Karrass et al., 2006) or variances in speech motor control (e.g., Alm, 2004;Max et al., 2004;Namasivayam & van Lieshout, 2008). Most relevant to the present study, differences in linguistic/cognitive processing of individuals who stutter have also been suggested as a contributing factor to stuttered speech (e.g., Byrd et al., 2012;Byrd et al., 2015a;Coalson & Byrd, 2015;Sasisekaran et al., 2006;Weber-Fox et al., 2004). ...
... Deficits in subvocal rehearsal have also been demonstrated in AWS via list recall tasks (e. g., Byrd et al., 2015b). Furthermore, results from nonword repetition tasks and/or additional metalinguistic tasks including phoneme manipulation (e.g., phoneme elision) indicate slower and less accurate performance in AWS (e.g., Byrd et al., 2012;Byrd et al., 2015a;Sasisekaran & Weisberg, 2014), providing further evidence for aberrant function of the phonological loop in AWS as opposed to AWNS. ...
... In this study, we anticipated that both groups would perform better in the neutral compared to the phonological condition (e.g., Byrd et al., 2015b;Mueller et al., 2003;Sweet et al., 2008;Vallar & Baddeley, 1984). Furthermore, based on evidence suggesting that AWS demonstrate deficits in lexical access, phonological loop, and central executive (e.g., Byrd et al., 2015aByrd et al., , 2015bMaxfield et al., 2012;McGill et al., 2016), we predicted that AWS would be significantly less accurate and slower than AWNS in the phonological condition at the 2-and 3-back levels, the most cognitively demanding of the required tasks. ...
Purpose
The purpose of this study was to investigate working memory in adults who do (AWS) and do not (AWNS) stutter using a visual N-back task. Processes involved in an N-back task include encoding, storing, rehearsing, inhibition, temporal ordering, and matching.
Methods
Fifteen AWS (11 males, 4 females;M = 23.27 years, SD = 5.68 years) and 15 AWNS (M = 23.47 years, SD = 6.21 years) were asked to monitor series of images and respond by pressing a “yes” button if the image they viewed was the same as the image one, two, or three trials back. Stimuli included images with phonologically similar (i.e., phonological condition) or phonologically dissimilar (i.e., neutral condition) names. Accuracy and manual reaction time (mRT) were analyzed.
Results
No difference was found between AWS and AWNS in accuracy. Furthermore, both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. Finally, AWNS demonstrated faster mRT in the phonological compared to neutral condition, whereas AWS did not.
Conclusion
Results from this study suggest different processing mechanisms between AWS and AWNS for visually presented phonologically similar stimuli. Specifically, a phonological priming effect occurred in AWNS but not in AWS, potentially due to reduced spreading activation and organization in the mental lexicon of AWS. However, the lack of differences between AWS and AWNS across all N-back levels does not support deficits in AWS in aspects of working memory targeted through a visual N-back task; but, these results are preliminary and additional research is warranted.
... monitoring tasks, dual tasks, and tasks with increased phonological complexity; Bosshardt et al., 2002;Coalson & Byrd, 2020;Howell & Bernstein Ratner, 2018;Saisekaran & de Nil, 2006;Sasiseakaran et al., 2006), phonological awareness (e.g. rhyme J o u r n a l P r e -p r o o f discrimination; Weber-Fox et al., 2004), and phonological working memory (at least for the more complex nonwords in a nonword repetition task; Byrd et al., 2015;Byrd et al. , 2012;Choopanian et al., 2019;Coalson & Byrd, 2017). In a rhyme discrimination task, Weber-Fox et al. (2004) found that AWS performed similarly to fluent controls, except for the most difficult condition (orthographic but not phonological overlap, gownown). ...
... This indicates the prevalence rate was not the result of educational experience. adults (AWD: Peter et al., 2018;Szenkovits & Ramus, 2005; AWS: Byrd et al., 2012Byrd et al., , 2015Coalson & Byrd, 2017) Note. Total print exposure assessed by author and title recognition; inverse efficiency scores (IES); British Picture Vocabulary Scales 2 nd edition (BPVS-2); Expressive Picture Vocabulary Test 2 nd edition (EVT-2); Gray Silent Reading Test (GSRT); Rapid Letter naming (RLN); Test of Word Reading Efficiency (TOWRE): sight word reading (TOWRE-W) and phonemic decoding/nonword reading (TOWRE-P) and Test of Irregular Word Efficiency (TIWRE). ...
... The finding of an impairment in phonological awareness, phonological memory, and phonological retrieval in AWS is in line with other works that points to certain phonological deficits in people who stutter. For instance, Byrd et al. (2012Byrd et al. ( , 2015 and Yaruss (2014, 2016) found that people who stutter were less accurate in nonword repetition tasks and phoneme elision tasks than people who do not stutter. These authors attributed these poor performances to a difficulty in phonological encoding and/or subvocal rehearsal for people who stutter compared to the neurotypical population. ...
This study assessed the prevalence of childhood stuttering in adults with dyslexia (AWD) and the prevalence of dyslexia in adults who stutter (AWS). In addition, the linguistic profiles of 50 AWD, 30 AWS and 84 neurotypical adults were measured. We found that 17 out of 50 AWD (34%) reported stuttering during childhood compared to 1% of the neurotypical population. This was moderated by the severity of dyslexia: People with mild dyslexia showed a lower prevalence rate (15%) of childhood stuttering than those with severe dyslexia (47%). In addition, we observed that 50% of the AWS (n = 30) fulfilled the diagnostic criteria of dyslexia, even though they had never been diagnosed as dyslexic. Compared to neurotypical adults, phonological working memory, awareness, and retrieval were similarly reduced in AWS and AWD. The findings supports the view that stuttering and dyslexia may share a phonological deficit.
... Various experimental paradigms have been used to measure WM abilities of PWS, such as rhyme judgment, letter recall, and phoneme monitoring Jones et al., 2012;Sasisekaran & Basu, 2017). In particular, nonword repetition task and dual task have been repeatedly employed in previous studies (Anderson & Wagovich, 2010;Anderson et al., 2006;Arends et al., 1988;Bosshardt, 1993Bosshardt, , 1999Bosshardt, , 2002Bosshardt et al., 2002;Byrd et al., 2015Byrd et al., , 2012Eichorn et al., 2016Eichorn et al., , 2019Hakim & Bernstein Ratner, 2004;Kamhi & McOsker, 1982;Metten et al., 2011;Sasisekaran, 2013;Vasić & Wijnen, 2005). ...
... Studies using a nonword repetition task purposefully exclude confounding factors such as semantics and pragmatics in order to solely focus on the phonological aspects of WM (Anderson & Wagovich, 2010;Anderson et al., 2006;Bosshardt, 1993;Byrd et al., 2015Byrd et al., , 2012Hakim & Bernstein Ratner, 2004;Sasisekaran, 2013). The errors and other parameters are studied for the repeated nonwords of various syllable lengths in these studies. ...
... However, other studies found that children who stutter produced significantly fewer correct responses for nonword repetitions than children who do not stutter (Anderson & Wagovich, 2010;Anderson et al., 2006;Hakim & Bernstein Ratner, 2004;Oyoun et al., 2010;Pelczarski & Yaruss, 2016;Spencer & Weber-Fox, 2014). Some other studies reported that adults who stutter produced significantly less accurate nonword repetitions than adults who do not stutter (Byrd et al., 2015(Byrd et al., , 2012Coalson & Byrd, 2017;Ludlow et al., 1997;Sasisekaran & Weisberg, 2014). Although the discrepancy among those studies cannot be well explained, most of the results indicate the existence of a deficit in the WM of PWS. ...
Purpose
Working memory (WM) deficits are implicated in various communication disorders, including stuttering. The reading span test (RST) measures WM capacity with the dual task of reading sentences aloud and remembering target words. This study demonstrates a difference in strategy between people who stutter (PWS) and people who do not stutter (PWNS) in performing the RST. The impact of the effective strategy and the stuttering-like disfluencies during the RST were investigated.
Method
Twenty-six PWS and 24 people who do not stutter performed the RST and a simple reading aloud task. After the RST, they were asked which strategy (“imagery” or “rehearsal”) they had used in order to remember the target words during the task.
Results
The proportion of those who used an “imagery” strategy during the RST was significantly smaller in the PWS group. However, the RST scores of those who used an “imagery” strategy were significantly higher than the RST scores of those who used a “rehearsal” strategy in both groups. The “rehearsal” users were asked to undertake one more RST with an “imagery” strategy, which resulted in an increased score for both groups. The disfluency frequency of the PWS group was significantly reduced during the RST than during the oral reading task, irrespective of the employed strategy.
Conclusions
PWS tended to use the less effective verbal “rehearsal” strategy during the RST. The differential effects of switching strategies on the measured WM capacity and on the disfluency rate suggest that the enhanced fluency during the RST would be mostly attributable to the reduced attention to speech motor control. Therefore, the use of the “imagery” strategy and focusing on the contents of communication, away from speech motor control, should help PWS communicate better in daily conversation.
... Nonword repetition tasks have widely been used to explore the PWM in children and in adults who stutter (AWS). Past studies along this line in AWS have found that these individuals tend to be less successful in repeating nonwords compared to their fluent peers (Byrd et al., 2012;Byrd, McGill, & Usler, 2015;Ludlow, Siren, & Zikria, 1997;Sasisekaran & Weisberg, 2014;Sasisekaran, 2013;Smith, Sadagopan, Walsh, & Weber-Fox, 2010). However, later studies suggested that AWS and adults who do not stutter (AWNS) both exhibit comparable accuracy while repeating nonwords of shorter syllable length and that the working memory deficits in AWS only surface on nonwords of longer syllable lengths. ...
... In a more recent study, Byrd et al. (2015) employed vocal and nonvocal tasks of nonword identification to explore the PWM capacity of AWS. The nonvocal nonword repetition involved the identification of a target nonword from a subsequent set of three nonwords. ...
... Analysis of the PWM in AWS using vocal and nonvocal nonword repetitions has revealed that these individuals exhibit difficulty only when vocal production of the nonword is required and not during silent identification of the words (Byrd et al., 2015). The current study is a partial replication of that of Byrd and colleagues, on school-aged CWS using nonword repetition and nonword identification tasks. ...
Purpose:
The present study employed nonword repetition and nonword identification tasks to explore the phonological working memory (PWM) abilities and its interaction with speech motor control in school-aged children who do and do not stutter.
Method:
Participants were 17 children who stutter (CWS) (Age range = 7-12) and 17 age and gender-matched children who do not stutter (CWNS). For the nonword repetition task, the participants repeated sets of 2-, 3-, and 4-syllable nonwords (n = 12 per set). The participants silently identified a target nonword from a subsequent set of three nonwords (n = 12 per 2-, 3- and 4-syllable length) for the nonword identification task. The performance of CWS on the nonword repetition task was compared with the CWNS for the mean number of accurate repetitions, number of trials taken, number of accurate repetitions on initial trial, and number of fluent repetitions across the three-syllable conditions for the tasks. For the nonword identification task, the number of nonwords identified accurately by the two groups were subjected to analysis.
Results:
CWS were significantly less accurate on the initial production of nonwords and required significantly more number of attempts to repeat the nonword accurately. Further for the nonword identification task, CWS were significantly less accurate than CWNS in correctly identifying the target nonword.
Conclusions:
The present findings suggest that, in addition to limitations in PWM capacity, an unstable speech motor control system in CWS may lead to dysfluent speech.
... Reading rates and nonword repetition tasks engage phonological loop in retrieving the stored phonological segments. Evidence from previous research indicates longer reading rate and poor nonword recognition in adults with stuttering (AWS; Bosshardt, 1990Bosshardt, , 1993Bosshardt & Nandyal, 1988;Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Jones, Fox, & Jacewicz, 2012;Sasisekaran & Weisberg, 2014). These studies suggest deficits in phonological working memory as one of the reasons for the poorer performance seen in AWS. ...
... Subvocal rehearsals are important during the phonological memory tasks, which require motor processing even in the absence of any spoken output. Impaired subvocal rehearsals have been attributed as one of the reasons behind the impaired recall of phonological elements in terms of reaction times (RTs) and accuracy (Byrd et al., 2012(Byrd et al., , 2015Jones et al., 2012;Sasisekaran & Weisberg, 2014). The input and output phonological buffers forming phonological memory recycle information between perceived speech and production of speech, which is essential for speech processing (Jacquemot & Scott, 2006). ...
... It has been established that the deficits in phonological working memory in AWS are leading to poorer performance on reading rate and nonword recognition tasks (Bosshardt, 1990(Bosshardt, , 1993Bosshardt & Nandyal, 1988;Byrd et al., 2012Byrd et al., , 2015Jones et al., 2012;Sasisekaran & Weisberg, 2014). However, underlying language disturbances might affect the performance of AWS, as these tasks demand good language processing skills. ...
Purpose
Adults with stuttering (AWS) exhibit compromised phonological working memory abilities, poor central auditory processing, and impaired auditory processing especially during overt speech production tasks. However, these tasks are sensitive to language disturbances already found in them. Thus, in this study, monosyllables were used ruling out the language effects, and auditory working memory ability was evaluated in AWS using the n-back task. In specific, the auditory sensory input of the working memory mechanism was evaluated.
Method
Thirty-two participants, 16 each of AWS and adults with no stuttering (AWNS), performed behavioral auditory 1-back and 2-back tasks. The long latency responses were also recorded during no-back and 2-back conditions from 64 electrode sites.
Results
Results revealed no significant differences between the groups in any of the behavioral parameters such as reaction time, accuracy, false alarm rate, or d′. N1 amplitude modulation was noted in AWNS, which was absent in AWS. The segmentation analysis showed a left hemisphere–oriented topographical distribution in the N2 region in AWS irrespective of conditions, whereas the scalp topography was right hemisphere–oriented with the involvement of parietal channels in AWNS. The timing differences existed between AWS and AWNS in the intervals that a topographical distribution lasted in all throughout the time window of analysis.
Conclusion
The results suggest altered neural pathway and hemispheric differences during auditory working memory tasks in AWS.
... Stuttering is generally known as a multi-factor phenomenon (1). Given the complexity of stuttering, many assumptions have been proposed regarding its origins (2). ...
... Phonological processing, as an umbrella term, includes various skills, which have many effects on phonological encoding (10). Phonological working memory and phonological awareness, which are part of phonological processing, are factors affecting phonological encoding (1,8,11). Working memory is a neuro-cognitive system that includes the central executive, a phonological loop, a visuospatial sketchpad, and an episodic buffer (2,9,12,13). ...
... Working memory is a neuro-cognitive system that includes the central executive, a phonological loop, a visuospatial sketchpad, and an episodic buffer (2,9,12,13). Phonological loop plays an important role in phoneme encoding and correct phoneme retrieval in the working memory (1,5). Another factor in phonological processing is having phonological awareness skills (8). ...
Objectives:
Correct phonological encoding is crucial to fluent speech production. Phonological working memory and phonological awareness are important phonological processes that affect phonological encoding. The purpose of this study was to investigate the effect of phonological processing on stuttering severity of Persian pre-school children.
Materials & methods:
Six children were targeted in this study in Ahvaz City, southern Iran in 2018, with Quasi-experimental design (Before and after clinical trial). These children participated in a treatment protocol, scheduled in 13-sessions. The treatment protocol of the phonological processing included nonword repetition in the phonological working memory and phonological awareness therapy. Overall, 30 nonwords were taken to examine the phonological working memory. The Persian test of language development was taken to examine phonological awareness. Stuttering severity measurements were performed with pre- and post-treatment. The severity rating was instructed to the parents based on Guitar protocol. They were asked to keep score every day until the end of the treatment sessions, and they reported the score to the therapist.
Results:
The stuttering severity score in pre and post-treatment was significant (P=0.027), and in the follow-up, phase was not significant (P=0.236); stuttering severity was reduced in children who stutter. Moreover, the severity rating score reported by parents during treatment was significant (P= 0.0001). This showed a reduction in stuttering severity.
Conclusion:
The poor performance of phonological awareness and phonological working memory in phonological processing affect stuttering severity. Treatment of sub-systems of phonological processing can have an important role in reducing stuttering severity and increasing speech fluency.
... Despite the potential significance of PWM, studies using tasks thought to load PWM in CWS and AWS have produced somewhat mixed results, and the underlying mechanisms mediating recently reported differences remain unclear (Anderson & Wagovich, 2010;Anderson, Wagovich, & Hall, 2006;Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Smith, Sadagopan, Walsh, & Weber-Fox, 2010). ...
