The clinical and social burden of Autism Spectrum Disorders (ASD) is staggering. They are the most prevalent of developmental disorders and their incidence is rising. ASD symptoms have large variability and can manifest at different ages and to different degrees. Moreover, the ASD clinical diagnosis is challenging and mostly subjective. Thus, there is an unmet need for a valid and reliable biomarker that would facilitate ASD diagnosis early in life, enable efficient study of ASD risk factors, and eventually inform the development of effective therapies and assess treatment response. This proposal is aimed at exploring the utility of transcranial magnetic stimulation (TMS) measures of neuroplasticity as a novel neurophysiologic biomarker in high- and low-functioning adults and children with ASD. Recent results from our lab demonstrate the potential utility of these measures in high-functioning adults with ASD and support their feasibility and safety among children and low-functioning adults, in whom the value of such a biomarker would be particularly high. I here propose to apply single-pulse TMS to evaluate the modulation in corticospinal excitability induced by a repetitive TMS protocol known as theta burst stimulation (TBS). The comparison of the motor evoked potentials (MEPs) induced by single-pulse TMS before and following TBS is a unique noninvasive measure of brain plasticity in humans, and recent evidence hints at a reliable abnormality in high-functioning adults with ASD. Our hypothesis is that the alteration of TBS-induced modulation of TMS responses is a common neurophysiologic trait that is reliably linked to the ASD phenotype, and that will not be limited to high functioning adults but be also valid in children and low-functioning individuals. I thus anticipate that data from the proposed study will address an important need for a rapid, noninvasive, reliable and safe biomarker available to ASD patients across ages and levels of function.
Interagency Autism Coordinating Committee (IACC)
Autism Research Database (AFD)
