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... In addition to the conventional ERP latency and amplitude measures, we applied time-frequency analysis to examine trial-by-trial consistency of neural oscillations in selected frequency bands of interest that could drive the MMR activity for speech and nonspeech discrimination. The cortical oscillations are thought to reflect the net excitatory and inhibitory neuronal activities that mediate sensory and cognitive events [39][40][41][42][43][44][45] . Time-frequency analysis on a trial-by-trial basis allows a more detailed examination of what oscillatory activities contribute to or do not contribute to the observed ERP responses that are averaged across trials. ...
... Thus trial-by-trial time-frequency analysis may reveal additional information about how various EEG frequencies may reflect multiple neural processes co-occurring and interacting in the service of integrative and dynamically adaptive information processing 47 . The phase-synchronized oscillations survive cross-trial averaging and are evident in the averaged ERPs 42,43 . Certain frequency bands have been linked to different neurocognitive process 48,49 . ...
... Our results showing the lack of CP for lexical tones in theta activity in the Chinese children with autism are consistent with previous findings that reveal the importance of the theta frequency band in the pre-attentive neural processing of auditory deviant stimuli 42,[51][52][53][54]78 . Our results differ from Bidelman 79 and Scharinger, et al. 60 , in which the beta band activity was correlated with categorical perception of vowel sounds. ...
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Recent studies reveal that tonal language speakers with autism have enhanced neural sensitivity to pitch changes in nonspeech stimuli but not to lexical tone contrasts in their native language. The present ERP study investigated whether the distinct pitch processing pattern for speech and nonspeech stimuli in autism was due to a speech-specific deficit in categorical perception of lexical tones. A passive oddball paradigm was adopted to examine two groups (16 in the autism group and 15 in the control group) of Chinese children's Mismatch Responses (MMRs) to equivalent pitch deviations representing within-category and between-category differences in speech and nonspeech contexts. To further examine group-level differences in the MMRs to categorical perception of speech/nonspeech stimuli or lack thereof, neural oscillatory activities at the single trial level were further calculated with the inter-trial phase coherence (ITPC) measure for the theta and beta frequency bands. The MMR and ITPC data from the children with autism showed evidence for lack of categorical perception in the lexical tone condition. In view of the important role of lexical tones in acquiring a tonal language, the results point to the necessity of early intervention for the individuals with autism who show such a speech-specific categorical perception deficit.
... Therefore, it is not expected that generalized linear models would provide better results. Koerner et al. (2016) aimed to examine whether noise-induced changes in the MMN and spectral power in the theta frequency band in response to a consonant change (/ba/ to /da/) and vowel change (/ba/ to /bu/) in a double-oddball paradigm were predictive of speech perception in noise at the syllable and sentence levels. ...
... The results showed how linear mixed-effects regression models (after verification of normality of residuals and homogeneity of variance) are able to depict relationships between the predictor and outcome variables while taking into account repeated measures across participants. While the LME models were able to confirm basic conclusions gained from the Pearson correlation analyses for both studies (Koerner & Zhang, 2015;Koerner et al., 2016), a comparison of methods and results for each model highlighted differences between the two approaches. ...
... While the two ERP studies reported here are clearly limited in scope and depth of analysis, the side-by-side comparisons clearly demonstrate the limitations and inappropriateness of the Pearson approach as well as its inflated correlation estimation results for the data sets. Given that multiple analysis techniques (for example, waveform analysis, source localization, time-frequency analysis) can be applied to the same neurophysiological data in cognitive neuroscience research (Koerner, Zhang, Nelson, Wang, & Zou, 2016;Koerner & Zhang, 2015;Zhang et al., 2011Zhang et al., , 2016, a cautionary note against the convenient use of the simple Pearson correlation test is necessary when selecting and applying statistical models to interpret brain-behavior correlations (e.g., biomarkers of various diseases and disorders) or correlations among the various brain measures with prior distributions and covariance structure for repeated measures. ...
... Previous studies have well established that the presence of background noise can impact auditory event-related potentials (AERPs) to speech as well as nonspeech stimuli (Bidelman et al., 2014;Billings et al., 2009;Koerner and Zhang, 2015;Kozou et al., 2005;Maamor and Billings, 2017;Muller-Gass et al., 2001;Whiting et al., 1998). Furthermore, noiseinduced changes in AERPs have been shown to be correlated with changes in the ability to perceive speech in background noise (Anderson et al., 2013b;Anderson et al., 2011;Bennett et al., 2012;Billings et al., 2013;Koerner et al., 2016;Song et al., 2011). However, most neurophysiological data were from adults with normal hearing or with careful control of subject variables such as age and hearing sensitivity. ...
... These studies also documented latency increases and amplitude decreases in the N1, MMN, N2, and P3 AERPs in response to a /ba/-/da/ stimulus contrast after simulating reduced audibility caused by different degrees and configurations of hearing loss. These findings are similar to those from previous work that examined the effects of noise masking on AERPs (Bennett et al., 2012;Billings et al., 2009Billings et al., , 2013Koerner et al., 2016Kozou et al., 2005;Anderson et al., 2013a). However, results showed that there was an important differential effect of noise on these AERP responses, such that the N1 response was present as long as stimuli were audible, while later AERP components such as the MMN and P3 responses were present only if stimuli were discriminable (Martin et al., 1997(Martin et al., , 1999Martin and Stapells, 2005). ...
... However, it is well known that the MMN has high inter-and intra-subject variability (Kurtzberg et al., 1995;Lang et al., 1995;Martin et al., 1999Martin et al., , 2008N€ a€ at€ anen et al., 2007Stapells, 2002), which greatly limits its use in assessing performance at the individual level. Recent findings suggest that a measure of cross-trial cortical oscillatory activity associated with the MMN response may represent a more robust measure of neural processing than MMN latency or amplitude (Koerner et al., 2016). Traditional AERP waveform averaging focuses on capturing synchronous neural activity that is time-and phase-locked to an auditory stimulus but does not allow for an examination of ongoing EEG oscillatory activity underlying AERP components, as any "random" trial-by-trial activity is canceled out during the averaging process. ...
Article
Understanding speech in background noise is difficult for many listeners with and without hearing impairment (HI). This study investigated the effects of HI on speech discrimination and recognition measures as well as speech-evoked cortical N1-P2 and MMN auditory event-related potentials (AERPs) in background noise. We aimed to determine which AERP components can predict the effects of HI on speech perception in noise across adult listeners with and without HI. The data were collected from 18 participants with hearing thresholds ranging from within normal limits to bilateral moderate-to-severe sensorineural hearing loss. Linear mixed effects models were employed to examine how hearing impairment, age, stimulus type, and SNR listening condition affected neural and behavioral responses and what AERP components were correlated with effects of HI on speech-in-noise perception across participants. Significant effects of age were found on the N1-P2 but not on MMN, and significant effects of HI were observed on the MMN and behavioral measures. The results suggest that neural responses reflecting later cognitive processing of stimulus discrimination may be more susceptible to the effects of HI on the processing of speech in noise than earlier components that signal the sensory encoding of acoustic stimulus features. Objective AERP responses were also potential neural predictors of speech perception in noise across participants with and without HI, which has implications for the use of AERPs as a potential clinical tool for assessing speech perception in noise. Full text for personal sharing available before December 6. 2018 at this web link: https://authors.elsevier.com/c/1XynD1M5IZOSKX
... Koerner et al. [57] aimed to examine whether noise-induced changes in the MMN and spectral power in the theta frequency band in response to a consonant change (/ba/ to /da/) and vowel change (/ba/ to /bu/) in a double-oddball paradigm were predictive of speech perception in noise at the syllable and sentence levels. ...
... Final p-values for each correlation coefficient were adjusted to account for multiple comparisons. As reported in Koerner et al. [57], repeated measures ANOVAs were used to examine the effects of background noise on MMN latency, amplitude, and EEG theta power. Linear mixed-effects models were developed to determine whether these objective neural measures were able to predict behavioral performance. ...
... Repeated measures ANOVA results from Koerner et al. [57] showed significant effects of background noise on MMN latency (F(1, 14) = 29.43, p < 0.001), amplitude (F(1, 14) = 32.52, ...
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Neurophysiological studies are often designed to examine relationships between measures from different testing conditions, time points, or analysis techniques within the same group of participants. Appropriate statistical techniques that can take into account repeated measures and multivariate predictor variables are integral and essential to successful data analysis and interpretation. This work implements and compares conventional Pearson correlations and linear mixed-effects (LME) regression models using data from two recently published auditory electrophysiology studies. For the specific research questions in both studies, the Pearson correlation test is inappropriate for determining strengths between the behavioral responses for speech-in-noise recognition and the multiple neurophysiological measures as the neural responses across listening conditions were simply treated as independent measures. In contrast, the LME models allow a systematic approach to incorporate both fixed-effect and random-effect terms to deal with the categorical grouping factor of listening conditions, between-subject baseline differences in the multiple measures, and the correlational structure among the predictor variables. Together, the comparative data demonstrate the advantages as well as the necessity to apply mixed-effects models to properly account for the built-in relationships among the multiple predictor variables, which has important implications for proper statistical modeling and interpretation of human behavior in terms of neural correlates and biomarkers.