... Perhaps as a consequence, while both CWS and AWS present with functional and structural anomalies in both sensorimotor (Buchsbaum & D'Esposito, 2008;Buchsbaum et al., 2011;Hickok, Houde, & Rong, 2011;Jacquemot & Scott, 2006) and neurocognitive networks implicated in PWM (Chang et al., 2017;Kell et al., 2017;Sitek et al., 2016), there have been no attempts to integrate existing cognitive-behavioral and neuroimaging findings with neurobiological models of language and cognition. As such, the aim of the current review is to examine how neurobiological models incorporating A C C E P T E D M A N U S C R I P T PWM in typical speech and language processing (Hickok & Poeppel, 2007;Jacquemot & Scott, 2006) and executive function (D'Esposito, 2007;Hazy, Frank, & O'Reilly, 2007) may shed light on underlying mechanisms mediating recent cognitive-behavioral studies implicating lower PWM capacity in CWS (Anderson & Wagovich, 2010;Anderson et al., 2006;Spencer & Weber-Fox, 2014) and AWS (Byrd et al., 2015;Byrd, et al., 2012;Smith et al., 2010). We argue that interpreting cognitive-behavioral findings in the context of neurobiological models may strengthen the relationship between underlying mechanisms affecting fluent speech production those underlying differences in PWM in both CWS (Spencer & Weber-Fox, 2014) and AWS (Byrd et al., 2015;Byrd, et al., 2012). ...
... As such, the aim of the current review is to examine how neurobiological models incorporating A C C E P T E D M A N U S C R I P T PWM in typical speech and language processing (Hickok & Poeppel, 2007;Jacquemot & Scott, 2006) and executive function (D'Esposito, 2007;Hazy, Frank, & O'Reilly, 2007) may shed light on underlying mechanisms mediating recent cognitive-behavioral studies implicating lower PWM capacity in CWS (Anderson & Wagovich, 2010;Anderson et al., 2006;Spencer & Weber-Fox, 2014) and AWS (Byrd et al., 2015;Byrd, et al., 2012;Smith et al., 2010). We argue that interpreting cognitive-behavioral findings in the context of neurobiological models may strengthen the relationship between underlying mechanisms affecting fluent speech production those underlying differences in PWM in both CWS (Spencer & Weber-Fox, 2014) and AWS (Byrd et al., 2015;Byrd, et al., 2012). In particular, we argue that interpreting cognitive-behavioral findings in the context of neurobiological models may strengthen the relationship between underlying mechanisms affecting fluent speech production and those underlying differences in PWM. ...
The current review examines how neurobiological models of language and cognition could shed light on the role of phonological working memory (PWM) in developmental stuttering (DS). Toward that aim, we review Baddeley's influential multicomponent model of PWM and evidence for load-dependent differences between children and adults who stutter and typically fluent speakers in nonword repetition and dual-task paradigms. We suggest that, while nonword repetition and dual-task findings implicate processes related to PWM, it is unclear from behavioral studies alone what mechanisms are involved. To address how PWM could be related to speech output in DS, a third section reviews neurobiological models of language proposing that PWM is an emergent property of cyclic sensory and motor buffers in the dorsal stream critical for speech production. We propose that anomalous sensorimotor timing could potentially interrupt both fluent speech in DS and the emergent properties of PWM. To further address the role of attention and executive function in PWM and DS, we also review neurobiological models proposing that prefrontal cortex (PFC) and basal ganglia (BG) function to facilitate working memory under distracting conditions and neuroimaging evidence implicating the PFC and BG in stuttering. Finally, we argue that cognitive-behavioral differences in nonword repetition and dual-tasks are consistent with the involvement of neurocognitive networks related to executive function and sensorimotor integration in PWM. We suggest progress in understanding the relationship between stuttering and PWM may be accomplished using high-temporal resolution electromagnetic experimental approaches.
... A number of studies have investigated whether adults who stutter exhibit a deficit or anomaly in phonological encoding that could contribute to stuttering. A range of tasks have been used to probe phonological encoding in adults who stutter, including silent phoneme monitoring (e.g., Sasisekaran, De Nil, Smyth, & Johnson, 2006), rhyme monitoring (e.g., Bosshardt, 2002;Bosshardt & Fransen, 1996;Weber-Fox, Spencer, Spruill, & Smith, 2004;Jones, Fox, & Jacewicz, 2012), nonword repetition (e.g., Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Pelczarski, 2011;Sasisekaran, 2013;Sasisekaran & Byrd, 2013), phonological priming (e.g., Hennessey, Nang, & Beilby, 2008), and phoneme elision (e.g., Byrd et al., 2012Byrd et al., , 2015Pelczarski, 2011). The findings have been mixed, with several studies pointing to aberrant phonological encoding whereas other studies suggest it does not differ in adults who do not stutter. ...
... A number of studies have investigated whether adults who stutter exhibit a deficit or anomaly in phonological encoding that could contribute to stuttering. A range of tasks have been used to probe phonological encoding in adults who stutter, including silent phoneme monitoring (e.g., Sasisekaran, De Nil, Smyth, & Johnson, 2006), rhyme monitoring (e.g., Bosshardt, 2002;Bosshardt & Fransen, 1996;Weber-Fox, Spencer, Spruill, & Smith, 2004;Jones, Fox, & Jacewicz, 2012), nonword repetition (e.g., Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Pelczarski, 2011;Sasisekaran, 2013;Sasisekaran & Byrd, 2013), phonological priming (e.g., Hennessey, Nang, & Beilby, 2008), and phoneme elision (e.g., Byrd et al., 2012Byrd et al., , 2015Pelczarski, 2011). The findings have been mixed, with several studies pointing to aberrant phonological encoding whereas other studies suggest it does not differ in adults who do not stutter. ...
... Phonetic encoding begins after phonological encoding has been initiated and provides the speech motor plan that is transmitted to the articulators for production of the utterance (articulatory stage). The phonological encoding stage preceding phonetic encoding and articulation is hypothesized to be more error-prone, or delayed, in stuttering from both theoretical (e.g., Howell & Au-Yeung, 2002;Perkins et al., 1991;Postma & Kolk, 1993) and empirical (e.g., Byrd et al., 2015;Sasisekaran, 2013;Sasisekaran & Weisberg, 2014) reports. ...
Stuttering is a multifactorial disorder that is characterized by disruptions in the forward flow of speech believed to be caused by differences in the motor and linguistic systems. Several psycholinguistic theories of stuttering suggest that delayed or disrupted phonological encoding contributes to stuttered speech. However, phonological encoding remains difficult to measure without controlling for the involvement of the speech-motor system. Eye-tracking is proposed to be a reliable approach for measuring phonological encoding duration while controlling for the influence of speech production. Eighteen adults who stutter and 18 adults who do not stutter read nonwords under silent and overt conditions. Eye-tracking was used to measure dwell time, number of fixations, and response time. Adults who stutter demonstrated significantly more fixations and longer dwell times during overt reading than adults who do not stutter. In the silent condition, the adults who stutter produced more fixations on the nonwords than adults who do not stutter, but dwell-time differences were not found. Overt production may have resulted in additional requirements at the phonological and phonetic levels of encoding for adults who stutter. Direct measurement of eye-gaze fixation and dwell time suggests that adults who stutter require additional processing that could potentially delay or interfere with phonological-to-motor encoding.
... That is, the rate of articulation required to repeat the target silently exceeds the theoretical capacity of the phonological store and, as a consequence, the input used to update the target held in storage within this time frame is incomplete or underspecified. AWS demonstrate reduced accuracy during nonword repetition (Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012) and recall (Coalson & Byrd, 2017;Ludlow, Siren, & Zikria, 1997) compared to AWNS. However, researchers across these studies have acknowledged that the difficulties observed in AWS when reproducing novel phonological sequences is difficult to link to any single subprocess of the phonological loop due to potential deficiencies in phonological encoding in AWS. ...
... Phonological working memory and phonological complexity in AWS One final consideration when interpreting previous investigations of phonological working memory in AWS is the segmental and metrical complexity of the stimuli. Phonological working memoryand, in particular, subvocal rehearsalin AWS appears vulnerable only if segmental length or complexity is increased (>4 syllables; Byrd, McGill, et al., 2015;Byrd et al., 2012;Ludlow et al., 1997;Sasisekaran & Weisberg, 2014), or metrical structure deviates from high-frequency stress patterns (Coalson & Byrd, 2017). For example, Coalson and Byrd (2017) found AWS (n = 26) recalled bisyllabic nonwords with less phonemic accuracy than AWNS (n = 26) when targets carried iambic stress, but not trochaic stress. ...
... These findings are consistent with research that suggests AWS and AWNS perform similarly on phonological working memory tasks when the phonological demand is low. For example, no differences emerge when (a) vocally repeating and/or nonvocally identifying nonwords of shorter lengths (e.g., Byrd et al., 2012;Byrd, McGill, et al., 2015), (b) recalling lists of words that are maximally phonologically dissimilar and maximally semantically similar (e.g., Byrd, Sheng, Gkalitsiou, & Bernstein Ratner, 2015), or (c) the novel phonological sequences have high-frequency trochaic stress assignment (Coalson & Byrd, 2017). In addition, both groups exhibited significantly faster response latencies, on average, when monitoring segmental information after subvocal rehearsal (4 s) than during phonological storage (1 s). ...
Previous research employed silent phoneme monitoring tasks to examine differences in phonological encoding in adults who stutter (AWS) compared to adults who do not stutter (AWNS). The primary purpose of this study was to apply a modified version of the task – the delayed silent phoneme monitoring task – to examine the integrity of the phonological speech plan within working memory in AWS and AWNS before and after subvocal rehearsal. The secondary purpose of this study was to examine whether group differences were more apparent when greater phonological demand was placed upon phonological working memory. In Experiment 1, 20 adults (10 AWNS, 10 AWS) identified target phonemes within trochaic nonwords held in memory before the initiation of subvocal rehearsal (1 s) and after subvocal rehearsal (4 s). In Experiment 2, an additional 20 adults (10 AWNS, 10 AWS) monitored identical nonwords with low-frequency iambic stress. Speed and accuracy of manual response was measured, as well as post-trial verbal productions. Both groups identified the initial phoneme of trochaic stimuli fastest, irrespective of stress, and both groups monitored phonemes faster after the 4 s delay. However, AWS identified phonemes within iambic stimuli with less accuracy than AWNS. Group differences in monitoring errors were most evident for phonemes immediately following syllable boundary, and after subvocal rehearsal. Preliminary findings suggest AWS may exhibit distinct difficulties relative to AWNS when accessing segmental information after subvocal rehearsal is required, but only when target words are more phonologically demanding (i.e., low-frequency iambic stress).
... In terms of speech planning difficulties, a considerable amount of data implicate weaknesses in phonological encoding early in life as a key area of compromise (e.g., [7][8][9], for an opposing viewpoint, see [10,11]), particularly for children whose stuttering persists into adulthood (e.g., [12][13][14][15]). These data are further supported by studies which indicate that many adults who stutter (AWS) perform more poorly than adults who do DOI: 10.1159/000485657 not stutter (AWNS) when completing experimental tasks that rely on efficient phonological processing (e.g., nonword repetition [16][17][18]; silent error monitoring [19]; phoneme elision [16,17]; word jumble tasks [20]; silent rhyme judgment [21,22]; silent phoneme monitoring [23][24][25]). Although differences in the phonological abilities of AWS are not unequivocal (cf. ...
... In terms of speech planning difficulties, a considerable amount of data implicate weaknesses in phonological encoding early in life as a key area of compromise (e.g., [7][8][9], for an opposing viewpoint, see [10,11]), particularly for children whose stuttering persists into adulthood (e.g., [12][13][14][15]). These data are further supported by studies which indicate that many adults who stutter (AWS) perform more poorly than adults who do DOI: 10.1159/000485657 not stutter (AWNS) when completing experimental tasks that rely on efficient phonological processing (e.g., nonword repetition [16][17][18]; silent error monitoring [19]; phoneme elision [16,17]; word jumble tasks [20]; silent rhyme judgment [21,22]; silent phoneme monitoring [23][24][25]). Although differences in the phonological abilities of AWS are not unequivocal (cf. ...
... To reiterate, the purpose of the present study was to replicate and extend the findings of Ozdemir et al. [33] in AWS rather than clarify this conceptual debate, and behavioral data may be insufficient to attribute causality exclusively to perception or exclusively to production. Nonetheless, in light of the findings of Lu et al. [70], it is possible that the differences observed in the present study support the larger body of data that implicate speech production issues in persons who stutter [12][13][14][15][16][17][18][19][20][21][22][23][24][25], rather than the perceptual monitor itself. Further neurophysiological examination may reveal that differences in monitoring in AWS, or lack thereof, are more closely associated with difficulties in perception rather than production in AWS. ...
Background/aims:
Previous studies employing a variety of tasks have demonstrated that adults who stutter (AWS) pre-sent with phonological encoding differences compared to adults who do not stutter (AWNS). The present study examined whether atypical preverbal monitoring also influenced AWS performance during one such paradigm - the silent phoneme monitoring task. Specifically, we investigated whether monitoring latencies for AWS were accelerated after the word's uniqueness point - the phoneme that isolates the word from all lexical competitors - as observed for AWNS when monitoring internal and external speech.
Methods:
Twenty adults (10 AWS, 10 AWNS) completed a silent phoneme monitoring task using stimuli which contained either (a) early uniqueness points (EUP), (b) late uniqueness points, or (c) no uniqueness point (NUP). Response latency when identifying word-final phonemes was measured.
Results:
AWNS exhibited the expected uniqueness point effect when monitoring internal speech; word-final phonemes were accessed more rapidly for words with EUP than NUP. In contrast, AWS did not differ in the phoneme monitoring speed. That is, AWS did not exhibit the expected uniqueness point effects.
Conclusion:
Findings suggest that inefficient or atypical preverbal monitoring may be present in AWS and support theories that implicate the internal speech monitor as an area of deficit.
... [2] Empirical evidence shows that adults with stuttering (AWS) exhibit longer reading rate and poor nonword recognition. [3][4][5][6][7][8][9][10][11][12] The poorer performance in them might be due to deficits in phonological working memory abilities as phonological coding along with visual information storage, and sentence comprehension is crucial for reading tasks. It has been shown that reading rate (time taken to read) can strongly predict memory span. ...
... Performance on reading rate and nonword recognition tasks in AWS indicates deficits in phonological working memory. [9][10][11][12] However, performance on these tasks tends to be affected by the underlying language disturbances also. All these tasks examined previously need good language processing skills which AWS are found lacking. ...
... Studies assessing phonological memory by increasing the load in terms of length of nonwords show deficits in AWS during nonword repetition and elision tasks as the length of nonwords increased. [10][11][12] However, these studies have language influences on working memory. A review article by Bajaj [29] has discussed how working memory deficits might be reflecting as phonological deficits and its importance in the sensory-motor processing in AWS. ...
Introduction: Adults with stuttering (AWS) exhibit longer reading rates and poor nonword recognition. This is attributed to deficits in phonological working memory abilities specific to language disturbances. In the present investigation, working memory abilities of AWS was investigated using n-back test which is not sensitive to subtle language deficits. Methods: Participants included nine AWS in the age range of 18–26 years, and nine age, gender, and language-matched adults who do not stutter. The participants performed auditory 1- and 2-back tasks, where they pressed a button whenever the same syllable was heard as the one and two syllables before, respectively. The reaction time, accuracy, false alarm rate, and d prime (difference in z-scores of hit rate and false alarm rate) were calculated for an individual participant in each n-back condition. Results: Results revealed significant difference between two groups only during 2-back task. Analysis showed that AWS had more false alarms, which might have resulted because of the anxiety in responding, due to increased attentional demands, which is in turn reflected as working memory deficits during the difficult task. Conclusion: The present results provide preliminary evidence for auditory working memory deficits in persons who stutter.
Keywords: N-back, stuttering, working memory
... In accordance with multifactorial accounts of stuttering, AWS repetition accuracy is comparable to AWNS when segmental demand is minimal and subvocal rehearsal is unnecessary (i.e., 1-to 4-syllable nonwords [21], [26], [27]). AWS become significantly less accurate than AWNS, however, as segmental length exceeds their temporary store and subvocal rehearsal is required (e.g., 7-syllables [26], [28]; 6-syllables [21]). These data support the notion that phonological working memory-as measured by nonword repetition tasks-is more susceptible to breakdown in AWS than AWNS, provided that the task is sufficiently challenging. ...
