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Individual differences in attentional control predict working memory capacity in adults who stutter
Abstract
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.
... Prior to inclusion in the study, AWS were evaluated by a licensed speech-language pathologist (CCC-SLP) with more than 10 years of experience evaluating stuttering. All participants included in the AWS group also self-identified as an AWS (Tichenor et al., 2022). As a part of the evaluation, the Stuttering Severity Instrument 4th edition was also administered by a speech-language pathologist or trained student clinician under the supervision of a speechlanguage pathologist. ...
... Severity rating according to the SSI-4 at evaluation ranged from Mild to Severe. While useful as part of an evaluation conducted by a qualified clinician, due to concerns about the validity (Tichenor et al., 2022), stability (Constantino et al., 2016), and overall reliability of the SSI-4 (Davidow et al., 2017), it was not used as a correlate in the current study or to inform severity-related subgroups (Tichenor et al., 2022). Participants were initially matched pairwise for age, sex, and handedness. ...
... Severity rating according to the SSI-4 at evaluation ranged from Mild to Severe. While useful as part of an evaluation conducted by a qualified clinician, due to concerns about the validity (Tichenor et al., 2022), stability (Constantino et al., 2016), and overall reliability of the SSI-4 (Davidow et al., 2017), it was not used as a correlate in the current study or to inform severity-related subgroups (Tichenor et al., 2022). Participants were initially matched pairwise for age, sex, and handedness. ...
... Finally, neurocomputational models of stuttering with the promise to predict brain imaging patterns focus on speech motor control (Chang & Guenther, 2020), whereas stuttering encompasses a much wider range of cognitive-affective processes and occurs in the context of and interacts with language production embedded in social interactions (Bloodstein et al., 2021;Garcia-Barrera & Davidow, 2015;Jackson et al., 2015;A. Smith & Weber, 2017;Tichenor et al., 2022;van Lieshout et al., 2004). Recent proposals intended to formally model (Arenas, 2017) or to provide neurobiological explanations for stuttering variability (Brocklehurst et al., 2013;Garcia-Barrera & Davidow, 2015;Usler, 2022) speak to the emerging interest in providing neurobiological frameworks that could address that problem. ...
... Similarly, a growing corpus of evidence contributed by multiple groups of researchers now strongly implicates links between widely recognized cognitive constructs (i.e., attention, language, working memory) and the development of stuttering (Anderson & Wagovich, 2010;Bowers et al., 2018;Eichorn et al., 2016;A. Smith & Weber, 2017;Tichenor et al., 2022). However, it is not yet clear by what mechanism these cognitive capacities are related to stuttering. ...
Purpose
This perspective article examines whether brain imaging in stuttering will lead to a translational neuroscience of stuttering.
Method
A brief narrative review of insights gained from neuroimaging in stuttering is provided, followed by a series of questions about whether such insights can facilitate better understanding sufficient to inform a translational neuroscience of stuttering.
Results and Conclusions
Despite the continually growing body of brain imaging data and the introduction of causal approaches, it is unclear whether or how neuroimaging will lead to brain-based approaches to facilitate neuroplasticity or the development of novel interventions. Most neuroimaging studies to date have focused on overt stuttering as a primary behavioral correlate of brain images or causal manipulations, but it is unclear how those measures are related to important insights derived from the internal experience of stuttering. It is suggested that additional knowledge working from cognitive–behavioral–affective measures derived from the experience of stuttering could lead to further insights into underlying mechanisms that would be a boon to translational neuroscience. Following broader objections to reductionism in neuroscience, it is argued that functional models and cognitive processes specific to stuttering in context are critical as epistemological priors followed by careful behavioral and then neurophysiological experiments. As a potential path forward, a pluralistic perspective is offered, working from multifactorial conceptualizations of stuttering and Marr's concept of multiple levels.
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.
Introduction
Working memory is considered to be essential for higher-level cognition and phonological encoding. The N-back task is a popular test for evaluating working memory capacity. Phonological working memory which is involved in temporary storage and manipulation of information plays an important role in speech fluency. Previous investigations have revealed a reduced phonological working memory in English-speaking adults with stuttering (AWS). No studies to date have explored the role of phonological memory in Kannada-speaking AWS. The present study aimed to compare the working memory performance in auditory two back tasks between AWS and adults with no stuttering (AWNS).
Methods
Participants included were 15 AWS (14 males and 1 female) and 16 AWNS (8 males and 8 females). The present study comprised of two tasks, namely auditory 2 back task for meaningful words (task 1) and auditory 2 back for nonwords (task 2). The participants performed two back tasks for the meaningful words and nonwords and were instructed to say “yes” whenever the same stimulus was heard 2 stimulus back and “no” for the different stimulus. Every accurate response received a score of 1, while an incorrect or no response received a score of 0.
Results
The results revealed that AWS performed significantly poorer than AWNS in both tasks 1 and 2, which indicate that AWS has impaired working memory skills.
Conclusion
The results of the present study indicated poorer performance of stutterers in auditory n-back test of phonological working memory. This shows that individuals with stuttering having an inadequate phonological working memory when compared to that of their counterparts. This could be due to their inaccurate phonological representations or attentional deficits.
