Behavioral and physiological responses to child-directed speech of children with autism spectrum disorders or typical development

Autonomic nervous system responses to social stimuli among autistic individuals: A systematic review and meta-analysis

Physiological responses to environmental and social stimuli have been studied broadly in relation to psychological states and processes. This may be especially important regarding autistic individuals, who show disparities in social interactions. However, findings from studies assessing autonomic nervous system (ANS) responses of autistic individuals present contradictions, with reports showing both autonomic disparities and intact autonomic functioning. The current study aimed to review the existing literature and to estimate if there is a difference between autistic individuals and neurotypical (NT) individuals in their autonomic responses to social stimuli. Furthermore, the study examined factors that may moderate this difference, including the type of physiological function measured, the level of participation required, as well as the age and intellectual functioning of the participants. The meta-analysis revealed a small and statistically insignificant overall difference between autistic and NT individuals, albeit with high heterogeneity. A further nested moderator analysis revealed a significant difference between autistic and NT individuals in physiological response that reflects mainly a parasympathetic nervous system (PNS) activity. Another difference was found in physiological response that reflects a combined activity of the sympathetic and parasympathetic systems, but only for experimental tasks that demanded active participation in social interactions. These results suggest a distinctiveness in autonomic regulation of autistic individuals in social situations, and point to the PNS as an important study objective for future investigation.

Non-autistic persons modulate their speech rhythm while talking to autistic individuals

How non-autistic persons modulate their speech rhythm while talking to autistic (AUT) individuals remains unclear. We investigated two types of phonological characteristics: (1) the frequency power of each prosodic, syllabic, and phonetic rhythm and (2) the dynamic interaction among these rhythms using speech between AUT and neurotypical (NT) individuals. Eight adults diagnosed with AUT (all men; age range, 24-44 years) and eight age-matched non-autistic NT adults (three women, five men; age range, 23-45 years) participated in this study. Six NT and eight AUT respondents were asked by one of the two NT questioners (both men) to share their recent experiences on 12 topics. We included 87 samples of AUT-directed speech (from an NT questioner to an AUT respondent), 72 of NT-directed speech (from an NT questioner to an NT respondent), 74 of AUT speech (from an AUT respondent to an NT questioner), and 55 of NT speech (from an NT respondent to an NT questioner). We found similarities between AUT speech and AUT-directed speech, and between NT speech and NT-directed speech. Prosody and interactions between prosodic, syllabic, and phonetic rhythms were significantly weaker in AUT-directed and AUT speech than in NT-directed and NT speech, respectively. AUT speech showed weaker dynamic processing from higher to lower phonological bands (e.g. from prosody to syllable) than NT speech. Further, we found that the weaker the frequency power of prosody in NT and AUT respondents, the weaker the frequency power of prosody in NT questioners. This suggests that NT individuals spontaneously imitate speech rhythms of the NT and AUT interlocutor. Although the speech sample of questioners came from just two NT individuals, our findings may suggest the possibility that the phonological characteristics of a speaker influence those of the interlocutor.

Development and Parasympathetic Regulation in Male and Female Adolescents with Autism Spectrum Disorder: A Two-Timepoint Longitudinal Study

Prolonged dysregulation of the autonomic nervous system (ANS) may increase propensity for physical or psychiatric illness. The current study examined differences in respiratory sinus arrhythmia (RSA) regulation in 215 adolescents with or without autism spectrum disorder (ASD) at Time 1 (T1; 10-13 years old) and 1 year later (Time 2; T2). Linear mixed effects models demonstrated lower RSA regulation in ASD, and a small interaction effect, showing blunted change in RSA from T1 to T2. Developmental differences in RSA regulation were particularly notable in females with ASD and those taking psychotropic medications. Results expand previous findings of reduced parasympathetic regulation in ASD by revealing a blunted developmental slope, indicating diagnostic differences may persist or worsen over time, particularly in females.

Identifying phenotypic and physiological subgroups of preschoolers with autism spectrum disorder

BACKGROUND

To understand the emergence of symptoms in autism spectrum disorder (ASD), we need to identify the mechanisms that underpin the development of core social skills. Mounting evidence indicates that young children with later ASD attend less to other people, which could compromise learning opportunities with cascading effects. Passive looking behaviour does not tell us about engagement with visual information, but measures of physiological arousal can provide information on the depth of engagement. In the current study, we use heart rate (HR) and heart rate variability (HRV) to measure engagement with social dynamic stimuli in ASD.

METHODS

Sixty-seven preschoolers with ASD and 65 typical developing preschoolers between 2 and 4 years of age participated in a study where HR was measured during viewing of social and non-social videos. Using latent profile analyses, more homogeneous subgroups of children were created based on phenotype and physiology.

RESULTS

Preschool-aged children with ASD, regardless of their non-verbal, verbal and social competencies, do not differ in overall HR or HRV compared to TD children. However, the ASD group showed a larger increase in HR (more disengagement) than the TD group to later-presented social stimuli. Phenotypic and physiological profiles showed this was primarily the case for children with below average verbal and non-verbal skills, but not necessarily those with more ASD symptoms.

CONCLUSION

Children with ASD, especially a subgroup showing moderate cognitive delays, show an increase in HR to social stimuli over time; this may reflect difficulties re-engaging with social information when attention is waning.

Level of Attention to Motherese Speech as an Early Marker of Autism Spectrum Disorder

Importance

Caregivers have long captured the attention of their infants by speaking in motherese, a playful speech style characterized by heightened affect. Reduced attention to motherese in toddlers with autism spectrum disorder (ASD) may be a contributor to downstream language and social challenges and could be diagnostically revealing.

