Distinctive prosodic features of people with autism spectrum disorder: a systematic review and meta-analysis study

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.

Predicting Social Competence in Autistic and Non-Autistic Children: Effects of Prosody and the Amount of Speech Input

PURPOSE

Autistic individuals often face challenges perceiving and expressing emotions, potentially stemming from differences in speech prosody. Here we explore how autism diagnoses between groups, and measures of social competence within groups may be related to, first, children's speech characteristics (both prosodic features and amount of spontaneous speech), and second, to these two factors in mothers' speech to their children.

METHODS

Autistic (n = 21) and non-autistic (n = 18) children, aged 7-12 years, participated in a Lego-building task with their mothers, while conversational speech was recorded. Mean F0, pitch range, pitch variability, and amount of spontaneous speech were calculated for each child and their mother.

RESULTS

The results indicated no differences in speech characteristics across autistic and non-autistic children, or across their mothers, suggesting that conversational context may have large effects on whether differences between autistic and non-autistic populations are found. However, variability in social competence within the group of non-autistic children (but not within autistic children) was predictive of children's mean F0, pitch range and pitch variability. The amount of spontaneous speech produced by mothers (but not their prosody) predicted their autistic children's social competence, which may suggest a heightened impact of scaffolding for mothers of autistic children.

CONCLUSION

Together, results suggest complex interactions between context, social competence, and adaptive parenting strategies in driving prosodic differences in children's speech.

Patients' Demographics and Risk Factors in Voice Disorders: An Umbrella Review of Systematic Reviews

OBJECTIVES

This study aimed to provide a comprehensive overview of the systematic reviews that focus on the prevalence of voice disorders (VDs), associated risk factors, and the demographic characteristics of patients with dysphonia. An umbrella review was conducted to identify general research themes in voice literature that might guide future research initiatives and contribute to the classification of VDs as a worldwide health concern.

STUDY DESIGN

Umbrella review of systematic reviews.

METHODS

Pubmed/Medline and Embase were searched for eligible systematic reviews by two authors independently. Extracted data items included the study publication details, study design, characteristics of the target population, sample size, region/country, and incidence and/or prevalence of the VD(s) of interest.

RESULTS

Forty systematic reviews were included. Sixteen reported a meta-analysis. Great heterogeneity in methods was found. A total of 277,035 patients across the included studies were included with a prevalence ranging from 0%-90%. The countries represented best were the United States and Brazil, with 13 studies each. Aging, occupational voice use, lifestyle choices, and specific comorbidities, such as obesity or hormonal disorders, seem to be associated with an increased prevalence of dysphonia.

CONCLUSIONS

This review underscores the influence of VDs on distinct patient groups and the general population. A variety of modifiable or non-modifiable risk factors, having varied degrees of impact on voice qualities, have been identified. The overall effect of VDs is probably underestimated due to factors, such as sample size, patient selection, underreporting of symptoms, and asymptomatic cases. Employing systematic reviews with consistent methodologies and criteria for diagnosing VDs would enhance the ability to determine the prevalence of VDs and their impact.

English Prosodic Focus Marking by Cantonese Trilingual Children With and Without Autism Spectrum Disorder

PURPOSE

The current study investigated English prosodic focus marking by autistic and typically developing (TD) Cantonese trilingual children, and examined the potential differences in this regard compared to native English-speaking children.

METHOD

Forty-eight participants were recruited with 16 speakers for each of the three groups (Cantonese-speaking autistic [CASD], Cantonese-speaking TD [CTD], and English-speaking TD [ETD] children), and prompt questions were designed to elicit desired focus type (i.e., broad, narrow, and contrastive focus). Mean duration, mean fundamental frequency (F0), F0 range, mean intensity, and F0 curves were used as the acoustic correlates for linear mixed-effects model fitting and functional data analyses in relation to groups and focus conditions (i.e., broad, narrow, and contrastive pre-, on-, and post-focus).

RESULTS

The CTD group had post-focus compression (PFC) patterns via reducing mean duration, narrowing F0 range, and lowering mean F0, F0 curve, and mean intensity for words under both narrow and contrastive post-focus conditions, while the CASD group only had shortened mean duration and lowered F0 curves. However, neither the CTD group nor CASD group showed much of on-focus expansion (OFE) patterns. The ETD group marked OFE by increasing mean duration, mean F0, mean intensity, and higher F0 curve for words under on-focus conditions.

