Sensitivity to communicative and non-communicative gestures in adolescents and adults with autism spectrum disorder: saccadic and pupillary responses

Intact gesture cueing of attention but attenuated sensitivity to peripheral social targets in autistic children: An eye-tracking and pupillometric study

BACKGROUND

Altered automatic attention cueing has been reported in autistic children. Yet less is known about how autistic children would respond when the social cue that directs attention occurs in an implied social interaction.

METHODS

By using eye-tracking, the current study examined orienting responses to a socially-relevant target or a nonsocial target cued by a goal-directed social gesture in autistic children. Saccadic reaction time and pupillary responses were employed to measure gaze behavior and physiological arousal of autistic children.

RESULTS

Both groups of children showed reflexive orienting to the target regardless of its sociality, whereas typically developing (TD) children exhibited faster gaze shift than autistic children when the target was a social stimulus. An increased pupil dilation was observed in autistic children in response to stimuli relative to TD children. Further, autistic children showed larger baseline pupil response.

CONCLUSIONS

Autistic children show attenuated sensitivity to social targets and atypical pupil responses, which may be due to the dysfunction of locus coeruleus (LC) - norepinephrine (NE) system.

Quicker Exogenous Orienting and Slower Endogenous Orienting in Autistic People

Research is equivocal on whether attention orienting is atypical in autism. This study investigated two types of attention orienting in autistic people and accounted for the potential confounders of alerting level, co-occurring symptoms of attention-deficit/hyperactivity disorder (ADHD) and anxiety, age, and sex. Twenty-seven autistic participants (14 males; 9-43 years) and 22 age- and sex-matched non-autistic participants (13 males; 9-42 years) completed the exogenous and endogenous Posner tasks. Response time and pupillometric data were recorded. Autistic participants were faster at orienting attention to valid cues in the exogenous task and slower at disengaging from invalid cues in the endogenous task compared to non-autistic participants. With increasing age, autistic participants showed faster exogenous and endogenous orienting, whereas non-autistic participants showed faster exogenous orienting but stable speed of endogenous orienting. Higher ADHD symptoms were associated with slower exogenous orienting in both groups, whereas higher anxiety symptoms were associated with faster exogenous orienting only in autistic participants. No group differences were noted for alerting levels, sex, or pupillary responses. This study provides new evidence of superior exogenous orienting and inefficient endogenous orienting in autistic people and suggests that age and co-occurring symptoms are important to consider when assessing attention orienting in autism.

Interpretations of meaningful and ambiguous hand gestures in autistic and non-autistic adults: A norming study

Gestures are ubiquitous in human communication, and a growing but inconsistent body of research suggests that people with autism spectrum disorder (ASD) may process co-speech gestures differently from neurotypical individuals. To facilitate research on this topic, we created a database of 162 gesture videos that have been normed for comprehensibility by both autistic and non-autistic raters. These videos portray an actor performing silent gestures that range from highly meaningful (e.g., iconic gestures) to ambiguous or meaningless. Each video was rated for meaningfulness and given a one-word descriptor by 40 autistic and 40 non-autistic adults, and analyses were conducted to assess the level of within- and across-group agreement. Across gestures, the meaningfulness ratings provided by raters with and without ASD correlated at r > 0.90, indicating a very high level of agreement. Overall, autistic raters produced a more diverse set of verbal labels for each gesture than did non-autistic raters. However, measures of within-gesture semantic similarity among the responses provided by each group did not differ, suggesting that increased variability within the ASD group may have occurred at the lexical rather than semantic level. This study is the first to compare gesture naming between autistic and non-autistic individuals, and the resulting dataset is the first gesture stimulus set for which both groups were equally represented in the norming process. This database also has broad applicability to other areas of research related to gesture processing and comprehension. The video database and accompanying norming data are available on the Open Science Framework.

Autism-Related Differences in Cortical Activation When Observing, Producing, and Imitating Communicative Gestures: An fNIRS Study

Children with autism spectrum disorder (ASD) have difficulties in gestural communication during social interactions. However, the neural mechanisms involved in naturalistic gestural communication remain poorly understood. In this study, cortical activation patterns associated with gestural communication were examined in thirty-two children with and without ASD (mean age: 11.0 years, SE: 0.6 years). Functional near-infrared spectroscopy (fNIRS) was used to record cortical activation while children produced, observed, or imitated communicative gestures. Children with ASD demonstrated more spatial and temporal errors when performing and imitating communicative gestures. Although both typically developing (TD) children and children with ASD showed left-lateralized cortical activation during gesture production, children with ASD showed hyperactivation in the middle/inferior frontal gyrus (MIFG) during observation and imitation, and hypoactivation in the middle/superior temporal gyrus (MSTG) during gesture production compared to their TD peers. More importantly, children with ASD exhibited greater MSTG activation during imitation than during gesture production, suggesting that imitation could be an effective intervention strategy to engage cortical regions crucial for processing and producing gestures. Our study provides valuable insights into the neural mechanisms underlying gestural communication difficulties in ASD, while also identifying potential neurobiomarkers that could serve as objective measures for evaluating intervention effectiveness in children with ASD.