Objective

To investigate whether attention toward motherese speech can be used as a diagnostic classifier of ASD and is associated with language and social ability.

Design, Setting, and Participants

This diagnostic study included toddlers aged 12 to 48 months, spanning ASD and non-ASD diagnostic groups, at a research center. Data were collected from February 2018 to April 2021 and analyzed from April 2021 to March 2022.

Exposures

Gaze-contingent eye-tracking test.

Main Outcomes and Measures

Using gaze-contingent eye tracking wherein the location of a toddler's fixation triggered a specific movie file, toddlers participated in 1 or more 1-minute eye-tracking tests designed to quantify attention to motherese speech, including motherese vs traffic (ie, noisy vehicles on a highway) and motherese vs techno (ie, abstract shapes with music). Toddlers were also diagnostically and psychometrically evaluated by psychologists. Levels of fixation within motherese and nonmotherese movies and mean number of saccades per second were calculated. Receiver operating characteristic (ROC) curves were used to evaluate optimal fixation cutoff values and associated sensitivity, specificity, positive predictive value (PPV), and negative predictive value. Within the ASD group, toddlers were stratified based on low, middle, or high levels of interest in motherese speech, and associations with social and language abilities were examined.

Results

A total of 653 toddlers were included (mean [SD] age, 26.45 [8.37] months; 480 males [73.51%]). Unlike toddlers without ASD, who almost uniformly attended to motherese speech with a median level of 82.25% and 80.75% across the 2 tests, among toddlers with ASD, there was a wide range, spanning 0% to 100%. Both the traffic and techno paradigms were effective diagnostic classifiers, with large between-group effect sizes (eg, ASD vs typical development: Cohen d, 1.0 in the techno paradigm). Across both paradigms, a cutoff value of 30% or less fixation on motherese resulted in an area under the ROC curve (AUC) of 0.733 (95% CI, 0.693-0.773) and 0.761 (95% CI, 0.717-0.804), respectively; specificity of 98% (95% CI, 95%-99%) and 96% (95% CI, 92%-98%), respectively; and PPV of 94% (95% CI, 86%-98%). Reflective of heterogeneity and expected subtypes in ASD, sensitivity was lower at 18% (95% CI, 14%-22%) and 29% (95% CI, 24%-34%), respectively. Combining metrics increased the AUC to 0.841 (95% CI, 0.805-0.877). Toddlers with ASD who showed the lowest levels of attention to motherese speech had weaker social and language abilities.

Conclusions and Relevance

In this diagnostic study, a subset of toddlers showed low levels of attention toward motherese speech. When a cutoff level of 30% or less fixation on motherese speech was used, toddlers in this range were diagnostically classified as having ASD with high accuracy. Insight into which toddlers show unusually low levels of attention to motherese may be beneficial not only for early ASD diagnosis and prognosis but also as a possible therapeutic target.

Child language and autism diagnosis impact hierarchical temporal structure of parent-child vocal interactions in early childhood

Timing is critical to successful social interactions. The temporal structure of dyadic vocal interactions emerges from the rhythm, timing, and frequency of each individuals' vocalizations and reflects how the dyad dynamically organizes and adapts during an interaction. This study investigated the temporal structure of vocal interactions longitudinally in parent-child dyads of typically developing (TD) infants (n = 49; 9-18 months; 48% male) and toddlers with ASD (n = 23; 27.2 ± 5.0 months; 91.3% male) to identify how developing language and social skills impact the temporal dynamics of the interaction. Acoustic hierarchical temporal structure (HTS), a measure of the nested clustering of acoustic events across multiple timescales, was measured in free play interactions using Allan Factor. HTS reflects a signal's temporal complexity and variability, with greater HTS indicating reduced flexibility of the dyadic system. Child expressive language significantly predicted HTS (ß = -0.2) longitudinally across TD infants, with greater dyadic HTS associated with lower child language skills. ASD dyads exhibited greater HTS (i.e., more rigid temporal structure) than nonverbal matched (d = 0.41) and expressive language matched TD dyads (d = 0.28). Increased HTS in ASD dyads occurred at timescales >1 s, suggesting greater structuring of pragmatic aspects of interaction. Results provide a new window into how language development and social reciprocity serve as constraints to shape parent-child interaction dynamics and showcase a novel automated approach to characterizing vocal interactions across multiple timescales during early childhood.

Diagnostic and Physical Effects in Parasympathetic Response to Social Evaluation in Youth With and Without Autism Spectrum Disorder

Individuals with autism spectrum disorder (ASD) may demonstrate atypical autonomic (ANS) responses; however, research remains inconsistent. This study examined parasympathetic response during social evaluation in 241 youth (10-13 years) with ASD (n = 138) or typical development (TD; n = 103). Diagnosis, age, pubertal development, and body mass index (BMI) were hypothesized to be associated with ANS function. Linear mixed effects models demonstrated lower RSA in ASD relative to TD in a base model with no covariates. However, when accounting for differences in BMI, there was no evidence of atypical parasympathetic regulation in youth with ASD. As lower parasympathetic regulation may increase susceptibility for a number of conditions, it will be important to elucidate the link between BMI and the ANS, especially in ASD.

