Pitch Processing in Tonal-Language-Speaking Children with Autism: An Event-Related Potential Study

Auditory Challenges and Listening Effort in School-Age Children With Autism: Insights From Pupillary Dynamics During Speech-in-Noise Perception

PURPOSE

This study aimed to investigate challenges in speech-in-noise (SiN) processing faced by school-age children with autism spectrum conditions (ASCs) and their impact on listening effort.

METHOD

Participants, including 23 Mandarin-speaking children with ASCs and 19 age-matched neurotypical (NT) peers, underwent sentence recognition tests in both quiet and noisy conditions, with a speech-shaped steady-state noise masker presented at 0-dB signal-to-noise ratio in the noisy condition. Recognition accuracy rates and task-evoked pupil responses were compared to assess behavioral performance and listening effort during auditory tasks.

RESULTS

No main effect of group was found on accuracy rates. Instead, significant effects emerged for autistic trait scores, listening conditions, and their interaction, indicating that higher trait scores were associated with poorer performance in noise. Pupillometric data revealed significantly larger and earlier peak dilations, along with more varied pupillary dynamics in the ASC group relative to the NT group, especially under noisy conditions. Importantly, the ASC group's peak dilation in quiet mirrored that of the NT group in noise. However, the ASC group consistently exhibited reduced mean dilations than the NT group.

CONCLUSIONS

Pupillary responses suggest a different resource allocation pattern in ASCs: An initial sharper and larger dilation may signal an intense, narrowed resource allocation, likely linked to heightened arousal, engagement, and cognitive load, whereas a subsequent faster tail-off may indicate a greater decrease in resource availability and engagement, or a quicker release of arousal and cognitive load. The presence of noise further accentuates this pattern. This highlights the unique SiN processing challenges children with ASCs may face, underscoring the importance of a nuanced, individual-centric approach for interventions and support.

Predictive processing of music and language in autism: Evidence from Mandarin and English speakers

Atypical predictive processing has been associated with autism across multiple domains, based mainly on artificial antecedents and consequents. As structured sequences where expectations derive from implicit learning of combinatorial principles, language and music provide naturalistic stimuli for investigating predictive processing. In this study, we matched melodic and sentence stimuli in cloze probabilities and examined musical and linguistic prediction in Mandarin- (Experiment 1) and English-speaking (Experiment 2) autistic and non-autistic individuals using both production and perception tasks. In the production tasks, participants listened to unfinished melodies/sentences and then produced the final notes/words to complete these items. In the perception tasks, participants provided expectedness ratings of the completed melodies/sentences based on the most frequent notes/words in the norms. While Experiment 1 showed intact musical prediction but atypical linguistic prediction in autism in the Mandarin sample that demonstrated imbalanced musical training experience and receptive vocabulary skills between groups, the group difference disappeared in a more closely matched sample of English speakers in Experiment 2. These findings suggest the importance of taking an individual differences approach when investigating predictive processing in music and language in autism, as the difficulty in prediction in autism may not be due to generalized problems with prediction in any type of complex sequence processing.

Pre-attentive and Attentive Auditory Event-related Potentials in Children With Attention-Deficit Hyperactivity Disorder and Autism

Abnormalities in auditory processing are believed to play a major role in autism and attention-deficit hyperactivity disorder (ADHD). Both conditions often co-occur in children, causing difficulties in deciding the most promising intervention. Event-related potentials (ERPs) have been investigated and are showing promise to act as potential biomarkers for both conditions. This study investigated mismatch negativity (MMN) using a passive listening task and P3b in an active auditory go/no-go discrimination task. Recordings were available from 103 children (24 females): 35 with ADHD, 27 autistic, 15 autistic children with co-occurring ADHD, and 26 neurotypical (NT) children. The age range considered was between 4 and 17 years, but varied between groups. The results revealed increases in the MMN and P3b amplitudes with age. Older children with ADHD exhibited smaller P3b amplitudes, while younger autistic children showed reduced MMN amplitudes in response to phoneme changes compared to their NT counterparts. Notably, children diagnosed with autism and ADHD did not follow this pattern; instead, they exhibited more similarities to NT children. The reduced amplitudes of phonetically elicited MMN in children with autism and reduced P3b in children with ADHD suggest that the two respective ERPs can act as potential biomarkers for each condition. However, optimisation and standardisation of the testing protocol, as well as longitudinal studies are required in order to translate these findings into clinical practice.

Reduced Neural Specialization for Word-level Linguistic Prosody in Children with Autism

Children with autism often show atypical brain lateralization for speech and language processing, however, it is unclear what linguistic component contributes to this phenomenon. Here we measured event-related potential (ERP) responses in 21 school-age autistic children and 25 age-matched neurotypical (NT) peers during listening to word-level prosodic stimuli. We found that both groups displayed larger late negative response (LNR) amplitude to native prosody than to nonnative prosody; however, unlike the NT group exhibiting left-lateralized LNR distinction of prosodic phonology, the autism group showed no evidence of LNR lateralization. Moreover, in both groups, the LNR effects were only present for prosodic phonology but not for phoneme-free prosodic acoustics. These results extended the findings of inadequate neural specialization for language in autism to sub-lexical prosodic structures.

Age-related changes in neural responses to sensory stimulation in autism: a cross-sectional study

BACKGROUND

Sensory over-responsivity (SOR) is an impairing sensory processing challenge in autism spectrum disorder (ASD) which shows heterogenous developmental trajectories and appears to improve into adulthood in some but not all autistic individuals. However, the neural mechanisms underlying interindividual differences in these trajectories are currently unknown.

METHODS

Here, we used functional magnetic resonance imaging (fMRI) to investigate the association between age and neural activity linearly and nonlinearly in response to mildly aversive sensory stimulation as well as how SOR severity moderates this association. Participants included 52 ASD (14F) and 41 (13F) typically developing (TD) youth, aged 8.6-18.0 years.

RESULTS

We found that in pre-teens, ASD children showed widespread activation differences in sensorimotor, frontal and cerebellar regions compared to TD children, while there were fewer differences between ASD and TD teens. In TD youth, older age was associated with less activation in the prefrontal cortex. In contrast, in ASD youth, older age was associated with more engagement of sensory integration and emotion regulation regions. In particular, orbitofrontal and medial prefrontal cortices showed a nonlinear relationship with age in ASD, with an especially steep increase in sensory-evoked neural activity during the mid-to-late teen years. There was also an interaction between age and SOR severity in ASD youth such that these age-related trends were more apparent in youth with higher SOR.

