Long-term effects of transcranial direct current stimulation in the treatment of autism spectrum disorder: A randomized controlled trial.

Researchers tested a brain stimulation technique called tDCS on 36 young boys with autism (around age 2). Children received either fake treatment, 5 sessions, or 20 sessions of tDCS while attending special education. Both 5 and 20 sessions reduced autism symptoms faster than fake treatment, with benefits lasting at least one year. Surprisingly, 5 sessions worked just as well as 20 sessions.

Even children who received fake treatment showed some improvement after 6 months of special education activities.

This randomized controlled trial examined transcranial direct current stimulation (tDCS) effectiveness for autism spectrum disorder symptoms in 36 young male children (mean age 2 years 3 months). Participants were randomized to receive 0, 5, or 20 sessions of tDCS alongside special education activities. Both 5-session and 20-session tDCS groups showed greater reductions in autism severity compared to controls at multiple timepoints (days 5 and 14, months 6 and 12). Notably, no significant differences were found between 5 and 20 sessions, suggesting 5 sessions may be sufficient.

Active tDCS groups demonstrated clinically meaningful improvements from day 5, while the control group showed improvements starting at month 6. All improvements were maintained at 12-month follow-up, indicating sustained benefits.

Results suggest tDCS may be a promising adjunctive treatment for young children with autism, with 5 sessions potentially sufficient for meaningful benefit. However, the small sample size and demographic restrictions require replication in larger, more diverse populations before clinical implementation.

Very small sample size (36 participants) limits generalizability. Study included only young male children, so findings may not apply to females or older children. All participants attended the same special education center in Thailand, which may limit broader applicability.

To compare the efficacy of 0, 5, and 20 sessions of transcranial direct current stimulation (tDCS) for reducing symptoms of autism spectrum disorder (ASD). Thirty-six male children with ASD (mean age 2 years 3 months, SD 4 months, age range 1 years 6 months-2 years 11 months) were balanced and stratified by age, sex, and baseline severity of ASD, to: (1) a control group that received 20 sessions of sham tDCS; (2) a 5-session tDCS group (5-tDCS) that received 5 sessions of active tDCS followed by 15 sessions of sham tDCS; and (3) a 20-session tDCS group (20-tDCS) that received 20 sessions of active tDCS. All groups participated in the special school activity of Khon Kaen Special Education Center, Thailand. The primary outcome was autism severity as measured by the Childhood Autism Severity Scale.

The 5-tDCS and 20-tDCS groups evidenced greater reductions in autism severity than the control group at days 5 and 14, and months 6 and 12. There were no significant differences in the outcome between the 5- and 20-tDCS groups at any time point. Within-group analysis showed clinically meaningful improvements starting at month 6 for the participants in the control group, and clinically meaningful improvements starting on day 5 in both active tDCS groups, all of which were maintained to month 12. The 5- and 20-session tDCS seems to reduce autism severity faster than sham tDCS.

These effects maintained at least for 1 year. Twenty sessions of transcranial direct current stimulation (tDCS) were not superior to five sessions. Sham tDCS with a special school activity can reduce autism severity starting at 6 months after treatment. The benefits observed for 5 and 20 sessions of tDCS last for at least 12 months.