... Previous auditory event-related potential (AERP) studies have demonstrated the detrimental effects of background noise on the timing and strength of neural responses to speech and non-speech stimuli (Billings et al., 2011;Koerner and Zhang, 2015;Parbery-Clark et al., 2011;Russo et al., 2009). Furthermore, the noise-induced changes in different AERP components have been shown to predict behavioral measures of perceptual and cognitive abilities (Anderson et al., 2011;Anderson et al., 2010b;Billings et al., 2013;Billings et al., 2015;Koerner et al., 2016;Song et al., 2011). The present AERP study represents a sequel to our previous work (Koerner et al., 2016) to determine neural correlates of speech-innoise perception at the syllable and sentence levels. ...
... Furthermore, the noise-induced changes in different AERP components have been shown to predict behavioral measures of perceptual and cognitive abilities (Anderson et al., 2011;Anderson et al., 2010b;Billings et al., 2013;Billings et al., 2015;Koerner et al., 2016;Song et al., 2011). The present AERP study represents a sequel to our previous work (Koerner et al., 2016) to determine neural correlates of speech-innoise perception at the syllable and sentence levels. ...
... At the subcortical level, frequency following response (FFR) measures showed larger noise-induced effects on consonant encoding than vowel encoding in the CV syllable context (Anderson et al., 2010a(Anderson et al., , 2010bRusso et al., 2004;Song et al., 2011), which is consistent with the behavioral finding of larger noiseinduced impact on the detection of consonants compared to vowels (Korczak and Stapells, 2010;Miller and Nicely, 1955;Parikh and Loizou, 2005;Phatak and Allen, 2007;Pickett, 1957). At the cortical level, however, recent studies showed that the neural coding of vowel contrasts as reflected in the mismatch negativity (MMN) response was more susceptible to the presence of background noise compared to consonants (Koerner et al., 2016;Niemitalo-Haapola et al., 2015). Unlike the P3 response that requires an overt behavioral response for detecting a stimulus change and peaks at a later time point than the MMN, the MMN is thought to index pre-attentive automatic change detection independent of focused attention (N€ a€ at€ anen et al., 2007). ...
Article
This study examined how speech babble noise differentially affected the auditory P3 responses and the associated neural oscillatory activities for consonant and vowel discrimination in relation to segmental- and sentence-level speech perception in noise. The data were collected from 16 normal-hearing participants in a double-oddball paradigm that contained a consonant (/ba/ to /da/) and vowel (/ba/ to /bu/) change in quiet and noise (speech-babble background at a -3 dB signal-to-noise ratio) conditions. Time-frequency analysis was applied to obtain inter-trial phase coherence (ITPC) and event-related spectral perturbation (ERSP) measures in delta, theta, and alpha frequency bands for the P3 response. Behavioral measures included percent correct phoneme detection and reaction time as well as percent correct IEEE sentence recognition in quiet and in noise. Linear mixed-effects models were applied to determine possible brain-behavior correlates. A significant noise-induced reduction in P3 amplitude was found, accompanied by significantly longer P3 latency and decreases in ITPC across all frequency bands of interest. There was a differential effect of noise on consonant discrimination and vowel discrimination in both ERP and behavioral measures, such that noise impacted the detection of the consonant change more than the vowel change. The P3 amplitude and some of the ITPC and ERSP measures were significant predictors of speech perception at segmental- and sentence-levels across listening conditions and stimuli. These data demonstrate that the P3 response with its associated cortical oscillations represents a potential neurophysiological marker for speech perception in noise.
... Electroencephalography (EEG) has been used extensively to examine dynamic changes in cortical activities when subjects listen to speech with multiscale hierarchical temporal structures because it enables the measurement of whole-brain activity at high temporal resolution (Kaan, 2010). Cortical responses to different phonemes have been investigated using isolated consonantevowel pairs based on event-related potentials (ERP), and the results suggest the presence of discriminant encoding at multiple time points (e.g., the P1eN1eP2 complex) and channel locations (Tremblay et al., 2003;Koerner et al., 2016). These typical neurophysiological features corresponding to the phonemic-level processing of consonantevowel pairs measured by the ERP related studies have revealed a high correlation with sentence-level intelligibility (e.g., Koerner et al., 2016;Von Holzen et al., 2018). ...
... Cortical responses to different phonemes have been investigated using isolated consonantevowel pairs based on event-related potentials (ERP), and the results suggest the presence of discriminant encoding at multiple time points (e.g., the P1eN1eP2 complex) and channel locations (Tremblay et al., 2003;Koerner et al., 2016). These typical neurophysiological features corresponding to the phonemic-level processing of consonantevowel pairs measured by the ERP related studies have revealed a high correlation with sentence-level intelligibility (e.g., Koerner et al., 2016;Von Holzen et al., 2018). Researchers have further assessed the intelligibility of continuous sentences by examining correlations between acoustic features and neural activities. ...
... ERPs reflect specific sensory and/or cognitive processes [30]. Specific ERPs that may be used to study the perception of signals in noise are the N1, P2, mismatch negativity (MMN) and P300 responses [31][32][33][34][35][36][37][38][39][40]. Of particular interest to the current study are the MMN and P300 components. ...
... Changes have been reported in ERPs in the presence of ipsilateral noise compared with a quiet condition [33,34,38,39,[77][78][79][80]. Generally, amplitudes are reduced and latencies are prolonged for the MMN and P300 when stimuli are presented in ipsilateral noise, which may be activating the efferent system. ...
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This electrophysiological study investigated the role of the medial olivocochlear (MOC) efferents in listening in noise. Both ears of eleven normal-hearing adult participants were tested. The physiological tests consisted of transient-evoked otoacoustic emission (TEOAE) inhibition and the measurement of cortical event-related potentials (ERPs). The mismatch negativity (MMN) and P300 responses were obtained in passive and active listening tasks, respectively. Behavioral responses for the word recognition in noise test were also analyzed. Consistent with previous findings, the TEOAE data showed significant inhibition in the presence of contralateral acoustic stimulation. However, performance in the word recognition in noise test was comparable for the two conditions (i.e., without contralateral stimulation and with contralateral stimulation). Peak latencies and peak amplitudes of MMN and P300 did not show changes with contralateral stimulation. Behavioral performance was also maintained in the P300 task. Together, the results show that the peripheral auditory efferent effects captured via otoacoustic emission (OAE) inhibition might not necessarily be reflected in measures of central cortical processing and behavioral performance. As the MOC effects may not play a role in all listening situations in adults, the functional significance of the cochlear effects of the medial olivocochlear efferents and the optimal conditions conducive to corresponding effects in behavioral and cortical responses remain to be elucidated.
... MMN is conventionally studied using an oddball paradigm which usually involves a sequence of repeated standard stimuli, which occurs in most of the trials, sporadically interrupted by a deviant stimulus. This component has been used in various work that is related to auditory discrimination and speech discrimination [13][14][15][16][17][18]. The presence of MMN in response to the deviant stimuli in an oddball task indicates that the user can distinguish between the particular deviant and standard sounds that are used in the task. ...
... We observed an MMN in response to deviant stimulus in Method 3 at approximately 100-300 ms after stimulus onset. This is consistent with the results from other works that utilizes MMN [13,15]. ...
Article
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Speech discrimination is used by audiologists in diagnosing and determining treatment for hearing loss patients. Usually, assessing speech discrimination requires subjective responses. Using electroencephalography (EEG), a method that is based on event-related potentials (ERPs), could provide objective speech discrimination. In this work we proposed a visual-ERP-based method to assess speech discrimination using pictures that represent word meaning. The proposed method was implemented with three strategies, each with different number of pictures and test sequences. Machine learning was adopted to classify between the task conditions based on features that were extracted from EEG signals. The results from the proposed method were compared to that of a similar visual-ERP-based method using letters and a method that is based on the auditory mismatch negativity (MMN) component. The P3 component and the late positive potential (LPP) component were observed in the two visual-ERP-based methods while MMN was observed during the MMN-based method. A total of two out of three strategies of the proposed method, along with the MMN-based method, achieved approximately 80% average classification accuracy by a combination of support vector machine (SVM) and common spatial pattern (CSP). Potentially, these methods could serve as a pre-screening tool to make speech discrimination assessment more accessible, particularly in areas with a shortage of audiologists.
