Assessment of anxiety symptoms in autism spectrum disorders (ASD) is a challenging task due to the symptom overlap between the two conditions as well as the difficulties in communication and awareness of emotions in ASD. This motivates the development of a physiological marker of anxiety in ASD that is independent of language and does not require observation of overt behaviour. In this study, we investigated the feasibility of using indicators of autonomic nervous system (ANS) activity for this purpose. Specially, the objectives of the study were to 1) examine whether or not anxiety causes significant measurable changes in indicators of ANS in an ASD population, and 2) characterize the pattern of these changes in ASD. We measured three physiological indicators of the autonomic nervous system response (heart rate, electrodermal activity, and skin temperature) during a baseline (movie watching) and anxiety condition (Stroop task) in a sample of typically developing children (n = 17) and children with ASD (n = 12). The anxiety condition caused significant changes in heart rate and electrodermal activity in both groups, however, a differential pattern of response was found between the two groups. In particular, the ASD group showed elevated heart rate during both baseline and anxiety conditions. Elevated and blunted phasic electrodermal activity were found in the ASD group during baseline and anxiety conditions, respectively. Finally, the ASD group did not show the typical decrease in skin temperature in response to anxiety. These results suggest that 1) signals of the autonomic nervous system may be used as indicators of anxiety in children with ASD, and 2) ASD may be associated with an atypical autonomic response to anxiety that is most consistent with sympathetic over-arousal and parasympathetic under-arousal.

The developing language abilities and increased risks of 'unaffected' siblings of children with autism spectrum disorder Practice points Siblings of children with autism spectrum disorder (ASD) have a one in five chance of being diagnosed with ASD. This risk is over 16 times higher than children in the general population. First degree relatives are at an increased risk for subclinical ASD traits, referred to as Broader Autism Phenotype, and other neurodevelopmental and psychiatric disorders. Structural language refers to the lexical and syntactic abilities in receptive and expressive language. In ASD, individuals demonstrate a wide range of structural language abilities. Common features in ASD include atypical language and early language delays. Prospective longitudinal studies of infant siblings of children with ASD reveal that those who do not go on to have ASD are still at greater risk for early language delays than low-risk controls. Many studies have shown particular delays in receptive language in this group. Very few studies have examined structural language in siblings in middle childhood, and results are mixed; larger sample sizes are needed. Pragmatics refers to the appropriate use of language in a social context. Pragmatic abilities are universally impaired in children with ASD, making these abilities a strong candidate for investigation in high-risk siblings. However, measurement of pragmatics can be challenging. Despite strong research rationale, currently, there is a scarcity of research on pragmatic abilities in non-ASD siblings.

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