Interpreting, a complicated and demanding bilingual task, depends heavily on attentional control. However, few studies have focused on the interpreters’ advantages in attention, and the findings so far have been inconsistent. Meanwhile, the connection between attentional networks and other cognitive abilities, such as working memory (WM), has rarely been explored in interpreters. The present study investigated whether interpreting experience (IE) contributed to the attentional networks of bilinguals and explored the link between interpreters’ attention and WM. Three groups of Chinese–English bilinguals, differing only in their duration of interpreting training (the More-IE group, the Less-IE group, and the No-IE group), completed the Attention Network Test (ANT). Results showed that only the alerting network was more efficient in the More-IE group than in the Less-IE and No-IE groups; moreover, the dynamics between the alerting and executive networks were significant only in the More-IE group. Furthermore, we found a negative correlation between the executive effect and the working memory capacity (WMC) in the More-IE group. Our study validated and provided empirical support for the Attentional Control Model, stimulating further research into neurocognitive mechanisms of advanced second language learning.
Purpose:
The purpose of this study was to investigate auditory verbal working memory in adults who do (AWS) and do not (AWNS) stutter using a highly demanding linguistic N-back task.
Methods:
Fifteen AWS and 15 AWNS matched in age, gender and educational level were asked to hear series of words and respond by pressing a "yes" button if the word they just heard was the same as the word one, two, or three trials back. Words were either phonologically similar (i.e., Phonological Linguistic Condition) or phonologically dissimilar (i.e., Neutral Linguistic Condition). Accuracy and false alarms rates as well as reaction time on correct target trials, missed target trials and false alarms were collected and analyzed.
Results:
Differences were not found between AWS and AWNS in accuracy. Both groups were more accurate and significantly faster in 1- followed by 2- followed by 3-back trials. However, AWS were significantly slower than AWNS in the 2-back level, regardless of linguistic condition. Furthermore, AWS demonstrated more false alarms compared to AWNS.
Conclusion:
Results revealed differences in auditory verbal working memory and interference control between AWS and AWNS when processing highly linguistically demanding stimuli.
Purpose:
Available studies of working memory (WM) in speakers who stutter tend to rely on parent report, focus on phonological WM, or measure WM in combination with other processes. The present research aimed to: (1) compare complex WM in adults who stutter (AWS) and adults who do not stutter (AWNS); (2) characterize group performance patterns; and (2) determine whether WM predicts stuttering severity.
Methods:
Eighteen AWS and 20 AWNS completed parallel verbal and spatial span tasks in which to-be-remembered items were interleaved with a distracting task across varying set sizes. Dependent variables included the number of correctly recalled items, accuracy on distraction tasks, and detailed analyses of item-level responses. We further examined whether span scores predicted subjective and objective measures of stuttering severity.
Results:
Relative to AWNS, AWS showed poorer recall, specifically on short set sizes in the spatial task. Groups performed similarly on distraction tasks and showed comparable error patterns. Predictive relationships differed by span task and severity measure. Lower verbal span scores predicted greater stuttering impact and more overt stuttering behaviors; lower spatial span scores predicted lower impact and was unrelated to overt behaviors.
Conclusions:
Findings suggest that AWS differ subtly from AWNS in WM performance. Group differences became more apparent under certain task conditions but could not be attributed to specific underlying processes. Data further indicated a complex relationship between WM and stuttering severity. Overall, results corroborate previous studies linking stuttering to domain-general weaknesses, but highlight the need for additional research to clarify the nature of this relationship.
Motor sequencing skills have been found to distinguish individuals who experience developmental stuttering from those who do not stutter, with these differences extending to non-verbal sequencing behaviour. Previous research has focused on measures of reaction time and practice under externally cued conditions to decipher the motor learning abilities of persons who stutter. Without the confounds of extraneous demands and sensorimotor processing, we investigated motor sequence learning under conditions of explicit awareness and focused practice among adults with persistent development stuttering. Across two consecutive practice sessions, 18 adults who stutter (AWS) and 18 adults who do not stutter (ANS) performed the finger-to-thumb opposition sequencing (FOS) task. Both groups demonstrated significant within-session performance improvements, as evidenced by fast on-line learning of finger sequences on day one. Additionally, neither participant group showed deterioration of their learning gains the following day, indicating a relative stabilization of finger sequencing performance during the off-line period. These findings suggest that under explicit and focused conditions, early motor learning gains and their short-term retention do not differ between AWS and ANS. Additional factors influencing motor sequencing performance, such as task complexity and saturation of learning, are also considered. Further research into explicit motor learning and its generalization following extended practice and follow-up in persons who stutter is warranted. The potential benefits of motor practice generalizability among individuals who stutter and its relevance to supporting treatment outcomes are suggested as future areas of investigation.
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.
Purpose
Recent studies have shown that many children who stutter may have elevated characteristics of attention-deficit/hyperactivity disorder (ADHD). Although childhood ADHD commonly persists into adulthood, it is unclear how many adults who stutter experience aspects of ADHD (e.g., inattention or hyperactivity/impulsivity). This study sought to increase understanding of how ADHD characteristics might affect individuals who stutter by evaluating (a) whether elevated ADHD characteristics are common in adults who stutter, (b) whether elevated ADHD characteristics in adults who stutter were significantly associated with greater adverse impact related to stuttering, and (c) whether individual differences in Repetitive Negative Thinking (RNT) and Effortful Control influenced this relationship.
Method
Two hundred fifty-four adults who stutter completed the Adult ADHD Self-Report Scale, the Perseverative Thinking Questionnaire, the Adult Temperament Questionnaire short form, and the Overall Assessment of the Speaker's Experience of Stuttering. Data were analyzed via multiple linear regression to determine whether the number of inattention or hyperactivity/impulsivity characteristics was significantly associated with RNT, Effortful Control, or Adverse Impact related to stuttering.