... These findings suggest a unique relationship between lowfrequency stress patterns and production accuracy in AWS, and that this relationship may be associated with phonological working memory abilities. However, no studies have directly examined whether metrical stress is a mediating factor in phonological working memory for AWS, as all stimuli used in previous nonword repetition studies in AWS were comprised exclusively ( [21], [26], [27], [28]) or predominately [42] of high-frequency stress patterns. ...
... Most studies of nonword production in AWS have employed immediate nonword repetition tasks with auditory stimuli presentation ( [21], [26], [27], [28], cf. [42], [43]). ...
Purpose
Adults who stutter (AWS) are less accurate in their immediate repetition of novel phonological sequences compared to adults who do not stutter (AWNS). The present study examined whether manipulation of the following two aspects of traditional nonword repetition tasks unmask distinct weaknesses in phonological working memory in AWS: (1) presentation of stimuli with less-frequent stress patterns, and (2) removal of auditory-orthographic cues immediately prior to response.
Method
Fifty-two participants (26 AWS, 26 AWNS) produced 12 bisyllabic nonwords in the presence of corresponding auditory-orthographic cues (i.e., immediate repetition task), and the absence of auditory-orthographic cues (i.e., short-term recall task). Half of each cohort (13 AWS, 13 AWNS) were exposed to the stimuli with high-frequency trochaic stress, and half (13 AWS, 13 AWNS) were exposed to identical stimuli with lower-frequency iambic stress.
Results
No differences in immediate repetition accuracy for trochaic or iambic nonwords were observed for either group. However, AWS were less accurate when recalling iambic nonwords than trochaic nonwords in the absence of auditory-orthographic cues.
Conclusions
Manipulation of two factors which may minimize phonological demand during standard nonword repetition tasks increased the number of errors in AWS compared to AWNS. These findings suggest greater vulnerability in phonological working memory in AWS, even when producing nonwords as short as two syllables.
... Nonword repetition entails, among other steps, the storage and retrieval of novel sound sequences, which is why it has been administered to individuals who stutter to gain further insight into their ability to process phonological information. Smith, Sadagopan, Walsh, and Weber-Fox (2010); Byrd, Vallely, Anderson, and Sussman (2012); Sasisekaran (2013); Sasisekaran and Weisberg (2014); and Byrd, McGill, and Usler (2015) found AWS to resemble ANS in the accuracy with which they repeated English-like nonwords of relatively short one-to four-syllable length, yet differ from them on other variables of interest. Specifically, AWS lagged behind ANS in the accuracy of producing lengthier and phonemically more complex nonwords (Byrd et al., 2015;Byrd et al., 2012;Sasisekaran, 2013;Sasisekaran & Weisberg, 2014) and in the consistency of lip movement coordination across three-, four-, six-, and 11-syllable stimuli (Sasisekaran, 2013;Sasisekaran & Weisberg, 2014;Smith et al., 2010). ...
... Smith, Sadagopan, Walsh, and Weber-Fox (2010); Byrd, Vallely, Anderson, and Sussman (2012); Sasisekaran (2013); Sasisekaran and Weisberg (2014); and Byrd, McGill, and Usler (2015) found AWS to resemble ANS in the accuracy with which they repeated English-like nonwords of relatively short one-to four-syllable length, yet differ from them on other variables of interest. Specifically, AWS lagged behind ANS in the accuracy of producing lengthier and phonemically more complex nonwords (Byrd et al., 2015;Byrd et al., 2012;Sasisekaran, 2013;Sasisekaran & Weisberg, 2014) and in the consistency of lip movement coordination across three-, four-, six-, and 11-syllable stimuli (Sasisekaran, 2013;Sasisekaran & Weisberg, 2014;Smith et al., 2010). This led the authors to consider the idea of phonological processing tampering with fluent speech production in AWS. ...
... Second, these paradigms may not have successfully disentangled the covert process of interest from other preceding and/or succeeding processes involved in the planning and execution of the required response. For example, the majority of protocols required that participants produce overt speech (e.g., Burger & Wijnen, 1999), process auditory cues (e.g., Byrd et al., 2015;Hennessey et al., 2008), and/or read single words or sentences (e.g., Bosshardt et al., 2002;Vincent et al., 2012), with each of these requirements possibly contaminating the results. Therefore, when significant between-group differences were found, the exact source of the difference could not always be located. ...
Purpose
Research on language planning in adult stuttering is relatively sparse and offers diverging arguments about a potential causative relationship between semantic and phonological encoding and fluency breakdowns. This study further investigated semantic and phonological encoding efficiency in adults who stutter (AWS) by means of silent category and phoneme identification, respectively.
Method
Fifteen AWS and 15 age- and sex-matched adults who do not stutter (ANS) participated. The groups were compared on the basis of the accuracy and speed of superordinate category (animal vs. object) and initial phoneme (vowel vs. consonant) decisions, which were indicated manually during silent viewing of pictorial stimuli. Movement execution latency was accounted for, and no other cognitive, linguistic, or motor demands were posed on participants' responses. Therefore, category identification accuracy and speed were considered indirect measures of semantic encoding efficiency and phoneme identification accuracy and speed of phonological encoding efficiency.
Results
For category decisions, AWS were slower but not less accurate than ANS, with objects eliciting more errors and slower responses than animals in both groups. For phoneme decisions, the groups did not differ in accuracy, with consonant errors outnumbering vowel errors in both groups, and AWS were slower than ANS in consonant but not vowel identification, with consonant response time lagging behind vowel response time in AWS only.
Conclusions
AWS were less efficient than ANS in semantic encoding, and they might harbor a consonant-specific phonological encoding weakness. Future independent studies are warranted to discover if these positive findings are replicable and a marker for persistent stuttering.
... Research indicates that AWS exhibited less effective phonological encoding abilities and more inconsistent articulatory coordination compared to adults who do not stutter (AWNS), particularly with longer and more phonologically complex non-words (21,22). Studies have highlighted deficits in phonological PA GE 10 working memory in AWS, particularly in maintaining fluent speech under complex task conditions (23,24). Overall, these studies suggest that both children and adults who stutter may experience challenges in phonological memory tasks, which could contribute to difficulties in speech production and maintenance of fluent speech. ...
... These phonemic accuracy deficits observed in younger stuttering groups suggest a continuity of phonological challenges into adolescence (20). Studies on adults also indicate persistent difficulties in nonword repetition accuracy, potentially linked to impaired phonological working memory (21,23). Measuring phonological memory ability through non-word repetition tasks has also been linked to predicting persistence and recovery of stuttering and hence can be considered a valuable tool to assess phonological memory (37). ...
Literature reports that in children and adults, individuals with stuttering perform poorly on phonological processing tasks, and syntactic abilities when compared to age-matched individuals with no disfluencies. The present study focuses on phonological and syntactic processing abilities among adolescents with disfluencies. The abilities were also compared to age-matched peers with no dysfluency. The prospective comparative study involved 32 participants, comprising two groups of 16 adolescent (11-19 years of age) participants each. One group consisted of adolescents with disfluencies and the other group included typically fluent adolescents. English was their second language. Four tasks measuring phonological and syntactical processing were administered to all participants. Tasks administered were: Rhyme judgment task in L2, Phoneme blending task in L2, Phonological memory task (repetition of nonwords in L2), and evaluation of syntactic and semantic appropriateness of sentences. Scores of the Control group and adolescent group with stuttering were compared using independent t test. Statistically significant differences were seen for all the tasks. The accuracy and time taken for completion of these tasks were compared across both the groups. Adolescents who stutter exhibited impaired performance on phonological and syntactic processing tasks while their fluent counterparts did not. The findings were similar to those of studies on children and adults with stuttering. Adolescent individuals with stuttering exhibit poorer performance on speech processing tasks such as rhyme judgment, syntactical judgment, and non-word repetition.
... In a replication of the phonological awareness (PA) task presented by Byrd et al. (2012Byrd et al. ( , 2015, participants were aurally presented with a nonword and asked to repeat it back to the researcher with a target sound deleted (e.g., "say 'fackton without the/f/"). Thirty trials were elicited, including nonwords of two, four, and seven syllables long. ...
... Thirty trials were elicited, including nonwords of two, four, and seven syllables long. Factors such as wordlikeness, segmental phonotactic probability, biphone phonotactic probability and phonemic onset were controlled for, as originally presented by Byrd et al. (2012Byrd et al. ( , 2015. Accuracy was assessed in real time and a percent accuracy was calculated for each individual. ...
Using diffusion tensor imaging (DTI), we assessed the extent to which fractional anisotropy values in the dorsal (i.e., arcuate fasciculus; AF) versus ventral (i.e., inferior fronto-occipital fasciculus; IFOF) distinction of structural white matter pathways associated with selected reading processes, could be replicated in skilled adult readers (N = 17) and extended to adults with reading impairments (N = 13). In addition to the AF and IFOF, motor-based tracts (i.e., posterior limb of the internal capsule (PLIC) and the frontal aslant tract (FAT)) were isolated to explore their role in reading performance. Several interesting relationships with reading performance emerged. First, orthographic awareness was related to the left IFOF in skilled readers, whereas orthographic awareness was related to left PLIC for impaired readers. Morphological awareness was related to left FAT for skilled readers, whereas morphological awareness was related to right AF, right IFOF and left PLIC for impaired readers. Overall, these findings support the notion that adult reading performance (both skilled and impaired) is related to the structural properties of the ventral white matter pathways. More consideration should be paid to motor pathways, particularly the PLIC, and their role in compensatory reading strategies in individuals with reading impairments.
... Studies of nonword repetition in adults who stutter (AWS) have been mixed, with some studies finding no differences for shorter nonword syllable repetition tasks (Smith et al., 2010) and others reporting lower accuracy at longer nonword lengths (e.g.,7 vs 3 syllables) or under manipulations of higher cognitive load even at shorter syllable lengths (Coalson and Byrd, 2017). Those findings suggest that task specific cognitive demands and other methodological considerations (e.g., sample size) may play an important role in whether differences in accuracy are detectable (Byrd et al., 2012;Byrd et al., 2015;Sasisekaran and Weisberg, 2014;Coalson and Byrd, 2017;Bowers et al., 2018;Jenson et al., 2020). Further, because NWR requires attending to auditorily presented nonword syllables, maintaining them in short-term memory, and finally repeating the syllables (Baddeley, 2012), it is unclear whether one or all those processes are related to decreases in accuracy in AWS (Byrd et al., 2012;Doneva et al., 2018;Spencer & Weber-fox, 2014;Smith et al., 2010;Sasisekaran and Byrd, 2013;Sasisekaran and Weisberg, 2014). ...
... While the finding of lower syllable repetition accuracy in the AWS group is consistent with previous studies of NWR, most of the studies have found differences only for heavily loaded conditions in various tasks. Studies have reported lower accuracy for shorter compared to longer nonword lengths (i.e., 4 vs 7 syllables) (Byrd et al., 2012(Byrd et al., , 2015Sasisekaran and Weisberg, 2014) and under other conditions that have manipulated cognitive load even at shorter syllable lengths (Coalson and Byrd, 2017;Sasisekaran and Weisberg, 2014). By contrast, other studies employing shorter nonword lengths have not reported differences in accuracy (Smith et al., 2010), including a preliminary analysis of 11 AWS using the same syllable repetition task in the current study (Jenson et al., 2020). ...
... In the phonological awareness task, participants were orally presented with a non-word, and then asked to delete a sound from the non-word and produce a new resulting non-word (e.g., say "hackton" without the sound/h/ ). Thirty non-words from Byrd, McGill, and Usler (2015) were presented. These words were two, four and seven syllables long, and were controlled for "real wordlikeness, segmental phonotactic probability, biphone phonotactic probability, and phonemic onset" (Byrd et al., 2015). ...
... Thirty non-words from Byrd, McGill, and Usler (2015) were presented. These words were two, four and seven syllables long, and were controlled for "real wordlikeness, segmental phonotactic probability, biphone phonotactic probability, and phonemic onset" (Byrd et al., 2015). Overall accuracy score (number of correct responses/number of non-words*100%) and total number of words produced correctly by the position of sound deletion (i.e., sound deleted from word initial position, medial position or final position) were calculated. ...
Reading and spelling skills are important to communicate in today's literate society, however, the underlying processes of spelling skills are under‐researched compared to reading skills. Our goals were to (a) study how the component skills of phonological, orthographic and morphological awareness are different in adults with and without reading difficulties, and (b) characterize the relationship between the component skills and reading and spelling performance in both skilled and poor readers. Participants (N = 37, N = 15 with reading impairments and N = 22 skilled readers) took part in the study where they completed several literacy‐based measures. We performed a series of mixed ANOVAs to study the between‐group differences in performance and the relationship between different literacy outcomes, respectively. We found evidence for poor phonological and morphological awareness in the poor readers compared to the skilled readers. We also found differential relationships between the component skills and reading and spelling behavior. Specifically, sound awareness was significantly related to reading and spelling measures in the skilled readers, whereas morphological and sound awareness played an important role in the same skills in the poor readers. We discuss these findings in the context of potential remediation strategies for adults with persistent literacy impairments.
... Given the functional overlap, it perhaps does not seem surprising that the effects of stuttering can transcend speech production and impact cognitive function. Thus, the growing behavioral evidence of these cognitive effects in PWS (Byrd et al., 2015;Eggers and Jansson-Verkasalo, 2017;Eichorn et al., 2018;Coalson et al., 2019), make it necessary to understand their neural correlates. An added advantage of studying the effects of stuttering on cognitive function is that it can provide a valuable window into understanding how sensorimotor function differs in PWS without the potentially contaminating effects of overt stuttering. ...
... A growing body of evidence implicates load-dependent differences in nonword repetition in both children (CWS) and adults (AWS) who stutter compared to matched controls (Bowers et al., 2018;Ofoe et al., 2018). Recent studies investigating nonword repetition tasks have demonstrated overall lower performance in both preschool CWS (Spencer and Weber-Fox, 2014;Pelczarski and Yaruss, 2016) and AWS (Byrd et al., 2012(Byrd et al., , 2015(Byrd et al., , 2018Coalson and Byrd, 2017). ...
Deficits in basal ganglia-based inhibitory and timing circuits along with sensorimotor internal modeling mechanisms are thought to underlie stuttering. However, much remains to be learned regarding the precise manner how these deficits contribute to disrupting both speech and cognitive functions in those who stutter. Herein, we examine the suitability of electroencephalographic (EEG) mu rhythms for addressing these deficits. We review some previous findings of mu rhythm activity differentiating stuttering from non-stuttering individuals and present some new preliminary findings capturing stuttering-related deficits in working memory. Mu rhythms are characterized by spectral peaks in alpha (8–13 Hz) and beta (14–25 Hz) frequency bands (mu-alpha and mu-beta). They emanate from premotor/motor regions and are influenced by basal ganglia and sensorimotor function. More specifically, alpha peaks (mu-alpha) are sensitive to basal ganglia-based inhibitory signals and sensory-to-motor feedback. Beta peaks (mu-beta) are sensitive to changes in timing and capture motor-to-sensory (i.e., forward model) projections. Observing simultaneous changes in mu-alpha and mu-beta across the time-course of specific events provides a rich window for observing neurophysiological deficits associated with stuttering in both speech and cognitive tasks and can provide a better understanding of the functional relationship between these stuttering symptoms. We review how independent component analysis (ICA) can extract mu rhythms from raw EEG signals in speech production tasks, such that changes in alpha and beta power are mapped to myogenic activity from articulators. We review findings from speech production and auditory discrimination tasks demonstrating that mu-alpha and mu-beta are highly sensitive to capturing sensorimotor and basal ganglia deficits associated with stuttering with high temporal precision. Novel findings from a non-word repetition (working memory) task are also included. They show reduced mu-alpha suppression in a stuttering group compared to a typically fluent group. Finally, we review current limitations and directions for future research.
... These differences are not limited to overt speech tasks as less rapid and less accurate phonological encoding have been demonstrated in adults who stutter using nonvocal speech tasks (e.g., Brocklehurst & Corley, 2011;Byrd, McGill, & Usler, 2015). Researchers have also found the more complex the phonological representations, the more difficult it is for persons who stutter to retain the word (e.g., Byrd, Sheng, Bernstein Ratner, Gkalitsiou, 2015;Sasisekaran & Weisberg, 2014). ...
... Adults who stutter were less accurate than fluent controls in their repetition of 7-syllable nonwords even when repeated vocal practice was allowed (Byrd et al., 2012). Byrd, McGill, and Usler (2015) replicated these findings in a distinct cohort of participants with the added comparison of vocal to nonvocal task performance. Adults who stutter were significantly less accurate at producing and silently identifying longer nonwords. ...