LIMITATIONS

The cross-sectional design limits causal interpretations of the data. Future longitudinal studies will be instrumental in determining how prefrontal engagement and SOR co-develop across adolescence.

CONCLUSIONS

Our results suggest that enhanced recruitment of prefrontal regions may underlie age-related decreases in SOR for a subgroup of ASD youth.

Production of Mandarin consonant aspiration and monophthongs in children with Autism Spectrum Disorder

Impaired speech sound production adds difficulties to social communication in children with Autism Spectrum Disorder (ASD), while a limited attempt has been made to figure out the speech sound production among Mandarin-speaking children with ASD. The current study conducted both auditory-perceptual scoring and quantitative acoustic analysis of speech sound imitated by 27 Mandarin-speaking children with ASD (3.33-7.00 years) and 30 chronological-age-matched typically developing (TD) children. Auditory-perceptual scoring showed significantly lower scores for aspirated/unaspirated consonants and monophthongs in children with ASD. Moreover, the correlation between the developmental age of language and production accuracy in children with ASD emphasised the importance of language assessment. The quantitative acoustic analysis further indicated that the ASD group produced a much shorter voice onset time for aspirated consonants and showed a reduced vowel space than the TD group. Early interventions focusing on these production patterns should be introduced to improve the speech sound production in Mandarin-speaking children with ASD.

Auditory evoked potentials in adolescents with autism: An investigation of brain development, intellectual impairment, and neural encoding

Limited research has evaluated neural encoding of sounds from a developmental perspective in individuals with autism (ASD), especially among those with intellectual disability. We compared auditory evoked potentials (AEPs) in autistic adolescents with a wide range of intellectual abilities (n = 40, NVIQ 30-160) to both age-matched cognitively able neurotypical adolescent controls (NT-A, n = 37) and younger neurotypical children (NT-C, n = 27) to assess potential developmental delays. In addition to a classic measure of peak amplitude, we calculated a continuous measure of intra-class correlation (ICC) between each adolescent participant's AEP and the age-normative, average AEP waveforms calculated from NT-C and NT-A to study differences in signal morphology. We found that peak amplitudes of neural responses were significantly smaller in autistic adolescents compared to NT-A. We also found that the AEP morphology of autistic adolescents looked more like NT-A peers than NT-C but was still significantly different from NT-A AEP waveforms. Results suggest that AEPs of autistic adolescents present differently from NTs, regardless of age, and differences cannot be accounted for by developmental delay. Nonverbal intelligence significantly predicted how closely each adolescent's AEP resembled the age-normed waveform. These results support an evolving theory that the degree of disruption in early neural responses to low-level inputs is reflected in the severity of intellectual impairments in autism.

The Relationship Between Autism and Pitch Perception is Modulated by Cognitive Abilities

Previous studies reported mixed findings on autistic individuals' pitch perception relative to neurotypical (NT) individuals. We investigated whether this may be partly due to individual differences in cognitive abilities by comparing their performance on various pitch perception tasks on a large sample (n = 164) of autistic and NT children and adults. Our findings revealed that: (i) autistic individuals either showed similar or worse performance than NT individuals on the pitch tasks; (ii) cognitive abilities were associated with some pitch task performance; and (iii) cognitive abilities modulated the relationship between autism diagnosis and pitch perception on some tasks. Our findings highlight the importance of taking an individual differences approach to understand the strengths and weaknesses of pitch processing in autism.

Hearing Assistive Technology Facilitates Sentence-in-Noise Recognition in Chinese Children With Autism Spectrum Disorder

PURPOSE

Hearing assistive technology (HAT) has been shown to be a viable solution to the speech-in-noise perception (SPIN) issue in children with autism spectrum disorder (ASD); however, little is known about its efficacy in tonal language speakers. This study compared sentence-level SPIN performance between Chinese children with ASD and neurotypical (NT) children and evaluated HAT use in improving SPIN performance and easing SPIN difficulty.

METHOD

Children with ASD (n = 26) and NT children (n = 19) aged 6-12 years performed two adaptive tests in steady-state noise and three fixed-level tests in quiet and steady-state noise with and without using HAT. Speech recognition thresholds (SRTs) and accuracy rates were assessed using adaptive and fixed-level tests, respectively. Parents or teachers of the ASD group completed a questionnaire regarding children's listening difficulty under six circumstances before and after a 10-day trial period of HAT use.

RESULTS

Although the two groups of children had comparable SRTs, the ASD group showed a significantly lower SPIN accuracy rate than the NT group. Also, a significant impact of noise was found in the ASD group's accuracy rate but not in that of the NT group. There was a general improvement in the ASD group's SPIN performance with HAT and a decrease in their listening difficulty ratings across all conditions after the device trial.

CONCLUSIONS

The findings indicated inadequate SPIN in the ASD group using a relatively sensitive measure to gauge SPIN performance among children. The markedly increased accuracy rate in noise during HAT-on sessions for the ASD group confirmed the feasibility of HAT for improving SPIN performance in controlled laboratory settings, and the reduced post-use ratings of listening difficulty further confirmed the benefits of HAT use in daily scenarios.

Temporal processing deficit in children and adolescents with autism spectrum disorder: An online assessment

Objective

The sensory deficit has been considered as one of the core features in children and adolescents with autism spectrum disorder (ASD). The present study aimed to examine the temporal processing of simple and more complex auditory inputs in ASD children and adolescents with an online assessment that can be conducted remotely.

Methods

One hundred fifty-eight children and adolescents aged 5-17 years participated in this study, including 79 ASD participants and 79 typically developing (TD) participants. The online assessment consisted of two temporal-order judgment tasks that required repeating the sequence of two pure tones or consonant-vowel (CV) syllabic pairs at varying interstimulus intervals (ISIs).

Results

Significantly lower accuracy rates were found in ASD than TD participants in the pure tone and the CV conditions with both short and long ISI. In addition, ASD participants (M  =  245.97 ms) showed a significantly higher passing threshold than TD participants (M  =  178.84 ms) in the CV task. Receiver operating characteristic analysis found that the age × ISI passing threshold composite yielded a sensitivity of 74.7% and a specificity of 50.6% at the cutoff point of -0.307 in differentiating ASD participants from TD participants.