Results
Almost one quarter of participants (23.2%; 60/254) self-reported experiencing six or more inattention characteristics, while fewer participants (8.3%; 21/254) self-reported experiencing six or more hyperactivity/impulsivity characteristics. Participants with lower Effortful Control and higher levels of both RNT and Adverse Impact were significantly more likely to self-report experiencing more inattention characteristics.
Discussion
Many adults who stutter may exhibit previously unaccounted for characteristics of ADHD, especially inattention. Results highlight the value of continued research on the intersectionality of stuttering, ADHD, and attention, and the importance of individualizing therapy to the needs of each unique person who stutters.
Purpose
It has long been known that stuttering behaviors vary across time and situation. Preliminary evidence suggests that this variability negatively affects people who stutter and that stuttering behaviors are more variable than adverse impact associated with stuttering. More information is needed to determine how variability affects people who stutter and what the clinical and research implications of variability may be.
Method
Two hundred and four adults who stutter participated in a mixed-methods study exploring (a) how variability of stuttering affects people who stutter in comparison to other aspects of the condition and (b) which aspects of the overall experience of stuttering are variable.
Results
Analyses indicated that variability is very commonly experienced by people who stutter and that it is among the most frustrating aspects of the condition. Qualitative analyses revealed that variability is experienced in all aspects of the stuttering condition, including the observable behavior other affective, behavioral, and cognitive reactions; and the adverse impact of stuttering. Notable individual differences were found in terms of which specific aspects of the condition were more variable for different respondents. Overall, analyses revealed that the variability of different aspects of stuttering can be viewed in a hierarchy from most variable to least variable: more external aspects (e.g., frequency, duration), more internal aspects (e.g., covert behaviors, physical tension), and cognitive–affective experiences (e.g., negative thoughts, feelings, and self-image).
Discussion
These findings suggest that variability is a common and burdensome aspect of the experience of stuttering and underscore the importance of considering variability in stuttering behavior, reactions, and impact in research, assessment, and treatment for adults who stutter.
Purpose
Phonological skills have been associated with developmental stuttering. The current study aimed to determine whether the neural processes underlying phonology, specifically for nonword rhyming, differentiated stuttering persistence and recovery.
Method
Twenty-six children who stutter (CWS) and 18 children who do not stutter, aged 5 years, completed an auditory nonword rhyming task. Event-related brain potentials were elicited by prime, rhyming, and nonrhyming targets. CWS were followed longitudinally to determine eventual persistence (n = 14) or recovery (n = 12). This is a retrospective analysis of data acquired when all CWS presented as stuttering.
Results
CWS who eventually recovered and children who do not stutter exhibited the expected rhyme effect, with larger event-related brain potential amplitudes elicited by nonrhyme targets compared to rhyme targets. In contrast, CWS who eventually persisted exhibited a reverse rhyme effect, with larger responses to rhyme than nonrhyme targets.
Conclusions
These findings suggest that CWS who eventually persisted are not receiving the same benefit of phonological priming as CWS who eventually recovered for complex nonword rhyming tasks. These results indicate divergent patterns of phonological processing in young CWS who eventually persisted, especially for difficult tasks with limited semantic context, and suggest that the age of 5 years may be an important developmental period for phonology in CWS.
Supplemental Material
https://doi.org/10.23641/asha.12682874
Purpose
Prior research has explored how repetitive negative thinking (RNT) contributes to both the increased persistence and severity of various disorders, such as depression, anxiety, and eating disorders. This study explored the potential role of RNT in the experience of stuttering, with a particular focus on the relationship between RNT, adverse impact, and certain temperament profiles.
Method
Three hundred thirteen adults who stutter completed a measurement of the frequency/severity of RNT (Perseverative Thinking Questionnaire; Ehring et al., 2011), 207 completed a temperament profile (Adult Temperament Questionnaire; Evans & Rothbart, 2007), and 205 completed a measurement of adverse stuttering impact (Overall Assessment of the Speaker's Experience of Stuttering; Yaruss & Quesal, 2016). Analyses were conducted within and across instruments to ascertain how RNT, temperament markers, and adverse impact interrelate within individuals.
Results
Results indicated that RNT significantly predicts Overall Assessment of the Speaker's Experience of Stuttering impact scores with great effect and that certain temperament markers (specifically, Effortful Control and Negative Affectivity) moderate this relationship for specific sections of the Overall Assessment of the Speaker's Experience of Stuttering.
Conclusion
By assessing RNT in people who stutter, clinicians can better understand individual differences in their clients, and this will allow them to make targeted diagnoses and develop more tailored intervention plans.
Purpose
This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings.
Method
In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences.
Results
Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states.
Conclusion
Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.
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.
Does producing a word slow performance of a concurrent, unrelated task? In 2 experiments, 108 participants named pictures and discriminated tones. In Experiment 1, pictures were named after cloze sentences; the durations of the word-production stages of lemma and phonological word-form selection were manipulated with high- and low-constraint cloze sentences and high- and low-frequency-name pictures, respectively. In Experiment 2, pictures were presented with simultaneous distractor words; the durations of lemma and phoneme selection were manipulated with conceptually and phonologically related distractors. All manipulations, except the phoneme-selection manipulation, delayed tone-discrimination responses as much as picture-naming responses. These results suggest that early word-production stages - lemma and phonological word-form selection - are subject to a central processing bottleneck, whereas the later stage - phoneme selection - is not.
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).
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.
Purpose
We advanced a multifactorial, dynamic account of the complex, nonlinear interactions of motor, linguistic, and emotional factors contributing to the development of stuttering. Our purpose here is to update our account as the multifactorial dynamic pathways theory.