... In order to examine whether or not the effect of rehabilitation on the measure of language outcome was influenced by the children's working memory span, a linear mixed-effects model analysis (LMM) was performed for the hearing-impaired group. The LMM analysis has been used in some previous studies to examine possible relationships among multivariate cognitive and linguistic measures from the same participants in different conditions (Nicenboim et al., 2015;Koerner et al., 2016). Therefore, a LMM analysis was conducted in the present study to examine the relationship between memory span and language outcome. ...
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Memory processes could account for a significant part of the variance in language performances of hearing-impaired children. However, the circumstance in which the performance of hearing-impaired children can be nearly the same as the performance of hearing children remains relatively little studied. Thus, a group of pre-school children with congenital, bilateral hearing loss and a group of pre-school children with normal hearing were invited to participate in this study. In addition, the hearing-impaired participants were divided into two groups according to their working memory span. A language disorder assessment test for Mandarin-speaking preschoolers was used to measure the outcomes of receptive and expressive language of the two groups of children. The results showed that the high-span group performed as good as the hearing group, while the low-span group showed lower accuracy than the hearing group. A linear mixed-effects analysis showed that not only length of rehabilitation but also the memory span affected the measure of language outcome. Furthermore, the rehabilitation length positively correlated with the measure of expressive language only among the participants of the high-span group. The pattern of the results indicates that working memory capacity is one of the factors that could support the children to acquire age-equivalent language skills.
... The maximum delta/theta/gamma phase locking value within the designated time windows of different AEP components was identified individually under each experimental condition for statistical analysis. Similar TF analysis approaches were adopted in previous studies (Koerner et al., 2016;Koerner & Zhang, 2015Yu et al., 2018). ...
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The presence of vowel exaggeration in infant‐directed speech (IDS) may adapt to the age‐appropriate demands in speech and language acquisition. Previous studies have provided behavioral evidence of atypical auditory processing towards IDS in children with autism spectrum disorders (ASD), while the underlying neurophysiological mechanisms remain unknown. This event‐related potential (ERP) study investigated the neural coding of formant‐exaggerated speech and nonspeech in 24 4‐ to 11‐year‐old children with ASD and 24 typically‐developing (TD) peers. The EEG data were recorded using an alternating block design, in which each stimulus type (exaggerated/non‐exaggerated sound) was presented with equal probability. ERP waveform analysis revealed an enhanced P1 for vowel formant exaggeration in the TD group but not in the ASD group. This speech‐specific atypical processing in ASD was not found for the nonspeech stimuli which showed similar P1 enhancement in both ASD and TD groups. Moreover, the time‐frequency analysis indicated that children with ASD showed differences in neural synchronization in the delta‐theta bands for processing acoustic formant changes embedded in nonspeech. Collectively, the results add substantiating neurophysiological evidence (i.e., a lack of neural enhancement effect of vowel exaggeration) for atypical auditory processing of IDS in children with ASD, which may exert a negative effect on phonetic encoding and language learning. Lay summary Atypical responses to motherese might act as a potential early marker of risk for children with ASD. This study investigated the neural responses to such socially relevant stimuli in the ASD brain, and the results suggested a lack of neural enhancement responding to the motherese even in individuals without intellectual disability.
... Time-frequency analysis shows other dimensions of processing, including non-time-locked activity, and provides information about speech processing at multiple frequency bands. In particular, the auditory MMN component has been related to changes in theta activity (Ko et al., 2012;Koerner et al., 2016;Yordanova & Kolev, 1998). In the present article, we aimed at investigating oscillatory correlates of subphonemic deviance in homophonous sequences, as indexed by the MMN. ...
Article
Speech perception involves segmenting a continuous stream of speech into its word components. This can be challenging in the case of homophonous utterances only differing in non-contrastive subphonemic features. Yet, the speech perception system seems able to discriminate subphonemic deviation in homophonous utterances, since it has been shown to elicit a mismatch response (MMN). Here, we focused on the oscillatory correlates, namely phase resetting and power, of non-contrastive subphonemic deviation processing in language. An oddball task that considered natural intraspeaker variability was used. Subphonemic deviance elicited intertrial phase coherence (ITC) differences in the theta band at Fz during the time window of the MMN. No differences in power were found. This suggests that the processing of subphonemic deviation in speech signals, reflected by the MMN, might rely on mechanisms of phase resetting. ITC might facilitate the synchronous firing of functional networks involved in the processing of subphonemic deviance.
... Electrophysiological measures, though, can assess how spectral and temporal features of speech are coded in the central auditory system and how neural responses to acoustic changes within and across speech sounds relate to behavioral perception (Easwar et al. 2012;Swink and Stuart 2012). Objective measurements of speech processing independent of cognitive or attentional skill are a potentially attractive tool for clinicians who monitor speech and language outcomes as the neural coding of speech segments has been shown to be predictive of sentence perception abilities in adult listeners with and without hearing impairment (Koerner et al. 2016;Koerner et al. 2017). It remains unclear whether syllable-final /s/-/ʃ/ fricatives produce different electrophysiological responses in listeners with and without hearing loss when stimuli are behaviorally discriminable. ...
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Background: Cortical auditory event-related potentials are a potentially useful clinical tool to objectively assess speech outcomes with rehabilitative devices. Whether hearing aids reliably encode the spectrotemporal characteristics of fricative stimuli in different phonological contexts and whether these differences result in distinct neural responses with and without hearing aid amplification remain unclear. Purpose: To determine whether the neural coding of the voiceless fricatives /s/ and /ʃ/ in the syllable-final context reliably differed without hearing aid amplification and whether hearing aid amplification altered neural coding of the fricative contrast. Research Design: A repeated-measures, within subject design was used to compare the neural coding of a fricative contrast with and without hearing aid amplification. Study Sample: Ten adult listeners with normal hearing participated in the study. Data Collection and Analysis: Cortical auditory event-related potentials were elicited to an /ɑs/–/ɑʃ/ vowel-fricative contrast in unaided and aided listening conditions. Neural responses to the speech contrast were recorded at 64-electrode sites. Peak latencies and amplitudes of the cortical response waveforms to the fricatives were analyzed using repeated-measures analysis of variance. Results: The P2' component of the acoustic change complex significantly differed from the syllable-final fricative contrast with and without hearing aid amplification. Hearing aid amplification differentially altered the neural coding of the contrast across frontal, temporal, and parietal electrode regions. Conclusions: Hearing aid amplification altered the neural coding of syllable-final fricatives. However, the contrast remained acoustically distinct in the aided and unaided conditions, and cortical responses to the fricative significantly differed with and without the hearing aid.
... Lang et al. (1990) was the first study that reported MMN response to small stimulus contrast could predict behavioral discrimination accuracy. Recently, Koerner et al. (2016) found that MMN latency but not MMN amplitude predicted phoneme detection accuracy. However, we did not find any correlation between behavioral discrimination accuracy and MMN responses or discrimination accuracy and LN responses. ...
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Language experience enhances discrimination of speech contrasts at a behavioral-perceptual level, as well as at a pre-attentive level, as indexed by event-related potential (ERP) mismatch negativity (MMN) responses. The enhanced sensitivity could be the result of changes in acoustic resolution and/or long-term memory representations of the relevant information in the auditory cortex. To examine these possibilities, we used a short (ca. 600 ms) vs. long (ca. 2,600 ms) interstimulus interval (ISI) in a passive, oddball discrimination task while obtaining ERPs. These ISI differences were used to test whether cross-linguistic differences in processing Mandarin lexical tone are a function of differences in acoustic resolution and/or differences in long-term memory representations. Bisyllabic nonword tokens that differed in lexical tone categories were presented using a passive listening multiple oddball paradigm. Behavioral discrimination and identification data were also collected. The ERP results revealed robust MMNs to both easy and difficult lexical tone differences for both groups at short ISIs. At long ISIs, there was either no change or an enhanced MMN amplitude for the Mandarin group, but reduced MMN amplitude for the English group. In addition, the Mandarin listeners showed a larger late negativity (LN) discriminative response than the English listeners for lexical tone contrasts in the long ISI condition. Mandarin speakers outperformed English speakers in the behavioral tasks, especially under the long ISI conditions with the more similar lexical tone pair. These results suggest that the acoustic correlates of lexical tone are fairly robust and easily discriminated at short ISIs, when the auditory sensory memory trace is strong. At longer ISIs beyond 2.5 s language-specific experience is necessary for robust discrimination.
... As deviants, four different syllables were created based on previous research on infants' MMRs at 2 months or younger. Specifically, the syllable /ga/ was used as the consonant deviant (see Cheng et al., 2015;Mahmoudzadeh et al., 2013) and the syllable /bu/ (see Cheng et al., 2015;Koerner et al., 2016) as the vowel deviant. For the frequency deviant /ba+ /, pitch was raised by + 16 Hz (see and for the vowel-length deviant /ba:/ the vowel /a/ was lengthened by 100 ms (see Friedrich et al., 2004). ...
