TMS for the Investigation of Brain Plasticity in Autism Spectrum Disorders

Autism Spectrum Disorders (ASD) are diagnosed clinically, based on key symptoms. As ASD phenotypic variability is large, and symptoms can manifest at different ages and degrees, the clinical diagnosis is challenging. To date, there remains an unmet need for a valid and reliable endophenotype that would facilitate ASD diagnosis early in life, enable efficient study of ASD risk factors, and eventually serve as a useful biomarker to inform the development of effective therapies and assess treatment response in future clinical trials. As compared with behavioral or neuroimaging methods, transcranial magnetic stimulation (TMS) offers the advantage of providing behaviorally independent results that are largely unaffected by attention or cognitive ability. Therefore, a TMS based endophenotype may be applicable to all individuals across the autism spectrum. At Boston Children's Hospital, each subject's participation in the study will consist of four visits: two screening visits, and two TMS sessions. At Beth Israel Deaconess Medical Center, each subject's participation will consist of three visits: one screening visit, and two TMS sessions. Each screening visit is expected to last between 2-3 hours, during which participants will first provide informed consent. Participants will then receive a thorough medical examination by a neurologist, and a neuropsychological evaluation (including IQ measures and ASD specific evaluations). If eligible to continue, participants will then come back for two identical TMS visits, that are spaced 1-5 weeks apart. These visits are expected to last between 3-4 hours, and include the TMS measures of brain plasticity.