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

Voice pitch and gender in autism

Autistic adults are often perceived as having an atypical speech. The acoustic characteristics of these impressions prove surprisingly difficult to delineate, but one feature that does robustly emerge across different studies is higher pitch (F0 values) in autistic versus neurotypical individuals. However, there is no clear explanation why autistic individuals should have higher-pitched voices. We propose that the solution lies in the gender imbalance still prevalent in autism, which entails an overrepresentation of male participants in research on speech in autism. We analyse speech samples from a gender-balanced group of 40 autistic and 40 neurotypical adults, controlling for potential stress levels through electrodermal activity recordings. We find that autistic males tend to have higher pitch than neurotypical males, but that autistic females tend to have lower pitch than neurotypical females. The interpretation we put forth for our finding - that the autistic versus neurotypical group difference in pitch goes in opposite directions between males and females - is that autistic individuals tend to be less influenced by neurotypical gender stereotypes.Lay abstractIt is has often been observed that autistic individuals have higher-pitched voices than non-autistic ones, but no clear explanation for this difference has been put forth. However, autistic males are still dramatically over-represented in published research, including the acoustic studies that report higher pitch in autistic participants. In this study, we collected speech samples from a group of autistic and neurotypical adults that, unlike in most studies, was perfectly balanced between groups and genders. In this gender-balanced sample, pitch was significantly higher in autistic versus neurotypical men, but lower in autistic versus neurotypical women. Overall, women tend to have higher-pitched voices than men, but the magnitude of this difference is culture dependent and may be significantly influenced by the internalisation of normative expectations towards one's gender. We propose that higher pitch in autistic males and lower pitch in autistic females could be due, at least in part, to a lesser integration of sociolinguistic markers of gender. Our report shows that speech atypicality should not be operationalised in terms of systematic and unidirectional deviation from the neurotypical baseline.

Atypical vocal imitation of speech and song in autism spectrum disorder: Evidence from Mandarin speakers

LAY ABSTRACT

Atypical vocal imitation has been identified in English-speaking autistic individuals, whereas the characteristics of vocal imitation in tone-language-speaking autistic individuals remain unexplored. By comparing speech and song imitation, the present study reveals a unique pattern of atypical vocal imitation across speech and music domains among Mandarin-speaking autistic individuals. The findings suggest that tone language experience does not compensate for difficulties in vocal imitation in autistic individuals and extends our understanding of vocal imitation in autism across different languages.

Perception and Production of Pitch Information in Mandarin-Speaking Children with Autism Spectrum Disorders

This study investigated the categorical perception (CP) of linguistic pitch (lexical tones) and nonlinguistic pitch (pure tones), as well as tonal production in Mandarin-speaking children with autism spectrum disorders (ASD). A total of 26 Mandarin-speaking children with ASD and 29 age-matched typically developing (TD) children were recruited for this study. The Mandarin T2-T3 contrast and corresponding pure tones with identical pitch contours were adopted to assess the nuanced pitch processing abilities of the child participants via the CP paradigm. Accordingly, tonal production was focused on T2 and T3 with analyses of the dynamic pitch contours and tonal differentiation. Mandarin-speaking children with ASD exhibited atypical CP for linguistic pitch in comparison with their TD peers. However, the categorization of linguistic pitch exceeded that of nonlinguistic pitch among the ASD participants, indicating a global over local processing pattern contrary to autistic individuals in non-tonal languages. Additionally, despite atypical pitch contours in producing T2 and T3, the ASD group showed comparable differentiable degrees of the two tones in production to the TD group. Findings of this study served as a foray into contesting current theories' claims of local bias and/or global impairment in the autistic population, prompting further inspections on individuals with different language backgrounds and stimuli processing with various complexities. Additionally, findings of this study underscore the necessity of developing tailored assessments and interventions to enhance the perception and production of complex and confusable tones, thereby improving perceptual robustness and communication skills in Mandarin-speaking children with ASD.

High variability phonetic training facilitates perception-to-production transfer in Mandarin-speaking children with cochlear implants: An acoustic investigation

This study primarily aimed to evaluate the effectiveness of high variability phonetic training (HVPT) for children with cochlear implants (CIs) via the cross-modal transfer of perceptual learning to lexical tone production, a scope that has been largely neglected by previous training research. Sixteen CI participants received a five-session HVPT within a period of three weeks, whereas another 16 CI children were recruited without receiving any formal training. Lexical tone production was assessed with a picture naming task before the provision (pretest) and immediately after (posttest) and ten weeks after (follow-up test) the completion of the training protocol. The production samples were coded and analyzed acoustically. Despite considerable distinctions from the typical baselines of normal-hearing peers, the trained CI children exhibited significant improvements in Mandarin tone production from pretest to posttest in pitch height of T1, pitch slope of T2, and pitch curvature of T3. Moreover, the training-induced acoustic changes in the concave characteristic of the T3 contour was retained ten weeks after training termination. This study represents an initial acoustic investigation on HVPT-induced benefits in lexical tone production for the pediatric CI population, which provides valuable insights into applying this perceptual training technique as a viable tool in clinical practices.