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Infants rapidly advance in their speech perception, electrophysiologically reflected in the transition from an immature, positive-going to an adult-like, negative-going mismatch response (MMR) to auditory deviancy. Although the MMR is a common tool to study speech perception development, it is not yet completely understood how different speech contrasts affect the MMR's characteristics across development. Thus, a systematic longitudinal investigation of the MMR's maturation depending on speech contrast is necessary. We here longitudinally explored the maturation of the infant MMR to four critical speech contrasts: consonant, vowel, vowel-length, and pitch. MMRs were obtained when infants (n = 58) were 2, 6 and 10 months old. To evaluate the maturational trajectory of MMRs, we applied second-order latent growth curve models. Results showed positive-going MMR amplitudes to all speech contrasts across all assessment points that decreased over time towards an adult-like negativity. Notably, the developmental trajectories of speech contrasts differed, implying that infant speech perception matures with different rates and trajectories throughout the first year, depending on the studied auditory feature. Our results suggest that stimulus-dependent maturational trajectories need to be considered when drawing conclusions about infant speech perception development reflected by the infant MMR.
... A recent study showed poorer consonant discrimination (/ba/ versus /da/) with increased background noise. Electroencephalography (EEG) analysis also revealed increased mismatch negativity latencies, decreased amplitudes, and decreased power in theta frequency band with decreased signal-to-noise ratio (Koerner et al., 2016). The effects of background noise on the speech-evoked frequency following response in infants was investigated by White-Schwoch et al. (2015). ...
Article
Background: Previous research suggests that a proportion of children experiencing reading and listening difficulties may have an underlying primary deficit in the way that the central auditory nervous system analyses the perceptually important, rapidly varying, formant frequency components of speech. Purpose: The Phoneme Identification Test (PIT) was developed to investigate the ability of children to use spectro-temporal cues to perceptually categorize speech sounds based on their rapidly changing formant frequencies. The PIT uses an adaptive two-alternative forced-choice procedure whereby the participant identifies a synthesized consonant-vowel (CV) (/ba/ or /da/) syllable. CV syllables differed only in the second formant (F2) frequency along an 11-step continuum (between 0% and 100%-representing an ideal /ba/ and /da/, respectively). The CV syllables were presented in either quiet (PIT Q) or noise at a 0 dB signal-to-noise ratio (PIT N). Research design: Development of the PIT stimuli and test protocols, and collection of normative and test-retest reliability data. Study sample: Twelve adults (aged 23 yr 10 mo to 50 yr 9 mo, mean 32 yr 5 mo) and 137 typically developing, primary-school children (aged 6 yr 0 mo to 12 yr 4 mo, mean 9 yr 3 mo). There were 73 males and 76 females. Data collection and analysis: Data were collected using a touchscreen computer. Psychometric functions were automatically fit to individual data by the PIT software. Performance was determined by the width of the continuum for which responses were neither clearly /ba/ nor /da/ (referred to as the uncertainty region [UR]). A shallower psychometric function slope reflected greater uncertainty. Age effects were determined based on raw scores. Z scores were calculated to account for the effect of age on performance. Outliers, and individual data for which the confidence interval of the UR exceeded a maximum allowable value, were removed. Nonparametric tests were used as the data were skewed toward negative performance. Results: Across participants, the median value of the F2 range that resulted in uncertain responses was 33% in quiet and 40% in noise. There was a significant effect of age on the width of this UR (p < 0.00001) in both quiet and noise, with performance becoming adult like by age 9 on the PIT Q and age 10 on the PIT N. A skewed distribution toward negative performance occurred in both quiet (p = 0.01) and noise (p = 0.006). Median UR scores were significantly wider in noise than in quiet (T = 2041, p < 0.0000001). Performance (z scores) across the two tests was significantly correlated (r = 0.36, p = 0.000009). Test-retest z scores were significantly correlated in both quiet and noise (r = 0.4 and 0.37, respectively, p < 0.0001). Conclusions: The PIT normative data show that the ability to identify phonemes based on changes in formant transitions improves with age, and that some children in the general population have performance much worse than their age peers. In children, uncertainty increases when the stimuli are presented in noise. The test is suitable for use in planned studies in a clinical population.
... Power modulations in the theta band are often found in correspondence to the presentation of deviant events in both passive (Jin et al., 2014;Ko et al., 2012;Koerner et al., 2016) and active oddball tasks with speech and non-speech stimuli (Citherlet et al., 2020;Kolev et al., 1997;Spencer & Polich, 1999;Szal ardy et al., 2021). These modulations appear to be sensitive to pitch variations (Hsu et al., 2015;Li & Chen, 2018) and have been associated with processes of encoding (Klimesch, 1999), retrieval (Bastiaansen et al., 2005;Klimesch et al., 2001) and WM load (Fuentemilla et al., 2008;Jensen & Tesche, 2002;Kolev et al., 1997). ...
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The present study investigated whether listeners can form abstract voice representations while ignoring constantly changing phonological information and if they can use the resulting information to facilitate voice‐change detection. Further, the study aimed at understanding whether the use of abstraction is restricted to the speech domain, or can be deployed also in non‐speech contexts. We ran an EEG experiment including one passive and one active oddball task, each featuring a speech and a rotated‐speech condition. In the speech condition, participants heard constantly changing vowels uttered by a male speaker (standard stimuli) which were infrequently replaced by vowels uttered by a female speaker with higher pitch (deviant stimuli). In the rotated‐speech condition, participants heard rotated vowels, in which the natural formant structure of speech was disrupted. In the passive task, the Mismatch Negativity was elicited after the presentation of the deviant voice in both conditions, indicating that listeners could successfully group together different stimuli into a formant‐invariant voice representation. In the active task, participants showed shorter RTs, higher accuracy and a larger P3b in the speech condition with respect to the rotated‐speech condition. Results showed that whereas at a pre‐attentive level the cognitive system can track pitch regularities while presumably ignoring constantly changing formant information both in speech and in rotated‐speech, at an attentive level the use of such information is facilitated for speech. This facilitation was also testified by a stronger synchronization in the theta band (4‐7 Hz), potentially pointing towards differences in encoding/retrieval processes.
... Spectral power in the theta band was also computed for both the pre-stimulus baseline and the response portion of the epochs using the spectopo function in EEGLAB based on Welch's power spectral density estimate (oversampling ×8). Similar time-frequency analysis procedures were used in published studies(Koerner et al. , 2015, Koerner et al. , 2016. The number of trials for analysis in the autism group were 332 (range 165-466) for the pure tone condition and 300 (172-383) for the word condition. ...
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Objective: This autism study investigated how inter-trial phase coherence (ITPC) drives abnormalities in auditory evoked potential (AEP) responses for speech and nonspeech stimuli. Methods: Auditory P1-N2 responses and ITPCs in the theta band (4~7 Hz) for pure tones and words were assessed with EEG data from 15 school-age children with autism and 16 age-matched typically developing (TD) controls. Results: The autism group showed enhanced P1 and reduced N2 for both speech and nonspeech stimuli in comparison with the TD group. Group differences were also found with enhanced theta ITPC for P1 followed by ITPC reduction for N2 in the autism group. The ITPC values were significant predictors of P1 and N2 amplitudes in both groups. Conclusions: Abnormal trial-to-trial phase synchrony plays an important role in AEP atypicalities in children with autism. ITPC-driven enhancement as well as attenuation in different AEP components may coexist, depending on the stage of information processing. Significance: It is necessary to examine the time course of auditory evoked potentials and the corresponding inter-trial coherence of neural oscillatory activities to better understand hyper- and hypo- sensitive responses in autism, which has important implications for sensory-based treatment. Web link: https://www.sciencedirect.com/science/article/pii/S1388245718309003
... In contrast to behavioral evidence, ERP evidence may provide a finer examination of sensitivity to consonant and vowel mispronunciations. Previous studies with adults have found sensitivity to both consonant and vowel mispronunciations in auditory processing-both with and without noise [30,31]-as well as in visual word recognition, but at different timing and scalp distributions [32][33][34]. ERP studies with infants have not directly compared consonant and vowel processing, but a series of auditory word recognition studies have examined consonant or vowel processing in older infants. ...