CONCLUSIONS

The CTD group utilized more acoustic cues than the CASD group when it comes to PFC. The ETD group differed from the CASD and CTD groups in the use of OFE. Furthermore, both the CASD and CTD groups showed positive first language transfer in the use of duration and intensity and, potentially, successful acquisition in the use of F0 for prosodic focus marking. Meanwhile, the differences in the use of OFE between the Cantonese-speaking and English-speaking groups, not PFC, might indicate that Cantonese-speaking children acquire PFC prior to OFE.

Foundations of Vocal Category Development in Autistic Infants

The present study compared the infant's tendency in the first year of life to produce clusters of particular vocal types (squeals, vocants, and growls) in typically developing (TD) and autistic infants. Vocal clustering provides evidence of vocal category formation and may establish a foundation for speech development. Specifically, we compared the extent of vocal clustering across outcome groups and age groups. We also examined the associations between the extent of vocal clustering and later outcomes at 2 years within the autistic group. Randomly selected 5-min segments (27,153 5-min segments total) from 1293 all-day home recordings from 103 TD infants and 44 autistic infants across the first year were humancoded (about 9.75 h of data coded per infant on average) to derive vocal clustering patterns. Fisher's exact tests were used to compare the occurrence of squeals versus vocants, as well as growls versus vocants, across coded segments. Infants in both groups demonstrated clear clustering patterns of squeals and growls across all age groups. The extent of vocal clustering in the autistic group did not correlate significantly with later language, repetitive behavior, or autism severity outcomes. These findings highlight the robustness of the systematic production of vocal categories across the first year of life. The similarity of the clustering patterns in the TD and autistic groups suggests that vocal category formation through active infant vocal exploration is a robust feature of early speech development.

Objective assessment of autism spectrum disorder based on performance in structured interpersonal acting-out tasks with prosodic stability and variability

In this study, we sought to objectively and quantitatively characterize the prosodic features of autism spectrum disorder (ASD) via the characteristics of prosody in a newly developed structured speech experiment. Male adults with high-functioning ASD and age/intelligence-matched men with typical development (TD) were asked to read 29 brief scripts aloud in response to preceding auditory stimuli. To investigate whether (1) highly structured acting-out tasks can uncover the prosodic of difference between those with ASD and TD, and (2) the prosodic stableness and flexibleness can be used for objective automatic assessment of ASD, we compared prosodic features such as fundamental frequency, intensity, and mora duration. The results indicate that individuals with ASD exhibit stable pitch registers or volume levels in some affective vocal-expression scenarios, such as those involving anger or sadness, compared with TD and those with TD. However, unstable prosody was observed in some timing control or emphasis tasks in the participants with ASD. Automatic classification of the ASD and TD groups using a support vector machine (SVM) with speech features exhibited an accuracy of 90.4%. A machine learning-based assessment of the degree of ASD core symptoms using support vector regression (SVR) also had good performance. These results may inform the development of a new easy-to-use assessment tool for ASD core symptoms using recorded audio signals.

Can Natural Speech Prosody Distinguish Autism Spectrum Disorders? A Meta-Analysis

Natural speech plays a pivotal role in communication and interactions between human beings. The prosody of natural speech, due to its high ecological validity and sensitivity, has been acoustically analyzed and more recently utilized in machine learning to identify individuals with autism spectrum disorders (ASDs). In this meta-analysis, we evaluated the findings of empirical studies on acoustic analysis and machine learning techniques to provide statistically supporting evidence for adopting natural speech prosody for ASD detection. Using a random-effects model, the results observed moderate-to-large pooled effect sizes for pitch-related parameters in distinguishing individuals with ASD from their typically developing (TD) counterparts. Specifically, the standardized mean difference (SMD) values for pitch mean, pitch range, pitch standard deviation, and pitch variability were 0.3528, 0.6744, 0.5735, and 0.5137, respectively. However, the differences between the two groups in temporal features could be unreliable, as the SMD values for duration and speech rate were only 0.0738 and -0.0547. Moderator analysis indicated task types were unlikely to influence the final results, whereas age groups showed a moderating role in pooling pitch range differences. Furthermore, promising accuracy rates on ASD identification were shown in our analysis of multivariate machine learning studies, indicating averaged sensitivity and specificity of 75.51% and 80.31%, respectively. In conclusion, these findings shed light on the efficacy of natural prosody in identifying ASD and offer insights for future investigations in this line of research.

