HD-tDCS effects on social impairment in autism spectrum disorder with sensory processing abnormalities: a randomized controlled trial

This study examined the effects of high-definition transcranial direct current stimulation (HD-tDCS) on social impairment in children with autism spectrum disorder (ASD), focusing on those with and without sensory processing abnormalities. A randomized double-blind sham-controlled trial involved 72 children with ASD, divided into three groups based on sensory integration status. A post-hoc analysis of 51 children aged 4–8 years who received true HD-tDCS was conducted, categorizing them into hypo-tactile, hyper-tactile, and typical tactile sensitivity groups. Therapeutic efficacy was compared across these groups. (1) The randomized cntrolled Trial: The typical sensory integration group showed significant improvements in social awareness (t = 5.032, p < 0.000) and autistic mannerisms (t = 3.085, p = 0.004) compared to the sensory integration dysfunction group. (2)The result of the post-hoc analysis: The hypo-tactile and typical tactile sensitivity groups exhibited notable improvements in social awareness, cognition, communication, autistic mannerisms, and total SRS scores. In contrast, the hyper-tactile group only had a significant reduction in social communication (t = 2.385, p = 0.022) post-intervention. HD-tDCS effectively improved social impairment symptoms in children with ASD, particularly those with typical sensory integration and either typical or hypo-tactile responsiveness.