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Segmentation skill and the preferential processing of consonants (C-bias) develop during the second half of the first year of life and it has been proposed that these facilitate language acquisition. We used Event-related brain potentials (ERPs) to investigate the neural bases of early word form segmentation, and of the early processing of onset consonants, medial vowels, and coda consonants, exploring how differences in these early skills might be related to later language outcomes. Our results with French-learning eight-month-old infants primarily support previous studies that found that the word familiarity effect in segmentation is developing from a positive to a negative polarity at this age. Although as a group infants exhibited an anterior-localized negative effect, inspection of individual results revealed that a majority of infants showed a negative-going response (Negative Responders), while a minority showed a positive-going response (Positive Responders). Furthermore, all infants demonstrated sensitivity to onset consonant mispronunciations, while Negative Responders demonstrated a lack of sensitivity to vowel mispronunciations, a developmental pattern similar to previous literature. Responses to coda consonant mispronunciations revealed neither sensitivity nor lack of sensitivity. We found that infants showing a more mature, negative response to newly segmented words compared to control words (evaluating segmentation skill) and mispronunciations (evaluating phonological processing) at test also had greater growth in word production over the second year of life than infants showing a more positive response. These results establish a relationship between early segmentation skills and phonological processing (not modulated by the type of mispronunciation) and later lexical skills.
... Similarly, Kozou et al. (2005) compared MMNs elicited in silence and in several types of weak background noise at +10 dB SNR, and found no significant effect of any type of noise on behavioral performance and no significant effect of broadband noise on MMN indices. In contrast, MMNs and P300s elicited in loud background noise (e.g., À3 dB SNR in Koerner et al., 2016Koerner et al., , 2017Bennett et al., 2012) are significantly deteriorated by the noise. All these observations are actually consistent with each other. ...
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Since sound perception takes place against a background with a certain amount of noise, both speech and non-speech processing involve extraction of target signals and suppression of background noise. Previous works on early processing of speech phonemes largely neglected how background noise is encoded and suppressed. This study aimed to fill in this gap. We adopted an oddball paradigm where speech (vowels) or non-speech stimuli (complex tones) were presented with or without a background of amplitude-modulated noise and analyzed cortical responses related to foreground stimulus processing, including mismatch negativity (MMN), N2b, and P300, as well as neural representations of the background noise, i.e. auditory steady-state response (ASSR). We found that speech deviants elicited later and weaker MMN, later N2b, and later P300 than non-speech ones, but N2b and P300 had similar strength, suggesting more complex processing of certain acoustic features in speech. Only for vowels, background noise enhanced N2b strength relative to silence, suggesting an attention-related speech-specific process to improve perception of foreground targets. In addition, noise suppression in speech contexts, quantified by ASSR amplitude reduction after stimulus onset, was lateralized towards the left hemisphere. The left-lateralized suppression following N2b was associated with the N2b enhancement in noise for speech, indicating that foreground processing may interact with background suppression, particularly during speech processing. Together, our findings indicate that the differences between perception of speech and non-speech sounds involve not only the processing of target information in the foreground but also the suppression of irrelevant aspects in the background.
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Importance Language development builds on speech perception, with early disruptions increasing the risk for later language difficulties. Although a major postpartum depressive episode is associated with language development, this association has not been investigated among infants of mothers experiencing a depressed mood at subclinical levels after birth, even though such a mood is frequently present in the first weeks after birth. Understanding whether subclinical depressed maternal mood after birth is associated with early language development is important given opportunities of coping strategies for subclinical depressed mood. Objective To examine whether depressed maternal mood at subclinical levels 2 months after birth is associated with infant speech perception trajectories from ages 2 to 6.5 months. Design, Setting, and Participants In this longitudinal cohort study conducted between January 1, 2018, and October 31, 2019, 46 healthy, monolingual German mother-infant dyads were tested. The sample was recruited from the infants database of the Max Planck Institute for Human Cognitive and Brain Sciences. Initial statistical analysis was performed between January 1 and March 31, 2021; the moderation analysis (results reported herein) was conducted between July 1 and July 31, 2022. Exposures Mothers reported postpartum mood via the German version of the Edinburgh Postnatal Depression Scale (higher scores indicated higher levels of depressed mood, with a cutoff of 13 points indicating a high probability of clinical depression) when their infants were 2 months old. Main Outcomes and Measures Electrophysiological correlates of infant speech perception (mismatch response to speech stimuli) were tested when the infants were aged 2 months (initial assessment) and 6.5 months (follow-up). Results A total of 46 mothers (mean [SD] age, 32.1 [3.8] years) and their 2-month-old children (mean [SD] age, 9.6 [1.2] weeks; 23 girls and 23 boys) participated at the initial assessment, and 36 mothers (mean [SD] age, 32.2 [4.1] years) and their then 6.5-month-old children (mean [SD] age, 28.4 [1.5 weeks; 18 girls and 18 boys) participated at follow-up. Moderation analyses revealed that more depressed maternal subclinical postpartum mood (mean [SD] Edinburgh Postnatal Depression Scale score, 4.8 [3.6]) was associated with weaker longitudinal changes of infants’ electrophysiological brain responses to syllable pitch speech information from ages 2 to 6.5 months (coefficient: 0.68; 95% CI, 0.03-1.33; P = .04). Conclusions and Relevance The results of this cohort study suggest that infant speech perception trajectories are correlated with subclinical depressed mood in postpartum mothers. This finding lays the groundwork for future research on early support for caregivers experiencing depressed mood to have a positive association with children’s language development.
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Auditory neuroscience has provided strong evidence that neural oscillations synchronize to the rhythm of speech stimuli, and oscillations at different frequencies have been linked to processing of different language structures. The present study aims to examine how these ubiquitous neurophysiological attributes may inform us about the brain processes that underpin individual differences in speech perception and production, which in turn elucidate the specific functions of neural oscillations in the domain of speech processing. To this end, we recorded electrophysiological responses to a lexical tone contrast in a passive auditory oddball paradigm from two groups of healthy tone-language speakers who were equal in perceptual discriminability but differed in response latency and production distinctiveness of the tone contrast. Time-frequency analysis was applied to the EEG data, and decomposed into theta (4–7 Hz), beta (12–30 Hz), and gamma (30–50 Hz) frequency bands. Results show that listeners with longer discrimination RT and less distinctive production showed significantly higher induced (non-phase-locked) gamma during tone processing. Moreover, among speakers with less distinctive production, individual differences in induced gamma were significantly correlated with discrimination latency and production distinction. Based on the present findings, we propose that differences in gamma oscillations reflect differential sensory/perceptual computations during acoustic encoding, impacting the quality of perceptual representations, which further mediates individual differences in speech perception and production.
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Purpose A growing body of evidence suggests that military service members and military veterans are at risk for deficits in central auditory processing. Risk factors include exposure to blast, neurotrauma, hazardous noise, and ototoxicants. We overview these risk factors and comorbidities, address implications for clinical assessment and care of central auditory processing deficits in service members and veterans, and specify knowledge gaps that warrant research. Method We reviewed the literature to identify studies of risk factors, assessment, and care of central auditory processing deficits in service members and veterans. We also assessed the current state of the science for knowledge gaps that warrant additional study. This literature review describes key findings relating to military risk factors and clinical considerations for the assessment and care of those exposed. Conclusions Central auditory processing deficits are associated with exposure to known military risk factors. Research is needed to characterize mechanisms, sources of variance, and differential diagnosis in this population. Existing best practices do not explicitly consider confounds faced by military personnel. Assessment and rehabilitation strategies that account for these challenges are needed. Finally, investment is critical to ensure that Veterans Affairs and Department of Defense clinical staff are informed, trained, and equipped to implement effective patient care.
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In this article, we present a summary of recent research linking speech perception in infancy to later language development, as well as a new empirical study examin-ing that linkage. Infant phonetic discrimination is initially language universal, but a decline in phonetic discrimination occurs for nonnative phonemes by the end of the 1st year. Exploiting this transition in phonetic perception between 6 and 12 months of age, we tested the hypothesis that the decline in nonnative phonetic dis-crimination is associated with native-language phonetic learning. Using a standard behavioral measure of speech discrimination in infants at 7 months and measures of their language abilities at 14, 18, 24, and 30 months, we show (a) a negative cor-relation between infants' early native and nonnative phonetic discrimination skills and (b) that native-and nonnative-phonetic discrimination skills at 7 months differ-entially predict future language ability. Better native-language discrimination at 7 months predicts accelerated later language abilities, whereas better nonnative-lan-guage discrimination at 7 months predicts reduced later language abilities. The dis-cussion focuses on (a) the theoretical connection between speech perception and language development and (b) the implications of these findings for the putative "critical period" for phonetic learning. Work in my laboratory has recently been focused on two fundamental questions and their theoretical intersect. The first is the role that infant speech perception plays in the acquisition of language. The second is whether early speech percep-tion can reveal the mechanism underlying the putative "critical period" in language acquisition.
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Mismatch negativity (MMN) is measured by subtracting the averaged response to a set of standard stimuli from the averaged response to rarer deviant stimuli, and taking the amplitude of this difference wave in a given time window. This method is problematic when used to evaluate individuals, because there is no estimate of variance. We describe a new approach, in which independent components with high trial-by-trial variance are first removed. Next, each deviant response has the preceding standard response subtracted, giving a set of single trial difference waves. We illustrate this approach in analysis of MMN to brief tones in 17 adults. The best criterion for MMN combined t-test with an index of inter-trial coherence, giving significant MMN in 14 (82%) of individuals. Single-trial methods can indicate which people show MMN. However, in some clinically normal individuals there was no MMN, despite good behavioral discrimination of stimuli.