Method
We review evidence related to how stuttering develops, including genetic/epigenetic factors; motor, linguistic, and emotional features; and advances in neuroimaging studies. We update evidence for our earlier claim: Although stuttering ultimately reflects impairment in speech sensorimotor processes, its course over the life span is strongly conditioned by linguistic and emotional factors.
Results
Our current account places primary emphasis on the dynamic developmental context in which stuttering emerges and follows its course during the preschool years. Rapid changes in many neurobehavioral systems are ongoing, and critical interactions among these systems likely play a major role in determining persistence of or recovery from stuttering.
Conclusion
Stuttering, or childhood onset fluency disorder (Diagnostic and Statistical Manual of Mental Disorders, 5th edition; American Psychiatric Association [APA], 2013), is a neurodevelopmental disorder that begins when neural networks supporting speech, language, and emotional functions are rapidly developing. The multifactorial dynamic pathways theory motivates experimental and clinical work to determine the specific factors that contribute to each child's pathway to the diagnosis of stuttering and those most likely to promote recovery.
Working memory capacity is an important construct in psychology because of its relationship with many higher-order cognitive abilities and psychopathologies. Working memory capacity is often measured using a type of paradigm known as complex span. Some recent work has focused on shortening the administration time of the complex span tasks, resulting in different versions of these tasks being used (Foster et al., 2015; Oswald, McAbee, Redick, & Hambrick, 2015). Variations in the complex span tasks, such as the number of set sizes, can lead to varying power to discriminate individuals at different ability levels. Thus, research findings may be inconsistent across populations due to differing appropriateness for the ability levels. The present study uses a combination of item response theory and correlational analyses to better understand the psychometric properties of the operation span, symmetry span, and rotation span. The findings show that the typical administration of these tasks, particularly the operation span, is not suitable for above average ability samples (Study 1; n = 573). When larger set sizes are added to the tasks (Study 2; n = 351), predictive validity and discriminability is improved for all complex span tasks, however the operation span is still inferior to the spatial tasks. The authors make several conclusions about which tasks and set sizes should be used depending on the intended population, and further suggest avoiding the standard-length operation span for average or higher ability populations.
Background:
Depressive thoughts are known to persist in persons with depressed mood leading to rumination and exacerbation of depressive symptoms. What has not yet been examined is whether this persistence of depressive thoughts can lead to impairment of working memory (WM).
Methods:
We assessed whether receiving a WM task featuring depressive cues could bias performance on a subsequent, non-depressive WM task for dysphoric individuals (DIs) compared to non-DIs.
Results:
DIs showed significantly attenuated performance on the WM task with depressive cues compared to non-DIs. Further, when DIs were given the WM task with depressive cues first, they showed deficits on a second WM task without depressive cues, compared to DIs given the non-depressive WM task first and non-DIs in either condition.
Limitations:
Unselected recruitment procedures did not permit balanced sample sizes in each group. Future research is needed to assess whether these results extend to a clinically depressed sample and whether WM deficits are the consequence of depressed mood, or a risk factor for the development and maintenance of depressed mood.
Conclusions:
Results suggest that, for DIs, the influence of depressive cues on performance transfers to subsequent tasks in which these cues are no longer present. These results support the hypothesis that when depressive thoughts are part of depressed persons' conscious experience, cognitive deficits arise. Further, these results suggest an ecologically-relevant mechanism by which day-to-day cognitive deficits in depression can develop.
More than 40 years ago, Baddeley and Hitch (1974) published an article with a wealth of experimentation and theorization on working memory, the small amount of information held in mind and often used within cognitive processes such as language comprehension and production, reasoning, and problem solving. We honor this seminal accomplishment in the present special issue, and take this opportunity to provide an introduction to our perspectives on the origin of the theory of working memory, how it has affected our work, what may be coming in the near future, and how the research articles in the present issue contribute to several related themes within the clearly thriving field of working memory.
Purpose
The purpose of this study was to explore metrical aspects of phonological encoding (i.e., stress and syllable boundary assignment) in adults who do and do not stutter (AWS and AWNS, respectively).
Method
Participants monitored nonwords for target sounds during silent phoneme monitoring tasks across two distinct experiments. For Experiment 1, the 22 participants (11 AWNS, 11 AWS) silently monitored target phonemes in nonwords with initial stress. For Experiment 2, an additional cohort of 22 participants (11 AWNS, 11 AWS) silently monitored phonemes in nonwords with noninitial stress.
Results
In Experiment 1, AWNS and AWS silently monitored target phonemes in initial stress stimuli with similar speed and accuracy. In Experiment 2, AWS demonstrated a within-group effect that was not present for AWNS. They required additional time when monitoring phonemes immediately following syllable boundary assignment in stimuli with noninitial stress. There was also a between-groups effect, with AWS exhibiting significantly greater errors identifying phonemes in nonwords with noninitial stress than AWNS.
Conclusions
Findings suggest metrical properties may affect the time course of phonological encoding in AWS in a manner distinct from AWNS. Specifically, in the absence of initial stress, metrical encoding of the syllable boundary may delay speech planning in AWS and contribute to breakdowns in fluent speech production.
