Temporal resolution relates to sensory hyperreactivity independently of stimulus detection sensitivity in individuals with autism spectrum disorder.

Researchers have been focusing on perceptual characteristics of autism spectrum disorder (ASD) in terms of sensory hyperreactivity. Previously, we demonstrated that temporal resolution, which is the accuracy to differentiate the order of two successive vibrotactile stimuli, is associated with the severity of sensory hyperreactivity. We currently examined whether an increase in the perceptual intensity of a tactile stimulus, despite its short duration, is derived from high temporal resolution and high frequency of sensory temporal summation. Twenty ASD and 22 typically developing (TD) participants conducted two psychophysical experimental tasks to evaluate detectable duration of vibrotactile stimulus with same amplitude and to evaluate temporal resolution. The sensory hyperreactivity was estimated using self-reported questionnaire. There was no relationship between the temporal resolution and the duration of detectable stimuli in both groups. However, the ASD group showed severe sensory hyperreactivity in daily life than TD group, and the ASD participants with severe sensory hyperreactivity tended to have high temporal resolution, not high sensitivity of detectable duration. Contrary to the hypothesis, there might be different processing between temporal resolution and sensitivity for stimulus detection. We suggested that the atypical temporal processing would affect to sensory reactivity in ASD.

Sensory and Social Subtypes of Japanese Individuals with Autism Spectrum Disorders.

Studies have proposed that individuals with autism spectrum disorder (ASD) can be divided into several subtypes depending on their sensory features. However, consideration of social communication features is also crucial for configuring ASD subtypes, because social and sensory features are tightly interrelated. In this study, we asked Japanese individuals with ASD to answer the Short Sensory Profile (SSP) and the Social Responsiveness Scale, Second Edition (SRS-2), which measure sensory and social aspects, respectively. Consequent latent profile analysis demonstrated that the participants could be divided into five subgroups: two groups exhibited opposite or inconsistent patterns between the SSP and SRS-2 scores, while the other groups exhibited consistent patterns. Our findings indicate the existence of diverse phenotypes in individuals with ASD.

State anxiety modulates the effect of emotion cues on visual temporal sensitivity in autism spectrum disorder.

Atypical processing of stimulus inputs across a range of sensory modalities in autism spectrum disorder (ASD) is widely reported. Sensory processing is known to be influenced by bodily internal states such as physiological arousal and anxiety. As a sizeable proportion of ASD reportedly have co-morbid anxiety disorders that are linked with dysregulated arousal, we investigated if face emotion arousal cues influenced visual sensory sensitivity (indexed by temporal resolution) in ASD (n = 20) compared to a matched group of typically developed individuals (TD, n = 21). We asked further if emotion-cued changes in visual sensitivity were associated with individual differences in state and trait anxiety. Participants reported the laterality of the second of two consecutive Gaussian-blob flashes in a visual temporal order judgment task (v-TOJ), demanding higher-level visual processing. The key manipulation was presenting a task-irrelevant face emotion cue briefly at unexpected time points preceding the task-relevant flashes. Disgust vs. Neutral emotion signals significantly enhanced the visual temporal resolution in ASD. Individual state-anxiety scores showed a fair correlative trend with the emotion-cued changes in temporal resolution (Disgust versus Neutral) in ASD but missed statistical significance. Both these effects were absent in TD. The results show that individual state-anxiety levels likely modulate the effect of emotions on visual temporal sensitivity in ASD. The findings support a nuanced approach to understand the disparate sensory features in ASD, by factoring in the interplay of the individual reactivity to environmental affective information and the severity of anxiety.