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In an increasingly globalized world mastering a second language (L2) provides a clear advantage. However, after early childhood, not everyone can easily learn a foreign language. The present study explored whether the large variability found in L2 attainment in the normal population, not diagnosed as learning disabled, is related to preattentive speech perception abilities. Using event-related potentials (ERPs) we examined the mismatch negativity, P3a, and the late discriminative negativity (MMN-P3a-LDN) complex, which served as an index for preattentive foreign phonological contrast discrimination abilities. Our results show that, compared to unsuccessful L2 learners, successful L2 learners had shorter latencies of the MMN and P3a components and higher amplitudes of the LDN component. These results suggest that unsuccessful L2 learners have a deficient speech perception mechanism.
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The present study examines the brain basis of listening to spoken words in noise, which is a ubiquitous characteristic of communication, with the focus on the dorsal auditory pathway. English-speaking young adults identified single words in 3 listening conditions while their hemodynamic response was measured using fMRI: speech in quiet, speech in moderately loud noise (signal-to-noise ratio [SNR] 20 dB), and in loud noise (SNR -5 dB). Behaviorally, participants' performance (both accuracy and reaction time) did not differ between the quiet and SNR 20 dB condition, whereas they were less accurate and responded slower in the SNR -5 dB condition compared with the other 2 conditions. In the superior temporal gyrus (STG), both left and right auditory cortex showed increased activation in the noise conditions relative to quiet, including the middle portion of STG (mSTG). Although the right posterior STG (pSTG) showed similar activation for the 2 noise conditions, the left pSTG showed increased activation in the SNR -5 dB condition relative to the SNR 20 dB condition. We found cortical task-independent and noise-dependent effects concerning speech perception in noise involving bilateral mSTG and left pSTG. These results likely reflect demands in acoustic analysis, auditory-motor integration, and phonological memory, as well as auditory attention.
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Speech scientists have long proposed that formant exaggeration in infant-directed speech plays an important role in language acquisition. This event-related potential (ERP) study investigated neural coding of formant-exaggerated speech in 6-12-month-old infants. Two synthetic /i/ vowels were presented in alternating blocks to test the effects of formant exaggeration. ERP waveform analysis showed significantly enhanced N250 for formant exaggeration, which was more prominent in the right hemisphere than the left. Time-frequency analysis indicated increased neural synchronization for processing formant-exaggerated speech in the delta band at frontal-central-parietal electrode sites as well as in the theta band at frontal-central sites. Minimum norm estimates further revealed a bilateral temporal-parietal-frontal neural network in the infant brain sensitive to formant exaggeration. Collectively, these results provide the first evidence that formant expansion in infant-directed speech enhances neural activities for phonetic encoding and language learning.
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This study investigated the relative contributions of consonants and vowels to the perceptual intelligibility of monosyllabic consonant-vowel-consonant (CVC) words. A noise replacement paradigm presented CVCs with only consonants or only vowels preserved. Results demonstrated no difference between overall word accuracy in these conditions; however, different error patterns were observed. A significant effect of lexical difficulty was demonstrated for both types of replacement, whereas the noise level used during replacement did not influence results. The contribution of consonant and vowel transitional information present at the consonant-vowel boundary was also explored. The proportion of speech presented, regardless of the segmental condition, overwhelmingly predicted performance. Comparisons were made with previous segment replacement results using sentences [Fogerty, and Kewley-Port (2009). J. Acoust. Soc. Am. 126, 847-857]. Results demonstrated that consonants contribute to intelligibility equally in both isolated CVC words and sentences. However, vowel contributions were mediated by context, with greater contributions to intelligibility in sentence contexts. Therefore, it appears that vowels in sentences carry unique speech cues that greatly facilitate intelligibility which are not informative and/or present during isolated word contexts. Consonants appear to provide speech cues that are equally available and informative during sentence and isolated word presentations.
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Objectives: Speech perception in background noise is difficult for many individuals, and there is considerable performance variability across listeners. The combination of physiological and behavioral measures may help to understand sources of this variability for individuals and groups and prove useful clinically with hard-to-test populations. The purpose of this study was threefold: (1) determine the effect of signal-to-noise ratio (SNR) and signal level on cortical auditory evoked potentials (CAEPs) and sentence-level perception in older normal-hearing (ONH) and older hearing-impaired (OHI) individuals, (2) determine the effects of hearing impairment and age on CAEPs and perception, and (3) explore how well CAEPs correlate with and predict speech perception in noise. Design: Two groups of older participants (15 ONH and 15 OHI) were tested using speech-in-noise stimuli to measure CAEPs and sentence-level perception of speech. The syllable /ba/, used to evoke CAEPs, and sentences were presented in speech-spectrum background noise at four signal levels (50, 60, 70, and 80 dB SPL) and up to seven SNRs (-10, -5, 0, 5, 15, 25, and 35 dB). These data were compared between groups to reveal the hearing impairment effect and then combined with previously published data for 15 young normal-hearing individuals to determine the aging effect. Results: Robust effects of SNR were found for perception and CAEPs. Small but significant effects of signal level were found for perception, primarily at poor SNRs and high signal levels, and in some limited instances for CAEPs. Significant effects of age were seen for both CAEPs and perception, while hearing impairment effects were only found with perception measures. CAEPs correlate well with perception and can predict SNR50s to within 2 dB for ONH. However, prediction error is much larger for OHI and varies widely (from 6 to 12 dB) depending on the model that was used for prediction. Conclusions: When background noise is present, SNR dominates both perception-in-noise testing and cortical electrophysiological testing, with smaller and sometimes significant contributions from signal level. A mismatch between behavioral and electrophysiological results was found (hearing impairment effects were primarily only seen for behavioral data), illustrating the possible contributions of higher order cognitive processes on behavior. It is interesting that the hearing impairment effect size was more than five times larger than the aging effect size for CAEPs and perception. Sentence-level perception can be predicted well in normal-hearing individuals; however, additional research is needed to explore improved prediction methods for older individuals with hearing impairment.
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Noise, as an unwanted sound, has become one of modern society's environmental conundrums, and many children are exposed to higher noise levels than previously assumed. However, the effects of background noise on central auditory processing of toddlers, who are still acquiring language skills, have so far not been determined. The authors evaluated the effects of background noise on toddlers' speech-sound processing by recording event-related brain potentials. The hypothesis was that background noise modulates neural speech-sound encoding and degrades speech-sound discrimination. Obligatory P1 and N2 responses for standard syllables and the mismatch negativity (MMN) response for five different syllable deviants presented in a linguistic multifeature paradigm were recorded in silent and background noise conditions. The participants were 18 typically developing 22- to 26-month-old monolingual children with healthy ears. The results showed that the P1 amplitude was smaller and the N2 amplitude larger in the noisy conditions compared with the silent conditions. In the noisy condition, the MMN was absent for the intensity and vowel changes and diminished for the consonant, frequency, and vowel duration changes embedded in speech syllables. Furthermore, the frontal MMN component was attenuated in the noisy condition. However, noise had no effect on P1, N2, or MMN latencies. The results from this study suggest multiple effects of background noise on the central auditory processing of toddlers. It modulates the early stages of sound encoding and dampens neural discrimination vital for accurate speech perception. These results imply that speech processing of toddlers, who may spend long periods of daytime in noisy conditions, is vulnerable to background noise. In noisy conditions, toddlers' neural representations of some speech sounds might be weakened. Thus, special attention should be paid to acoustic conditions and background noise levels in children's daily environments, like day-care centers, to ensure a propitious setting for linguistic development. In addition, the evaluation and improvement of daily listening conditions should be an ordinary part of clinical intervention of children with linguistic problems.
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HERE we report that training-associated changes in neural activity can precede behavioral learning. This finding suggests that speech-sound learning occurs at a pre-attentive level which can be measured neurophysiologically (in the absence of a behavioral response) to assess the efficacy of training. Children with biologically based perceptual learning deficits as well as people who wear cochlear implants or hearing aids undergo various forms of auditory training. The effectiveness of auditory training can be difficult to assess using behavioral methods because these populations are communicatively impaired and may have attention and/or cognitive deficits. Based on our findings, if neurophysiological changes are seen during auditory training, then the training method is effectively altering the neural representation of the speech/sounds and changes in behavior are likely to follow.
