P4.031: The effectiveness of Non-Invasive Transcranial Electrical Stimulation (tDCS) in pediatric patients with Autism Spectrum Disorder: a Systematic Review and Meta-Analysis

Background: Autism Spectrum Disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by impairments in communication and social interactions, along with repetitive and restrictive behaviors. Despite the availability of various treatments, including behavioral and pharmacological therapies, outcomes remain limited. Transcranial Direct Current Stimulation (tDCS) and Transcranial random noise stimulation (tRNS) have emerged as potential non-invasive, cost-effective treatment options. tDCS modulates brain activity through low-intensity voltage stimulation, potentially enhancing neuroplasticity and improving the symptoms of ASD. This study aimed to assess the effectiveness of tDCS and tRNS in reducing ASD symptoms in children and adolescents through a meta-analysis of randomized controlled trials.

Methods: A systematic search was conducted across PubMed/MEDLINE, EMBASE, Cochrane Central Register, and Clinicaltrials.gov for studies published up to February 2025. Studies were selected based on predefined criteria, including randomized controlled trials (RCTs) involving pediatric patients with clinically diagnosed ASD, tDCS and tRNS intervention, and a placebo control group. The primary outcome was mean changes in validated scales such as the Autism Treatment Evaluation Checklist (ATEC) and Childhood Autism Rating Scale (CARS). Data extraction and quality assessment were conducted independently by two reviewers, and statistical analyses were performed using Review Manager 5.4.1 software.

Results: 19 studies were selected for inclusion in the systematic review. Four studies were included in the analysis of ATEC scores. tDCS showed a significant effect on the total ATEC score (MD -5.48, 95% CI: -7.96 to -3.01, I² 0%, p < 0.0001), as well as on the physical/health behavior (MD -5.48, 95% CI: -7.96 to -3.01, I² 0%, p < 0.0001) and sociability (MD -3.55, 95% CI: -5.75 to -1.35, I² 0%, p = 0.002) subscales. No significant effects were found in the speech/language and communication (MD -0.64, 95% CI: -2.81 to 1.53, I² 0%, p = 0.56) and sensory/cognitive awareness (MD -1.47, 95% CI: -3.52 to 0.57, I² 27%, p = 0.016) subscales. In the analysis of CARS scores, four studies were included. tDCS demonstrated a significant effect on CARS scores (MD -3.65, 95% CI: -4.90 to -2.39, I² 94%, p < 0.00001), although high heterogeneity was observed.

Conclusion: This meta-analysis provides evidence supporting the efficacy of Non-invasive transcranial electrical stimulation (tES) in reducing core ASD symptoms in children and adolescents. The significant improvements in ATEC and CARS scores indicate that tDCS and tRNS may be viable treatment options for pediatric ASD. However, further research is needed to explore which aspects of ASD are most responsive to tES. Large, standardized clinical trials with long-term follow-up are necessary to confirm the sustainability and generalizability of these findings.