Endophenotype trait domains for advancing gene discovery in autism spectrum disorder

Autism spectrum disorder (ASD) is associated with a diverse range of etiological processes, including both genetic and non-genetic causes. For a plurality of individuals with ASD, it is likely that the primary causes involve multiple common inherited variants that individually account for only small levels of variation in phenotypic outcomes. This genetic landscape creates a major challenge for detecting small but important pathogenic effects associated with ASD. To address similar challenges, separate fields of medicine have identified endophenotypes, or discrete, quantitative traits that reflect genetic likelihood for a particular clinical condition and leveraged the study of these traits to map polygenic mechanisms and advance more personalized therapeutic strategies for complex diseases. Endophenotypes represent a distinct class of biomarkers useful for understanding genetic contributions to psychiatric and developmental disorders because they are embedded within the causal chain between genotype and clinical phenotype, and they are more proximal to the action of the gene(s) than behavioral traits. Despite their demonstrated power for guiding new understanding of complex genetic structures of clinical conditions, few endophenotypes associated with ASD have been identified and integrated into family genetic studies. In this review, we argue that advancing knowledge of the complex pathogenic processes that contribute to ASD can be accelerated by refocusing attention toward identifying endophenotypic traits reflective of inherited mechanisms. This pivot requires renewed emphasis on study designs with measurement of familial co-variation including infant sibling studies, family trio and quad designs, and analysis of monozygotic and dizygotic twin concordance for select trait dimensions. We also emphasize that clarification of endophenotypic traits necessarily will involve integration of transdiagnostic approaches as candidate traits likely reflect liability for multiple clinical conditions and often are agnostic to diagnostic boundaries. Multiple candidate endophenotypes associated with ASD likelihood are described, and we propose a new focus on the analysis of "endophenotype trait domains" (ETDs), or traits measured across multiple levels (e.g., molecular, cellular, neural system, neuropsychological) along the causal pathway from genes to behavior. To inform our central argument for research efforts toward ETD discovery, we first provide a brief review of the concept of endophenotypes and their application to psychiatry. Next, we highlight key criteria for determining the value of candidate endophenotypes, including unique considerations for the study of ASD. Descriptions of different study designs for assessing endophenotypes in ASD research then are offered, including analysis of how select patterns of results may help prioritize candidate traits in future research. We also present multiple candidate ETDs that collectively cover a breadth of clinical phenomena associated with ASD, including social, language/communication, cognitive control, and sensorimotor processes. These ETDs are described because they represent promising targets for gene discovery related to clinical autistic traits, and they serve as models for analysis of separate candidate domains that may inform understanding of inherited etiological processes associated with ASD as well as overlapping neurodevelopmental disorders.

Automated extraction of speech and turn-taking parameters in autism allows for diagnostic classification using a multivariable prediction model

Autism spectrum disorder (ASD) is diagnosed on the basis of speech and communication differences, amongst other symptoms. Since conversations are essential for building connections with others, it is important to understand the exact nature of differences between autistic and non-autistic verbal behaviour and evaluate the potential of these differences for diagnostics. In this study, we recorded dyadic conversations and used automated extraction of speech and interactional turn-taking features of 54 non-autistic and 26 autistic participants. The extracted speech and turn-taking parameters showed high potential as a diagnostic marker. A linear support vector machine was able to predict the dyad type with 76.2% balanced accuracy (sensitivity: 73.8%, specificity: 78.6%), suggesting that digitally assisted diagnostics could significantly enhance the current clinical diagnostic process due to their objectivity and scalability. In group comparisons on the individual and dyadic level, we found that autistic interaction partners talked slower and in a more monotonous manner than non-autistic interaction partners and that mixed dyads consisting of an autistic and a non-autistic participant had increased periods of silence, and the intensity, i.e. loudness, of their speech was more synchronous.

Negative first impression judgements of autistic children by non-autistic adults

Introduction

Although autism inclusion and acceptance has increased in recent years, autistic people continue to face stigmatization, exclusion, and victimization. Based on brief 10-second videos, non-autistic adults rate autistic adults less favourably than they rate non-autistic adults in terms of traits and behavioural intentions. In the current study, we extended this paradigm to investigate the first impressions of autistic and non-autistic children by non-autistic adult raters and examined the relationship between the rater's own characteristics and bias against autistic children.

Method

Segments of video recorded interviews from 15 autistic and 15 non-autistic children were shown to 346 undergraduate students in audio with video, audio only, video only, transcript, or still image conditions. Participants rated each child on a series of traits and behavioural intentions toward the child, and then completed a series of questionnaires measuring their own social competence, autistic traits, quantity and quality of past experiences with autistic people, and explicit autism stigma.

Results

Overall, autistic children were rated more negatively than non-autistic children, particularly in conditions containing audio. Raters with higher social competence and explicit autism stigma rated autistic children more negatively, whereas raters with more autistic traits and more positive past experiences with autistic people rated autistic children more positively.