Stress System Activation in Children and Adolescents With Autism Spectrum Disorder

The mission of the human stress system is the maintenance of homeostasis in the presence of real or perceived, acute or chronic stressors. The hypothalamic–pituitary–adrenal (HPA) axis and the autonomic nervous system (ANS) are the stress system-related neuroendocrine pathways. There is abundant evidence that children and adolescents with autism spectrum disorder (ASD) may exhibit atypical function within the HPA axis and the ANS both at the resting state and during the presence of social and/or non-social stressors. The aim of this review is to provide an up-to-date summary of the findings regarding stress system alterations in children and adolescents with ASD. We focus on the variations of stress hormones circadian rhythms, specifically cortisol and alpha-amylase (i.e., a surrogate index of epinephrine/norepinephrine secretion), and on the alterations of stress system responsivity to different stressors. Also, we present imaging and immunological findings that have been associated with stress system dysregulation in children and adolescents with ASD. Finally, we review the pivotal role of HPA axis-ANS coordination, the developmental trajectory of the stress system in ASD, and the possible role of early life stress in the dysregulation of the stress system demonstrated in children and adolescents with ASD. This synthesis will hopefully provide researchers with a foundation for an integrated approach to future research into stress system variations in children and adolescents with ASD.

Autism Spectrum Disorder in Children Is Not Associated With Abnormal Autonomic Nervous System Function: Hypothesis and Theory

The quest to understand the pathophysiology of autism spectrum disorder (ASD) has led to extensive literature that purports to provide evidence for autonomic dysfunction based on heart rate and heart rate variability (HRV), in particular respiratory sinus arrhythmia (RSA), a measure of parasympathetic functioning. Many studies conclude that autism is associated with vagal withdrawal and sympathetic hyperactivation based on HRV and electrodermal analyses. We will argue that a critical analysis of the data leads to the hypothesis that autonomic nervous system dysfunction is not a dominant feature of autism. Most children with ASD have normal parasympathetic baseline values and normal autonomic responses to social stimuli. The existing HRV and electrodermal data cannot lead to the conclusion of an over-excitation of the sympathetic nervous system. A small subgroup of ASD children in experimental settings has relatively low RSA values and relatively high heart rates. The data suggest that this is likely associated with a relatively high level of anxiety during study conditions, associated with co-morbidities such as constipation, or due to the use of psychoactive medication. Many studies interpret their data to conform with a preferred hypothesis of autonomic dysfunction as a trait of autism, related to the polyvagal theory, but the HRV evidence is to the contrary. HRV analysis may identify children with ASD having autonomic dysfunction due to co-morbidities.

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.

Brief Report: Can a Composite Heart Rate Variability Biomarker Shed New Insights About Autism Spectrum Disorder in School-Aged Children?

Several studies show altered heart rate variability (HRV) in autism spectrum disorder (ASD), but findings are neither universal nor specific to ASD. We apply a set of linear and nonlinear HRV measures-including phase rectified signal averaging-to segments of resting ECG data collected from school-age children with ASD, age-matched typically developing controls, and children with other psychiatric conditions characterized by altered HRV (conduct disorder, depression). We use machine learning to identify time, frequency, and geometric signal-analytical domains that are specific to ASD (receiver operating curve area = 0.89). This is the first study to differentiate children with ASD from other disorders characterized by altered HRV. Despite a small cohort and lack of external validation, results warrant larger prospective studies.

Automatic Classification of Adult Males With and Without Autism Spectrum Disorder by Non-contact Measurement of Autonomic Nervous System Activation

People with autism spectrum disorder (ASD) exhibit atypicality in various domains of behavior. Previous psychophysiological studies have revealed an atypical pattern of autonomic nervous system (ANS) activation induced by psychosocial stimulation. Thus, it might be feasible to develop a novel assessment tool to evaluate the risk of ASD by measuring ANS activation in response to emotional stimulation. The present study investigated whether people with ASD could be automatically classified from neurotypical adults based solely on physiological data obtained by the recently introduced non-contact measurement of pulse wave. We video-recorded faces of adult males with and without ASD while watching emotion-inducing video clips. Features reflective of ANS activation were extracted from the temporal fluctuation of facial skin coloration and entered into a machine-learning algorithm. Though the performance was modest, the gradient boosting classifier succeeded in classifying people with and without ASD, which indicates that facial skin color fluctuation contains information useful for detecting people with ASD. Taking into consideration the fact that the current study recruited only high-functioning adults who have relatively mild symptoms and probably developed some compensatory strategies, ASD screening by non-contact measurement of pulse wave could be a promising assessment tool to evaluate ASD risk.

A wearable heart rate measurement device for children with autism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by early impairment in social and communication domains and autonomic nervous system unbalance. This study evaluated heart rate (HR) as a possible indicator of stress response in children with ASD as compared to children with language disorder (LD). Twenty-four patients [mean age = 42.62 months; SD = 8.14 months,12 with ASD (10 M/2F) and 12 with LD (8 M/4F)] underwent clinical [Leiter International Performance Scale-Revised, Autism Diagnostic Observation Schedule, second edition (ADOS-2)] and physiological evaluation (HR monitoring) during five interactive activities, while wearing an HR measurement device. IQ (ASD:IQ = 103.33 ± 12.85 vs. LD:IQ = 111.00 ± 8.88, p = 0.103) and fluid reasoning on the Leiter-R Scale were within the normal range in all subjects. Increased HR during the third activity (ADOS-2 bubble play) significantly correlated with autistic symptoms (r = 0.415; p = 0.044), while correlations between ADOS-2 total score and HR during the first activity (ADOS-2 free play; r = 0.368; p = 0.077), second activity (Leiter-R figure ground subscale; r = 0.373, p = 0.073), and fifth activity (ADOS-2 anticipation of a routine with objects; r = 0.368; p = 0.076) did not quite reach statistical significance. Applying a linear regression model, we found that the ADOS-2 total score significantly influenced HR variations (p = 0.023). HR monitoring may provide a better understanding of the stress-provoking situations for children with ASD. Furthermore, it could help clinicians detect the impact of the stressful condition on the autistic core and adress treatment strategy.