Conclusion

In sum, children and adolescents with ASD showed impaired temporal processing of both simple and more complex auditory stimuli, and the online assessment seems to be sensitive in differentiating individuals with ASD from those with TD.

Auditory Pitch Perception in Autism Spectrum Disorder: A Systematic Review and Meta-Analysis

PURPOSE

Pitch plays an important role in auditory perception of music and language. This study provides a systematic review with meta-analysis to investigate whether individuals with autism spectrum disorder (ASD) have enhanced pitch processing ability and to identify the potential factors associated with processing differences between ASD and neurotypicals.

METHOD

We conducted a systematic search through six major electronic databases focusing on the studies that used nonspeech stimuli to provide a qualitative and quantitative assessment across existing studies on pitch perception in autism. We identified potential participant- and methodology-related moderators and conducted metaregression analyses using mixed-effects models.

RESULTS

On the basis of 22 studies with a total of 464 participants with ASD, we obtained a small-to-medium positive effect size (g = 0.26) in support of enhanced pitch perception in ASD. Moreover, the mean age and nonverbal IQ of participants were found to significantly moderate the between-studies heterogeneity.

CONCLUSIONS

Our study provides the first meta-analysis on auditory pitch perception in ASD and demonstrates the existence of different developmental trajectories between autistic individuals and neurotypicals. In addition to age, nonverbal ability is found to be a significant contributor to the lower level/local processing bias in ASD. We highlight the need for further investigation of pitch perception in ASD under challenging listening conditions. Future neurophysiological and brain imaging studies with a longitudinal design are also needed to better understand the underlying neural mechanisms of atypical pitch processing in ASD and to help guide auditory-based interventions for improving language and social functioning.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21614271.

Categorical perception of Mandarin lexical tones in language-delayed autistic children

Enhanced pitch perception has been identified in autistic individuals, but it remains understudied whether such enhancement can be observed in the lexical tone perception of language-delayed autistic children. This study examined the categorical perception of Mandarin lexical tones in 23 language-delayed autistic children and two groups of non-autistic children, with one matched on chronological age ( n = 23) and the other on developmental age in language ability ( n = 23). The participants were required to identify and discriminate lexical tones. A wider identification boundary width and a lower between-category discrimination accuracy were found in autistic children than their chronological-age-matched non-autistic peers, but the autistic group exhibited seemingly comparable performance to the group of developmental-age-matched non-autistic children. While both non-autistic groups displayed a typical categorical perception pattern with enhanced sensitivity to between-category tone pairs relative to within-category ones, such a categorical perception pattern was not observed in the autistic group. These findings suggest among language-delayed autistic children with a developmental age around 4, categorical perception is still developing. Finally, we found categorical perception performance correlated with language ability, indicating autistic children’s language disability might be predictive of their poor categorical perception of speech sounds.

Lay abstract

Some theories suggested that autistic people have better pitch perception skills than non-autistic people. However, in a context where pitch patterns are used to differentiate word meanings (i.e. lexical tones), autistic people may encounter difficulties, especially those with less language experience. We tested this by asking language-delayed autistic children to identify and discriminate two Mandarin lexical tones (/yi/ with Tone 1, meaning ‘clothes’; /yi/ with Tone 2, meaning ‘aunt’; /yi/: the standard romanization of Mandarin Chinese). On average, these autistic children were 7.35 years old, but their developmental age in language ability was 4.20, lagging behind 7-year-old non-autistic children in terms of language ability. Autistic children’s performance in identifying and discriminating lexical tones was compared with two groups of non-autistic children: one group was matched with the autistic group on age, and the other was matched based on language ability. Autistic children performed differently from the non-autistic children matched on age, while autistic and non-autistic children matched on language ability exhibited seemingly similar performance. However, both the non-autistic groups have developed the perceptual ability to process lexical tones as different categories, but this ability was still developing in autistic children. Finally, we found autistic children who performed worse in identifying lexical tones had poorer language ability. The results suggest that language disability might have adverse influence on the development of skills of speech sound processing.

Atypical patterns of tone production in tone-language-speaking children with autism

Speakers with autism spectrum disorder (ASD) are found to exhibit atypical pitch patterns in speech production. However, little is known about the production of lexical tones (T1, T2, T3, T4) as well as neutral tones (T1N, T2N, T3N, T4N) by tone-language speakers with ASD. Thus, this study investigated the height and shape of tones produced by Mandarin-speaking children with ASD and their age-matched typically developing (TD) peers. A pronunciation experiment was conducted in which the participants were asked to produce reduplicated nouns. The findings from the acoustic analyses showed that although ASD children generally produced both lexical tones and neutral tones with distinct tonal contours, there were significant differences between the ASD and TD groups for tone height and shape for T1/T1N, T3/T3N, and T4/T4N. However, we did not find any difference in T2/T2N. These data implied that the atypical acoustic pattern in the ASD group could be partially due to the suppression of the F0 range. Moreover, we found that ASD children tended to produce more errors for T2/T2N, T3/T3N than for T1/T1N, T4/T4N. The pattern of tone errors could be explained by the acquisition principle of pitch, similarities among different tones, and tone sandhi. We thus concluded that deficits in pitch processing could be responsible for the atypical tone pattern of ASD children, and speculated that the atypical tonal contours might also be due to imitation deficits. The present findings may eventually help enhance the comprehensive understanding of the representation of atypical pitch patterns in ASD across languages.

Atypical prosodic realization by Mandarin-speaking autistic children: Evidence from tone sandhi and neutral tone

Introduction Atypical prosodic features have been widely reported in autism spectrum disorder (ASD), primarily in non-tonal language speakers. Nevertheless, the prosodic realizations in autistic people who speak tonal languages were relatively understudied. This study aimed to investigate the acoustic and phonetic patterns at the word-level speech in Mandarin-speaking autistic and typically developing (TD) children at different age ranges. Methods Thirty Mandarin-speaking autistic children (15 three- to five-year-olds and 15 six- to eight-year-olds) were recruited into the ASD group. The TD group consisted of 30 age- and gender-matched children. We employed a picture-naming task to elicit the spontaneous speech production of Mandarin disyllabic words in which tone change processes occur, namely Tone 3 (T3) sandhi and neutral tone (T0). Results The phonetic analysis showed that the ASD group generally could produce typical-like T3 sandhi and T0 in terms of pitch height. However, relative to the TD group, they exhibited flatter pitch contours during T3 sandhi production. Moreover, the acoustic pitch mean of citation tones in the ASD group was also significantly higher, accompanied by more rigid pitch curves in contour tones. In addition, the atypical temporal realization in the ASD group was manifested by the longer duration of T0 and the earlier inflection position of T3. Conclusions Mandarin-speaking autistic children under eight had the phonological ability to produce context-dependent tones based on connected tonal information at the word level. Nevertheless, their phonetic prosodic realization of tone change processes was atypical. Our findings provide evidence of atypical prosody in autistic children who speak tone languages. Clinically, these findings may be attributable to underlying neural differences in autistic children.