Discussion

These rapid negative judgments may contribute to the social exclusion experienced by autistic children. The findings indicate that certain personal characteristics may be related to more stigmatised views of autism and decreased willingness to interact with the autistic person. The implications of the findings are discussed in relation to the social inclusion and well-being of autistic people.

The role of interpersonal synchrony in forming impressions of autistic and non-autistic adults

When people meet, they almost instantaneously form an impression of each other. First impressions of character traits and rapport are less favourable when people with autism spectrum condition (ASC) are judged compared to non-autistic people. Little is known about the behavioural differences that drive these altered impressions. In the present study, we investigated the influence of interpersonal synchrony on impression formation of autistic and non-autistic people. Specifically, we used lagged cross-correlations to assess how much each interactant's motion energy, a measure which can be determined from video recordings, influenced the other interactant's motion energy. In short, silent clips of dyadic conversations, we asked non-autistic participants to rate their impression of one of the two interactants, which was solely based on the outlines of both interactants. We expected that the amount of leading of the target interactant, their diagnostic status as well as the interaction of these factors would influence impression formation. We found that while the amount of leading had a positive effect on the impressions of non-autistic interactants, this was not true for interactants with ASC. This suggests that interpersonal synchrony of motion energy is one driver of less favourable impressions of autistic compared to non-autistic people.

Prosodic signatures of ASD severity and developmental delay in preschoolers

Atypical prosody in speech production is a core feature of Autism Spectrum Disorder (ASD) that can impact everyday life communication. Because the ability to modulate prosody develops around the age of speech acquisition, it might be affected by ASD symptoms and developmental delays that emerge at the same period. Here, we investigated the existence of a prosodic signature of developmental level and ASD symptom severity in a sample of 74 autistic preschoolers. We first developed an original diarization pipeline to extract preschoolers' vocalizations from recordings of naturalistic social interactions. Using this novel approach, we then found a robust voice quality signature of ASD developmental difficulties in preschoolers. Furthermore, some prosodic measures were associated with one year later outcome in participants who had not acquired speech yet. Altogether, our results highlight the potential benefits of automatized diarization algorithms and prosodic metrics for digital phenotyping in psychiatry, helping clinicians establish early diagnosis and prognosis.

Differences in speech articulatory timing and associations with pragmatic language ability in autism

Background

Speech articulation difficulties have not traditionally been considered to be a feature of Autism Spectrum Disorder (ASD). In contrast, speech prosodic differences have been widely reported in ASD, and may even be expressed in subtle form among clinically unaffected first-degree relatives, representing the expression of underlying genetic liability. Some evidence has challenged this traditional dichotomy, suggesting that differences in speech articulatory mechanisms may be evident in ASD, and potentially related to perceived prosodic differences. Clinical measurement of articulatory skills has traditionally been phoneme-based, rather than by acoustic measurement of motor control. Subtle differences in articulatory/motor control, prosodic characteristics (acoustic), and pragmatic language ability (linguistic) may each be contributors to differences perceived by listeners, but the interrelationship is unclear. In this study, we examined the articulatory aspects of this relationship, in speech samples from individuals with ASD and their parents during narration.

Method

Using Speechmark® analysis, we examined articulatory landmarks, fine-grained representations of articulatory timing as series of laryngeal and vocal-tract gestures pertaining to prosodic elements crucial for conveying pragmatic information.

Results

Results revealed articulatory timing differences in individuals with ASD but not their parents, suggesting that although potentially not influenced by broader genetic liability to ASD, subtle articulatory differences may indeed be evident in ASD as the recent literature indicates. A follow-up path analysis detected associations between articulatory timing differences and prosody, and subsequently, pragmatic language ability.

Conclusion

Together, results suggest a complex relationship where subtle differences in articulatory timing may result in atypical acoustic signals, and serve as a distal mechanistic contributor to pragmatic language ability ASD.

Verbal entrainment in autism spectrum disorder and first-degree relatives

Entrainment, the unconscious process leading to coordination between communication partners, is an important dynamic human behavior that helps us connect with one another. Difficulty developing and sustaining social connections is a hallmark of autism spectrum disorder (ASD). Subtle differences in social behaviors have also been noted in first-degree relatives of autistic individuals and may express underlying genetic liability to ASD. In-depth examination of verbal entrainment was conducted to examine disruptions to entrainment as a contributing factor to the language phenotype in ASD. Results revealed distinct patterns of prosodic and lexical entrainment in individuals with ASD. Notably, subtler entrainment differences in prosodic and syntactic entrainment were identified in parents of autistic individuals. Findings point towards entrainment, particularly prosodic entrainment, as a key process linked to social communication difficulties in ASD and reflective of genetic liability to ASD.

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.