The role of early social motivation in explaining variability in functional language in toddlers with autism spectrum disorder

LAY ABSTRACT

About one-third of children with autism spectrum disorder never develop the language that they need in different day-to-day situations. Identifying potential factors that can predict later language development is crucial to understanding why some children with autism spectrum disorder successfully develop language while others do not. This study sought to investigate one of the understudied predictors of language development, social motivation, and to test theories for why this association may occur. Testing the theories requires that we measure children's ability to deliberately and directly communicate with others (i.e. intentional communication) and children's language understanding between the measures of social motivation and later expressive language. We tested 87 children with autism spectrum disorder, aged 14-31 months, at four times over 24 months. We found that children with relatively stronger social motivation had relatively better language use 2 years later. This positive link was partly due to a child's ability to produce intentional communication and to understand language. Although we did not measure parents' talking to their children, a theory that inspired this study suggests that children who use frequent intentional communication probably motivate others to talk with them frequently, which facilitates children's language understanding which leads to the development of expressive language. This theory, if confirmed to be true, can provide guidance for parents who want to help their children learn to talk. Parents could look for intentional communication from their children and respond by talking to their children. Effective intervention on both parent and child targets will likely enhance treatment efficacy. Future work is needed to test these ideas.

Content Words in Child-Directed Speech of Mothers Toward Children With Autism Spectrum Disorder

Purpose Our study aimed to analyze the characteristics of content word usage in mother's child-directed speech ( CDS) toward children with autism spectrum disorder compared to mother's CDS toward typically developing children. Method We analyzed the lexical characteristics of CDS of mothers of children with autism (16 dyads) and compared them from a language developmental perspective to mothers of 20 typical children at the same level of expressive language development. Results Results suggest that mothers of children with autism use equal amounts of content words at the same language level, but the content consists of significantly more concrete nouns and active verbs and rarely the use of abstract nouns, stative verbs, adjectives, and adverbs. Conclusion This study suggests that professionals and parents of children with autism should be aware of the importance of varying their language use of content words.

Exploring Key Physiological System Profiles at Rest and the Association with Depressive Symptoms in Autism Spectrum Disorder

Depression is often associated with dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Individuals with autism spectrum disorder (ASD) may experience physiological dysregulation and psychological comorbidities; however, the extent to which the interactions between these systems predict internalizing symptoms in ASD has not been investigated. The study examined interactions with the HPA axis and ANS in 10-13-year-old children with ASD (n = 41) and typical development (TD; n = 46). The interrelated systems uniquely contributed to depressive symptoms in ASD above and beyond any system in isolation. A reciprocal, parasympathetic-dominant ANS was related to fewer affective symptoms in ASD. Findings highlight the importance of examining arousal across multiple systems to more precisely identify profiles associated with maladaptive psychiatric outcomes in ASD.

Physiological regulation and social-emotional processing in female carriers of the FMR1 premutation

The FMR1 gene is associated with a wide range of clinical and cognitive phenotypes, ranging from intellectual disability and autism symptoms in fragile X syndrome (caused by the FMR1 full mutation), to a more varied, and still poorly understood range of clinical and cognitive phenotypes among carriers of the gene in its premutation state. Because the FMR1 premutation is relatively common among women (as high as 1 in 150), investigations of its phenotypic impact could have broad implications for understanding gene-behavior relationships underlying complex human traits, with potential clinical implications. This study investigated physiological regulation measured by pupillary responses, along with fixation patterns while viewing facial expressions among women who carry the FMR1 premutation (PM group; n = 47), to examine whether the FMR1 gene may relate to physiological regulation, social-emotional functioning, and social language skills (where subclinical differences have been previously reported among PM carriers that resemble those documented in autism-related conditions). Relative to controls (n = 25), the PM group demonstrated atypical pupillary responses and fixation patterns, controlling for IQ. In the PM group, pupillary response and fixation patterns were related to social cognition, social language abilities, and FMR1-related variation. Results indicate a pattern of atypical attention allocation among women who carry the FMR1 PM that could reflect different emotion-processing strategies mediated by autonomic dysregulation and the FMR1 gene. These findings lend insight into the FMR1 gene's potential contributions to complex human traits such as social emotional processing and social language.

Williams Syndrome, Human Self-Domestication, and Language Evolution

Language evolution resulted from changes in our biology, behavior, and culture. One source of these changes might be human self-domestication. Williams syndrome (WS) is a clinical condition with a clearly defined genetic basis which results in a distinctive behavioral and cognitive profile, including enhanced sociability. In this paper we show evidence that the WS phenotype can be satisfactorily construed as a hyper-domesticated human phenotype, plausibly resulting from the effect of the WS hemideletion on selected candidates for domestication and neural crest (NC) function. Specifically, we show that genes involved in animal domestication and NC development and function are significantly dysregulated in the blood of subjects with WS. We also discuss the consequences of this link between domestication and WS for our current understanding of language evolution.