This study was a preliminary investigation of the relations between stuttering development and the maturation of speech motor processes. Electromyographic (EMG) activity was recorded from the orofacial muscles of children who stutter and their normally fluent peers during fluent and disfluent speech. Nine children who stutter (8 boys and 1 girl), ranging in age from 2:7 to 14:0, and 9 age- and sex-matched children who do not stutter were subjects. Pairs of surface EMG electrodes were placed on children’s faces overlying the anterior belly of the digastric (ABD), levator labii superior (ULIP), and orbicularis oris inferior (LLIP) muscles. Twenty segments of stuttered (for the children who stutter) and perceptually fluent speech were extracted from children’s conversational speech samples. Spectra of the amplitude envelopes of the EMG activity were computed. The 3 oldest children who stutter showed evidence of tremorlike oscillations of EMG activity in the 5 to 15 Hz range during stuttering in either ULIP, LLIP, or ABD muscles. The younger children who stutter and the children who do not stutter demonstrated primary spectral peaks in the 1 to 4 Hz range during stuttered and/or perceptually fluent speech. It is hypothesized that the emergence of tremorlike instabilities in the speech motor processes of children who stutter may coincide with aspects of their general neural maturation and with the development of stuttering.
Measures of working memory capacity (WMC), such as complex span tasks (e.g., operation span), have become some of the most frequently used tasks in cognitive psychology. However, due to the length of time it takes to complete these tasks many researchers trying to draw conclusions about WMC forgo properly administering multiple tasks. But can the complex span tasks be shortened to take less administration time? We address this question by splitting the tasks into three blocks of trials, and analyzing each block's contribution to measuring WMC and predicting fluid intelligence (Gf). We found that all three blocks of trials contributed similarly to the tasks' ability to measure WMC and Gf, and the tasks can therefore be substantially shortened without changing what they measure. In addition, we found that cutting the number of trials by 67 % in a battery of these tasks still accounted for 90 % of the variance in their measurement of Gf. We discuss our findings in light of administering the complex span tasks in a method that can maximize their accuracy in measuring WMC, while minimizing the time taken to administer.
Researchers designing experiments in which a sample of participants responds to a sample of stimuli are faced with difficult questions about optimal study design. The conventional procedures of statistical power analysis fail to provide appropriate answers to these questions because they are based on statistical models in which stimuli are not assumed to be a source of random variation in the data, models that are inappropriate for experiments involving crossed random factors of participants and stimuli. In this article, we present new methods of power analysis for designs with crossed random factors, and we give detailed, practical guidance to psychology researchers planning experiments in which a sample of participants responds to a sample of stimuli. We extensively examine 5 commonly used experimental designs, describe how to estimate statistical power in each, and provide power analysis results based on a reasonable set of default parameter values. We then develop general conclusions and formulate rules of thumb concerning the optimal design of experiments in which a sample of participants responds to a sample of stimuli. We show that in crossed designs, statistical power typically does not approach unity as the number of participants goes to infinity but instead approaches a maximum attainable power value that is possibly small, depending on the stimulus sample. We also consider the statistical merits of designs involving multiple stimulus blocks. Finally, we provide a simple and flexible Web-based power application to aid researchers in planning studies with samples of stimuli. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
This study reexamines the issue of how much of working memory storage is central, or shared across sensory modalities and verbal and nonverbal codes, and how much is peripheral, or specific to a modality or code. In addition to the exploration of many parameters in 9 new dual-task experiments and reanalysis of some prior evidence, the innovations of the present work compared to previous studies of memory for 2 stimulus sets include (a) use of a principled set of formulas to estimate the number of items in working memory and (b) a model to dissociate central components, which are allocated to very different stimulus sets depending on the instructions, from peripheral components, which are used for only 1 kind of material. We consistently find that the central contribution is smaller than was suggested by Saults and Cowan (2007) and that the peripheral contribution is often much larger when the task does not require the binding of features within an object. Previous capacity estimates are consistent with the sum of central plus peripheral components observed here. We consider the implications of the data as constraints on theories of working memory storage and maintenance. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
Understanding temperament is central to our understanding of development, and temperament constructs are linked to individual differences in both personality and underlying neural function. In this article, I review findings on the structure of temperament, its relation to the Big Five traits of personality, and its links to development and psychopathology. In addition, I discuss the relation of temperament to conscience, empathy, aggression, and the development of behavior problems, and describe the relation between effortful control and neural networks of executive attention. Finally, I present research on training executive attention.
Working memory is currently a 'hot' topic in cognitive psychology and neuroscience. Because of their radically different scopes and emphases, however, comparing different models and theories and understanding how they relate to one another has been a difficult task. This volume offers a much-needed forum for systematically comparing and contrasting existing models of working memory. It does so by asking each contributor to address the same comprehensive set of important theoretical questions on working memory. The answers to these questions provided in the volume elucidate the emerging general consensus on the nature of working memory among different theorists and crystallize incompatible theoretical claims that must be resolved in future research. As such, this volume serves not only as a milestone that documents the state-of-the-art in the field but also as a theoretical guidebook that will likely promote new lines of research and more precise and comprehensive models of working memory.