Recent data indicate individuals who stutter may exhibit unique differences in the ability to store and maintain phonological information in phonological working memory. These proceedings will review a series of studies that examine the nature of these differences and their theoretical contribution to stuttered speech.
... The behavioral tasks consisted of 'awareness' tasks (phonological [29], orthographic [30,31], morphological [32]) and 'letter probe' tasks (phonological, orthographic-phonological, orthographic [33,34]). Participants also completed two standardized measures of reading performance, namely the test of word reading [35]. ...
Evidence has been provided for a clear structural distinction between the dorsal and ventral portions of the inferior frontal occipital fasciculus (IFOF). As such, there is reason to propose that there might also be a functional differentiation of the dorsal and ventral components of the IFOF. Here, we explored three main hypotheses/schools of thought with regards to the functional frameworks of the dorsal and ventral components of the IFOF: (1) the phonological vs. semantic processing hypothesis, (2) the difficult vs. non-difficult task processing hypothesis and (3) the automatic vs. non-automatic processing hypothesis. Methods: Participants (N = 32) completed a series of behavioral tasks that aligned with each of the main hypotheses. Using a regression-based approach, we assessed the unique contribution of behavioral performance to dorsal and ventral IFOF white matter indicators (i.e., fractional anisotropy and mean diffusivity). Results: We found significant relationships between ventral IFOF indices and orthographic awareness (p = 0.018) and accuracy (p = 0.009). Overall, our results provide converging evidence that the IFOF primarily operates as a ventral language tract in adults. Thus, the structural distinction between dorsal and ventral IFOF does not manifest as a parallel functional distinction.
... The use of digit span tasks, along with arithmetic and letter-number sequencing, have previously provided evidence of lower WM performance in AWS when compared to ANS, but was not found to significantly influence participants' response to temporal changes in syllable sequencing (Schwartze and Kotz, 2020). The more commonly used non-word repetition task, to measure phonological WM, has typically been found to differentiate AWS and ANS in their accuracy of repeating complex segmental structures (Coalson et al., 2019), their repetition of non-words with increasing syllabic length (Byrd et al., 2015), as well as in their improved performance and retention of syllable sequencing (Sasisekaran and Weisberg, 2014). Notably, these measures of WM, as well as the digit-span task used in the current study, are specific to the verbal domain. ...
Implicit learning allows us to acquire complex motor skills through repeated exposure to sensory cues and repetition of motor behaviours, without awareness or effort. Implicit learning is also critical to the incremental fine-tuning of the perceptual-motor system. To understand how implicit learning and associated domain-general learning processes may contribute to motor learning differences in people who stutter, we investigated implicit finger-sequencing skills in adults who do (AWS) and do not stutter (ANS) on an Alternating Serial Reaction Time task. Our results demonstrated that, while all participants showed evidence of significant sequence-specific learning in their speed of performance, male AWS were slower and made fewer sequence-specific learning gains than their ANS counterparts. Although there were no learning gains evident in accuracy of performance, AWS performed the implicit learning task more accurately than ANS, overall. These findings may have implications for sex-based differences in the experience of developmental stuttering, for the successful acquisition of complex motor skills during development by individuals who stutter, and for the updating and automatization of speech motor plans during the therapeutic process.
... There is a growing body of research pointing to lower phonological awareness, including in elision, in those who stutter compared with their typically fluent peers (e.g., C. T. Byrd et al., 2015;Pelczarski & Yaruss, 2014). Based on this finding, ASRs-S would be expected to show weaker phonological awareness compared with ASRs-NS, and ASRs-S who utilize a phonological awareness strategy would be predicted to show weaker reading comprehension. ...
Stuttering is a disorder that affects about 1% of the population and manifests as speech disfluencies. Reading difficulties and disabilities are commonly found in this population. Nonetheless, speech disfluencies have not been explored in adult struggling readers (ASRs). In the current study, we examined the rate of stuttering in ASRs as well as the relationships between their speech fluency and reading skills. A total of 120 participants were interviewed about their experiences with reading and administered standardized reading and reading-related assessments. Speech fluency and the criterion for stuttering were based on the interview. About 18.3% of the sample met the criterion for stuttering. ASRs who stutter (ASRs-S) and ASRs who do not stutter (ASRs-NS) did not differ in their reading and reading-related skills. ASRs-S had higher rates of negative correlations between reading and reading-related skills compared with ASRs-NS. Correlation patterns between performance on standardized assessments point to higher rates of uneven skills or dissociations in ASRs-S. These findings may have implications for the assessment and instruction for ASRs.
... Cognitive and affective aspects of the Blank Center programming were targeted during the second half of weekly group sessions and then personalized during weekly individual sessions to elaborate each concept within the context of the clients' life. Topics included client education about stuttering, dispelling myths about stuttering, and discussing the cause of stuttering (e.g., heritability [Frigerio-Domingues & Drayna, 2017]; atypical sensory-motor processing [Chang et al., 2019]; vulnerable linguistic-phonological processing [Byrd et al., 2015;Coalson & Byrd, 2017]), as well as the personal utility of selfdisclosure (Byrd, Croft, et al., 2017;Byrd, McGill, et al., 2017;, voluntary stuttering (Byrd, Gkalitsiou, Donaher, et al., 2016), self-advocacy (Boyle et al., 2016(Boyle et al., , 2017, and participation in mindfulness activities (Boyle, 2011;De Veer et al., 2009 ...
The purpose of this study was to examine the benefits of a treatment approach for adults who stutter that focuses on core communication competencies rather than attempt to modify speech fluency. Eleven adults who stutter completed a 12-week treatment program at The Arthur M. Blank Center for Stuttering Education and Research. Pre-and posttreatment measures included (a) self-reported cognitive and affective aspects of stuttering (Overall Assessment of the Speaker's Experience of Stuttering [OASES], Self-Perceived Communication Competence [SPCC], Devereux Adult Resilience Survey [DARS], and Self-Compassion Scale [SCS]) and (b) ratings of 9 core communication competencies by an unfamiliar clinician blind to pre/posttreatment status. Participants reported significant mitigation of the adverse impact of stuttering (OASES) and greater resilience (DARS) after treatment. Participants also demonstrated significant gains in 8 of the 9 clinician-perceived communication competencies. Lower pretreatment stuttering frequencies were not significantly associated with posttreatment gains in clinician-perceived communication competencies. Preliminary findings suggest that, similar to findings for children and adolescents who stutter in previous studies, significant psychosocial and communicative benefit can be obtained for adults who stutter following treatment designed to focus on communication effectiveness rather than fluency, and that these gains are not contingent on the participants' stuttering frequency prior to enrollment.
... Closeness centrality measures the distance from one node to all other nodes in the network (following the shortest path between any two nodes being considered). Although stuttering is often viewed as a disorder that primarily affects the fluent production of speech, subtle differences-that are not yet well understood-have been observed in the phonological processing abilities of people who stutter as compared to typically fluent peers (e.g., Byrd, McGill, & Usler, 2015;Newman & Bernstein Ratner, 2007;Pelczarski & Yaruss, 2014, 2016Sasisekaran & De Nil, 2006). The tools of network science might be able to reveal more of these subtle differences in people who stutter, which are not always revealed using traditional psycholinguistic tasks. ...
Contemporary psycholinguistic models place significant emphasis on the cognitive processes involved in the acquisition, recognition, and production of language but neglect many issues related to the representation of language‐related information in the mental lexicon. In contrast, a central tenet of network science is that the structure of a network influences the processes that operate in that system, making process and representation inextricably connected. Here, we consider how the structure found across phonological networks of several languages from different language families may influence language processing as we age and experience diseases that affect cognition during the typical and atypical acquisition of new words, during typical perception and production of speech in adults, and during language change over time. We conclude that the network science approach may not only provide insights into specific language processes but also provide a way to connect the work from these domains, which are becoming increasingly balkanized.
... Untuk menuturkan suatu morfem tidak dapat dilepaskan dari fungsi artikulasi penutur. Menurut Byrd, Mcgill, & Usler (2015) gangguan fonem lebih dominan pada anak-anak. Gangguan fonem terjadi pada saat responden melafalkan morfem-morfem. ...
... WM underpins the ability to store and manipulate relevant information during complex tasks, and is proposed to be critical for fluency [64,[81][82][83]. Children and adults who stutter show lower performance (more errors, slower reaction time) in WM tasks (e.g., nonword repetition [NWR] and digit span tasks) compared to CWNS [e.g., [84][85][86][87][88][89][90][91][92]. However, WM deficits may be less evident in CWS during less complex tasks (e.g., 2-vs. ...
Background
The aim of this study was to investigate the relationship between executive function (EF), stuttering, and comorbidity by examining children who stutter (CWS) and children who do not stutter (CWNS) with and without comorbid conditions. Data from the National Health Interview Survey were used to examine behavioral manifestations of EF, such as inattention and self-regulation, in CWS and CWNS.
Methods
The sample included 2258 CWS (girls = 638, boys = 1620), and 117,725 CWNS (girls = 57,512; boys = 60,213). EF, and the presence of stuttering and comorbid conditions were based on parent report. Descriptive statistics were used to describe the distribution of stuttering and comorbidity across group and sex. Regression analyses were to determine the effects of stuttering and comorbidity on EF, and the relationship between EF and socioemotional competence.
Results
Results point to weaker EF in CWS compared to CWNS. Also, having comorbid conditions was also associated with weaker EF. CWS with comorbidity showed the weakest EF compared to CWNS with and without comorbidity, and CWS without comorbidity. Children with stronger EF showed higher socioemotional competence. A majority (60.32%) of CWS had at least one other comorbid condition in addition to stuttering. Boys who stutter were more likely to have comorbid conditions compared to girls who stutter.
Conclusion
Present findings suggest that comorbidity is a common feature in CWS. Stuttering and comorbid conditions negatively impact EF.
... Several studies have explored the relationship between working memory and stuttering (see Bajaj, 2007, for a review), with most studies focusing on the phonological loop or central executive components of working memory (e.g., Baddeley, 2003). Regarding the link between phonological loop and stuttering, various tasks have been incorporated, such as nonword repetition and/or phoneme elision (e.g., Byrd, McGill, & Usler, 2015;Byrd et al., 2012;Coalson & Byrd, 2017;Sasisekaran, 2013), phoneme monitoring (e.g., Coalson & Byrd, 2015;, rhyme judgment (e.g., Weber-Fox et al., 2004), or word list recall (Byrd, Sheng, et al., 2015). Results demonstrate deviant performance in people who stutter in terms of accuracy and reaction time. ...
Purpose
The purpose of this study was to investigate executive control in adults who stutter (AWS) and adults who do not stutter (AWNS) via a nonspeech paradigm, wherein eye movements were monitored (i.e., antisaccade task). Processes involved in an antisaccade task include working memory, attention, and voluntary motor control, but the task primarily provides insight into inhibitory control.
Method
Seventeen AWS (14 men, three women; M = 23.41 years) and 17 AWNS (M = 23.29 years) were presented with a combination of prosaccade (i.e., looking toward a target) and antisaccade (i.e., suppress a reflexive saccade toward the target and look in the opposite direction) trials. The distance of the target from the center of the screen was also manipulated (i.e., 5.5o = short distance and 10.8o = long distance). Data for accuracy and reaction time of the first accurate saccade were collected and analyzed.
Results
No difference was found between AWS and AWNS in accuracy or in reaction time. Both groups were more accurate in the prosaccade than the antisaccade trials and in the long compared to the short distance trials. Furthermore, both groups demonstrated longer saccade latencies for long compared to short distances and for antisaccade compared to prosaccade trials.
Conclusions
Preliminary results do not support deficits in inhibition in AWS during a motorically simple, non–speech-related oculomotor task, but additional research is warranted.
... One such operation is phonological working memorythe ability to briefly maintain and manipulate the sounds important for speech and languagewhich likely involves broad integration of a variety of perception, language, cognition, and motor regions (Fiez, 2015). While reductionist approaches can investigate each of the potential constituent operations of phonological working memory in isolation, the clinical importance of this integrated faculty to language development Gathercole, 1995, 1996;Baddeley et al., 1998;Dufva et al., 2001;Gathercole and Baddeley, 1993;Gathercole et al., 2006;Martin, 2005;van der Schuit et al., 2011) and its impairment in numerous developmental and communication disorders (Bowers et al., 2018;Byrd et al., 2015;Graf Estes et al., 2007;Kjelgaard and Tager-Flusberg, 2001;Lanfranchi et al., 2009;Peter et al., 2011) makes understanding its holistic and nuanced neural basis of particular importance. ...
... Gangguan bicara pada anak dapat terjadi pada gangguan artikulasi seperti: gangguan pada langit-langit, gangguan pada mulut, gangguan pada sariawan. Terjadinya gangguan itu berakibat pada pelafalan fonem yang dituturkan oleh anak-anak tersebut, Byrd, Mcgill, & Usler, (2015) gangguan fonem lebih dominan pada anak-anak. Gangguan fonem terjadi pada saat responden melafalkan morfem-morfem. ...
Neurolinguistics is the study of how humans acquire language. This study has two objectives, the first objective is to explain which level the phonemes are spoken by respondents the second is to explain the morphemes produced by respondents in speaking. To collect data from this study, researchers used a participatory option personal method, where researchers were actively involved in provoking respondents to talk more. Then the method used is records and techniques noted. Then to analyze this data researchers using the method of distribution / distribution method will be supported by the immediate segmenting constituents technique and basic techniques with the process of adding, dropping and changing, After the data collection and data analysis are considered complete, the results are obtained. The results are the presence of a process of dissolution, change. Immersion that occurs in the research data can occur in all positions, both front, center, and behind the morpheme. Meanwhile, changes also occur in all areas. The most dominant phoneme is obtained in phoneme / r /> / l /. While the phoneme / r / in the antepenultimate position cannot be told by the respondent at all, so there is a breakdown of the phoneme / r /.
... Penggunaan fonem yang tepat dapat membuat orang lain mengerti dengan mudah apa yang dimaksud oleh pembicara. Hal sama diungkapkan oleh (Byrd, Mcgill, & Usler, 2015) bahwa fonem sangat berpengaruh terhadap ujaran. Kalau terjadi penghilangan fonem akan memberi makna yang berbeda. ...
Penelitian ini merupakan kajian neurolinguistik yang bertujuan untuk menjelaskanbentukgangguan fonem yang dilafalkan oleh penderita strok. Teknik pengumpulan data yang digunakan yakni dengan teknik rekam dan metode Simak Libat Cakap (SLC). Selanjutnya untuk menganalisis data, penulis menggunakan metode agih dan teknik bagi unsur langsung. Teknik bagi unsur langsung akan didukung teknik-teknik dasar dan teknik lanjutan seperti teknik lesap, teknik ganti, teknik ulang, dan teknik ekspansi. Adapun hasil penelitian membuktikan bahwa gangguan yang terjadi pada penderita strok pada saat melafalkan fonem yakni adanya penghilangan, penambahan dan pergantian fonem pada posisi yang tidak menentu. Penderita strok yang mengalami gangguan pada saraf kiri tidak dapat melafalkan fonem-fonem dengan tepat. Gangguan ini termasuk kategori afasia dan disartria. Adapun hasil penelitian menunjukkan bahwa peristiwa yang terjadi pada para penderita strok adalah peristiwa pelesapan, perganti, dan penambahan fonem.
... Another possible mechanism of improved speech fluency may be that the tDCS on RB modulated working memory processes. Indeed, there has been behavioral evidence suggesting verbal working memory deficits in PWS [43,44]. Because the RB is involved in verbal working memory particularly when memory load is high [45], modulation of the altered working memory system in PWS might influence on speech fluency. ...
Aim
Previous functional imaging studies demonstrate that people who stutter (PWS) exhibit over‐ and under‐activation of Broca’s and Wernicke’s areas and their right hemisphere homologues when speaking. However, it is unclear whether this altered activation represents the neural cause of speech dysfluency or a secondary compensatory activation in PWS. To clarify the functional significance of the altered activation pattern in classic language areas and their right homologues, we examined whether the severity of stuttering was affected when the activation of these areas was modulated by brain stimulation.
Methods
While PWS read passages aloud, we applied transcranial direct current stimulation (tDCS) using electrode montages that included an anodal or cathodal electrode placed over one of the language areas and its right hemisphere homologue, with the second electrode placed over the contralateral supraorbital region. Each participant underwent both anodal and cathodal tDCS sessions, each of which included a sham stimulation. Effects of stimulation polarity and electrode location on the frequency of stuttering were analyzed.
