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

Abstract

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.

Keywords: Autism spectrum disorder; High definition transcranial direct current stimulation; Sensory abnormalities; Sensory integration dysfunction; Social impairment.

Fig. 1

Experimental scheme diagram.

Fig. 2

Comparison of ATEC score reduction before and after treatment in three groups: ASD with and without Sensory Dysfunction. ①the typical sensory integration group; ②the sensory integration dysfunction group; ③the sham stimulation group. ATEC consists of four subtest scales: Scale I (speech/language/communication; has 14 items. Scores can range from 0 to 28), Scale II (sociability; has 20 items. Scores can range from 0 to 40), Scale III (sensory/cognitive awareness; has 18 items. Scores can range from 0 to 36) and Scale IV (Health/Physical/Behaviour; has 25 items). Each subcategory of the ATEC scale is scored using a 0–3 point scale as follows: 0 = not a problem, 1 = minor problem, 2 = moderate problem and 3 = serious problem.

Fig. 3

Comparisons of intergroup differences in score differences of social responsiveness scale subscale items before and after high definition transcranial direct current stimulation intervention. The X-axis represents the social responsiveness scale subscale items, while the Y-axis represents the score change calculated by subtracting post-intervention scores from baseline scores, with positive values indicating improvements.

Fig. 4

Comparison of reduction percentages in the total scale and subscale scores of social responsiveness scale in three groups of autism spectrum disorder children after high definition transcranial direct current stimulation interventions.

Fig. 5

Comparison of intergroup score differences of social responsiveness scale subscale items before and after high definition transcranial direct current stimulation intervention. The X-axis represents the social responsiveness scale subscale items, while the Y-axis represents the score change calculated by subtracting post-intervention scores from baseline scores, with positive values indicating improvements.

Fig. 6

Percentage change from baseline in total scores and average score reductions of the social responsiveness scale for three groups of children with autism spectrum disorder before and after treatment.