Late mismatch negativity of lexical tone at age 8 predicts Chinese children’s reading ability at age 10

Background

Deficits in phonological processing are commonly reported in dyslexia but longitudinal evidence that poor speech perception compromises reading is scant. This 2-year longitudinal ERP study investigates changes in pre-attentive auditory processing that underlies categorical perception of mandarin lexical tones during the years children learn to read fluently. The main purpose of the present study was to explore the development of lexical tone categorical perception to see if it can predict children’s reading ability.

Methods

Both behavioral and electrophysiological measures were taken in this study. Auditory event-related potentials were collected with a passive listening oddball paradigm. Using a stimulus continuum spanning from one lexical tone category exemplar to another, we identified a between-category and a within-category tone deviant that were acoustically equidistant from a standard stimulus. The standard stimulus occurred on 80% of trials, and one of two deviants (between-category or within-category) equiprobably on the remaining trials. 8-year-old Mandarin speakers participated in both an initial ERP oddball paradigm and returned for a 2-year follow-up.

Results

The between-category MMN and within-category MMN significantly correlate with each other at age 8 (p = 0.001) but not at age 10. The between-category MMN at age 8 can predict children’s ability at age 10 (p = 0.03) but the within-category cannot.

Conclusion

The categorical perception of lexical tone is still developing from age 8 to age 10. The behavioral and electrophysiological results demonstrate that categorical perception of lexical tone at age 8 predicts children’s reading ability at age 10.

Mismatch negativity and P3a amplitude in children with familial high risk of schizophrenia or bipolar disorder - A Danish register-based EEG study

BACKGROUND

Infrequent deviants in a rapid sequence of sounds elicit a negative cortical potential over the frontocentral midline (mismatch negativity, MMN) followed by a positive deflection (P3a). Both cortical potentials are consistently attenuated in patients with schizophrenia (SZ), and, to a lesser degree, in patients with bipolar disorder (BP).

OBJECTIVE

Since it is unclear when MMN and P3a deficits arise relative to the emergence of symptoms, we examined whether MMN and P3a alterations are already detectable in children with familial high risk.

METHODS

Using 128-channel electroencephalography, we recorded auditory MMN and P3a evoked by a deviation in sound duration, frequency, or both in 51 children with familial high-risk for SZ (FHR-SZ), 41 children with familial high-risk for BP (FHR-BP), and 39 population-based children (PBC) at a mean age of 12.10.

RESULTS

MMN amplitude evoked by a duration deviant was larger in children with FHR-BP compared to PBC and FHR-SZ. P3a amplitude in response to a duration ∗ frequency deviant was larger in children with FHR-BP compared to children with FHR-SZ, but not compared to PBC. MMN- and P3a-peak latency did not differ between groups.

CONCLUSIONS

At an age of around 12 years, children with FHR-BP display enhanced neural sensitivity to change detection of duration deviants, while FHR-SZ showed a normal response pattern. Longitudinal recordings in high-risk children during adolescence are required to elucidate the temporal trajectories of MMN and P3a responses and how they relate to the emergence of first clinical symptoms in SZ and BP.

Cross-linguistic patterns of speech prosodic differences in autism: A machine learning study

Differences in speech prosody are a widely observed feature of Autism Spectrum Disorder (ASD). However, it is unclear how prosodic differences in ASD manifest across different languages that demonstrate cross-linguistic variability in prosody. Using a supervised machine-learning analytic approach, we examined acoustic features relevant to rhythmic and intonational aspects of prosody derived from narrative samples elicited in English and Cantonese, two typologically and prosodically distinct languages. Our models revealed successful classification of ASD diagnosis using rhythm-relative features within and across both languages. Classification with intonation-relevant features was significant for English but not Cantonese. Results highlight differences in rhythm as a key prosodic feature impacted in ASD, and also demonstrate important variability in other prosodic properties that appear to be modulated by language-specific differences, such as intonation.

Reduced mismatch negativity in children and adolescents with autism spectrum disorder is associated with their impaired adaptive functioning

Children and adolescents on the autism spectrum display sensory disturbances, rigid and repetitive behavior, social communication problems and a high prevalence of impaired adaptive functioning. Autism is associated with slowed behavioral and neural habituation to repeated sensory input and decreased responses to sensory deviations. Mismatch negativity (MMN) reflects a pre‐attentive difference in the neural response to sensory deviations relative to regularities and studies overall suggest that children and adolescents with autism tend to have smaller MMN. However, it remains unclear whether reduced MMN in autism is coupled to severity of specific autistic symptoms or more generally to lower level of adaptive functioning. To address these questions, the present study used electroencephalography (EEG) to assess whether auditory MMN in 59 children and adolescents with autism aged 7–14 years compared to 59 typically developing children and adolescents were related to specific autistic symptoms or level in adaptive functioning. As hypothesized, the autism group had a lower MMN amplitude than controls. Smaller MMN amplitudes were specifically associated with lower adaptive functioning in the autistic subjects but not in controls while no apparent relationships were observed with autistic‐like social interaction and communication problems, atypical language, rigidity, stereotypy or sensory sensitivity symptoms. Our findings indicate that a blunted response to changes in sensory input may underlie or contribute to the generalized difficulties with adapting to daily life circumstances seen in children and adolescents with autism.

Multichannel Perception of Emotion in Speech, Voice, Facial Expression, and Gesture in Individuals With Autism: A Scoping Review

PURPOSE

Numerous studies have identified individuals with autism spectrum disorder (ASD) with deficits in unichannel emotion perception and multisensory integration. However, only limited research is available on multichannel emotion perception in ASD. The purpose of this review was to seek conceptual clarification, identify knowledge gaps, and suggest directions for future research.

METHOD

We conducted a scoping review of the literature published between 1989 and 2021, following the 2005 framework of Arksey and O'Malley. Data relating to study characteristics, task characteristics, participant information, and key findings on multichannel processing of emotion in ASD were extracted for the review.

