Transcranial direct current stimulation in children with autism spectrum disorder: a systematic scoping review

Aim Our aim was to review available studies which test transcranial direct current stimulation (tDCS) to reduce symptom severity in children with autism spectrum disorder (ASD). Method We performed a systematic scoping review in PubMed and PsychINFO databases for studies employing tDCS in children and adolescents with ASD. Results We found five studies (two small randomized controlled studies, one experimental study, one quasi-experimental study, and one case study) reporting positive effects of tDCS in ASD symptom reduction. Study design varied greatly and sample size ranged from 1 to 20 patients. Interpretation Preliminary evidence is encouraging of the potential usefulness of tDCS for treatment of ASD in children and adolescents. It suggests tentative support for reductions in symptom severity and, according to parental reports and clinical observations, improvements in some aspects of language. However, the evidence is sparse and of low quality, so the true effect of tDCS is likely to be substantially different from the estimate of effect in this review. Therefore, future randomized controlled trials are needed to draw conclusions regarding tDCS efficacy in paediatric samples with ASD.