Comparing stress and arousal systems in response to different social contexts in children with ASD

Response to psychological stress can vary based on the extent to which the context is perceived as stressful, especially under different social conditions. The purpose of this preliminary study was to compare physiological stress (cortisol) and regulation (respiratory sinus arrhythmia, RSA) of 10-12 year old children with autism spectrum disorder (ASD, n = 31) or typical development (TD, n = 25) when exposed to two social stress protocols. The extent to which perceived emotion (affect recognition) and anxiety (state and trait) mediate the stress response was also explored. Results revealed different patterns of stress responses dependent on the type of stressor. During a friendly social interaction, both groups generally showed an adaptive, synergistic response between cortisol and RSA. In response to social evaluation, however, the ASD group did not show correlating responses between physiological systems, which was likely due to a blunted stress response to the social evaluative stressor. The ability to recognize neutral faces mediated the relationship between diagnostic group and physiological response to social evaluation, indicating that perception of threat is essential to triggering a stress response. The current study emphasizes the need to consider the important role of social context, social perception, and perceived anxiety when examining social interaction and stress.

Predicting Receptive-Expressive Vocabulary Discrepancies in Preschool Children With Autism Spectrum Disorder

PURPOSE

Correlates of receptive-expressive vocabulary size discrepancies may provide insights into why language development in children with autism spectrum disorder (ASD) deviates from typical language development and ultimately improve intervention outcomes.

METHOD

We indexed receptive-expressive vocabulary size discrepancies of 65 initially preverbal children with ASD (20-48 months) to a comparison sample from the MacArthur-Bates Communicative Development Inventories Wordbank (Frank, Braginsky, Yurovsky, & Marchman, 2017) to quantify typicality. We then tested whether attention toward a speaker and oral motor performance predict typicality of the discrepancy 8 months later.

RESULTS

Attention toward a speaker correlated positively with receptive-expressive vocabulary size discrepancy typicality. Imitative and nonimitative oral motor performance were not significant predictors of vocabulary size discrepancy typicality. Secondary analyses indicated that midpoint receptive vocabulary size mediated the association between initial attention toward a speaker and end point receptive-expressive vocabulary size discrepancy typicality.

CONCLUSIONS

Findings support the hypothesis that variation in attention toward a speaker might partially explain receptive-expressive vocabulary size discrepancy magnitude in children with ASD. Results are consistent with an input-processing deficit explanation of language impairment in this clinical population. Future studies should test whether attention toward a speaker is malleable and causally related to receptive-expressive discrepancies in children with ASD.

Heart Rate Variability During a Joint Attention Task in Toddlers With Autism Spectrum Disorders

Background: Autism Spectrum Disorders (ASD) are a heterogeneous group of neurodevelopmental disorders featuring early impairments in social domain, with autonomic nervous system (ANS) unbalance possibly representing a useful marker for such disturbances. Impairments in joint attention (JA) are one of the earliest markers of social deficits in ASD. In this study, we assessed the feasibility of using wearable technologies for characterizing the ANS response in ASD toddlers during the presentation of JA stimuli. Methods: Twenty ASD toddlers and 20 age- and gender-matched typically developed (TD) children were recorded at baseline and during a JA task through an unobtrusive chest strap for electrocardiography (ECG). Specific algorithms for feature extraction, including Heart Rate (HR), Standard Deviation of the Normal-to-Normal Intervals (SDNN), Coefficient of Variation (CV), pNN10 as well as low frequency (LF) and high frequency (HF), were applied to the ECG signal and a statistical comparison between the two groups was performed. Results: As regards the single phases, SDNN (p = 0.04) and CV (p = 0.021) were increased in ASD at baseline together with increased LF absolute power (p = 0.034). Moreover, CV remained higher in ASD during the task (p = 0.03). Considering the phase and group interaction, LF increased from baseline to task in TD group (p = 0.04) while it decreased in the ASD group (p = 0.04). Conclusions: The results of this study indicate the feasibility of characterizing the ANS response in ASD toddlers through a minimally obtrusive tool. Our analysis showed an increased SDNN and CV in toddlers with ASD particularly at baseline compared to TD and lower LF during the task. These findings could suggest the possibility of using the proposed approach for evaluating physiological correlates of JA response in young children with ASD.

Differing Developmental Trajectories in Heart Rate Responses to Speech Stimuli in Infants at High and Low Risk for Autism Spectrum Disorder

We investigated heart rate (HR) in infants at 3, 6, 9, and 12 months of age, at high (HRA) and low (LRC) familial risk for ASD, to identify potential endophenotypes of ASD risk related to attentional responses. HR was extracted from functional near-infrared spectroscopy recordings while infants listened to speech stimuli. Longitudinal analysis revealed that HRA infants and males generally had lower baseline HR than LRC infants and females. HRA infants showed decreased HR responses to early trials over development, while LRC infants showed increased responses. These findings suggest altered developmental trajectories in physiological responses to speech stimuli over the first year of life, with HRA infants showing less social orienting over time.

Physiological Response to Social Evaluative Threat in Adolescents with Autism Spectrum Disorder

The Trier Social Stress Test (TSST) was employed to study response to social evaluative threat in male adolescents with Autism Spectrum Disorder (ASD, n = 21) and typical development (n = 13). Participants wore a mobile electrocardiogram to collect heart rate data. There were significant group effects on respiratory sinus arrhythmia (RSA), a measure of parasympathetic nervous system function, with lower values in ASD (F = 4.97). Bivariate correlations also showed a significant relationship between parent reports of social problems and RSA response to the TSST (r = -0.586). These findings suggest that autonomic dysregulation may contribute to social deficits in adolescents with ASD.

Joint attention and oromotor abilities in young children with and without autism spectrum disorder

PURPOSE

This study examined the relationship between joint attention ability and oromotor imitation skill in three groups of young children with and without Autism Spectrum Disorder using both nonverbal oral and verbal motor imitation tasks. Research questions addressed a) differences among joint attention and oromotor imitation abilities; b) the relationship between independently measured joint attention and oromotor imitation, both nonverbal oral and verbal motor; c) the relationships between joint attention and verbal motor imitation during interpersonal interaction; and d) the relationship between the sensory input demands (auditory, visual, and tactile) and oromotor imitation, both nonverbal oral and verbal motor.