RESULTS

Discrepancies were identified regarding multichannel emotion perception deficits, which are related to participant age, developmental level, and task demand. Findings are largely consistent regarding the facilitation and compensation of congruent multichannel emotional cues and the interference and disruption of incongruent signals. Unlike controls, ASD individuals demonstrate an overreliance on semantics rather than prosody to decode multichannel emotion.

CONCLUSIONS

The existing literature on multichannel emotion perception in ASD is limited, dispersed, and disassociated, focusing on a variety of topics with a wide range of methodologies. Further research is necessary to quantitatively examine the impact of methodological choice on performance outcomes. An integrated framework of emotion, language, and cognition is needed to examine the mutual influences between emotion and language as well as the cross-linguistic and cross-cultural differences.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19386176.

Psychological and Neural Differences of Music Processing in Autistic Individuals: A Scoping Review

Despite abundant research and clinical evidence of the effectiveness of music interventions for people in the autism spectrum, understanding of music processing in this community is limited. We explored whether research evidence of differences in music processing within the autistic community is available. We developed a scoping review to search for literature with the terms "music", "processing," and "autism" (and variants). We searched PubMed, CINAHL, Scopus, Web of Science, PsycInfo, Academic Search Complete, ERIC, and Music Index databases for a total of 10,857 articles, with 5,236 duplicates. The remaining 5,621 titles and abstracts were screened for eligibility by a team of four undergraduate and graduate students and the PI. Seventy-five studies were included for data extraction. Data were analyzed with descriptive statistics regarding author, study, stimulus, and participant information, and a thematic analysis of outcome and findings. Our findings are preliminary given the emerging nature of the literature, the use of mostly non-musical auditory stimuli, passive listening experiences, and underreported demographics. However, the literature shows some evidence of differences in music processing for autistic individuals, including reduced habituation to non-musical and musical stimuli; truncated, delayed, or divergent developmental trajectories; and possible compensatory higher-order mechanisms that yield similar behavioral responses even in the presence of divergent neural correlates. Music therapists are encouraged to adopt a developmental perspective, not only of general skills, but specifically of music skill development in this community, and to extrapolate these findings with caution, given the current limitations in the evidence.

Auditory-Motor Mapping Training Facilitates Speech and Word Learning in Tone Language-Speaking Children With Autism: An Early Efficacy Study

PURPOSE

It has been reported that tone language-speaking children with autism demonstrate speech-specific lexical tone processing difficulty, although they have intact or even better-than-normal processing of nonspeech/melodic pitch analogues. In this early efficacy study, we evaluated the therapeutic potential of Auditory-Motor Mapping Training (AMMT) in facilitating speech and word output for Mandarin-speaking nonverbal and low-verbal children with autism, in comparison with a matched non-AMMT-based control treatment.

METHOD

Fifteen Mandarin-speaking nonverbal and low-verbal children with autism spectrum disorder participated and completed all the AMMT-based treatment sessions by intoning (singing) and tapping the target words delivered via an app, whereas another 15 participants received control treatment. Generalized linear mixed-effects models were created to evaluate speech production accuracy and word production intelligibility across different groups and conditions.

RESULTS

Results showed that the AMMT-based treatment provided a more effective training approach in accelerating the rate of speech (especially lexical tone) and word learning in the trained items. More importantly, the enhanced training efficacy on lexical tone acquisition remained at 2 weeks after therapy and generalized to untrained tones that were not practiced. Furthermore, the low-verbal participants showed higher improvement compared to the nonverbal participants.

CONCLUSIONS

These data provide the first empirical evidence for adopting the AMMT-based training to facilitate speech and word learning in Mandarin-speaking nonverbal and low-verbal children with autism. This early efficacy study holds promise for improving lexical tone production in Mandarin-speaking children with autism but should be further replicated in larger scale randomized studies. Supplemental Material https://doi.org/10.23641/asha.16834627.

Speech Processing in Autism Spectrum Disorder: An Integrative Review of Auditory Neurophysiology Findings

Purpose Investigations into the nature of communication disorders in autistic individuals increasingly evaluate neural responses to speech stimuli. This integrative review aimed to consolidate the available data related to speech and language processing across levels of stimulus complexity (from single speech sounds to sentences) and to relate it to the current theories of autism. Method An electronic database search identified peer-reviewed articles using event-related potentials or magnetoencephalography to investigate auditory processing from single speech sounds to sentences in autistic children and adults varying in language and cognitive abilities. Results Atypical neural responses in autistic persons became more prominent with increasing stimulus and task complexity. Compared with their typically developing peers, autistic individuals demonstrated mostly intact sensory responses to single speech sounds, diminished spontaneous attentional orienting to spoken stimuli, specific difficulties with categorical speech sound discrimination, and reduced processing of semantic content. Atypical neural responses were more often observed in younger autistic participants and in those with concomitant language disorders. Conclusions The observed differences in neural responses to speech stimuli suggest that communication difficulties in autistic individuals are more consistent with the reduced social interest than the auditory dysfunction explanation. Current limitations and future directions for research are also discussed.

Categorical Perception of Pitch Contours and Voice Onset Time in Mandarin-Speaking Adolescents With Autism Spectrum Disorders

Purpose Previous studies have shown enhanced pitch and impaired time perception in individuals with autism spectrum disorders (ASD). However, it remains unclear whether such deviated patterns of auditory processing depending on acoustic dimensions would transfer to the higher level linguistic pitch and time processing. In this study, we compared the categorical perception (CP) of lexical tones and voice onset time (VOT) in Mandarin Chinese, which utilize pitch and time changes, respectively, to convey phonemic contrasts. Method The data were collected from 22 Mandarin-speaking adolescents with ASD and 20 age-matched neurotypical controls. In addition to the identification and discrimination tasks to test CP performance, all the participants were evaluated with their language ability and phonological working memory. Linear mixed-effects models were constructed to evaluate the identification and discrimination scores across different groups and conditions. Results The basic CP pattern of cross-boundary benefit when perceiving both native lexical tones and VOT was largely preserved in high-functioning adolescents with ASD. The degree of CP of lexical tones in ASD was similar to that in typical controls, whereas the degree of CP of VOT in ASD was greatly reduced. Furthermore, the degree of CP of lexical tones correlated with language ability and digit span in ASD participants. Conclusions These findings suggest that the unbalanced acoustic processing capacities for pitch and time can be generalized to the higher level linguistic processing in ASD. Furthermore, the higher degree of CP of lexical tones correlated with better language ability in Mandarin-speaking individuals with ASD.