Differences in functional brain organization during gesture recognition between autistic and neurotypical individuals

Persons with and without autism process sensory information differently. Differences in sensory processing are directly relevant to social functioning and communicative abilities, which are known to be hampered in persons with autism. We collected functional magnetic resonance imaging data from 25 autistic individuals and 25 neurotypical individuals while they performed a silent gesture recognition task. We exploited brain network topology, a holistic quantification of how networks within the brain are organized to provide new insights into how visual communicative signals are processed in autistic and neurotypical individuals. Performing graph theoretical analysis, we calculated two network properties of the action observation network: 'local efficiency', as a measure of network segregation, and 'global efficiency', as a measure of network integration. We found that persons with autism and neurotypical persons differ in how the action observation network is organized. Persons with autism utilize a more clustered, local-processing-oriented network configuration (i.e. higher local efficiency) rather than the more integrative network organization seen in neurotypicals (i.e. higher global efficiency). These results shed new light on the complex interplay between social and sensory processing in autism.

Reduced Pupil Oscillation During Facial Emotion Judgment in People with Autism Spectrum Disorder

People with autism spectrum disorder (ASD) show abnormal face perception and emotion recognition. However, it remains largely unknown whether these differences are associated with abnormal physiological responses when viewing faces. In this study, we employed a sensitive emotion judgment task and conducted a detailed investigation of pupil dilation/constriction and oscillation in high-functioning adult participants with ASD and matched controls. We found that participants with ASD showed normal pupil constriction to faces; however, they demonstrated reduced pupil oscillation, which was independent of stimulus properties and participants' perception of the emotion. Together, our results have revealed an abnormal physiological response to faces in people with ASD, which may in turn be associated with impaired face perception previously found in many studies.

Neural-level associations of non-verbal pragmatic comprehension in young Finnish autistic adults

This video-based study examines the pragmatic non-verbal comprehension skills and corresponding neural-level findings in young Finnish autistic adults, and controls. Items from the Assessment Battery of Communication (ABaCo) were chosen to evaluate the comprehension of non-verbal communication. Inter-subject correlation (ISC) analysis of the functional magnetic resonance imaging data was used to reveal the synchrony of brain activation across participants during the viewing of pragmatically complex scenes of ABaCo videos. The results showed a significant difference between the ISC maps of the autistic and control groups in tasks involving the comprehension of non-verbal communication, thereby revealing several brain regions where correlation of brain activity was greater within the control group. The results suggest a possible weaker modulation of brain states in response to the pragmatic non-verbal communicative situations in autistic participants. Although there was no difference between the groups in behavioural responses to ABaCo items, there was more variability in the accuracy of the responses in the autistic group. Furthermore, mean answering and reaction times correlated with the severity of autistic traits. The results indicate that even if young autistic adults may have learned to use compensatory resources in their communicative-pragmatic comprehension, pragmatic processing in naturalistic situations still requires additional effort.

Differences in the production and perception of communicative kinematics in autism

In human communication, social intentions and meaning are often revealed in the way we move. In this study, we investigate the flexibility of human communication in terms of kinematic modulation in a clinical population, namely, autistic individuals. The aim of this study was twofold: to assess (a) whether communicatively relevant kinematic features of gestures differ between autistic and neurotypical individuals, and (b) if autistic individuals use communicative kinematic modulation to support gesture recognition. We tested autistic and neurotypical individuals on a silent gesture production task and a gesture comprehension task. We measured movement during the gesture production task using a Kinect motion tracking device in order to determine if autistic individuals differed from neurotypical individuals in their gesture kinematics. For the gesture comprehension task, we assessed whether autistic individuals used communicatively relevant kinematic cues to support recognition. This was done by using stick-light figures as stimuli and testing for a correlation between the kinematics of these videos and recognition performance. We found that (a) silent gestures produced by autistic and neurotypical individuals differ in communicatively relevant kinematic features, such as the number of meaningful holds between movements, and (b) while autistic individuals are overall unimpaired at recognizing gestures, they processed repetition and complexity, measured as the amount of submovements perceived, differently than neurotypicals do. These findings highlight how subtle aspects of neurotypical behavior can be experienced differently by autistic individuals. They further demonstrate the relationship between movement kinematics and social interaction in high-functioning autistic individuals. LAY SUMMARY: Hand gestures are an important part of how we communicate, and the way that we move when gesturing can influence how easy a gesture is to understand. We studied how autistic and typical individuals produce and recognize hand gestures, and how this relates to movement characteristics. We found that autistic individuals moved differently when gesturing compared to typical individuals. In addition, while autistic individuals were not worse at recognizing gestures, they differed from typical individuals in how they interpreted certain movement characteristics.

