Adults with autism overestimate the volatility of the sensory environment.

Insistence on sameness and intolerance of change are among the diagnostic criteria for autism spectrum disorder (ASD), but little research has addressed how people with ASD represent and respond to environmental change. Here, behavioral and pupillometric measurements indicated that adults with ASD are less surprised than neurotypical adults when their expectations are violated, and decreased surprise is predictive of greater symptom severity. A hierarchical Bayesian model of learning suggested that in ASD, a tendency to overlearn about volatility in the face of environmental change drives a corresponding reduction in learning about probabilistically aberrant events, thus putatively rendering these events less surprising. Participant-specific modeled estimates of surprise about environmental conditions were linked to pupil size in the ASD group, thus suggesting heightened noradrenergic responsivity in line with compromised neural gain. This study offers insights into the behavioral, algorithmic and physiological mechanisms underlying responses to environmental volatility in ASD

Increased Sensory Processing Atypicalities in Parents of Multiplex ASD Families Versus Typically Developing and Simplex ASD Families

Recent studies have suggested that sensory processing atypicalities may share genetic influences with autism spectrum disorder (ASD). To further investigate this, the adolescent/adult sensory profile (AASP) questionnaire was distributed to 85 parents of typically developing children (P-TD), 121 parents from simplex ASD families (SPX), and 54 parents from multiplex ASD families (MPX). After controlling for gender and presence of mental disorders, results showed that MPX parents significantly differed from P-TD parents in all four subscales of the AASP. Differences between SPX and MPX parents reached significance in the Sensory Sensitivity subscale and also in subsequent modality-specific analyses in the auditory and visual domains. Our finding that parents with high genetic liability for ASD (i.e., MPX) had more sensory processing atypicalities than parents with low (i.e., SPX) or no (i.e., P-TD) ASD genetic liability suggests that sensory processing atypicalities may contribute to the genetic susceptibility for ASD

A revised method for measuring distraction by tactile stimulation

Sensory hypersensitivity (SH) refers to the tendency to attend to subtle stimuli, to persist in attending to them, and to find them noxious. SH is relatively common in several developmental disorders including Tourette Syndrome and Chronic Tic Disorder (TS/CTD). This study was an attempt to quantify the extent to which a mild tactile stimulus distracts one’s attention in TS/CTD. Fourteen adults with TS/CTD and 14 tic-free control subjects completed questionnaires regarding SH and ADHD, and TS/CTD subjects completed self-report measures of current and past tic disorder symptoms and of current obsessions and compulsions. All subjects performed a sustained attention choice reaction time task during alternating blocks in which a mildly annoying stimulus (von Frey hair) was applied to the ankle (“ON”) or was not applied (“OFF”). We present here the clinical and cognitive task data for each subject