CAM-14-004 Here, we present results for the first rigorous double-blind, randomized-controlled trial (RCT) examining repetitive transcranial magnetic stimulation (rTMS) as a therapeutic intervention in older youth and young adults with autism spectrum disorder. Our pilot RCT demonstrated that a 4-week high frequency rTMS protocol targeting the dorsolateral prefrontal cortex can be feasibly implemented, is well tolerated, and most importantly, improved working memory performance in a subset of our clinical autism sample that featured the most prominent impairments in this domain. Our study indicated that among our total ASD sample, individuals with more impaired functioning responded to rTMS with significant reductions found for working memory impairments following active compared to sham treatment. Our brain imaging data, collected at baseline prior to TMS treatment indicated that DLPFC modulation was altered in our ASD group during working memory performance compared to a healthy control comparison group, confirming this site as a useful target for brain stimulation treament in ASD. Our pilot study demonstrated the feasibility and tolerability of rTMS as an intervention tool in older youth and young adults with ASD, and indicates that rTMS may have efficacy as a treatment for executive function deficits in ASD.

CAM-14-004 Executive function(EF) deficits in patients with autism spectrum disorder(ASD) are ubiquitous and understudied. Repetitive transcranial magnetic stimulation(rTMS) has demonstrated promise in improving EF deficits in adult neuropsychiatric disorders. Here, we present results for the first double-blind, randomized-controlled trial of bilateral, 20 Hz, rTMS applied to dorsolateral prefrontal cortex (DLPFC) for treatment of EF deficits in ASD. Forty youth and emerging adults, aged 16-35, with confirmed ASD without intellectual disability and with impairment in everyday executive function skills participated. Participants were tested using a spatial working memory(SWM) task before and after rTMS and at one-month follow-up. Neuronavigation-guided rTMS stimulating bilateral DLPFC sequentially (750 pulses/side at 20 Hz) for 20 treatments was used. Mixed-effects models including treatment, time and treatment by time interaction as predictors of interest were used to examine effects of rTMS versus sham treatment on SWM performance. 38/40 participants completed the full rTMS treatment protocol. Rate of adverse effects did not differ between groups. A significant main effect of time but no effect of treatment group x time was found for SWM performance. Post-hoc analysis indicated a significant three-way interaction between treatment group, time and adaptive functioning for SWM performance (F2,64=3.15, p=0.049), where SWM total errors significantly decreased in ASD participants with lower adaptive functioning who received active rTMS but not sham treatment. These pilot data suggest that bilateral rTMS for EF deficits is safe, well tolerated and may be efficacious for treatment of SWM deficits in a subset of individuals with ASD featuring prominent impairments in functioning.