This article presents a theoretical perspective on stuttering based on numerous findings regarding speech and nonspeech neuromotor control in individuals who stutter in combination with recent empirical data and theoretical models from the literature on the neuroscience of motor control. Specifically, this perspective on stuttering relies heavily on recent work regarding feedforward and feedback control schemes; the formation, consolidation, and updating of inverse and forward internal models of the motor systems; and cortical, subcortical, and cerebellar activation patterns during speech and nonspeech motor tasks. Against this background, we propose that stuttering may result when producing speech (a) with unstable or insufficiently activated internal models or (b) with a motor
Unlabelled:
This paper reviews Bloodstein's (1975) Anticipatory Struggle Hypothesis of stuttering, identifies its weaknesses, and proposes modifications to bring it into line with recent advances in psycholinguistic theory. The review concludes that the Anticipatory Struggle Hypothesis provides a plausible explanation for the variation in the severity of stuttered disfluencies across speaking situations and conversation partners. However, it fails to explain the forms that stuttered disfluencies characteristically take or the subjective experience of loss of control that accompanies them. The paper then describes how the forms and subjective experiences of persistent stuttering can be accounted for by a threshold-based regulatory mechanism of the kind described in Howell's (2003) revision of the EXPLAN hypothesis. It then proposes that shortcomings of both the Anticipatory Struggle and EXPLAN hypotheses can be addressed by combining them together to create a 'Variable Release Threshold' hypothesis whereby the anticipation of upcoming difficulty leads to the setting of an excessively high threshold for the release of speech plans for motor execution. The paper also reconsiders the possibility that two stuttering subtypes exist: one related to formulation difficulty and other to difficulty initiating motor execution. It concludes that research findings that relate to the one may not necessarily apply to the other.
Learning outcomes:
After reading this article, the reader will be able to: (1) summarize the key strengths and weaknesses of Bloodstein's Anticipatory Struggle Hypothesis; (2) describe two hypothesized mechanisms behind the production of stuttered disfluencies (tension and fragmentation & release threshold mechanisms); and (3) discuss why the notion of anticipation is relevant to current hypotheses of stuttering.
Purpose:
This study described the proportion of children who stutter who exhibit Attention Deficit Hyperactivity Disorder (ADHD) symptoms, manifesting in inattentive and hyperactive/impulsive behaviours. Children who stutter with these challenging behaviours may not respond as quickly and successfully to stuttering treatment. A preliminary exploration of differences in treatment responsiveness for children with and without ADHD symptoms was undertaken.
Method:
Participants were 185 preschool children who stutter who had completed stuttering therapy within 3 months prior to study commencement. Differences between groups of children who stutter with and without elevated ADHD symptoms were investigated, in terms of pre-treatment stuttering features (stuttering severity and typography), demographic variables (age at onset, time between onset and commencement of therapy, family history and sex) and treatment data (post-treatment stuttering severity and number of sessions to achieve discharge criteria).
Results:
One-half (50%) of participants exhibited elevated ADHD symptoms. These children required 25% more clinical intervention time to achieve successful fluency outcomes than children without elevated ADHD symptoms. Findings suggest that more ADHD symptoms, increased pre-treatment stuttering severity, and male sex were associated with poorer responsiveness to stuttering treatment.
Conclusion:
The large proportion of children exhibiting elevated ADHD symptoms, and the increase in clinical contact time required in this subgroup to achieve successful fluency outcomes, is suggestive of the need for clinicians to tailor stuttering intervention to address these concomitant behaviour challenges. Findings support the use of careful caseload management strategies to account for individual differences between children, and strengthen prognostic information available to parents and clinicians.
In this follow-up to my 2002 article on working memory capacity, fluid intelligence, and executive attention in Current Directions in Psychological Science, I review even more evidence supporting the idea that the ability to control one’s attention (i.e., executive attention) is important to working memory and fluid intelligence. I now argue that working memory tasks reflect primarily the maintenance of information, whereas fluid intelligence tests reflect primarily the ability to disengage from recently attended and no longer useful information. I also point out some conclusions in the 2002 article that now appear to be wrong.
Working memory - the ability to maintain and manipulate information over a period of seconds - is a core component of higher cognitive functions. The storage capacity of working memory is limited but can be expanded by training, and evidence of the neural mechanisms underlying this effect is accumulating. Human imaging studies and neurophysiological recordings in non-human primates, together with computational modelling studies, reveal that training increases the activity of prefrontal neurons and the strength of connectivity in the prefrontal cortex and between the prefrontal and parietal cortex. Dopaminergic transmission could have a facilitatory role. These changes more generally inform us of the plasticity of higher cognitive functions.
This study investigated phonological memory in 5- and 6-year old children who stutter. Participants were 11 children who stutter matched on general language abilities, maternal education level, and sex to 11 typically fluent children. Participants completed norm-referenced nonword repetition and digit span tasks, as well as measures of expressive and receptive vocabulary and articulation. The nonword repetition task included stimuli that ranged from 1 to 7 syllables, while the digit naming task contained number strings containing 2 to 10 digits. Standardized tests of vocabulary and articulation abilities were tested as well. Groups were comparable on measures expressive vocabulary, receptive vocabulary, and articulation. Despite the fact that the majority of participants scored within typical limits, young children who stutter still performed significantly less well than children who do not stutter on the nonword repetition task. No between-group differences were revealed in the digit naming task. Typically fluent children demonstrated strong correlations between phonological memory tasks and language measures, while children who stutter did not. These findings indicate that young children who stutter may have sub-clinical differences in nonword repetition.
Evidence indicates that speech movements are planned to follow auditory trajectories. This is followed by a description of the Directions Into Velocities of Articulators (DIVA) model, which provides a detailed account of the role of auditory feedback in speech motor development and control. A brief description of the higher-order brain areas involved in speech sequencing (including the pre-SMA and inferior frontal sulcus) is then provided, followed by a description of the Hierarchical State Feedback Control (HSFC) model, which posits internal error detection and correction processes that can detect and correct speech production errors prior to articulation. The chapter closes with a treatment of promising future directions of research into auditory-motor interactions in speech, including the use of intracranial recording techniques such as electrocorticography in humans, the investigation of the potential roles of various large-scale brain rhythms in speech perception and production, and the development of brain–computer interfaces that use auditory feedback to allow profoundly paralyzed users to learn to produce speech using a speech synthesizer.