METHOD

A descriptive, nonexperimental design was used to compare joint attention and oromotor skills of 10 preschool-aged children with ASD, with those of two control groups: 6 typically developing children (TD), and 6 children with suspected Childhood Apraxia of Speech (sCAS) or apraxic-like symptoms. All children had at least a 3.0 mean length utterance.

RESULTS

Children with ASD had poorer joint attention skills overall than children with sCAS or typically developing children. Typically developing children demonstrated higher verbal motor imitation skills overall compared to children with sCAS. Correlational analyses revealed that nonverbal oral imitation and verbal motor imitation were positively related to joint attention abilities only in the children with ASD. Strong positive relationships between joint attention in a naturalistic context (e.g., shared story experience) and oromotor imitation skills, both nonverbal oral and verbal motor, were found only for children with ASD. These data suggest there is a strong positive relationship between joint attention skills and the ability to sequence nonverbal oral and verbal motor movements in children with ASD. The combined sensory input approach involving auditory, visual, and tactile modalities contributed to significantly higher nonverbal oral and verbal motor imitation performance for all groups of children.

CONCLUSIONS

Verbal children with ASD in this study had difficulties with both the social and cognitive demands of oromotor imitation within a natural environment that demanded cross-modal processing of incoming stimuli within an interpersonal interaction. Further, joint attention and oral praxis may serve as components of an important coupling mechanism in the development of spoken communication and later developing socialcognitive skills.

Atypical preference for infant-directed speech as an early marker of autism spectrum disorders? A literature review and directions for further research

Autism spectrum disorders (ASD) refer to a complex group of neurodevelopmental disorders causing difficulties with communication and interpersonal relationships, as well as restricted and repetitive behaviours and interests. As early identification, diagnosis, and intervention provide better long-term outcomes, early markers of ASD have gained increased research attention. This review examines evidence that auditory processing enhanced by social interest, in particular auditory preference of speech directed towards infants and young children (i.e. infant-directed speech - IDS), may be an early marker of risk for ASD. Although this review provides evidence for IDS preference as, indeed, a potential early marker of ASD, the explanation for differences in IDS processing among children with ASD versus other children remains unclear, as are the implications of these impairments for later social-communicative development. Therefore, it is crucial to explore atypicalities in IDS processing early on development and to understand whether preferential listening to specific types of speech sounds in the first years of life may help to predict the impairments in social and language development.

A systematic review of physiological reactivity to stimuli in autism

OBJECTIVE

The prevalence of abnormal behavioural responses to a variety of stimuli among individuals with autism has led researchers to examine whether physiological reactivity (PR) is typical in this population. This article reviewed studies assessing PR to sensory, social and emotional, and stressor stimuli in individuals with autism.

METHODS

Systematic searches of electronic databases identified 57 studies that met our inclusion criteria. Studies were analysed to determine: (a) participant characteristics; (b) physiological measures used; (c) PR to sensory, social and emotional or stressor stimuli; (d) the relation between PR and behavioural or psychological variables and (e) baseline physiological activity. A novel measure of methodological quality suitable for use with non-randomized, non-interventional, psychophysiological studies was also developed and applied.

RESULTS

Individuals with autism were found to respond differently than typically developing controls in 78.6%, 66.7% and 71.4% of sensory, social and emotional, and stressor stimulus classes, respectively. However, this extant literature is characterized by variable and inconsistent findings, which do not appear to be accounted for by varying methodological quality, making it difficult to determine what specific factors differentiate individuals with autism who present with atypical PR from those who do not.

CONCLUSIONS

Despite this uncertainty, individual differences in PR are clearly present in autism, suggesting additional research is needed to determine the variables relating to PR among those with ASD and to examine the possible existence of physiological subtype responders in the population.

The integrity of lexical acquisition mechanisms in autism spectrum disorders: A research review

Research on autism spectrum disorders (ASD) has rapidly expanded in recent years, yielding important developments in both theory and practice. While we have gained important insights into how children with ASD differ from typically developing (TD) children in terms of phenotypic features, less has been learned about if and how development in ASD differs from typical development in terms of underlying mechanisms of change. This article aims to provide a review of processes subserving lexical development in ASD, with the goal of identifying contributing factors to the heterogeneity of language outcomes in ASD. The focus is on available evidence of the integrity or disruption of these mechanisms in ASD, as well as their significance for vocabulary development; topics include early speech perception and preference, speech segmentation, word learning, and category formation. Significant gaps in the literature are identified and future directions are suggested. Autism Res 2016, 9: 810-828. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Value-added predictors of expressive and receptive language growth in initially nonverbal preschoolers with autism spectrum disorders

Eighty-seven preschoolers with autism spectrum disorders who were initially nonverbal (under 6 words in language sample and under 21 parent-reported words said) were assessed at five time points over 16 months. Statistical models that accounted for the intercorrelation among nine theoretically- and empirically-motivated predictors, as well as two background variables (i.e., cognitive impairment level, autism severity), were applied to identify value-added predictors of expressive and receptive spoken language growth and outcome. The results indicate that responding to joint attention, intentional communication, and parent linguistic responses were value-added predictors of both expressive and receptive spoken language growth. In addition, consonant inventory was a value-added predictor of expressive growth; early receptive vocabulary and autism severity were value-added predictors of receptive growth.