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This study investigated the effects of decreased audibility produced by high-pass noise masking on cortical event-related potentials (ERPs) N1, N2, and P3 to the speechsounds /ba/ and /da/ presented at 65 and 80 dB SPL. Normal-hearing subjects pressed a button in response to the deviant sound in an oddball paradigm. Broadband masking noise was presented at an intensity sufficient to completely mask the response to the 65-dB SPLspeechsounds, and subsequently high-pass filtered at 4000, 2000, 1000, 500, and 250 Hz. With high-pass masking noise, pure-tone behavioral thresholds increased by an average of 38 dB at the high-pass cutoff and by 50 dB one octave above the cutoff frequency. Results show that as the cutoff frequency of the high-pass masker was lowered, ERP latencies to speechsounds increased and amplitudes decreased. The cutoff frequency where these changes first occurred and the rate of the change differed for N1 compared to N2, P3, and the behavioral measures. N1 showed gradual changes as the masker cutoff frequency was lowered. N2, P3, and behavioral measures showed marked changes below a masker cutoff of 2000 Hz. These results indicate that the decreased audibility resulting from the noise masking affects the various ERP components in a differential manner. N1 is related to the presence of audible stimulus energy, being present whether audible stimuli are discriminable or not. In contrast, N2 and P3 were absent when the stimuli were audible but not discriminable (i.e., when the second formant transitions were masked), reflecting stimulus discrimination. These data have implications regarding the effects of decreased audibility on cortical processing of speechsounds and for the study of cortical ERPs in populations with hearing impairment.
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Speech recognition in noise can be challenging for older adults and elicits elevated activity throughout a cingulo-opercular network that is hypothesized to monitor and modify behaviors to optimize performance. A word recognition in noise experiment was used to test the hypothesis that cingulo-opercular engagement provides performance benefit for older adults. Healthy older adults (N = 31; 50-81 years of age; mean pure tone thresholds <32 dB HL from 0.25 to 8 kHz, best ear; species: human) performed word recognition in multitalker babble at 2 signal-to-noise ratios (SNR = +3 or +10 dB) during a sparse sampling fMRI experiment. Elevated cingulo-opercular activity was associated with an increased likelihood of correct recognition on the following trial independently of SNR and performance on the preceding trial. The cingulo-opercular effect increased for participants with the best overall performance. These effects were lower for older adults compared with a younger, normal-hearing adult sample (N = 18). Visual cortex activity also predicted trial-level recognition for the older adults, which resulted from discrete decreases in activity before errors and occurred for the oldest adults with the poorest recognition. Participants demonstrating larger visual cortex effects also had reduced fractional anisotropy in an anterior portion of the left inferior frontal-occipital fasciculus, which projects between frontal and occipital regions where activity predicted word recognition. Together, the results indicate that older adults experience performance benefit from elevated cingulo-opercular activity, but not to the same extent as younger adults, and that declines in attentional control can limit word recognition. Copyright © 2015 the authors 0270-6474/15/353929-09$15.00/0.
Article
We compared processing of speech and non-speech by means of the Mismatch Negativity (MMN). For this purpose, the MMN elicited by vowels was compared to those elicited by two non-speech stimulus types: spectrally rotated vowels, having the same stimulus complexity as the speech stimuli, and sounds based on the bands of formants of the vowels, representing non-speech stimuli of lower complexity as compared to the other stimulus types. This design allows controlling for effects of stimulus complexity when comparing neural correlates of processing speech to non-speech. Deviants within a modified multi-feature design differed either in duration or spectral property. Moreover, the difficulty to discriminate between the standard and the two deviants was controlled for each stimulus type by means of an additional active discrimination task. Vowels elicited a larger MMN compared to both non-speech stimulus types, supporting the concept of language-specific phoneme representations and the role of the participants’ prior experience.
Article
Speech perception in background noise is a common challenge across individuals and health conditions (e.g., hearing impairment, aging, etc.). Both behavioral and physiological measures have been used to understand the important factors that contribute to perception-in-noise abilities. The addition of a physiological measure provides additional information about signal-in-noise encoding in the auditory system and may be useful in clarifying some of the variability in perception-in-noise abilities across individuals. Fifteen young normal-hearing individuals were tested using both electrophysiology and behavioral methods as a means to determine (1) the effects of signal-to-noise ratio (SNR) and signal level and (2) how well cortical auditory evoked potentials (CAEPs) can predict perception in noise. Three correlation/regression approaches were used to determine how well CAEPs predicted behavior. Main effects of SNR were found for both electrophysiology and speech perception measures, while signal level effects were found generally only for speech testing. These results demonstrate that when signals are presented in noise, sensitivity to SNR cues obscures any encoding of signal level cues. Electrophysiology and behavioral measures were strongly correlated. The best physiological predictors (e.g., latency, amplitude, and area of CAEP waves) of behavior (SNR at which 50 % of the sentence is understood) were N1 latency and N1 amplitude measures. In addition, behavior was best predicted by the 70-dB signal/5-dB SNR CAEP condition. It will be important in future studies to determine the relationship of electrophysiology and behavior in populations who experience difficulty understanding speech in noise such as those with hearing impairment or age-related deficits.
Article
Limited success has been noted in prior attempts to predict language and cognitive performance during the toddler and preschool years from measures obtained at birth. Most perinatal measures, although demonstrating some success in predicting motor and early cognitive skills at 1 year of age, have generally failed to maintain their predictive effectiveness when used to predict abilities that emerge later in development. However, 1 electrophysiological technique that involves the recording of event‐related potentials (ERPs) to speech sounds may provide a means to improve such predictions. This article describes a successful extension of an earlier attempt to predict language performance during the preschool years from neonatal scalp recorded ERPs. Auditory ERPs were recorded from the frontal, temporal, and parietal scalp regions of 71 newborn infants in response to a series of 9 consonant‐vowel syllables. Following artifact rejection and averaging, these ERPs were input to a principal components analysis that isolated 7 factors to account for 89.02% of the total variance in the data set. Selected factor scores from 2 factors matching the latency configuration of those identified earlier by D. L. Molfese and V. J. Molfese (1985) were then used in a series of discriminant function analyses to separate these infants into 2 groups based on performance on the verbal subtest of the Stanford‐Binet at 5 years of age. Three different discriminant function analyses involving different variables showed high classification accuracy in predicting later developmental outcomes.
Article
Mismatch negativity (MMN) is a negative component of event-related potential (ERP) that reflects auditory deviant detection. Previous studies repeatedly suggested that MMN is generated by the fronto-temporal network. However, it is still unclear how the frontal and temporal areas interact. To verify this, we observed the spatiotemporal pattern of inter-regional functional connectivity using phase synchrony and Granger causality, by analyzing event-related electroencephalograms (EEGs) elicited by standard and deviant tones in an oddball paradigm. Strong theta-band phase synchrony and bidirectional Granger causality were observed between the frontal and temporal areas during the processing of auditory deviants, especially at the temporal interval of MMN. Our results support the hypothesis that fronto-temporal interactions are crucial to the generation of MMN during auditory deviant processing.
Article
The perception of vowels heard in noises of various spectra is analyzed by means of stimulus‐response matrices. The stimulus vowels were spoken in PB‐word lists and in syllable lists in which the vowels were equally probable. The matrices show shifts in vowel confusions depending on how different noise spectra mask the vowelformants.Vowel duration and intensity are measured and related to vowel perception. Vowel guessing is related to past training.
Article
The aim of this study was to develop a paradigm for obtaining a multi-feature profile for central auditory processing of different magnitudes of prosodic and phonetic changes in speech sounds. We recorded the MMNs to three vowel identity changes, three magnitudes of changes in intensity, and vowel duration as well as to two magnitudes of pitch changes from semi-synthetic vowels in 34 minutes. Furthermore, we examined how the type and magnitude of deviation affects the size and timing of the MMN. All sound changes elicited statistically significant MMN responses, with the MMN amplitudes increasing with increasing sound deviance. Importantly, the MMN amplitudes for the vowel changes reflected the differences between the phonemes, as did the MMNs to vowel-duration changes reflect the categorization of these sounds to short and long vowel categories, meaningful in the Finnish language. This new multi-feature MMN paradigm is suitable for investigating central auditory processing of different magnitudes of speech-sound changes and can be used, for instance, in investigation of pre-attentive phoneme categorization. The paradigm is especially useful for studying speech and language disorders in general, language development, and evolution of phoneme categories early in life, as well as brain plasticity during native or second language learning.
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Research has shown that the amplitude and latency of neural responses to passive mismatch negativity (MMN) tasks are affected by noise (Billings et al., 2010). Further studies have revealed that informational masking noise results in decreased P3 amplitude and increased P3 latency, which correlates with decreased discrimination abilities and reaction time (Bennett et al., 2012). This study aims to further investigate neural processing of speech in differing types of noise by attempting to correlate MMN neural responses to consonant and vowel stimuli with results from behavioral sentence recognition tasks. Preliminary behavioral data indicate that noise conditions significantly compromise the perception of consonant change in an oddball discrimination task. Noise appears to have less of an effect on the perception of vowel change. The MMN data are being collected for the detection of consonant change and vowel change in different noise conditions. The results will be examined to address how well the pre-attentive MMN measures at the phonemic level can predict speech intelligibility at the sentence level using the same noise conditions.