Results
We observed a significant interaction between polarity and location on the frequency of stuttering. Follow‐up analyses revealed that a tDCS montage including the cathodal electrode over right Broca’s area (RB) significantly reduced the frequency of stuttering.
Conclusion
The results indicated that stuttering severity was ameliorated when overactivation in RB was reduced by tDCS. This observation further suggests that speech dysfluency in PWS may be caused either by functional alteration in RB or by abnormal activation in speech motor control areas that are connected with RB.
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... As a result, a relationship between phonological WM deficiency and stuttering has been hypothesized (Bajaj, 2007), with empirical evidence from behavioral studies. Behavioral performance of nonword repetition has been found to be poorer in stuttering children (Anderson & Wagovich, 2010;Hakim & Ratner, 2004;Pelczarski & Yaruss, 2016) and adults (Byrd, McGill, & Usler, 2015). The central executive component is also dysfunctional in PWS, as demonstrated in previous behavioral research showing reduced behavioral performance in dual tasks (Jones, Fox, & Jacewicz, 2012;Smits-Bandstra, De Nil, & Rochon, 2006). ...
Persistent developmental stuttering is a neurological disorder that commonly manifests as a motor problem. Cognitive theories, however, hold that poorly developed cognitive skills are the origins of stuttering. Working memory (WM), a multicomponent cognitive system that mediates information maintenance and manipulation, is known to play an important role in speech production, leading us to postulate that the neurophysiological mechanisms underlying stuttering may be associated with a WM deficit. Using functional magnetic resonance imaging, we aimed to elucidate brain mechanisms in a phonological WM task in adults who stutter and controls. A right‐lateralized compensatory mechanism for a deficit in the rehearsal process and neural disconnections associated with the central executive dysfunction were found. Furthermore, the neural abnormalities underlying the phonological WM were independent of memory load. This study demonstrates for the first time the atypical neural responses to phonological WM in PWS, shedding new light on the underlying cause of stuttering.
... This demand may have been particularly salient for CWS, as childhood stuttering has been associated with subclinical differences in phonological working memory (Pelczarski & Yaruss, 2016). Moreover, evidence suggests that the subvocal rehearsal abilities of adults who stutter may not be as robust as those of controls (Bosshardt, 1990(Bosshardt, , 1993Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012). ...
Purpose
Early childhood stuttering is associated with atypical speech motor development. Compared with children who do not stutter (CWNS), the speech motor systems of school-age children who stutter (CWS) may also be particularly susceptible to breakdown under increased processing demands. The effects of increased syntactic complexity and sentence length on articulatory coordination were investigated.
Method
Kinematic, temporal, and behavioral indices of articulatory coordination were quantified for school-age CWS (n = 19) and CWNS (n = 18). Participants produced 4 sentences varying in syntactic complexity (simple declarative/complex declarative with a relative clause) and sentence length (short/long). Lip aperture variability (LAVar) served as a kinematic measure of interarticulatory consistency over repeated productions. Articulation rate (syllables per second) was also calculated as a related temporal measure. Finally, we computed accuracy and stuttering frequency percentages for each sentence to assess task performance.
Results
Increased sentence length, but not syntactic complexity, increased LAVar in both groups. This effect was disproportionately greater for CWS compared with CWNS. No group differences were observed for articulation rate. CWS were also less accurate in their sentence productions than fluent peers and exhibited more instances of stuttering when processing demands associated with length and syntactic complexity increases.
Conclusions
The speech motor systems of school-age CWS appear to be particularly vulnerable to processing demands associated with increased sentence length, as evidenced by increased LAVar. Increasing the length and complexity of the sentence stimuli also resulted in reduced production accuracy and increased stuttering frequency. We discuss these findings within a motor control framework of speech production.
... Spencer & Weber-Fox, 2014). Adults who stutter (AWS) may also be uniquely compromised when repeating or recalling novel stimuli compared to adults who do not stutter (AWNS) as the length of the target non-word increases (>5 syllables; Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Sasisekaran & Weisberg, 2014). Additional research has demonstrated AWS are significantly less accurate than AWNS, even when repeating shorter non-words, when the segmental complexity (three syllables; Sasisekaran & Weisberg, 2014) and/or metrical complexity (two syllables; Coalson & Byrd, 2015, 2017 are manipulated. ...
Non-word repetition is weaker for adults who stutter (AWS) compared
to adults who do not stutter (AWNS) as phonological demands
increase. However, non-word stimuli used in previous studies varied
by length, but did not vary with regard to segmental or metrical
complexity. The purpose of the present study was to examine the
unique influence of these two distinct types of complexity on nonword
repetition in AWS and AWNS via administration of the Test of
Phonological Structure (TOPhS). Twenty-four adults (12 AWNS, 12
AWS) repeated 96 non-words within a soundproof booth immediately
after auditory presentation. All 96 non-word targets included on
the TOPhS were one to four syllables in length and ranked based on
segmental complexity (simple, moderate and complex) and metrical
complexity (simple, moderate and complex). No main effect of metrical
complexity was detected between groups, and no differences in
accuracy were observed for non-words with simple or moderate
segmental complexity. However, AWS were significantly more likely
to produce a phonemic error when repeating words with complex
segmental structure than AWNS, irrespective of metrical complexity.
Segmental complexity may contribute to the differences in phonological
working memory in AWS when controlling for metrical complexity
and length.
... Although not diagnostic of the disorder, phonological working memory impairment is frequently observed in individuals with developmental dyslexia (e.g., Larrivee & Catts, 1999;Peter et al., 2011) and is related to other phonological measures prior to the onset of reading instruction (Clark, McRoberts, Van Dyke, Shankweiler, & Braze, 2012). Children and adults who stutter also appear to have deficits in phonological working memory that may be independent of speech fluency (Anderson, Wagovich, & Hall, 2006;Byrd, McGill, & Usler, 2015;Hakim & Ratner, 2004). In autism, too, there is a pronounced impairment in phonological working memory (Kjelgaard & Tager-Flusberg, 2001), which appears to extend even to first-degree family members evincing the broad autism phenotype (Wilson et al., 2013). ...
Purpose
The primary purpose of this study was to identify the brain bases of phonological working memory (the short-term maintenance of speech sounds) using behavioral tasks analogous to clinically sensitive assessments of nonword repetition. The secondary purpose of the study was to identify how individual differences in brain activation were related to participants' nonword repetition abilities.
Method
We used functional magnetic resonance imaging to measure neurophysiological response during a nonword discrimination task derived from standard clinical assessments of phonological working memory. Healthy adult control participants (N = 16) discriminated pairs of real words or nonwords under varying phonological working memory load, which we manipulated by parametrically varying the number of syllables in target (non)words. Participants' cognitive and phonological abilities were also measured using standardized assessments.
Results
Neurophysiological responses in bilateral superior temporal gyrus, inferior frontal gyrus, and supplementary motor area increased with greater phonological working memory load. Activation in left superior temporal gyrus during nonword discrimination correlated with participants' performance on standard clinical nonword repetition tests.
Conclusion
These results suggest that phonological working memory is related to the function of cortical structures that canonically underlie speech perception and production.
... It also suggests that direct manipulation of this additional factor, which was relatively invariant across word subtypes, may have diminished the magnitude of SRT differences between groups. Given the unique susceptibility to phonological complexity AWS exhibit during tasks that require single-word production (e.g., Byrd, Vallely, Anderson, & Sussman, 2010;Sasisekaran & Weisberg, 2014) and during non-vocal tasks that require no phonetic processing (e.g., Byrd, McGill, & Usler, 2015;Brocklehurst & Corley, 2010;Coalson & Byrd, 2015;Sasisekaran, 2013;Sasisekaran, de Nil, Smyth, & Johnson, 2006;Weber-Fox, Spencer, Spruill, & Smith, 2004), future studies should continue to explore the precise relationship between phonological and phonetic factors in addition to those controlled in the present study. ...
... Evidence suggests that children and AWS have subtle, subclinical differences in their phonological processing abilities as compared with typically fluent peers (e.g., Byrd, McGill, & Usler, 2015;Byrd, Vallely, Anderson, & Sussman, 2012;Newman & Bernstein Ratner, 2007;Pelczarski & Yaruss, 2014Sasisekaran & De Nil, 2006;Sasisekaran & Byrd, 2013;cf. Bosshardt & Fransen, 1996;Hennessey, Nang, & Beilby, 2008), yet these differences are not yet well understood and not always revealed during traditional behavioral tasks. ...
Purpose
Methods from network science have examined various aspects of language processing. Clinical populations may also benefit from these novel analyses. Phonological and lexical factors have been examined in adults who stutter (AWS) as potential contributing factors to stuttering, although differences reported are often subtle. We reexamined the performance of AWS and adults who do not stutter (AWNS) from a previously conducted lexical decision task in an attempt to determine if network science measures would provide additional insight into the phonological network of AWS beyond traditional psycholinguistic measures.
Method
Multiple regression was used to examine the influence of several traditional psycholinguistic measures as well as several new measures from network science on response times.
Results
AWS responded to low-frequency words more slowly than AWNS; responses for both groups were equivalent for high-frequency words. AWS responded to shorter words more slowly than AWNS, producing a reverse word-length effect. For the network measures, degree/neighborhood density and closeness centrality, but not whether a word was inside or outside the giant component, influenced response times similarly between groups.
Conclusions
Network analyses suggest that multiple levels of the phonological network might influence phonological processing, not just the micro-level traditionally considered by mainstream psycholinguistics.
... Presumably, impaired speech abilities may be related to a faulty phonological working memory. Various aspects of phonological processing (e.g., vision-to-sound conversions, sub-vocal rehearsal and lexical access) were found to differ between persons who stutter and fluent controls (Byrd, McGill, & Usler, 2015). For example, adults who stutter were slower and less accurate than fluent adults in a word jumble task, requiring them to silently manipulate scrambled letters to form a real word (McGill, Sussman, & Byrd, 2016). ...
People show better memory for words read aloud relative to words read silently, the Production Effect (PE). Vocalisation at study makes the produced (aloud) words more distinct than the non-produced (silent) words, hence more memorable. Such encoding distinctiveness is related to the additional processing of aloud words that is later used during retrieval. This study investigated the PE in dysarthric adults, characterised by speech production difficulties. Their memory performance (recognition) was compared to a group of healthy adults. Results showed a PE for both groups. The production benefit was significantly larger for the dysarthric adults, despite their overall memory performance being reduced relative to controls. The results demonstrate long-term verbal memory deficits in dysarthria, and suggest that vocalisation (although impaired) may assist in remembering. Hence, vocalisation may be used in intervention contexts with this population, to compensate for memory decrease.
... Based on imaging data (for a review see Neef et al., 2015), and behavioral studies (e.g. Byrd et al., 2015;McGill et al., 2016;Smith et al., 2010) demonstrating subtle vulnerabilities in the speech production systems of PWS, it is likely that there is more inherent conflicting activation, or noise, in the prearticulatory neural activity of PWS. Increased conflicting activation would increase the chances that the monitoring system would respond with cognitive control processes (e.g. ...
Researchers, clinicians and people who stutter (PWS) find it difficult to adequately explain the variability across contexts in the frequency and severity of stuttering. The purpose of this paper is to present the Speech and Monitoring Interaction (SAMI) framework of stuttering that incorporates potential deficits within the speech production system and a contextually modulated monitoring system to provide a biologically plausible explanation for the contextual variability of stuttering. SAMI incorporates trait and state factors within the speech production system and the monitoring system that can account for stuttering variability. The specificity of the neural substrates of the monitoring system and how the monitor interacts with the speech production system can be used to drive hypotheses based research and computational modeling of the contextual variable stuttering. The framework can also be used clinically to inform clients of the social and emotional factors contributing to their stuttering; while highlighting the importance of addressing these factors in therapy.
... Therefore, some of the performance patterns that are observed in children's syntax may reflect immature memory systems rather than, or in addition to, immature grammatical ability (McElree, 2000;McElree et al., 2003). Adults who stutter have weak working memory during language processing tasks and working memory is more vulnerable to interference as demands increase (e.g., Bosshardt, 1995;Byrd, McGill, & Usler, 2014;Byrd, Vallely, Anderson, & Sussman, 2012). It is rational to infer that these weaknesses are present (or even more evident) when examined in CWS in a less mature language system. ...
Comprehension of predicates and reflexives was examined in children who stutter (CWS) and children who do not stutter (CWNS) who were between 9 years, 7 months and 10 years, 2 months. Demands on working memory and manual reaction time were also assessed in two experiments that employed a four-choice picture-selection sentence comprehension task. CWS were less accurate than CWNS on the attachment of predicates. For reflexives, there was no between-group difference in accuracy, but there was a difference in speed. The two constructions induced processing at different points on a speed–accuracy continuum with CWS sacrificing accuracy to respond fast with predicates, while they maintained accuracy of reflexives by responding slower relative to CWNS. Predicates made more demands on language than nonspeech motor reaction time, whereas the reverse was the case with reflexives for CWS compared to CWNS.
Purpose: Difficulty discarding irrelevant negative stimuli activated in working memory has been linked to increased rumination. Adults who stutter (AWS) report (a) rumination about communication events, and (b) difficulties during tasks that require manipulation of information held in working memory compared to non-stuttering adults (AWNS). Given the link between rumination and working memory, this study examined whether AWS discard negative stimuli faster or slower compared to AWNS, and whether speed of discarding negative information is linked to generalized rumination.
Method: To assess the relationship between working memory and rumination, 26 participants (14 AWS, 12 AWNS) completed a version of the Modified Sternberg Task. Participants first memorized wordlists with positive or negative emotional valence. Participants were then cued to recall a specific wordlist, followed by a prompt word that either matched or conflicted with the
wordlist. Manual response latency was compared between groups.
Results: AWS and AWNS exhibit comparable speed when discarding irrelevant stimuli, with both groups slower to discard negative rather than positive irrelevant stimuli. Latency of discarding negative information was not associated with self-reported rumination in AWS.
Conclusions: Preliminary data indicate no differences in the rate at which AWS and AWNS regulate negative stimuli. Additionally, rumination does not appear to be uniquely associated with the
speed at which negative information is discarded. Further research is warranted to determine what role, if any, working memory has in the repetitive negative thinking reported by some, but not all, individuals who stutter.
Studies on neurobiological mechanisms of dyslexia-related interventions are ubiquitous in the literature; however, almost all of the studies come from interventions performed with children. Since dyslexia is a lifelong disorder, there needs to be more work done to understand an adult’s brain response to intervention. We recruited twenty adults with dyslexia to participate in an eight-week online intervention study. Before and after the intervention, all participants completed two functional near-infrared spectroscopy (fNIRS) tasks to assess sound awareness (i.e., phoneme deletion) and sentence comprehension (i.e., sentence comprehension) skills. We found group-specific intervention effects, in which the Skill-based group significantly improved their accuracy of phoneme deletion task. In contrast, no intervention impact was evident for the sentence comprehension task. The fNIRS results provided evidence for both normalizing (i.e., significant activation in the typical reading network) and compensatory changes (i.e., significant activation in the regions outside of the reading network) in brain, namely in the left fusiform gyrus and right superior temporal gyrus, respectively. These results are further discussed in the context of function of the brain structures and the previous evidence from intervention studies.
Purpose
Prior research has suggested that people who stutter exhibit differences in some working memory tasks, particularly when more phonologically complex stimuli are used. This study aimed to further specify working memory differences in adults who stutter by not only accounting for linguistic demands of the stimuli but also individual differences in attentional control and experimental influences, such as concomitant processing requirements.
Method
This study included 40 adults who stutter and 42 adults who do not stutter who completed the Attention Network Test (ANT; Fan et al., 2002) and three complex span working memory tasks: the Operation Span (OSPAN), Rotation Span, and Symmetry Span (Draheim et al., 2018; Foster et al., 2015; Unsworth et al., 2005, 2009). All complex span tasks were dual-tasks and varied in linguistic content in task stimuli.
Results
Working memory capacities demonstrated by adults who stutter paralleled the hierarchy of linguistic content across the three complex span tasks, with statistically significant between-group differences in working memory capacity apparent in the task with the highest linguistic demand (i.e., OSPAN). Individual differences in attentional control in adults who stutter also significantly predicted working memory capacity on the OSPAN.
