Non-invasive brain stimulation (NIBS) is increasingly being trialled in people with neurodevelopmental disorders, including autism spectrum disorder (ASD), but limited literature exists examining safety and tolerability. We explored safety and tolerability data from an ongoing clinical trial of intermittent theta burst stimulation (iTBS) in young people with ASD.

Interim analyses of safety and tolerability included data from 73 young people (14-40 years) participating in an Australian clinical trial of iTBS in ASD. Intervention involved twenty sessions of active [m_age=22.0 (7.50), 56.8% male] or sham [m_age=21.9 (6.70); 63.2% male] stimulation to the right temporoparietal junction. Baseline measures were collected prior to intervention and safety was evaluated four times throughout the course of iTBS using a structured questionnaire.

Preliminary data show that 73.2% of participants report experiencing at least one side effect at any stage of intervention [(active=75%, sham=71%), χ2(1, N=82)=6.45, p>.05]. Commonly reported symptoms at any stage across the twenty sessions were headaches (active = 59%, sham=50%), anxiety (active=41%, sham=53%), fatigue (active=39%, sham=42%) and neck pain (active=27%, sham=21%). Mean symptom severity ranged from 1 (mild) to 3 (moderate) out of 5 (severe). Chi-squared testing indicated that anxiety was more commonly reported in the sham condition compared to active [χ2(1, N=82)=6.16, p=.01], however this effect was small (φ=0.15). No serious adverse events have been reported.

These interim findings suggest that side effects from iTBS in autism are relatively common but are typically of mild severity and not specific to active stimulation. The incidence of reported symptoms across treatment conditions could at least partially be explained by factors other than iTBS (e.g., travel) and methodology (e.g., obtaining weekly reports). While the trial is continuing, these findings add to a growing body of literature supporting the safety and tolerability of NIBS in neurodevelopmental disorders.

Clinical Research: 10. Transcranial Magnetic Stimulation (TMS)

TMS, Safety, Autism, RCT