Cardiac autonomic regulation in autism and Fragile X syndrome: a review

Despite the significance of efforts to understand the biological basis of autism, progress in this area has been hindered, in part, by the considerable heterogeneity in the disorder. Fragile X syndrome (FXS), a monogenic condition associated with high risk for autism, may pave the way for the dissection of biological heterogeneity within idiopathic autism. This article adopts a cross-syndrome biomarker approach to evaluate potentially overlapping profiles of cardiac arousal dysregulation (and broader autonomic dysfunction) in autism and FXS. Approaches such as this, aimed at delineating shared mechanisms across genetic syndromes, hold great potential for improving diagnostic precision, promoting earlier identification, and uncovering key systems that can be targeted in pharmaceutical/behavioral interventions. Biomarker approaches may be vital to deconstructing complex psychiatric disorders and are currently promoted as such by major research initiatives such as the NIMH Research Domain Criteria (RDoC). Evidence reviewed here supports physiological dysregulation in a subset of individuals with autism, as evidenced by patterns of hyperarousal and dampened parasympathetic vagal tone that overlap with the well-documented physiological profile of FXS. Moreover, there is growing support for a link between aberrant cardiac activity and core deficits associated with autism, such as communication and social impairment. The delineation of physiological mechanisms common to autism and FXS could lend insight into relationships between genetic etiology and behavioral endstates, highlighting FMR1 as a potential candidate gene. Research gaps and potential pitfalls are discussed to inform timely, well-controlled biomarker research that will ultimately promote better diagnosis and treatment of autism and associated conditions.

Social smiling and its components in high-risk infant siblings without later ASD symptomatology

Impaired affective expression, including social smiling, is common in children with autism spectrum disorder (ASD), and may represent an early marker for ASD in their infant siblings (Sibs-ASD). Social smiling and its component behaviors (eye contact and non-social smiling) were examined at 15 months in Sibs-ASD who demonstrated later ASD symptomatology (Sibs-ASD/AS), those who did not (Sibs-ASD/NS), and low-risk controls (Sibs-TD). Both Sibs-ASD subgroups demonstrated lower levels of social smiling than Sibs-TD, suggesting that early social smiling may reflect elevated genetic vulnerability rather than a specific marker for ASD. Only the Sibs-ASD/AS demonstrated less eye contact and non-social smiling than Sibs-TD, suggesting that different processes, threshold effects, or protective factors may underlie social smiling development in the two Sibs-ASD subgroups.

Differences in HPA-axis and heart rate responsiveness to psychosocial stress in children with autism spectrum disorders with and without co-morbid anxiety

Children and adolescents with autism spectrum disorder (ASD) have much higher rates of anxiety disorders relative to their typically developing peers. However, there have been few attempts to investigate what physiological parameters may be associated with this elevated rate of anxiety. Therefore, this study investigated the physiological correlates of anxiety in ASD, with a focus on whether measures of heart rate and cortisol responsiveness to psychosocial stress differentiate those participants with ASD with and without a co-occurring anxiety disorder. A total of 75 male participants aged 10-16 years with normal intellectual ability underwent a psychosocial stress test. The participants included healthy controls (n=23), ASD only (ASD; n=20) and ASD with a comorbid anxiety disorder (ASDanx; n=32). Heart rate, heart rate variability and salivary cortisol were compared by fitting a piecewise regression model to examine baseline levels and change over time within and between the rest, stress and recovery phases of the stress test. The ASDanx group had different response patterns from both the ASD and control groups. The ASDanx group was characterized by a blunted cortisol and heart rate response to psychosocial stress. Furthermore, in the ASDanx group, reduced heart rate and cortisol responsiveness were significantly related to increased anxiety symptoms. This is the first study to report a possible physiological basis for co-occurring anxiety disorders in children and adolescents with ASD. It is possible that a non-adaptive physiological response to psychosocial stress may be related to the high prevalence of co-occurring anxiety disorders in people with ASD.

Functional autonomic nervous system profile in children with autism spectrum disorder

Background

Autonomic dysregulation has been recently reported as a feature of autism spectrum disorder (ASD). However, the nature of autonomic atypicalities in ASD remain largely unknown. The goal of this study was to characterize the cardiac autonomic profile of children with ASD across four domains affected in ASD (anxiety, attention, response inhibition, and social cognition), and suggested to be affected by autonomic dysregulation.

Methods

We compared measures of autonomic cardiac regulation in typically developing children (n = 34) and those with ASD (n = 40) as the children performed tasks eliciting anxiety, attention, response inhibition, and social cognition. Heart rate was used to quantify overall autonomic arousal, and respiratory sinus arrhythmia (RSA) was used as an index of vagal influences. Associations between atypical autonomic findings and intellectual functioning (Weschler scale), ASD symptomatology (Social Communication Questionnaire score), and co-morbid anxiety (Revised Children’s Anxiety and Depression Scale) were also investigated.

Results

The ASD group had marginally elevated basal heart rate, and showed decreased heart rate reactivity to social anxiety and increased RSA reactivity to the social cognition task. In this group, heart rate reactivity to the social anxiety task was positively correlated with IQ and task performance, and negatively correlated with generalized anxiety. RSA reactivity in the social cognition task was positively correlated with IQ.

Conclusions

Our data suggest overall autonomic hyperarousal in ASD and selective atypical reactivity to social tasks.

Media use and sleep among boys with autism spectrum disorder, ADHD, or typical development

OBJECTIVE

The current study examined the relationships between media use (television, computer, and video games) and sleep among boys with autism spectrum disorder (ASD) compared with those with attention-deficit/hyperactivity disorder (ADHD) or with typical development (TD).