Early Auditory Temporal Processing Deficit in Children with Autism Spectrum Disorder: The Research Domain Criteria Framework

Altered sensory processing especially in the auditory system is considered a typical observation in children with autism spectrum disorder (ASD). Auditory temporal processing is known to be impaired in ASD children. Although research suggests that auditory temporal processing abnormalities could be responsible for the core aspects of ASD, few studies have examined early time processing and their results have been conflicting. The present event-related potential (ERP) study investigated the early neural responses to duration and inter-stimulus interval (ISI) deviants in nonspeech contexts in children with ASD and a control group of typically developing (TD) children matched in terms of age and IQ. A passive auditory oddball paradigm was employed to elicit the mismatch negativity (MMN) for change detection considering both the duration and ISI-based stimulus. The MMN results showed that the ASD group had a relatively diminished amplitude and significant delayed latency in response to duration deviants. The findings are finally discussed in terms of hyper-hyposensitivity of auditory processing and the fact that the observed patterns may potentially act as risk factors for ASD development within the research domain criteria (RDoC) framework.

Focus-marking in a tonal language: Prosodic differences between Cantonese-speaking children with and without autism spectrum disorder

Abnormal speech prosody has been widely reported in individuals with autism. Many studies on children and adults with autism spectrum disorder speaking a non-tonal language showed deficits in using prosodic cues to mark focus. However, focus marking by autistic children speaking a tonal language is rarely examined. Cantonese-speaking children may face additional difficulties because tonal languages require them to use prosodic cues to achieve multiple functions simultaneously such as lexical contrasting and focus marking. This study bridges this research gap by acoustically evaluating the use of Cantonese speech prosody to mark information structure by Cantonese-speaking children with and without autism spectrum disorder. We designed speech production tasks to elicit natural broad and narrow focus production among these children in sentences with different tone combinations. Acoustic correlates of prosodic focus marking like f0, duration and intensity of each syllable were analyzed to examine the effect of participant group, focus condition and lexical tones. Our results showed differences in focus marking patterns between Cantonese-speaking children with and without autism spectrum disorder. The autistic children not only showed insufficient on-focus expansion in terms of f0 range and duration when marking focus, but also produced less distinctive tone shapes in general. There was no evidence that the prosodic complexity (i.e. sentences with single tones or combinations of tones) significantly affected focus marking in these autistic children and their typically-developing (TD) peers.

Using Pivotal Response Treatment to Improve Language Functions of Autistic Children in Special Schools: A Randomized Controlled Trial

Language difficulties exert profound negative effects on the cognitive and social development of autistic children. Pivotal Response Treatment (PRT) is a promising intervention for improving social communication in autistic children, but there is a lack of a comprehensive examination of language functions. This study aimed to investigate the effectiveness of PRT in promoting the primary language functions (requesting, labeling, repeating, responding) defined by (Skinner, B. F. (1957). Verbal behavior. Martino Publishing.) theory of verbal behavior in autistic children. Thirty autistic children were randomly divided into the PRT group (Mage = 6.20, SDage = 1.21) and control group (Mage = 6.07, SDage = 1.49). The PRT group were provided with an 8-week training of the PRT motivation component in addition to treatment as usual (TAU) in their schools, whereas the control group only received TAU. Parents of the PRT group were also trained to practice the PRT motivation procedures at home. The PRT group demonstrated greater improvements in all four measured language functions compared to the control group. The improvement in language functions in the PRT group was generalized and maintained at the follow-up assessment. In addition, the PRT intervention enhanced untargeted social and communicative functioning, cognition, motor skills, imitation, and adaptive behaviors in the autistic children. In conclusion, language intervention using the motivation component of PRT is effective in promoting language functions as well as widespread untargeted cognitive and social functions in autistic children.

Language in autism: domains, profiles and co-occurring conditions

This article reviews the current knowledge state on pragmatic and structural language abilities in autism and their potential relation to extralinguistic abilities and autistic traits. The focus is on questions regarding autism language profiles with varying degrees of (selective) impairment and with respect to potential comorbidity of autism and language impairment: Is language impairment in autism the co-occurrence of two distinct conditions (comorbidity), a consequence of autism itself (no comorbidity), or one possible combination from a series of neurodevelopmental properties (dimensional approach)? As for language profiles in autism, three main groups are identified, namely, (i) verbal autistic individuals without structural language impairment, (ii) verbal autistic individuals with structural language impairment, and (iii) minimally verbal autistic individuals. However, this tripartite distinction hides enormous linguistic heterogeneity. Regarding the nature of language impairment in autism, there is currently no model of how language difficulties may interact with autism characteristics and with various extralinguistic cognitive abilities. Building such a model requires carefully designed explorations that address specific aspects of language and extralinguistic cognition. This should lead to a fundamental increase in our understanding of language impairment in autism, thereby paving the way for a substantial contribution to the question of how to best characterize neurodevelopmental disorders.

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.

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.

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.