Discussion
Findings from this study extend existing working memory research in stuttering by showing that: (1) significant working memory differences are present between adults who stutter and adults who do not stutter even using relatively simple linguistic stimuli in dual-task working memory conditions; (2) adults who stutter with stronger executive control of attention demonstrate working memory capacity more comparable to adults who do not stutter on the OSPAN compared to adults who stutter with lower executive control of attention.
Purpose
Previous literature has documented that college professors view hypothetical students who stutter more negatively than their fluent peers. The purpose of the present study was to investigate whether individuals who stutter report they experience more negative perceptions in the college classroom, and the impact of those perceptions on their comfort approaching professors.
Methods
Two hundred forty-six adults who do and do not stutter, matched for age, participated in this study. Participants were presented with 16 positive and negative personality traits and asked to rate how strongly they believed their professor viewed them along each trait. All participants were asked whether they felt comfortable approaching their professors to discuss their performance. Adults who stutter were asked additional questions to investigate their college experience more comprehensively.
Results
Adults who stutter reported they experienced significantly more negative perceptions from their professors than adults who do not stutter, and were significantly less likely to feel comfortable approaching their professors. These reported negative perceptions, specifically being perceived as less self-assured, predicted comfort approaching professors to receive performance feedback for adults who stutter. Finally, amongst adults who stutter, perception of how they were evaluated compared to their peers was significantly related to comfort approaching professors.
Conclusions
Results support that the negative perceptions towards hypothetical students who stutter reported in previous literature are experienced by individuals who stutter, and that these perceptions drive comfort approaching professors for performative feedback. Results suggest professors may increase students’ comfort by clearly outlining equality in evaluation procedures.
Despite the widespread use of nonword repetition in child neuropsychological research and clinical practice, the specific cognitive, linguistic and motor processes that contribute to variability in performance are unclear. The aim of this work was to determine the role of phonological memory, word reading, oromotor sequencing, and oromotor control on nonword repetition performance in the context of children’s speech and language abilities. Ninety one children between the ages of 9 and 11 years, with a broad range of speech and language abilities participated in the study. Hierarchical regression was used to a) evaluate the contribution of phonological memory, word reading, oromotor sequencing and oromotor control to nonword repetition and b) determine whether speech and/or language ability moderated the relationship between these specific skills and nonword repetition performance. Results showed all four predictor variables were related to nonword repetition performance, accounting for 59% of variance. The variable with the strongest association with nonword repetition was phonological memory, followed by oromotor sequencing ability, word reading, and oromotor control. Contrary to expectations, neither speech nor language ability were significantly associated with the degree to which these specific skills were drawn upon to perform the nonword repetition task. These findings underline the multidimensional nature of the nonword repetition task and provide further evidence of the major contributions made by phonological memory, word reading, speech sequencing and control to performance on this task. Further, findings suggest that speech and language ability, as measured here, do not significantly influence the skills employed for nonword repetition performance.
The present study investigated the relationship between working memory capacity (WMC) and shadowing latency in 21 people who stutter (PWS) and 15 people who do not stutter (PWNS). WMC was measured using the Reading Span Test (RST). The mean RST score of the PWS group was significantly lower than that of the PWNS group. The PWS group also showed significantly shorter shadowing latency than the PWNS group. In terms of the relationship between WMC and shadowing latency, the PWS group had a significant positive correlation, whereas the PWNS group showed a significant negative correlation. These results suggest that PWS and PWNS employ different processing strategies in verbal working memory and shadowing tasks.
Purpose: To describe the cross-cultural adaptation process of the Public Opinion Survey of Human Attributes (POSHA-S) to European Portuguese (EP). The POSHA-S was developed by the International Project on Atitudes Toward Human Attributes (IPATHA) to measure the public attitudes toward stuttering and people who stutter. The POSHA-S was created to be used internationally, through translation into other languages. Method: The EP translation and adaptation process followed five steps: 1) production of two forward translations; 2) synthesis of the translations; 3) production of two back-translations based on the synthesised version; 4) multidisciplinary expert committee review to develop the pre-final version; 5) cognitive debriefing of the new translation. To assess the agreement between the judges during the cognitive debriefing phase, a modified Bland and Altman (1986) method (Jesus, Valente and Hall 2015, pp. 4-5) was used. Results and discussion: Two forward translations were produced and syntesised by the two translators. Two back-translations were produced by two persons with English as mother tongue. The expert commitee revised the documents in terms of semantic and idiomatic content and conceptual equivalence; the level of agreement was high and discrepancies were solved through a decentering technique. Eight discrepancies relating to the POSHA-S instructions and seven discrepancies with regard to the items were solved. The pre-final version of the POSHA-S in EP was filled in by five native speakers of the translated language and similar to the target population of the assessment tool. Five individuals completed a questionnaire relating to relevance, clarity, simplicity and accuracy of instructions and items, using a visual analogue scale (VAS). The Bland and Altman method revealed that there was one item about which the judges did not agree (simplicity of instructions). The POSHA-S EP version presented good cross-cultural equivalence. Conclusions: The exhaustive traslation and adaptation process of POSHA-S’ original version into EP can be considered a good model to guarantee the equivalence and sensibility of the translated tool, in order to allow comparisons between the attitudes of the general Portuguese public and the total sample of POSHA-S.
This study describes relationships between speech, language, and related behaviors exhibited during an initial diagnostic evaluation by 2- to 6-year-old children referred for evaluation of their speech and language development. These children were referred as a result of their parents’ concerns that they might be at risk for stuttering. Subjects were 100 children (85 boys and 15 girls; mean age=54.7 months; SD=12.2 months) who appeared to be representative of the children that clinicians are likely to evaluate in a clinical setting. Analyses were based on a retrospective examination of detailed diagnostic records prepared during the diagnostic evaluations. Results indicated that children recommended for treatment exhibited significantly higher scores than children recommended for reevaluation or for neither treatment nor reevaluation on all measures of speech fluency except the duration of disfluencies (which approached, but did not reach, significance). Importantly, analyses also revealed significant behavioral overlaps between children in the three recommendation subgroups, suggesting that absolute referral criteria probably should not be used when making treatment recommendations. In addition, diagnostic testing revealed that a proportion of these children exhibited concomitant difficulties with language, phonology, or oral motor skills, suggesting that stuttering is not necessarily independent of other aspects of children’s speech and language development. Based on the distribution of children’s scores on a variety of measures in this relatively large database, benchmarks are presented that may provide clinicians with a means for comparing their own treatment recommendations to those made by others.
Purpose: The purposes of this survey study were to (a) determine the number of children who stutter with verified concomitant phonological and language disorders, (b) determine the number of children who stutter with suspected concomitant phonological and language disorders, and (c) determine the type of treatment clinicians use with these children.
Method: A systematic sampling plan was used to obtain survey responses from 241 American Speech-Language-Hearing Association (ASHA)-certified, school-based speech-language pathologists from 10 states that were considered to have similar state verification criteria for fluency, articulation/phonology, and language disorders. Respondents were asked to provide information concerning verified and suspected concomitant disorders in children who stutter. They also were asked to select one of four types of intervention approaches suggested by Bernstein Ratner (1995) in treating concomitant disorders in stuttering (i.e., blended, cyclic, sequential, and concurrent).
Results: The speech-language pathologists reported on 467 children who stuttered. Of that total, 262 (56%) children had a fluency disorder only and 205 (44%) had a verified concomitant phonological and/or language disorder. A subgroup of children with verified fluency-only disorders were suspected of having a concomitant disorder. When treating a fluency and a concomitant phonological and/or language disorder, the majority of clinicians used a blended approach.
Clinical Implications: Using similar state verification guidelines, this survey showed that a large percentage of preschool through high school students possessed a verified fluency disorder and a phonological and/or language disorder. Thus, clinicians need to be aware of the strong possibility that school-age children who stutter might have a phonological disorder and/or a language disorder. Additionally, because the majority of respondents used a blended treatment approach when treating children with a fluency and a verified concomitant phonological and/or language disorder, it appears that many school-based clinicians believe it is best to address both problems simultaneously.
In the profession of speech-language pathology, there is a strong belief that phonological disorders frequently occur in children who stutter. The purpose of this article is to examine recently published studies that addressed the frequency with which the two disorders co-occur. Over 10 years ago, a similar article was published in which studies that had been conducted from the 1920s through the 1980s were examined. Unfortunately, methodological problems with the earlier studies limited the conclusions that could be drawn. Because of the uncertainty generated by those studies, researchers since 1990 have continued to investigate this topic. Based on the previous review, it is argued that more rigorous methods are needed, including the use of more objective and comprehensive measures of phonological development and matched control groups of non-stuttering children. The current review indicates that frequency rates vary widely from one study to another, making it difficult to state with confidence just how often the two disorders co-occur. Possible explanations for the discrepancies are discussed, including differences in how phonological disorders are defined and identified. Suggestions are offered for future research to obtain more precise estimates of co-occurrence.
The aim of this study is to assess working memory (WM) abilities in normal children and Children Who Stutter (CWS) then to compare the results in order to detect if WM deficits have a role in the development of stuttering. 30 normal children and 30 children who stutter were subjected to WM recall abilities tests and nonword repetition tasks. The WM recall tests included recall of word sets different in length and rhyming, digit span, letter sequences and picture-number test. The nonword repetition test was used to assess phonological encoding through measuring number of phonological errors produced on repeating the task, and to measure the reaction time. The children who stutter (CWS) had performed poorly on some working memory tests compared to the control group. Conclusion: Children who stutter may have diminished ability to recall nonwords and some of working memory abilities and that further investigation into this possibility may shed light on the emergence and characteristics of childhood stuttering. [Hazem Aboul Oyoun; Hossam El Dessouky; Sahar Shohdi and Aisha Fawzy. Assessment of Working Memory in Normal Children and Children Who Stutter. Journal of American Science 2010;6(11):562-569]. (ISSN: 1545-1003).
Purpose
To determine whether phonological processing in adults who stutter (AWS) is disrupted by increased amounts of cognitive load in a concurrent attention-demanding task.
Method
Nine AWS and 9 adults who do not stutter (AWNS) participated. Using a dual-task paradigm, the authors presented word pairs for rhyme judgments and, concurrently, letter strings for memory recall. The rhyme judgment task manipulated rhyming type (rhyming/nonrhyming) and orthographic representation (similar/dissimilar). The memory recall task varied stimulus complexity (no letters, 3 letters, 5 letters). Rhyme judgment accuracy and reaction time (RT) were used to assess phonological processing, and letter recall accuracy was used to measure memory recall.
Results
For rhyme judgments, AWS were as accurate as AWNS, and the increase in the cognitive load did not affect rhyme judgment accuracy of either group. Significant group differences were found in RTs (delays by AWS were 241 ms greater). RTs of AWS were also slower in the most demanding rhyme condition and varied with the complexity of the memory task. Accuracy of letter recall of AWS was comparatively worse in the most demanding 5-letter condition.
Conclusion
Phonological and cognitive processing of AWS is more vulnerable to disruptions caused by increased amounts of cognitive load in concurrent attention-demanding tasks.
Purpose
This article explains why it is reasonable to question the view that stuttering and language ability in children are linked—the so-called “stuttering–language connection.”
Method
Studies that focused on syntactic, morphologic, and lexical development in children who stutter (CWS) are examined for evidence to support the following claims: (a) that CWS, as a group, are more likely to have disordered or weak language skills (“language deficits”) than children who do not stutter (CWNS); (b) that language deficits play a causal role in the onset of stuttering; and (c) that stuttering, over time, restricts children’s language development.
Results
Analysis of the evidence suggests that CWS, like CWNS, show the full range of language abilities (high, average, low); that language deficits are not associated with stuttering onset or persistence; and that stuttering has little or no impact on language development.
Conclusions
A connection between stuttering and language ability was not supported. An alternative perspective is that CWS have a compromised motor control system that makes it difficult for them to move forward in speech and that the tie to language lies not in a deficient linguistic system but in difficulty expressing the intended meaning via a fully functional speech system.
A classic question in cognitive psychology concerns the nature of memory search in short-term recognition. Despite its long history of investigation, however, there is still no consensus on whether memory search takes place serially or in parallel or is based on global access. In the present investigation, we formalize a variety of models designed to account for detailed response time distribution data in the classic Sternberg (Science 153: 652-654, 1966) memory-scanning task. The models vary in their mental architectures (serial exhaustive, parallel self-terminating, and global access). Furthermore, the component processes within the architectures that make match/mismatch decisions are formalized as linear ballistic accumulators (LBAs). In fast presentation rate conditions, the parallel and global access models provide far better accounts of the data than does the serial model. LBA drift rates are found to depend almost solely on the lag between study items and test probes, whereas response thresholds change with memory set size. Under slow presentation rate conditions, even simple versions of the serial-exhaustive model provide accounts of the data that are as good as those of the parallel and global access models. We provide alternative interpretations of the results in our General Discussion.
Purpose
The purpose of this study was to examine the influence of phonotactic probability, which is the frequency of different sound segments and segment sequences, on the overall fluency with which words are produced by preschool children who stutter (CWS) as well as to determine whether it has an effect on the type of stuttered disfluency produced.
Method
A 500+ word language sample was obtained from 19 CWS. Each stuttered word was randomly paired with a fluently produced word that closely matched it in grammatical class, word length, familiarity, word and neighborhood frequency, and neighborhood density. Phonotactic probability values were obtained for the stuttered and fluent words from an online database.
Results
Phonotactic probability did not have a significant influence on the overall susceptibility of words to stuttering, but it did impact the type of stuttered disfluency produced. In specific, single-syllable word repetitions were significantly lower in phonotactic probability than fluently produced words, part-word repetitions, and sound prolongations.
Conclusions
In general, the differential impact of phonotactic probability on the type of stuttering-like disfluency produced by young CWS provides some support for the notion that different disfluency types may originate in the disruption of different levels of processing.
Purpose
To identify, integrate, and summarize evidence from empirical studies of the language abilities of children who stutter (CWS) and children who do not stutter (CWNS).
Method
Candidate studies were identified through electronic databases, the tables of contents of speech-language journals, and reference lists of relevant articles and literature reviews. The 22 included studies met the following criteria: studied both children who did and did not stutter between ages 2;0 (years;months) and 8;0, and reported norm-referenced language measures and/or measures from spontaneous language samples amenable to effect size calculation. Data were extracted using a coding manual and were assessed by application of general and specialized analytical software. Mean difference effect size was estimated using Hedges’s g (Hedges, 1982).
Results
Findings indicated that CWS scored significantly lower than CWNS on norm-referenced measures of overall language (Hedges’s g = −0.48), receptive (Hedges’s g = −0.52) and expressive vocabulary (Hedges’s g = −0.41), and mean length of utterance (Hedges’s g = −0.23).
Conclusions
Present findings were taken to suggest that children’s language abilities are potentially influential variables associated with childhood stuttering.
Unlabelled:
The potential role of phonological complexity in destabilizing the speech motor systems of adults who stutter was explored by assessing the performance of 17 adults who stutter and 17 matched control participants on a nonword repetition task. The nonwords varied in length and phonological complexity. Behavioral results revealed no differences between the stuttering and normally fluent groups on accuracy of nonword repetition. In contrast, dramatic differences between groups were observed in the kinematic data. Indices of the consistency of inter-articulator coordination revealed that adults who stutter were much less consistent in their coordinative patterns over repeated productions. With increasing length and complexity of the nonwords, between-group differences in coordinative consistency were more pronounced. Coordination consistency measures revealed that adults who stutter (but not normally fluent adults) showed within-session practice effects; their coordinative consistency improved in five later compared to five earlier productions. Adults who stutter produced the nonwords at a slower rate, but both groups showed increased rates of production on the later trials, indicating a practice effect for duration for both groups. We conclude that, though the adults who stutter performed behaviorally with the same accuracy as normally fluent adults, the nonword repetition task reveals remarkable differences in the speech motor dynamics underlying fluent speech production in adults who stutter compared to their normally fluent peers. These results support a multifactorial, dynamic model of stuttering in which linguistic complexity and utterance length are factors that contribute to the probability of breakdown of the speech motor system.
Educational objectives:
After reading this article, the reader will be able to: (1) summarize the literature on potential language/motor interactions in stuttering, and (2) evaluate to what extent the study findings support the hypothesis that phonologically complex utterances have a destabilizing effect on the speech motor system in individuals who stutter.