Purpose:
Variability in frequency of stuttering has made the results of treatment outcome studies difficult to interpret. Many factors that affect variability have been investigated; yet the typical range of variability experienced by speakers remains unknown. This study examined the day-to-day variability in the percentage of syllables containing stuttered and nonstuttered disfluencies in the speech of six adult speakers in three spontaneous speaking situations and two reading tasks.
Methods:
The frequency of moments stuttering during the tasks were compared within and between speakers and days to document the degree of variability in stuttering frequency and explore whether there were any consistent patterns. The Stuttering Severity Instrument-Fourth Edition (SSI-4) and Overall Assessment of the Speaker's Experience of Stuttering for Adults (OASES-A) were also tested for day-to-day variability. Correlations between frequency, severity, and life impact were made.
Results:
The primary result of this study was the large range over which frequency of stuttering varied from day to day for the same individual. This variability did not correlate with any measures of stuttering severity but did correlate with life impact as measured by the OASES-A. No global pattern was detected in variability from day to day within or between participants. However, there were significantly more nonstuttered disfluencies present during the spontaneous speaking tasks than during the reading tasks. The day-to-day variability in the life impact of the disorder (OASES-A) was less than the day-to-day variability in observable stuttering behavior (percentage of syllables stuttered and SSI-4).
Conclusion:
Frequency of stuttering varies significantly from situation to situation and day to day, with observed variability exceeding the degree of change often reported in treatment outcomes studies from before to after treatment. This variability must be accounted for in future clinical and scientific work.
Objective: We investigated whether language production is atypically resource-demanding in adults who stutter (AWS) versus typically-fluent adults (TFA).
Methods: Fifteen TFA and 15 AWS named pictures overlaid with printed Semantic, Phonological or Unrelated Distractor words while monitoring frequent low tones versus rare high tones. Tones were pre- sented at a short or long Stimulus Onset Asynchrony (SOA) relative to picture onset. Group, Tone Type, Tone SOA and Distractor Type effects on P3 amplitudes were the main focus. P3 amplitude was also investigated separately in a simple tone oddball task.
Results: P3 morphology was similar between groups in the simple task. In the dual task, a P3 effect was detected in TFA in all three distractor conditions at each Tone SOA. In AWS, a P3 effect was attenuated or undetectable at the Short Tone SOA depending on Distractor Type.
Conclusions: In TFA, attentional resources were available for P3-indexed processes in tone perception and categorization in all distractor conditions at both Tone SOAs. For AWS, availability of attentional resources for secondary task processing was reduced as competition in word retrieval was resolved.
Significance: Results suggest that language production can be atypically resource-demanding in AWS. Theoretical and clinical implications of the findings are discussed.
This book is the magnum opus of one of the most influential cognitive psychologists of the past 50 years. This new volume on the model he created (with Graham Hitch) discusses the developments that have occurred in the past 20 years, and places it within a broader context. Working memory is a temporary storage system that underpins onex' capacity for coherent thought. Some 30 years ago, Baddeley and Hitch proposed a way of thinking about working memory that has proved to be both valuable and influential in its application to practical problems. This book updates the theory, discussing both the evidence in its favour, and alternative approaches. In addition, it discusses the implications of the model for understanding social and emotional behaviour, concluding with an attempt to place working memory in a broader biological and philosophical context. Inside are chapters on the phonological loop, the visuo-spatial sketchpad, the central executive and the episodic buffer. There are also chapters on the relevance to working memory of studies of the recency effect, of work based on individual differences, and of neuroimaging research. The broader implications of the concept of working memory are discussed in the chapters on social psychology, anxiety, depression, consciousness, and on the control of action. Finally, the author discusses the relevance of a concept of working memory to the classic problems of consciousness and free will.
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.
Copyright © 2015 Elsevier Inc. All rights reserved.
Dysphoria is associated with persistence of attention on mood-congruent information. Longer time attending to mood-congruent information for dysphoric individuals (DIs) detracts from goal-relevant information processing and should reduce working memory (WM) capacity. Study 1 showed that DIs and non-DIs have similar WM capacities. Study 2 embedded depressive information into a WM task. Compared to non-DIs, DIs showed significantly reduced WM capacity for goal-relevant information in this task. Study 3 replicated results from Studies 1 and 2, and further showed that DIs had a significantly greater association between processing speed and recall on the depressively modified WM task compared to non-DIs. The presence of inter-task depressive information leads to DI-related decreased WM capacity. Results suggest dysphoria-related WM capacity deficits when depressive thoughts are present. WM capacity deficits in the presence of depressive thoughts are a plausible mechanism to explain day-to-day memory and concentration difficulties associated with depressed mood.
