Paired-pulse tactile stimulation enhances tactile perception in neurotypical but not autistic children

Tactile sensory differences are common in autism. Sensory gating, a mechanism by which perception is filtered, is of relevance, yet it is unknown if atypical sensory filtering in autistic people directly impacts the perception of sensory stimuli. In this study we used a novel psychophysical protocol to examine the effect of pre-pulse sub-threshold stimulation on tactile detection thresholds in 8-12 year old autistic (n = 24) and neurotypical (n = 51) children. We used two pre-pulse conditions with either a 30 ms or 100 ms interval. We hypothesised, based on prior work, that sub-threshold stimulation would worsen detection threshold in neurotypical controls whereas the effect of sub-threshold stimulation would be absent in autism. We further hypothesised that the absence of gating would correlate with autism outcomes. Contrary to these expectations, we observed that both pre-pulse stimulation conditions significantly improved detection thresholds in neurotypical children but not autistic children. The improvement is consistent with recent work examining the impact of different pulse types and intervals and reflects the importance of sensory filtering mechanisms on tactile perception. These findings reinforce prior findings that sensory filtering may underlie poorer perceptual capacity in autism. We did not find associations with clinical measures suggesting that the relationship between perceptual and behavioural sensory differences and their relation to autistic traits is complex. This work shows that atypical sensory gating is directly related to differences in perception in autistic children. This work has strong implications for understanding how different brain mechanisms give rise to altered sensory processing, core to autism.