Sensogenomics and the Biological Background Underlying Musical Stimuli: Perspectives for a New Era of Musical Research

What is the actual impact of music on the human being and the scope for scientific research in this realm? Compared to other areas, the study of the relationship between music and human biology has received limited attention. At the same time, evidence of music's value in clinical science, neuroscience, and social science keeps increasing. This review article synthesizes the existing knowledge of genetics related to music. While the success of genomics has been demonstrated in medical research, with thousands of genes that cause inherited diseases or a predisposition to multifactorial disorders identified, much less attention has been paid to other human traits. We argue for the development of a new discipline, sensogenomics, aimed at investigating the impact of the sensorial input on gene expression and taking advantage of new, discovery-based 'omic' approaches that allow for the exploration of the whole transcriptome of individuals under controlled experiments and circumstances.

Linguistic Tone and Non-Linguistic Pitch Imitation in Children with Autism Spectrum Disorders: A Cross-Linguistic Investigation

The conclusions on prosodic pitch features in autism spectrum disorders (ASD) have primarily been derived from studies in non-tonal language speakers. This cross-linguistic study evaluated the performance of imitating Cantonese lexical tones and their non-linguistic (nonspeech) counterparts by Cantonese- and Mandarin-speaking children with and without ASD. Acoustic analyses showed that, compared with typically developing peers, children with ASD exhibited increased pitch variations when imitating lexical tones, while performed similarly when imitating the nonspeech counterparts. Furthermore, Mandarin-speaking children with ASD failed to exploit the phonological knowledge of segments to improve the imitation accuracy of non-native lexical tones. These findings help clarify the speech-specific pitch processing atypicality and phonological processing deficit in tone-language-speaking children with ASD.

Early differences in auditory processing relate to Autism Spectrum Disorder traits in infants with Neurofibromatosis Type I

BACKGROUND

Sensory modulation difficulties are common in children with conditions such as Autism Spectrum Disorder (ASD) and could contribute to other social and non-social symptoms. Positing a causal role for sensory processing differences requires observing atypical sensory reactivity prior to the emergence of other symptoms, which can be achieved through prospective studies.

METHODS

In this longitudinal study, we examined auditory repetition suppression and change detection at 5 and 10 months in infants with and without Neurofibromatosis Type 1 (NF1), a condition associated with higher likelihood of developing ASD.

RESULTS

In typically developing infants, suppression to vowel repetition and enhanced responses to vowel/pitch change decreased with age over posterior regions, becoming more frontally specific; age-related change was diminished in the NF1 group. Whilst both groups detected changes in vowel and pitch, the NF1 group were largely slower to show a differentiated neural response. Auditory responses did not relate to later language, but were related to later ASD traits.

CONCLUSIONS

These findings represent the first demonstration of atypical brain responses to sounds in infants with NF1 and suggest they may relate to the likelihood of later ASD.

Neural coding of formant-exaggerated speech and nonspeech in children with and without autism spectrum disorders

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.

Left hemispheric deficit in the sustained neuromagnetic response to periodic click trains in children with ASD

BACKGROUND

Deficits in perception and production of vocal pitch are often observed in people with autism spectrum disorder (ASD), but the neural basis of these deficits is unknown. In magnetoencephalogram (MEG), spectrally complex periodic sounds trigger two continuous neural responses-the auditory steady state response (ASSR) and the sustained field (SF). It has been shown that the SF in neurotypical individuals is associated with low-level analysis of pitch in the 'pitch processing center' of the Heschl's gyrus. Therefore, alternations in this auditory response may reflect atypical processing of vocal pitch. The SF, however, has never been studied in people with ASD.

METHODS

We used MEG and individual brain models to investigate the ASSR and SF evoked by monaural 40 Hz click trains in boys with ASD (N = 35) and neurotypical (NT) boys (N = 35) aged 7-12-years.

RESULTS

In agreement with the previous research in adults, the cortical sources of the SF in children were located in the left and right Heschl's gyri, anterolateral to those of the ASSR. In both groups, the SF and ASSR dominated in the right hemisphere and were higher in the hemisphere contralateral to the stimulated ear. The ASSR increased with age in both NT and ASD children and did not differ between the groups. The SF amplitude did not significantly change between the ages of 7 and 12 years. It was moderately attenuated in both hemispheres and was markedly delayed and displaced in the left hemisphere in boys with ASD. The SF delay in participants with ASD was present irrespective of their intelligence level and severity of autism symptoms.

LIMITATIONS

We did not test the language abilities of our participants. Therefore, the link between SF and processing of vocal pitch in children with ASD remains speculative.

CONCLUSION

Children with ASD demonstrate atypical processing of spectrally complex periodic sound at the level of the core auditory cortex of the left-hemisphere. The observed neural deficit may contribute to speech perception difficulties experienced by children with ASD, including their poor perception and production of linguistic prosody.

Individuals With Autism Have No Detectable Deficit in Neural Markers of Prediction Error When Presented With Auditory Rhythms of Varied Temporal Complexity

The brain's ability to encode temporal patterns and predict upcoming events is critical for speech perception and other aspects of social communication. Deficits in predictive coding may contribute to difficulties with social communication and overreliance on repetitive predictable environments in individuals with autism spectrum disorder (ASD). Using a mismatch negativity (MMN) task involving rhythmic tone sequences of varying complexity, we tested the hypotheses that (1) individuals with ASD have reduced MMN response to auditory stimuli that deviate in presentation timing from expected patterns, particularly as pattern complexity increases and (2) amplitude of MMN signal is inversely correlated with level of impairment in social communication and repetitive behaviors. Electroencephalography was acquired as individuals (age 6-21 years) listened to repeated five-rhythm tones that varied in the Shannon entropy of the rhythm across three conditions (zero, medium-1 bit, and high-2 bit entropy). The majority of the tones conformed to the established rhythm (standard tones); occasionally the fourth tone was temporally shifted relative to its expected time of occurrence (deviant tones). Social communication and repetitive behaviors were measured using the Social Responsiveness Scale and Repetitive Behavior Scale-Revised. Both neurotypical controls (n = 19) and individuals with ASD (n = 21) show stepwise decreases in MMN as a function of increasing entropy. Contrary to the result forecasted by a predictive coding hypothesis, individuals with ASD do not differ from controls in these neural mechanisms of prediction error to auditory rhythms of varied temporal complexity, and there is no relationship between these signals and social communication or repetitive behavior measures. LAY SUMMARY: We tested the idea that the brain's ability to use previous experience to influence processing of sounds is weaker in individuals with autism spectrum disorder (ASD) than in neurotypical individuals. We found no difference between individuals with ASD and neurotypical controls in brain wave responses to sounds that occurred earlier than expected in either simple or complex rhythms. There was also no relationship between these brain waves and social communication or repetitive behavior scores.