Purpose
In preschool children, we investigated whether expressive and receptive language, phonological, articulatory, and/or verbal working memory proficiencies aid in predicting eventual recovery or persistence of stuttering. Methods. Participants included 65 children, including 25 children who do not stutter (CWNS) and 40 who stutter (CWS) recruited at age 3;9-5;8. At initial testing, participants were administered the Test of Auditory Comprehension of Language, 3rd edition (TACL-3), Structured Photographic Expressive Language Test, 3rd edition (SPELT-3), Bankson-Bernthal Test of Phonology-Consonant Inventory subtest (BBTOP-CI), Nonword Repetition Test (NRT; Dollaghan & Campbell, 1998), and Test of Auditory Perceptual Skills-Revised (TAPS-R) auditory number memory and auditory word memory subtests. Stuttering behaviors of CWS were assessed in subsequent years, forming groups whose stuttering eventually persisted (CWS-Per; n = 19) or recovered (CWS-Rec; n = 21). Proficiency scores in morphosyntactic skills, consonant production, verbal working memory for known words, and phonological working memory and speech production for novel nonwords obtained at the initial testing were analyzed for each group. Results. CWS-Per were less proficient than CWNS and CWS-Rec in measures of consonant production (BBTOP-CI) and repetition of novel phonological sequences (NRT). In contrast, receptive language, expressive language, and verbal working memory abilities did not distinguish CWS-Rec from CWS-Per. Binary logistic regression analysis indicated that preschool BBTOP-CI scores and overall NRT proficiency significantly predicted future recovery status. Conclusion. Results suggest that phonological and speech articulation abilities in the preschool years should be considered with other predictive factors as part of a comprehensive risk assessment for the development of chronic stuttering.
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.
The complex span measure of working memory is a word/digit span measured while performing a secondary task. Two experiments investigated whether correlations between the complex span and reading comprehension depend on the nature of the secondary task and individual skill in that task. The secondary task did not have to be reading related for the span to predict reading comprehension. An arithmetic-related secondary task led to correlations with reading comprehension similar to those found when the secondary task was reading. The relationship remained significant when quantitative skills were factored out of the complex span/comprehension correlations. Simple digit and word spans (measured without a background task) did not correlate with reading comprehension and SAT scores. The second experiment showed that the complex span/comprehension correlations were a function of the difficulty of the background task. When the difficulty level of the reading-related or arithmetic-related background tasks was moderate, the span/comprehension correlations were higher in magnitude than when the background tasks were very simple, or, were very difficult.
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.
This chapter describes the nature of working memory capacity (WMC), and addresses the nature of WMC limitations, their effects on higher order cognitive tasks, their relationship to attention control and general fluid intelligence, and their neurological substrates. Much of work explores these issues in the context of individual differences in WMC and the cause of those individual differences. Measures of WMC are highly reliable and highly valid indicators of some construct of clear relevance to feral cognition. Macroanalytic studies have demonstrated that the construct reflected by WMC tasks has a strong relationship with gF above and beyond what these tasks share with simple span tasks. The conflict might also arise from stimulus representations of competing strength. This two-factor model fits with current thinking about the role of two brain structures: the prefrontal cortex as important to the maintenance of information in an active and easily accessible state and the anterior cingulate as important to the detection and resolution of conflict.
Performance on measures of working memory (WM) capacity predicts performance on a wide range of real-world cognitive tasks. I review the idea that WM capacity (a) is separable from short-term memory, (b) is an important component of general fluid intelligence, and (c) represents a domain-free limitation in ability to control attention. Studies show that individual differences in WM capacity are reflected in performance on antisaccade, Stroop, and dichotic-listening tasks. WM capacity, or executive attention, is most important under conditions in which interference leads to retrieval of response tendencies that conflict with the current task.
Working memory is currently a 'hot' topic in cognitive psychology and neuroscience. Because of their radically different scopes and emphases, however, comparing different models and theories and understanding how they relate to one another has been a difficult task. This volume offers a much-needed forum for systematically comparing and contrasting existing models of working memory. It does so by asking each contributor to address the same comprehensive set of important theoretical questions on working memory. The answers to these questions provided in the volume elucidate the emerging general consensus on the nature of working memory among different theorists and crystallize incompatible theoretical claims that must be resolved in future research. As such, this volume serves not only as a milestone that documents the state-of-the-art in the field but also as a theoretical guidebook that will likely promote new lines of research and more precise and comprehensive models of working memory.
Unlabelled:
The present study investigated segmentation and rhyme abilities, skills critical for phonological encoding, of children who stutter (CWS) and those who do not (CNS). Participants were 9 CWS (8 males and 1 female, mean age=11.1, SD=2.31) in the age range of 7 and 13 years and 9 age and sex matched CNS (mean age=11.2, SD=2.19). Participants performed two verbal monitoring tasks, phoneme and rhyme monitoring, in silent naming. Performances in the verbal monitoring tasks were compared to a neutral, nonverbal tone monitoring task. Additionally, the complexity of the phoneme monitoring task was varied such that participants had to monitor for singletons vs. consonant clusters. Repeated measures analysis of the response time data did not reveal significant differences between the groups in the three monitoring tasks. Analysis of the complexity data revealed a trend for slower monitoring of the consonant clusters in the CWS group compared to the CNS. Present findings do not support a deficit in segmentation and rhyme abilities in CWS, although there was some preliminary evidence of segmentation difficulties with increasing phonological complexity of the stimuli.
Educational objectives:
At the end of this activity the reader will be able to: (a) discuss the literature on phonological encoding skills in children who stutter, (b) describe skills underlying the phonological encoding process, (c) summarize whether or not children who stutter differ from those who do not in segmentation and rhyme abilities, (d) suggest future areas of research in the investigation of segmentation and rhyme monitoring abilities in children who stutter.
The DIVA model of speech production provides a computationally and neuroanatomically explicit account of the network of brain regions involved in speech acquisition and production. An overview of the model is provided along with descriptions of the computations performed in the different brain regions represented in the model. The latest version of the model, which contains a new right-lateralized feedback control map in ventral premotor cortex, will be described, and experimental results that motivated this new model component will be discussed. Application of the model to the study and treatment of communication disorders will also be briefly described.