Transcranial Alternating Current Stimulation at 40 Hz Improves Social Functioning in Children With Autism Spectrum Disorder: A Randomized Clinical Trial.

BACKGROUND

Autism spectrum disorder (ASD) lacks rapid and effective interventions for its core social difficulties. The right temporoparietal junction (rTPJ), a critical hub for social cognition, together with gamma band abnormalities implicated in ASD, provides a promising neuromodulation target.

METHODS

In this randomized, double-blind, sham-controlled trial, 47 children with ASD (39 male; mean [SD] age = 8.79 [2.71] years) were assigned to receive either 21 sessions of 40-Hz high-definition transcranial alternating current stimulation (tACS) targeting the rTPJ (3 sessions/day for 7 days) or sham stimulation, with assessments conducted at baseline, postintervention (week 1), and a 3-week follow-up (week 4). The primary outcome was change in Ohio State University Autism Rating Scale-DSM-5 (OARS-5) total scores. Secondary outcomes included the Aberrant Behavior Checklist-Second Edition, Social Responsiveness Scale-Second Edition, and Short Sensory Profile. Eye-tracking metrics during Frith-Happé animations were exploratory measures of theory of mind (ToM)-related social cognitive processing.

RESULTS

The active group demonstrated significant improvements in OARS-5 total scores at week 1 (mean difference = -1.13, 95% CI [-1.78 to -0.47], p < .001) and week 4 (mean difference = -1.47, 95% CI [-2.20 to -0.74], p < .001). Improvements in selected behavioral and sensory domains were observed. Average fixation duration during ToM animations showed a significant group × time interaction. No serious adverse events occurred.

CONCLUSIONS

These findings suggest that 40-Hz tACS targeting the rTPJ may be associated with rapid improvements in ASD symptom severity, particularly social functioning, in children with ASD, while being well tolerated. Clinical significance requires further evaluation.