Processing of pragmatic communication in ASD: a video-based brain imaging study

Social and pragmatic difficulties in autism spectrum disorder (ASD) are widely recognized, although their underlying neural level processing is not well understood. The aim of this study was to examine the activity of the brain network components linked to social and pragmatic understanding in order to reveal whether complex socio-pragmatic events evoke differences in brain activity between the ASD and control groups. Nineteen young adults (mean age 23.6 years) with ASD and 19 controls (mean age 22.7 years) were recruited for the study. The stimulus data consisted of video clips showing complex social events that demanded processing of pragmatic communication. In the analysis, the functional magnetic resonance imaging signal responses of the selected brain network components linked to social and pragmatic information processing were compared. Although the processing of the young adults with ASD was similar to that of the control group during the majority of the social scenes, differences between the groups were found in the activity of the social brain network components when the participants were observing situations with concurrent verbal and non-verbal communication events. The results suggest that the ASD group had challenges in processing concurrent multimodal cues in complex pragmatic communication situations.

Autism spectrum disorder and pupillometry: A systematic review and meta-analysis

Pupillometry, measuring pupil size and reactivity, has been proposed as a measure of autonomic nervous system functioning, the latter which might be altered in individuals with autism spectrum disorder (ASD). This study aims to evaluate if pupillary responses differ in individuals with and without ASD. After performing a systematic literature search, we conducted a meta-analysis and constructed a qualitative synthesis. The meta-analysis shows a longer latency of the pupil response in the ASD-group as a substantial group difference, with a Hedges' g of 1.03 (95% CI 0.49-1.56, p = 0.008). Evidence on baseline pupil size and amplitude change is conflicting. We used the framework method to perform a qualitative evaluation of these differences. Explanations for the group differences vary between studies and are inconclusive, but many authors point to involvement of the autonomous nervous system and more specifically the locus coeruleus-norepinephrine system. Pupillometry reveals differences between people with and without ASD, but the exact meaning of these differences remains unknown. Future studies should align research designs and investigate a possible effect of maturation.

KAMUTHE video microanalysis system for use in Brazil: translation, cross-cultural adaptation and evidence of validity and reliability

<b>Background</b><br /> KAMUTHE is a video microanalysis system which observes preverbal communication within the music therapy setting. This system is indicated for children with autism spectrum disorder (ASD) or multiple disabilities. The purpose of this study was to translate, adapt to Brazilian Portuguese language and analyze some psychometric properties (reliability and validity evidence) of KAMUTHE administration in Brazil for individuals with ASD.<br /> <br /> <b>Participants and procedure</b><br /> Translation, back translation, analysis by judges, and pilot application were performed to obtain evidence of content and face validity. The second part of this study was to administer KAMUTHE in 39 consecutive children with ASD. An individual session of improvisational music therapy was applied to assess the different behaviors included in KAMUTHE. The intra-rater reliability, concurrent validity and convergent validity were analyzed.<br /> <br /> <b>Results</b><br /> Translation and cross-cultural adaptation were followed and some cultural adaptations were needed. Inter-rater reliability was very good (ICCs 0.95-0.99) for the three child’s behaviors analyzed. Criteria validity with a moderate negative association was found (r = –.38, p = .017) comparing the behavior “Gazes at therapist” and the level of ASD along with the Childhood Autism Rating Scale (CARS). Convergent validity was established between the behavior “Gazes at therapist” and the two nonlinguistic communication scales (social interaction and interests) of the Children’s Communication Checklist (CCC) with a moderate correlation (r = –.43, p = .005).<br /> <br /> <b>Conclusions</b><br /> The administration of the KAMUTHE video microanalysis system showed positive results in children with ASD. Further studies are needed to improve the reliability and validity of the instrument in Brazil.