METHODS

Participants included parents of boys with ASD (n = 49), ADHD (n = 38), or TD (n = 41) (ages 8-17 years). Questionnaires assessed daily hours of media use, bedroom access to media, and average sleep hours per night.

RESULTS

Bedroom media access was associated with less time spent sleeping per night, irrespective of diagnostic group. Bedroom access to a television or a computer was more strongly associated with reduced sleep among boys with ASD compared with boys with ADHD or TD. Multivariate models showed that, in addition to bedroom access, the amount of time spent playing video games was uniquely associated with less sleep among boys with ASD. In the ASD group only, the relationship between bedroom access to video games and reduced sleep was mediated by hours of video game play.

CONCLUSIONS

The current results suggest that media-related variables may be an important consideration in understanding sleep disturbances in children with ASD. Further research is needed to better characterize the processes by which media use may affect sleep among individuals with ASD. Overall, the current findings suggest that screen-based media time and bedroom media access should be routinely assessed and may be important intervention targets when addressing sleep problems in children with ASD.

A multimethod assessment of anxiety and problem behavior in children with autism spectrum disorders and intellectual disability

Despite the increased risk for anxiety disorders in children with autism spectrum disorders (ASD), there is a lack of research on the assessment and treatment of anxiety in this population, particularly for those with an intellectual disability (ID). The present study evaluated a multimethod strategy for the assessment of anxiety and problem behavior in three children with ASD and ID. Anxiety was operationally defined using: (1) behavioral data from anxious behaviors, (2) affective/contextual data from parent-report and observer ratings of overall anxiety, and (3) physiological data (heart rate [HR] and respiratory sinus arrhythmia [RSA]). A functional assessment of problem behavior during high- and low-anxiety conditions was conducted. Higher levels of problem behavior and HR and lower RSA were found in the high-anxiety than in the low-anxiety conditions.

Physiological arousal in autism and fragile X syndrome: group comparisons and links with pragmatic language

This study tested the hypothesis that pragmatic (i.e., social) language impairment is linked to arousal dysregulation in autism spectrum disorder (ASD) and fragile X syndrome (FXS). Forty boys with ASD, 39 with FXS, and 27 with typical development (TD), aged 4-15 years, participated. Boys with FXS were hyperaroused compared to boys with TD but did not differ from boys with ASD. Dampened vagal tone predicted pragmatic impairment in ASD, and associations emerged between cardiac activity and receptive/expressive vocabulary across groups. Findings support autonomic dysfunction as a mechanism underlying pragmatic impairment in ASD and suggest that biophysiological profiles are shared in ASD and FXS, which has implications for understanding the role of fragile X mental retardation-1 (FMR1, the FXS gene) in the pathophysiology of ASD.

Psychophysiological responses to emotional stimuli in children and adolescents with autism and fragile X syndrome

Individuals with autism demonstrate atypical and variable responses to social and emotional stimuli, perhaps reflecting heterogeneity of the disorder. The goal of this study was to determine whether unique profiles of psychophysiological responses to such stimuli could be identified in individuals diagnosed with autism spectrum disorder (ASD), with fragile X syndrome (FXS), and with comorbid autism and fragile X syndrome (ASD + FXS), and in typically developing (TYP) individuals. This study included 52 boys (ages 10-17): idiopathic ASD (n = 12), FXS (n = 12), comorbid ASD + FXS (n = 17), and TYP (n = 11). Physiological responses, including potentiated startle, electrodermal response, heart rate variability, and vagal tone, were collected concurrently while participants viewed emotionally evocative pictures of human faces or nonsocial images. Although some of these measures have been utilized separately for investigations on these diagnostic groups, they have not been considered together. Results using Kruskal-Wallis one-way analysis of variance by ranks indicate statistically significant differences in distributions of autonomic regulation responses between groups. The most notable differences were between the ASD group and both the FXS groups on measures of sympathetic activity, with FXS groups evincing increased activity. Also, both the ASD and ASD + FXS groups showed significantly decreased parasympathetic activity compared with FXS and TYP groups. In addition, the ASD + FXS group demonstrated a unique distribution of startle potentiation and arousal modulation. This study provides evidence that autonomic arousal and regulation profiles could be useful for distinguishing subgroups of autism and shed light on the variability underlying emotional responsivity.

Do parentese prosody and fathers' involvement in interacting facilitate social interaction in infants who later develop autism?

BACKGROUND

Whether development of autism impacts the interactive process between an infant and his/her parents remains an unexplored issue.

METHODOLOGY AND PRINCIPAL FINDINGS

Using computational analysis taking into account synchronic behaviors and emotional prosody (parentese), we assessed the course of infants' responses to parents' type of speech in home movies from typically developing (TD) infants and infants who will subsequently develop autism aged less than 18 months. Our findings indicate: that parentese was significantly associated with infant responses to parental vocalizations involving orientation towards other people and with infant receptive behaviours; that parents of infants developing autism displayed more intense solicitations that were rich in parentese; that fathers of infants developing autism spoke to their infants more than fathers of TD infants; and that fathers' vocalizations were significantly associated with intersubjective responses and active behaviours in infants who subsequently developed autism.

CONCLUSION

The parents of infants who will later develop autism change their interactive pattern of behaviour by both increasing parentese and father's involvement in interacting with infants; both are significantly associated with infant's social responses. We stress the possible therapeutic implications of these findings and its implication for Dean Falk's theory regarding pre-linguistic evolution in early hominins.