Lifelong Tone Language Experience does not Eliminate Deficits in Neural Encoding of Pitch in Autism Spectrum Disorder

Atypical pitch processing is a feature of Autism Spectrum Disorder (ASD), which affects non-tone language speakers' communication. Lifelong auditory experience has been demonstrated to modify genetically-predisposed risks for pitch processing. We examined individuals with ASD to test the hypothesis that lifelong auditory experience in tone language may eliminate impaired pitch processing in ASD. We examined children's and adults' Frequency-following Response (FFR), a neurophysiological component indexing early neural sensory encoding of pitch. Univariate and machine-learning-based analytics suggest less robust pitch encoding and diminished pitch distinctions in the FFR from individuals with ASD. Contrary to our hypothesis, results point to a linguistic pitch encoding impairment associated with ASD that may not be eliminated even by lifelong sensory experience.

Age-sensitive associations of segmental and suprasegmental perception with sentence-level language skills in Mandarin-speaking children with cochlear implants

BACKGROUND AND AIM

It remains unclear how recognition of segmental and suprasegmental phonemes contributes to sentence-level language processing skills in Mandarin-speaking children with cochlear implants (CIs). Our study examined the influence of implantation age on the recognition of consonants, lexical tones and sentences respectively, and more importantly, the contribution of phonological skills to sentence repetition accuracy in Mandarin-speaking children with CIs.

METHODS

The participants were three groups of prelingually deaf children who received cochlear implants at various ages and their age-matched controls with normal hearing. Three tasks were administered to assess their consonant perception, lexical tone recognition and language skills in open-set sentence repetition.

RESULTS

Children with CIs lagged behind NH peers in all the three tests, and performances on segmental, suprasegmental and sentence-level processing were differentially modulated by implantation age. Furthermore, performances on recognition of consonants and lexical tones were significant predictors of sentence repetition accuracy in the children with CIs.

CONCLUSION

Overall, segmental and suprasegmental perception as well as sentence-level processing is impaired in Mandarin-speaking children with CIs compared with age-matched children with NH. In children with CIs recognition of segmental and suprasegmental phonemes at the lower level predicts sentence repetition accuracy at the higher level. More importantly, implantation age plays an important role in the development of phonological skills and higher-order language skills, suggesting that age-appropriate aural rehabilitation and speech intervention programs need to be developed in order to better help CI users who receive CIs at different ages.

Effects of native language experience on Mandarin lexical tone processing in proficient second language learners

Learning the acoustic and phonological information in lexical tones is significant for learners of tonal languages. Although there is a wealth of knowledge from studies of second language (L2) tone learning, it remains unclear how L2 learners process acoustic versus phonological information differently depending on whether their first language (L1) is a tonal language. In the present study, we first examined proficient L2 learners of Mandarin with tonal and nontonal L1 in a behavioral experiment (identifying a Mandarin tonal continuum) to construct tonal contrasts that could differentiate the phonological from the acoustic information in Mandarin lexical tones for the L2 learners. We then conducted an ERP experiment to investigate these learners' automatic processing of acoustic and phonological information in Mandarin lexical tones by mismatch negativity (MMN). Although both groups of L2 learners showed similar behavioral identification features for the Mandarin tonal continuum as native speakers, L2 learners with nontonal L1, as compared with both native speakers and L2 learners with tonal L1, showed longer reaction time to the tokens of the Mandarin tonal continuum. More importantly, the MMN data further revealed distinct roles of acoustic and phonological information on the automatic processing of L2 lexical tones between the two groups of L2 learners. Taken together, the results indicate that the processing of acoustic and phonological information in L2 lexical tones may be modulated by L1 experience with a tonal language. The theoretical implications of the current study are discussed in light of models of L2 speech learning.

Mismatch Negativity and P3a in Adolescents and Young Adults with Autism Spectrum Disorders: Behavioral Correlates and Clinical Implications

In a sample of 37 adolescents and young adults with autism spectrum disorder (ASD) and 35 typically-developing controls (TDC), we investigated sensory symptoms by clinical measures, and Mismatch Negativity and P3a component at Fz with the frequency and duration oddball paradigms of event-related potentials. Results showed that compared to TDC, ASD participants reported more sensory symptoms, and presented a shorter P3a peak latency in the duration paradigm, which was correlated with more social awareness deficits. In the frequency paradigm, P3a parameters were correlated with sensation avoiding and attention characteristics of ASD. Our findings suggest that sensory abnormality in ASD may extend into adolescence and young adulthood. P3a latency might be a potential neurophysiological marker for ASD.

Early enhanced processing and delayed habituation to deviance sounds in autism spectrum disorder

Children with autism spectrum disorder (ASD) exhibit difficulties processing and encoding sensory information in daily life. Cognitive response to environmental change in control individuals is naturally dynamic, meaning it habituates or reduces over time as one becomes accustomed to the deviance. The origin of atypical response to deviance in ASD may relate to differences in this dynamic habituation. The current study of 133 children and young adults with and without ASD examined classic electrophysiological responses (MMN and P3a), as well as temporal patterns of habituation (i.e., N1 and P3a change over time) in response to a passive auditory oddball task. Individuals with ASD showed an overall heightened sensitivity to change as exhibited by greater P3a amplitude to novel sounds. Moreover, youth with ASD showed dynamic ERP differences, including slower attenuation of the N1 response to infrequent tones and the P3a response to novel sounds. Dynamic ERP responses were related to parent ratings of auditory sensory-seeking behaviors, but not general cognition. As the first large-scale study to characterize temporal dynamics of auditory ERPs in ASD, our results provide compelling evidence that heightened response to auditory deviance in ASD is largely driven by early sensitivity and prolonged processing of auditory deviance.