The hypothesis tested was that stutterers subvocalize more slowly than nonstutterers and that they need more time for the overt production of the fluent parts of their speech. We also investigated whether rate differences could only be observed for those words on which the stutterers expect to stutter. Fifty-nine school children (27 stutterers and 32 nonstutterers) and 19 adults (18 stutterers and 21 nonstutterers) performed a reading task in which a noun was presented together with its definite article. The presentation times of the reading material were controlled by the subjects. Half of the material had to be read silently, the other half orally. In oral reading, only the data from those trials without any indication of disfluencies were used. Dependent variables were presentation times, speech latency, and speech duration. The stutterers’ silent presentation times were significantly longer than those of nonstutterers and this difference was significantly greater for children than for adults. In oral reading all stutterers, regardless of age, had longer presentation times, speech latencies, and article durations than the nonstutterers. Some nouns, however, were uttered significantly more rapidly by stutterers than by nonstutterers. These time differences were found to be independent of the stutterers’ expectation to stutter. Our results indicate that a strictly motoric explanation of stuttering is inadequate. The data show that the stutterers and nonstutterers differ with respect to the temporal parameters not only during speech execution, but during speech planning as well.
Longer rehearsal times presumably reduce the efficiency of rehearsal and, hence, of short-term recall. The present experiment examined the question as to whether the slower subvocalization rate of people who stutter is correlated with inferior short-term serial recall and recognition performance. Rate of overt articulation was taken as a measure of rehearsal time. Lists of four nonlexical CVC syllables were presented for short-term serial recall and for short-term recognition. Nineteen adults who stutter and 30 nonstutterers participated in the experiment. In the serial reproduction task the subjects who stuttered reproduced significantly fewer items correctly than did nonstutterers. Recognition performance was measured by nonparametric measures of sensitivity and bias as defined in signal detection theory. The stuttering subjects had a significantly lower sensitivity resulting primarily from a higher false alarm rate. Rate of overt articulation was significantly related to one measure of short-term recall but not to the sensitivity of recognition. These results were interpreted as suggesting that people who stutter have slower phonological encoding and rehearsal times, that they make less use of nonphonological forms of coding than do nonstutterers, and that within their phonological system, activation more easily spills over to similar items.
A brief, processing-dependent, nonword repetition task, designed to minimize biases associated with traditional language tests, was investigated. In Study 1, no overlap in nonword repetition performance was found between a group of 20 school-age children enrolled in language intervention (LI) and a group of 20 age-matched peers developing language normally (LN). In Study 2, a comparison of likelihood ratios for the nonword repetition task and for a traditional language test revealed that nonword repetition distinguished between children independently identified as LI and LN with a high degree of accuracy, by contrast with the traditional language test. Nonword repetition may have considerable clinical utility as a screening measure for language impairment in children. Information on the likelihood ratios associated with all diagnostic tests of language is badly needed.
Although it is generally accepted that the word length effect in short-term memory operates through output delay or interference, there is less agreement on whether it also influences performance through its impact on rehearsal. We investigated this issue by studying the effect of word length on recall and on a recognition task in which output delay was controlled. Word sequences were repeated exactly, or with one pair of words reversed. Two experiments using auditory presentation showed clear word length effects for both recall and serial recognition, although the magnitude of the effect tended to be less for recognition. A third experiment using visual presentation studied the effect of articulatory suppression during the recognition test; again we found a clear word length effect. It is concluded that the word length effect can influence retention through both rehearsal and output factors, as proposed by the phonological loop hypothesis.
The purpose of this study was to assess the influence of phonological priming on the speech reaction time (SRT) of children who do (CWS) and who do not (CWNS) stutter during a picture-naming task. Participants were eighteen 3–5-year-old CWS (M= 50.67 months, SD= 11.83 months), matched in age and gender with 18 CWNS (M= 49.44 months, SD= 10.22 months). The picture-naming task required each child to name, one at a time, computer-presented, white-on-black line drawings of common, age-appropriate objects "as quickly as you can" during 3 different conditions: (a) no prime, (b) related prime, and (c) unrelated prime, with naming latency (alternatively referred to as SRT; in milliseconds) as the main dependent variable. Results indicated that all children exhibited faster or shorter SRTs during the related condition compared to the no prime condition. Similarly, SRT was influenced with advancing age for all children, with 5-year-olds exhibiting faster SRTs than 3-year-olds. Furthermore, CWNS, but not CWS, demonstrated a negative correlation between articulatory mastery and SRT. Findings were taken to suggest that phonological priming is a feasible procedure for studying the speech-language planning and production of 3–5-year-old children and that preschool children who stutter, as a group, may have somewhat less well developed articulatory systems than preschool children who do not stutter.
This study investigated the comparative reliability of 2 stuttering measurement tools when used by experienced judges: percentage of syllables stuttered (%SS) and a 9-point severity scale (SEV). The study also investigated the degree to which scores on 1 tool predict scores on the other and the distributions of stuttering when measured by these tools. Twelve experienced judges watched 3-min videotapes of 90 stuttering and 10 nonstuttering participants. Half the judges rated %SS, and half made severity ratings. Results showed very high intrajudge and interjudge agreement for both measures. There was a strong linear correlation between %SS scores and SEV scores. Based on this finding, it seems that the 2 measures can be regarded as largely interchangeable. The exception to this, however, was in cases where there was either a small number of significant fixed postures (blocks and prolongations) or a large number of innocuous repeated movements (repetitions) in the speech sample. In such cases, it appears that %SS and SEV scores combined would be needed to provide a valid measure of stuttering. SEV scores were more normally distributed than %SS scores, which were clearly skewed. The advantages and limitations of the SEV scale are discussed.
Phonotactic probability refers to the frequency with which phonological segments and sequences of phonological segments occur in words in a given language. We describe one method of estimating phonotactic probabilities based on words in American English. These estimates of phonotactic probability have been used in a number of previous studies and are now being made available to other researchers via a Web-based interface. Instructions for using the interface, as well as details regarding how the measures were derived, are provided in the present article. The Phonotactic Probability Calculator can be accessed at http://www.people.ku.edu/-mvitevit/PhonoProbHome.html.
Event-related brain potentials (ERPs), judgment accuracy, and reaction times (RTs) were obtained for 11 adults who stutter and 11 normally fluent speakers as they performed a rhyme judgment task of visually presented word pairs. Half of the word pairs (i.e., prime and target) were phonologically and orthographically congruent across words. That is, the words looked orthographically similar and rhymed (e.g., thrown, own) or did not look similar and did not rhyme (e.g., cake, own). The phonologic and orthographic information across the remaining pairs was incongruent. That is, the words looked similar but did not rhyme (e.g., gown, own) or did not look similar but rhymed (e.g., cone, own). Adults who stutter and those who are normally fluent exhibited similar phonologic processing as indexed by ERPs, response accuracy, and RTs. However, longer RTs for adults who stutter indicated their greater sensitivity to the increased cognitive loads imposed by phonologic/orthographic incongruency. Also, unlike the normally fluent speakers, the adults who stutter exhibited a right hemisphere asymmetry in the rhyme judgment task, as indexed by the peak amplitude of the rhyming effect (difference wave) component. Overall, these findings do not support theories of the etiology of stuttering that posit a core phonologic-processing deficit. Rather we provide evidence that adults who stutter are more vulnerable to increased cognitive loads and display greater right hemisphere involvement in late cognitive processes.
Purpose
To investigate the holistic versus incremental phonological encoding processes of young children who stutter (CWS; N = 26) and age- and gender-matched children who do not stutter (CWNS; N = 26) via a picture-naming auditory priming paradigm.
Method
Children named pictures during 3 auditory priming conditions: neutral, holistic, and incremental. Speech reaction time (SRT) was measured from the onset of picture presentation to the onset of participant response.
Results
CWNS shifted from being significantly faster in the holistic priming condition to being significantly faster in the incremental priming condition from 3 to 5 years of age. In contrast, the majority of 3- and 5-year-old CWS continued to exhibit faster SRT in the holistic than the incremental condition.
Conclusion
CWS are delayed in making the developmental shift in phonological encoding from holistic to incremental processing, a delay that may contribute to their difficulties establishing fluent speech.
Purpose
The purpose of this study was to examine (a) the role of neighborhood density (number of words that are phonologically similar to a target word) and frequency variables on the stuttering-like disfluencies of preschool children who stutter, and (b) whether these variables have an effect on the type of stuttering-like disfluency produced.
Method
A 500+ word speech sample was obtained from each participant (N = 15). Each stuttered word was randomly paired with the firstly produced word that closely matched it in grammatical class, familiarity, and number of syllables/phonemes. Frequency, neighborhood density, and neighborhood frequency values were obtained for the stuttered and fluent words from an online database.
Results
Findings revealed that stuttered words were lower in frequency and neighborhood frequency than fluent words. Words containing part-word repetitions and sound prolongations were also lower in frequency and/or neighborhood frequency than fluent words, but these frequency variables did not have an effect on single-syllable word repetitions. Neighborhood density failed to influence the susceptibility of words to stuttering, as well as the type of stuttering-like disfluency produced.
Conclusions
In general, findings suggest that neighborhood and frequency variables not only influence the fluency with which words are produced in speech, but also have an impact on the type of stuttering-like disfluency produced.
Purpose
The purpose of this study was to investigate whether lexical access in adults who stutter (AWS) differs from that in people who do not stutter. Specifically, the authors examined the role of 3 lexical factors on naming speed, accuracy, and fluency: word frequency, neighborhood density, and neighborhood frequency. If stuttering results from an impairment in lexical access, these factors were hypothesized to differentially affect AWS performance on a confrontation naming task.
Method
Twenty-five AWS and 25 normally fluent comparison speakers, matched for age and education, participated in a confrontation naming task designed to explore within-speaker performance on naming accuracy, speed, and fluency based on stimulus word frequency and neighborhood characteristics. Accuracy, fluency, and reaction time (from acoustic waveform analysis) were computed.
Results
In general, AWS demonstrated the same effects of lexical factors on their naming as did adults who do not stutter. However, accuracy of naming was reduced for AWS. Stuttering rate was influenced by word frequency but not other factors.
Conclusions
Results suggest that AWS could have a fundamental deficit in lexical retrieval, but this deficit is unlikely to be at the level of the word’s abstract phonological representation. Implications for further research are discussed.
Stuttering has a life span incidence and it significantly impacts academic, social, emotional and vocational achievements of patients who stutter.
The purpose of the present study was to examine phonological encoding in young children who stutter (CWS) during a non word repetition task and to test the covert repair hypothesis (CRH) and phonological skills in Persian native children.
The study was conducted among 12 CWS and 12 children who do not stutter (CWNS) between the ages of 5.1 and 7.10 at the rehabilitation clinics in Tehran.
A list of 40 bisyllabic and trisyllabic nonwords was used in a nonword repetition task to collect information about the following dependent variables: (a) reaction times (RTs), (b) the number of phonological errors (PEs) and (c) nonword length.
An independent sample T-test was performed to compare means of PEs and RTs between the two groups and a paired t-test for analysis of nonword length impacts.
Results indicated that the CWS had a slightly poor performance than CWNS but there was no significant difference between the groups. Also, the differences between bisyllabic and trisyllabic nonwords were significant for phonological errors but not for reaction times.
In general, it is concluded that CWS might not have a gross problem in phonological retrieval of the novel phonological context even with increase in syllable length. Also, some predictions of CRH were not supported by this research. However, further research into this possibility may shed light on the emergence and characteristics of childhood stuttering.
Several empirical studies suggest that children who stutter, when compared to typically fluent peers, demonstrate relatively subtle, yet robust differences in phonological encoding. Phonological encoding can be measured through the use of tasks that reflect the underlying mechanisms of phonological processing, such as phonological awareness. This study investigated the phonological encoding abilities of five- and six-year old children who stutter.
Young children who stutter were paired according to language ability, maternal education, and sex to their typically fluent peers. Participants completed multiple measures of phonological awareness abilities (i.e., sound matching, phoneme blending, elision), as well as measures of expressive and receptive vocabulary and articulation.
Young children who stutter performed significantly less well than nonstuttering peers on tasks of elision and sound blending. No between-group differences were found in sound matching abilities or in any of the background language measures.
Results suggest that young children who stutter have subtle, yet robust, linguistic differences in certain aspects of phonological encoding that may contribute to an unstable language planning system in young children who stutter. Educational Objectives: The reader will be able to: (a) describe how phonological awareness can inform our understanding of phonological encoding; (b) summarize the findings of previously published studies that examined some aspects of phonological awareness in children who do and do not stutter; and (c) compare the results of the current study with other investigations of phonological awareness skills in children who stutter and their typically fluent peers.
Purpose
We investigated short-term practice and retention of nonwords in 10 adults who stutter (Mean age = 30.7 years, SD = 15.1) and age and sex-matched 10 control participants (Mean age = 30.8 years, SD = 14.9). Methods. Participants were required to repeat nonwords varying in length (3, 4, 6 syllables), phonotactic constraint (PC vs. NPC, on 3-syllable nonwords only), and complexity (simple, complex). They were tested twice with one hour gap between sessions. Results. Logistic mixed model of speech accuracy revealed that the AWS showed a significantly lower probability of correct responses with increasing length and complexity. Analysis of speech kinematics revealed practice effects within Session 1 in AWS seen as a reduction in movement variability for the 3-syllable nonwords; the control group was performing at ceiling at this length. For the 4-syllable nonwords, the control group showed a significant reduction in movement variability with practice, and retained this reduction in Session 2, while the AWS group did not show practice or retention. Group differences were not evident at the 6-syllable level. Conclusions. Group differences in speech accuracy suggest differences in phonemic encoding and/or speech motor processes. Group differences in changes in movement variability within and between sessions suggest reduced practice and retention in AWS. Relevance of the combined use of both behavioral and kinematic measures to interpret the nature of the skill acquisition deficit in persons who stutter is discussed.
Purpose:
In the present study a nonword repetition and a nonword reading task were used to investigate the behavioral (speech accuracy) and speech kinematic (movement variability measured as lip aperture variability index; speech duration) profiles of groups of young adults who do (AWS) and do not stutter (control).
Method:
Participants were 9 AWS (8 males, Mean age=32.2, SD=14.7) and 9 age- and sex-matched control participants (Mean age=31.8, SD=14.6). For the nonword repetition task, participants were administered the Nonword Repetition Test (Dollaghan & Campbell, 1998). For the reading task, participants were required to read out target nonwords varying in length (6 vs. 11 syllables). Repeated measures analyses of variance were conducted to compare the groups in percent speech accuracy for both tasks; only for the nonword reading task, the groups were compared in movement variability and speech duration.
Results:
The groups were comparable in percent accuracy in nonword repetition. Findings from nonword reading revealed a trend for the AWS to show a lower percent of accurate productions compared to the control group. AWS also showed significantly higher movement variability and longer speech durations compared to the control group in nonword reading. Some preliminary evidence for group differences in practice effect (seen as differences between the early vs. later 5 trials) was evident in speech duration.
Conclusions:
Findings suggest differences between AWS and control groups in phonemic encoding and/or speech motor planning and production. Findings from nonword repetition vs. reading highlight the need for careful consideration of nonword properties.
Educational objectives:
At the end of this activity the reader will be able to: (a) summarize the literature on nonword repetition skills in adults who stutter, (b) describe processes underlying nonword repetition and nonword reading, (c) summarize whether or not adults who stutter differ from those who do not in the behavioral and kinematic markers of nonword reading performance, (d) discuss future directions for research.
Nonword repetition and phoneme elision represent the combined influence of several speech and language processes. In the present study we investigated nonword repetition and phoneme elision performance in school-age children who stutter (CWS) and children who do not stutter (CNS). Participants were 14 CWS (mean = 11.7 years, SD = 2.1 years) and age- and sex-matched CNS (mean = 11.8 years, SD = 2.0 years). Each talker group was further subdivided into two age groups: younger (N = 7; 8-11.5 years) and older (N = 7; 11.6-15 years). Repeated-measures analyses were conducted on the accuracy and response time (in seconds) data. In nonword repetition, the CWS showed a trend for lower per cent of correct phonemes at the two-syllable level compared with the CNS. In phoneme elision, the younger CWS showed a significantly lower accuracy rate than the older CWS at the two- and three-syllable nonword lengths, while similar differences were not evident between the younger versus older CNS at any of the nonword lengths. No accuracy difference in phoneme elision was noted between the two talker groups. Group differences in speech initiation times were also not evident in either of the tasks. Findings from nonword repetition offer tentative support for difficulties experienced by school-age CWS in phonemic encoding/working memory abilities. Findings from the phoneme elision task suggest a complex pattern of age-dependent performance by the CWS. Comparison of response accuracy and speech initiation times in both the tasks failed to show speed-accuracy trade-off strategies in either of the groups.