Article
a b s t r a c t Research on the development of speech processing in bilingual children has typically implemented a cross-sectional design and relied on behavioral measures. The present study is the first to explore brain measures within a longitudinal study of this population. We report results from the first phase of data analysis in a longitudinal study exploring Spanish-English bilingual children and the relationships among (a) early brain measures of phonetic discrimination in both languages, (b) degree of exposure to each language in the home, and (c) children's later bilingual word production abilities. Speech discrimination was assessed with event-related brain potentials (ERPs). A bilingual questionnaire was used to quantify the amount of language exposure from all adult speakers in the household, and subsequent word production was evaluated in both languages. Our results suggest that bilingual infants' brain responses to speech differ from the pattern shown by monolingual infants. Bilingual infants did not show neural discrimination of either the Spanish or English contrast at 6–9 months. By 10–12 months of age, neural discrimination was observed for both contrasts. Bilingual infants showed continuous improvement in neural discrimination of the phonetic units from both languages with increasing age. Group differences in bilingual infants' speech discrimination abilities are related to the amount of exposure to each of their native languages in the home. Finally, we show that infants' later word production measures are significantly related to both their early neural discrimination skills and the amount exposure to the two languages early in development.
Article
Sixteen English consonants were spoken over voice communication systems with frequency distortion and with random masking noise. The listeners were forced to guess at every sound and a count was made of all the different errors that resulted when one sound was confused with another. With noise or low‐pass filtering the confusions fall into consistent patterns, but with high‐pass filtering the errors are scattered quite randomly. An articulatory analysis of these 16 consonants provides a system of five articulatory features or “dimensions” that serve to characterize and distinguish the different phonemes: voicing, nasality, affrication, duration, and place of articulation. The data indicate that voicing and nasality are little affected and that place is severely affected by low‐pass and noisy systems. The indications are that the perception of any one of these five features is relatively independent of the perception of the others, so that it is as if five separate, simple channels were involved rather than a single complex channel.
Article
The neural mechanisms that support speech discrimination in noisy conditions are poorly understood. In quiet conditions, spike timing information appears to be used in the discrimination of speech sounds. In this study, we evaluated the hypothesis that spike timing is also used to distinguish between speech sounds in noisy conditions that significantly degrade neural responses to speech sounds. We tested speech sound discrimination in rats and recorded primary auditory cortex (A1) responses to speech sounds in background noise of different intensities and spectral compositions. Our behavioral results indicate that rats, like humans, are able to accurately discriminate consonant sounds even in the presence of background noise that is as loud as the speech signal. Our neural recordings confirm that speech sounds evoke degraded but detectable responses in noise. Finally, we developed a novel neural classifier that mimics behavioral discrimination. The classifier discriminates between speech sounds by comparing the A1 spatiotemporal activity patterns evoked on single trials with the average spatiotemporal patterns evoked by known sounds. Unlike classifiers in most previous studies, this classifier is not provided with the stimulus onset time. Neural activity analyzed with the use of relative spike timing was well correlated with behavioral speech discrimination in quiet and in noise. Spike timing information integrated over longer intervals was required to accurately predict rat behavioral speech discrimination in noisy conditions. The similarity of neural and behavioral discrimination of speech in noise suggests that humans and rats may employ similar brain mechanisms to solve this problem.
Article
We investigated a neural basis of speech-in-noise perception in older adults. Hearing loss, the third most common chronic condition in older adults, is most often manifested by difficulty understanding speech in background noise. This trouble with understanding speech in noise, which occurs even in individuals who have normal-hearing thresholds, may arise, in part, from age-related declines in central auditory processing of the temporal and spectral components of speech. We hypothesized that older adults with poorer speech-in-noise (SIN) perception demonstrate impairments in the subcortical representation of speech. In all participants (28 adults, age 60-73 yr), average hearing thresholds calculated from 500 to 4000 Hz were ≤ 25 dB HL. The participants were evaluated behaviorally with the Hearing in Noise Test (HINT) and neurophysiologically using speech-evoked auditory brainstem responses recorded in quiet and in background noise. The participants were divided based on their HINT scores into top and bottom performing groups that were matched for audiometric thresholds and intelligent quotient. We compared brainstem responses in the two groups, specifically, the average spectral magnitudes of the neural response and the degree to which background noise affected response morphology. In the quiet condition, the bottom SIN group had reduced neural representation of the fundamental frequency of the speech stimulus and an overall reduction in response magnitude. In the noise condition, the bottom SIN group demonstrated greater disruption in noise, reflecting reduction in neural synchrony. The role of brainstem timing is particularly evident in the strong relationship between SIN perception and quiet-to-noise response correlations. All physiologic measures correlated with SIN perception. Adults in the bottom SIN group differed from the audiometrically matched top SIN group in how speech was neurally encoded. The strength of subcortical encoding of the fundamental frequency appears to be a factor in successful speech-in-noise perception in older adults. Given the limitations of amplification, our results suggest the need for inclusion of auditory training to strengthen central auditory processing in older adults with SIN perception difficulties.
Article
To advance our understanding of the biological basis of speech-in-noise perception, we investigated the effects of background noise on both subcortical- and cortical-evoked responses, and the relationships between them, in normal hearing young adults. The addition of background noise modulated subcortical and cortical response morphology. In noise, subcortical responses were later, smaller in amplitude and demonstrated decreased neural precision in encoding the speech sound. Cortical responses were also delayed by noise, yet the amplitudes of the major peaks (N1, P2) were affected differently, with N1 increasing and P2 decreasing. Relationships between neural measures and speech-in-noise ability were identified, with earlier subcortical responses, higher subcortical response fidelity and greater cortical N1 response magnitude all relating to better speech-in-noise perception. Furthermore, it was only with the addition of background noise that relationships between subcortical and cortical encoding of speech and the behavioral measures of speech in noise emerged. Results illustrate that human brainstem responses and N1 cortical response amplitude reflect coordinated processes with regards to the perception of speech in noise, thereby acting as a functional index of speech-in-noise perception.
Article
Children are known to be particularly vulnerable to the effects of noise on speech perception, and it is commonly acknowledged that failure of central auditory processes can lead to these difficulties with speech-in-noise (SIN) perception. However, little is known about the mechanistic relationship between central processes and the perception of SIN. Our aims were twofold: to examine the effects of noise on the central encoding of speech through measurement of cortical event-related potentials and to examine the relationship between cortical processing and behavioral indices of SIN perception. We recorded cortical responses to the speech syllable [da] in quiet and multi-talker babble noise in 32 children with a broad range of SIN perception. Outcomes suggest inordinate effects of noise on auditory function in the bottom SIN perceivers compared with the top perceivers. The cortical amplitudes in the top SIN group remained stable between conditions, whereas amplitudes increased significantly in the bottom SIN group, suggesting a developmental central processing impairment in the bottom perceivers that may contribute to difficulties in encoding and perceiving speech in challenging listening environments.
Article
Children often have difficulty understanding speech in challenging listening environments. In the absence of peripheral hearing loss, these speech perception difficulties may arise from dysfunction at more central levels in the auditory system, including subcortical structures. We examined brainstem encoding of pitch in a speech syllable in 38 school-age children. In children with poor speech-in-noise perception, we find impaired encoding of the fundamental frequency and the second harmonic, two important cues for pitch perception. Pitch, an essential factor in speaker identification, aids the listener in tracking a specific voice from a background of voices. These results suggest that the robustness of subcortical neural encoding of pitch features in time-varying signals is a key factor in determining success with perceiving speech in noise.
Article
The presence of irrelevant auditory information (other talkers, environmental noises) presents a major challenge to listening to speech. The fundamental frequency (F(0)) of the target speaker is thought to provide an important cue for the extraction of the speaker's voice from background noise, but little is known about the relationship between speech-in-noise (SIN) perceptual ability and neural encoding of the F(0). Motivated by recent findings that music and language experience enhance brainstem representation of sound, we examined the hypothesis that brainstem encoding of the F(0) is diminished to a greater degree by background noise in people with poorer perceptual abilities in noise. To this end, we measured speech-evoked auditory brainstem responses to /da/ in quiet and two multitalker babble conditions (two-talker and six-talker) in native English-speaking young adults who ranged in their ability to perceive and recall SIN. Listeners who were poorer performers on a standardized SIN measure demonstrated greater susceptibility to the degradative effects of noise on the neural encoding of the F(0). Particularly diminished was their phase-locked activity to the fundamental frequency in the portion of the syllable known to be most vulnerable to perceptual disruption (i.e., the formant transition period). Our findings suggest that the subcortical representation of the F(0) in noise contributes to the perception of speech in noisy conditions.