Role of inter-trial phase coherence in atypical auditory evoked potentials to speech and nonspeech stimuli in children with autism

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.

Meta-analysis and systematic review of the literature characterizing auditory mismatch negativity in individuals with autism

A number of past studies have used mismatch negativity (MMN) to identify auditory processing deficits in individuals with autism spectrum disorder (ASD). Our meta-analysis compared MMN responses for individuals with ASD and typically developing controls (TD). We analyzed 67 experiments across 22 publications that employed passive, auditory-based MMN paradigms with ASD and TD participants. Most studies lacked design characteristics that would lead to an accurate description of the MMN. Variability between experiments measuring MMN amplitude was smaller when limited to studies that counterbalanced stimuli. Reduced MMN amplitude was found among young children with ASD compared to controls and in experiments that used nonspeech sounds. Still, few studies included adolescents or those with below-average verbal IQ. Most studies suffered from small sample sizes, and aggregating these data did not reveal significant group differences. This analysis points to a need for research focused specifically on understudied ASD samples using carefully designed MMN experiments. Study of individual differences in MMN may provide further insights into distinct subgroups within the heterogeneous ASD population.

Exploring the neural correlates of lexical stress perception in english among Chinese-English bilingual children with autism spectrum disorder: An ERP study

Previous studies found that individuals with autism spectrum disorder (ASD) were less sensitive to the variations of lexical stress in their native language than typically developing controls. However, no study has been conducted to explore the perception of lexical stress in the second language among individuals with ASD. Using ERPs (event-related potentials) measurement with an oddball paradigm, the current study examined and compared the neural responses by Chinese-English bilingual children with ASD and typically developing controls in the processing of English lexical stress. The results showed that when compared with typically developing controls, children with ASD manifested reduced MMN (mismatch negativity) amplitude at the left temporal-parietal and parietal sites, indicating that they were less sensitive to lexical stress. However, a more negative MMN response was found for ASD group than for typically developing group at the right central-parietal, temporal-parietal, and temporal sites. In addition, the right hemisphere was more activated than the left hemisphere for ASD group, which might be derived from the reversed asymmetry of brain activation for individuals with ASD when processing language-related stimuli.

The impact of atypical sensory processing on social impairments in autism spectrum disorder

Altered sensory processing has been an important feature of the clinical descriptions of autism spectrum disorder (ASD). There is evidence that sensory dysregulation arises early in the progression of ASD and impacts social functioning. This paper reviews behavioral and neurobiological evidence that describes how sensory deficits across multiple modalities (vision, hearing, touch, olfaction, gustation, and multisensory integration) could impact social functions in ASD. Theoretical models of ASD and their implications for the relationship between sensory and social functioning are discussed. Furthermore, neural differences in anatomy, function, and connectivity of different regions underlying sensory and social processing are also discussed. We conclude that there are multiple mechanisms through which early sensory dysregulation in ASD could cascade into social deficits across development. Future research is needed to clarify these mechanisms, and specific focus should be given to distinguish between deficits in primary sensory processing and altered top-down attentional and cognitive processes.

Brief Report: Discrimination of Foreign Speech Pitch and Autistic Traits in Non-Clinical Population

Individuals with Autism Spectrum Conditions (ASC) are widely suggested to show enhanced perceptual discrimination but inconsistent findings have been reported for pitch discrimination. Given the high variability in ASC, this study investigated whether ASC traits were correlated with pitch discrimination in an undergraduate sample when musical and language experiences were taken into consideration. Results indicated that the social skills subscale of the Autism Spectrum Quotient was associated with foreign speech pitch discrimination, suggesting that individuals who were less sociable and socially skillful were less able to discriminate foreign speech pitch. Current findings have an implication in investigating individual differences in ASC and further investigation is needed for spelling out the relationship between the non-social and social aspects of ASC.

Speech-specific categorical perception deficit in autism: An Event-Related Potential study of lexical tone processing in Mandarin-speaking children

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.

A mismatch negativity study in Mandarin-speaking children with sensorineural hearing loss

OBJECTIVE

a) To examine the effects of sensorineural hearing loss on the discriminability of linguistic and non-linguistic stimuli at the cortical level, and b) to examine whether the cortical responses differ based on the chronological age at intervention, the degree of hearing loss, or the acoustic stimulation mode in children with severe and profound hearing loss.

METHODS

Mismatch negativity (MMN) responses were collected from 43 children with severe and profound bilateral sensorineural hearing loss, and 20 children with normal hearing (age: 3-6 years). In the non-verbal stimulation condition, pure tones with frequencies of 1 kHz and 1.1 kHz were used as the standard and the deviant respectively. In the verbal stimulation condition, the Chinese mandarin tokens/ba2/and/ba4/were used as the standard and the deviant respectively. Latency and amplitude of the MMN responses were collected and analyzed.

RESULTS

Overall, children with hearing loss showed longer latencies and lower amplitudes of the MMN responses to both non-verbal and verbal stimulations. The latency of the verbal/ba2/-/ba4/pair was longer than that of the nonverbal 1 kHz-1.1 kHz pair in both groups of children.

CONCLUSIONS

Children with hearing loss, especially those who received intervention after 2 years of age, showed substantial weakness in the neural responses to lexical tones and pure tones. Thus, the chronological age when the children receive hearing intervention may have an impact on the effectiveness of discriminating between verbal and non-verbal signals.

Processing Cantonese lexical tones: Evidence from oddball paradigms

Two event-related potential (ERP) experiments were conducted to investigate whether Cantonese lexical tones are processed with general auditory perception mechanisms and/or a special speech module. Two tonal features (f0 direction and f0 height deviation) were manipulated to reflect acoustic processing, and the contrast between syllables and hums was used to reveal the involvement of a speech module. Experiment 1 adopted a passive oddball paradigm to study a relatively early stage of tonal processing. Mismatch negativity (MMN) and novelty P3 (P3a) were modulated by the interaction between tonal feature and stimulus type. Similar interactions were found for N2 and P3 in Experiment 2, where more in-depth tonal processing was examined with an active oddball paradigm. Moreover, detecting tonal deviants of syllables elicited N1 and P2 that were not found in hum detection. Together, these findings suggest that the processing of lexical tone relies on both acoustic and linguistic processes from the early stage. Another noteworthy finding is the absence of brain lateralization in both experiments, which challenges the use of a lateralization pattern as evidence for processing lexical tones through a special speech module.