Current theories of spoken-word recognition posit two levels of representation and process: lexical and sublexical. By manipulating probabilistic phonotactics and similarity-neighborhood density, we attempted to determine if these two levels of representation have dissociable effects on processing. Whereas probabilistic phonotactics have been associated with facilitatory effects on recognition, increases in similarity-neighborhood density typically result in inhibitory effects on recognition arising from lexical competition. Our results demonstrated that when the lexical level is invoked using real words, competitive effects of neighborhood density are observed. However, when strong lexical effects are removed by the use of nonsense word stimuli, facilitatory effects of phonotactics emerge. These results are consistent with a two-level framework of process and representation embodied in certain current models of spoken-word recognition.
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The purpose of the present study was to explore the phonological working memory of adults who stutter through the use of a non-word repetition and a phoneme elision task. Participants were 14 adults who stutter (M=28 years) and 14 age/gender matched adults who do not stutter (M=28 years). For the non-word repetition task, the participants had to repeat a set of 12 non-words across four syllable lengths (2-, 3-, 4-, and 7-syllables) (N=48 total non-words). For the phoneme elision task, the participants repeated the same set of non-words at each syllable length, but with a designated target phoneme eliminated. Adults who stutter were significantly less accurate than adults who do not stutter in their initial attempts to produce the longest non-words (i.e., 7-syllable). Adults who stutter also required a significantly higher mean number of attempts to accurately produce 7-syllable non-words than adults who do not stutter. For the phoneme elision task, both groups demonstrated a significant reduction in accuracy as the non-words increased in length; however, there was no significant interaction between group and syllable length. Thus, although there appear to be advancements in the phonological working memory for adults who stutter relative to children who stutter, preliminary data from the present study suggest that the advancements may not be comparable to those demonstrated by adults who do not stutter.
Educational objectives:
At the end of this activity the reader will be able to (a) summarize the nonword repetition data that have been published thus far with children and adults who stutter; (b) describe the subvocal rehearsal system, an aspect of the phonological working memory that is critical to nonword repetition accuracy; (c) employ an alternative means to explore the phonological working memory in adults who stutter, the phoneme elision task; and (d) discuss both phonological and motoric implications of deficits in the phonological working memory.
Unlabelled:
The purpose of this study was to compare the speed of phonological encoding between adults who stutter (AWS) and adults who do not stutter (ANS). Fifteen male AWS and 15 age- and gender-matched ANS participated in the study. Speech onset latency was obtained for both groups and stuttering frequency was calculated for AWS during three phonological priming tasks: (1) heterogeneous, during which the participants' single-word verbal responses differed phonemically; (2) C-homogeneous, during which the participants' response words shared the initial consonant; and (3) CV-homogeneous, during which the participants' response words shared the initial consonant and vowel. Response words containing the same C and CV patterns in the two homogeneous conditions served as phonological primes for one another, while the response words in the heterogeneous condition did not. During each task, the participants produced a verbal response after being visually presented with a semantically related cue word, with cue-response pairs being learned beforehand. The data showed that AWS had significantly longer speech onset latency when compared to ANS in all priming conditions, priming had a facilitating effect on word retrieval for both groups, and there was no significant change in stuttering frequency across the conditions for AWS. This suggests that phonological encoding may play no role, or only a minor role, in stuttering.
Educational objectives:
The reader will be able to: (1) describe previous research paradigms that have been used to assess phonological encoding in adults and children who stutter; (2) explain performance similarities and differences between adults who do and do not stutter during various phonological priming conditions; (3) compare the present findings to past research that examined the relationship between phonological encoding and stuttering.
In this study, the maximum speaking rates of 19 stutterers and 19 nonstutterers were measured for three speech conditions: silent, lipped, and overt. Two types of stimulus sentences were used: tongue twisters and matched control sentences. The data show that stutterers are slower than nonstutterers for each combination of stimulus type and speech condition. The difference between stutterers and nonstutterers is larger for lipped speech than for silent speech and is strongest in the overt condition. These results suggest that speech planning is impaired in stutterers. Speech execution may be independently affected, or, alternatively, the planning impairment may have stronger repercussions with actual speech motor execution.
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In their Covert Repair Hypothesis, Postma and Kolk (1993) suggest that people who stutter make greater numbers of phonological encoding errors, which are detected during the monitoring of inner speech and repaired, with stuttering-like disfluencies as a consequence. Here, we report an experiment that documents the frequency with which such errors are made. Thirty-two people who stutter (PWS) and thirty-two normally fluent controls, matched for age, gender and education, recited tonguetwisters and self-reported any errors they perceived themselves to have made. In 50% of trials the tonguetwisters were recited silently and errors reported were those detected in inner speech. Compared to controls, PWS produced significantly more word-onset and word-order errors. Crucially, this difference was found in inner as well as in overt speech. Comparison of experimenter ratings and participants' own self-ratings of their overt speech revealed similar levels of accuracy across the two groups, ruling out a suggestion that PWS were simply more sensitive to the errors they made. However, the frequency of participants' inner-speech errors was not correlated to their SSI4 scores, nor to two other measures of stuttering severity. Our findings support Postma and Kolk's contention that, when speech rate is held constant, PWS make, and therefore detect, more errors of phonological encoding. They do not, however, support the hypothesis that stuttering-like disfluencies in everyday speech stem from covert repairs of errors of phonological encoding.
Learning outcomes:
Readers will learn about three current psycholinguistic theories of stuttering, and how speech-errors elicited during tonguetwister recitation can be used to explore the controversies that exist surrounding: (a) Whether or not people who stutter are more prone to making language production errors; and (b) The extent to which stuttering-like disfluencies stem from covert repairs of language-production errors.
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Relatively recently, experimental studies of linguistic processing speed in children who stutter (CWS) have emerged, some of which suggest differences in performance among CWS compared to children who do not stutter (CWNS). What is not yet well understood is the extent to which underlying cognitive skills may impact performance on timed tasks of linguistic performance. The purpose of this study was to explore possible relationships between measures of linguistic processing speed and two aspects of cognition: phonological working memory and attention. Participants were 9 CWS and 14 CWNS between the ages of 3;6 and 5;2. Children participated in a computerized picture naming task (an index of linguistic processing speed) and a nonword repetition task (an index of phonological working memory). Parents completed a temperament behavior questionnaire, from which information about the children's attentional skills was collected. Findings revealed that the groups did not differ from each other on speed of picture naming or attention; however, the CWS performed significantly worse in nonword repetition. In addition, after partialling out the effects of age, (a) for CWS only, there was a significant negative relationship between picture naming speed and nonword repetition; (b) there were no significant relationships for either group between aspects of attention and picture naming speed; and (c) only the CWNS showed a significant relationship between nonword repetition and focused attentional skills. These results underscore the need to consider the underlying skills associated with lexically related aspects of language production when examining the task performances of CWS and CWNS.
Educational objectives:
The reader will be able to: (a) summarize findings from previous studies examining the speech and language performance of children who do (CWS) and do not stutter (CWNS); (b) describe findings of previous studies related to nonword repetition and attention in CWS; (c) compare the results of the present study with previous work in this area; and (d) discuss speculations concerning the relationship between linguistic processing speed, phonological working memory, and attention in CWS and CWNS.
This article presents a theoretical framework designed to accommodate core evidence that the abilities to repeat nonwords and to learn the phonological forms of new words are closely linked. Basic findings relating nonword repetition and word learning both in typical samples of children and adults and in individuals with disorders of language learning are described. The theoretical analysis of this evidence is organized around the following claims: first, that nonword repetition and word learning both rely on phonological storage; second, that they are both multiply determined, constrained also by auditory, phonological, and speech–motor output processes; third, that a phonological storage deficit alone may not be sufficient to impair language learning to a substantial degree. It is concluded that word learning mediated by temporary phonological storage is a primitive learning mechanism that is particularly important in the early stages of acquiring a language, but remains available to support word learning across the life span.
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Linguistic encoding deficits in people who stutter (PWS, n=18) were investigated using auditory priming during picture naming and word vs. non-word comparisons during choice and simple verbal reaction time (RT) tasks. During picture naming, PWS did not differ significantly from normally fluent speakers (n=18) in the magnitude of inhibition of RT from semantically related primes and the magnitude of facilitation from phonologically related primes. PWS also did not differ from controls in the degree to which words were faster than non-words during choice RT, although PWS were slower overall than controls. Simple RT showed no difference between groups, or between words and non-words, suggesting differences in speech initiation time do not explain the choice RT results. The findings are consistent with PWS not being deficient in the time course of lexical activation and selection, phonological encoding, and phonetic encoding. Potential deficits underlying slow choice RTs outside of linguistic encoding are discussed.
Educational objectives:
The reader will be able to (1) describe possible relationships between linguistic encoding processes and speech motor control difficulties in people who stutter; (2) explain the role of lexical priming tasks during speech production in evaluating the efficiency of linguistic encoding; (3) describe the different levels of processing that may be involved in slow verbal responding by people who stutter, and identify which levels could be involved based on the findings of the present study.
A new instrument for measuring stuttering severity has been standardized on 109 children and 28 adults. The instrument attempted to meet the criteria of simplicity, objectivity, sensitivity to fluency changes of clinical significance, reliability, validity, and usability with children and adults. The frequency, duration, and associated physical concomitants of prolongations or repetitions of short speech segments are described. Procedures have been devised for scoring so that a range of 0 to 45 is possible. The statistical reliability and validity appear to qualify the instrument for clinical and research uses.
The extent to which children's performance on tests of nonword repetition is constrained by phonological working memory and long-term lexical knowledge was investigated in a longitudinal study of 70 children tested at 4 and 5 years of age. At each time of testing, measures of nonword repetition, memory span, and vocabulary knowledge were obtained. Reading ability was also assessed at 5 years. At both ages, repetition accuracy was greater for nonwords of high- rather than low-rated wordlikeness, and memory-span measures were more closely related to repetition accuracy for the low-wordlike than for the high-wordlike stimuli. It is argued that these findings indicate that nonword repetition for unwordlike stimuli is largely dependent on phonological memory, whereas repetition for wordlike items is also mediated by long-term lexical knowledge and is therefore less sensitive to phonological memory constraints. Reading achievement was selectively linked with earlier repetition scores for low-wordlike nonwords, suggesting a phonological memory contribution in the early stages of reading development. Vocabulary knowledge was associated with repetition accuracy for both low- and high-wordlike nonwords, consistent with the notion that lexical knowledge and nonword repetition share a reciprocal developmental relationship.
Working memory involves the temporary storage and manipulation of information that is assumed to be necessary for a wide range of complex cognitive activities. In 1974, Baddeley and Hitch proposed that it could be divided into three subsystems, one concerned with verbal and acoustic information, the phonological loop, a second, the visuospatial sketchpad providing its visual equivalent, while both are dependent upon a third attentionally-limited control system, the central executive. A fourth subsystem, the episodic buffer, has recently been proposed. These are described in turn, with particular reference to implications for both the normal processing of language, and its potential disorders. The reader will be introduced to the concept of a multi-component working memory. Particular emphasis will be placed on the phonological loop component, and (a) its fractionation into a storage and processing component, (b) the neuropsychological evidence for this distinction, and (c) its implication for both native and second language learning. This will be followed by (d) a brief overview of the visuospatial sketchpad and its possible role in language, culminating in (e) discussion of the higher-level control functions of working memory which include (f) the central executive and its multi-dimensional storage system, the episodic buffer. An attempt throughout is made to link the model to its role in both normal and disordered language functions.
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Past research has suggested that children who stutter (CWS) may have less well-developed language skills than fluent children, and that such relative linguistic deficiencies may play a role in precipitating their disfluencies. However, data to support this position are primarily derived from results of standardized diagnostic inventories, which are originally designed to identify frank language impairment. Nonword repetition has emerged as a more sensitive measure of children's linguistic abilities. In this exploratory study, eight CWS (mean age 5:10, range 4:3-8:4) were compared to eight normally developing children (ND) (mean age 5:9, range 4:1-8:4) in their ability to repeat the nonwords of the Children's Test of Nonword Repetition. CWS performed more poorly than NS on measures of Number of Words Correct and Number of Phoneme Errors at all nonword lengths, although statistical differences were observed only for 3-syllable nonwords. When lexical stress of the nonwords was varied to a non-English stress pattern, all participants repeated the stimuli with less accuracy, and the CWS again exhibited more errors than NS. Fluency for the CWS group did not change systematically with increasing nonword length. These preliminary findings are interpreted in light of a number of extant theories of the underlying deficit in childhood stuttering. We conclude that children who stutter may have diminished ability to remember and/or reproduce novel phonological sequences, and that further investigation into this possibility may shed light on the emergence and characteristics of childhood stuttering.
Educational objectives:
After completing this activity, the learner will: (1) be able to evaluate the research support for a linguistic component to stuttering; (2) describe the use of nonword repetition as an experimental and assessment device with children with SLI and children who stutter; (3) suggest future directions for research to further refine the potential role that linguistic encoding plays in the etiology and persistence of stuttering.
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The purpose of the present study was to investigate the role of phonological encoding in the silent speech of persons who stutter (PWS) and persons who do not stutter (PNS). Participants were 10 PWS (M=30.4 years, S.D.=7.8), matched in age, gender, and handedness with 11 PNS (M=30.1 years, S.D.=7.8). Each participant performed five tasks: a familiarization task, an overt picture naming task, a task of self-monitoring target phonemes during concurrent silent picture naming, a task of monitoring target pure tones in aurally presented tonal sequences, and a simple motor task requiring finger button clicks in response to an auditory tone. Results indicated that PWS were significantly slower in phoneme monitoring compared to PNS. No significant between-group differences were present for response speed during the auditory monitoring, picture naming or simple motor tasks, nor did the two groups differ for percent errors in any of the experimental tasks. The findings were interpreted to suggest a specific deficiency at the level of phonological monitoring, rather than a general monitoring, reaction time or auditory monitoring deficit in PWS.
Educational objectives:
As a result of this activity, the participant should: (1) identify and assess the literature on phonological encoding skills in PWS, (2) enumerate and evaluate some major psycholinguistic theories of stuttering, and (3) describe the mechanism by which defective phonological encoding can disrupt fluent speech production.
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The purpose of this study was to assess the nonword repetition skills of 24 children who do (CWS; n = 12) and do not stutter (CWNS; n = 12) between the ages of 3;0 and 5;2. Findings revealed that CWS produced significantly fewer correct two- and three-syllable nonword repetitions and made significantly more phoneme errors on three-syllable nonwords relative to CWNS. In addition, there was a significant relationship between performance on a test of expressive phonology and nonword repetition for CWS, but not CWNS. Findings further revealed no significant fluctuation in fluency as nonwords increased in length. Taken together, findings lend support to previous work, suggesting that nonword repetition skills differ for CWS compared with CWNS, and that these findings cannot be attributed to (a) weak language performance on the part of CWS, or (b) the occurrence of stuttering in the course of nonword production.
Educational objectives:
After reading this article, the learner will be able to: (a) describe one common means of assessing phonological working memory in children; (b) summarize the performance differences of children who stutter compared to peers on a nonword repetition task; (c) compare the results of the present study with previous work in this area.
Unlabelled:
The present study investigated phonological encoding skills in persons who stutter (PWS). Participants were 10 PWS (M=31.8 years, S.D.=5.9) matched for age, gender, and handedness with 12 persons who do not stutter (PNS) (M=24.3 years, S.D.=4.3). The groups were compared in a phoneme monitoring task performed during silent picture naming. The phonological complexity of the target items in the task was varied such that participants monitored either compound words or noun phrases. Performance in this task was compared to phoneme monitoring performed on aurally presented target words to investigate whether any differences observed in silent naming were also evident in perception. Analysis of the response time data, in milliseconds, indicated that PWS were significantly slower as compared to PNS in phoneme monitoring during silent naming; group differences were not obtained in the perception task. The groups were also comparable in the response time to phoneme monitoring within compound words and noun phrases in both silent naming and perception. The findings suggested that PWS were slower in the encoding of segmental, phonological units during silent naming. Furthermore, absence of such differences in perception ruled out a general monitoring deficit in PWS. Findings are interpreted within the context of the psycholinguistic theories of stuttering that postulate phonological encoding and/or monitoring as a causal variable in stuttering.
Educational objectives:
As a result of this activity, the participant should: (1) describe relevant literature on phonological encoding skills in children and adults who stutter, (2) identify paradigms that can be used to investigate phonological processing in PWS, and (3) discuss the role of phonological encoding in speech production.