Several postmortem studies of autism spectrum disorders (ASDs) have found cortical abnormalities consistent with focal cortical dysplasias (FCDs). FCDs are associated with abnormal neural migration and often form seizure foci but have been reported in individuals with ASDs presenting both with and without epilepsy 1, 2. Identification of FCDs using in vivo magnetic resonance imaging (MRI) is difficult as FCDs are subtle, often eluding detection in visual inspection of clinical scans. Thus, FCDs may be present more frequently in people with ASDs than is currently appreciated.
The development of surface-based quantitative measurements has improved FCD detection, and diffusion-weighted imaging promises additional sensitivity. However, these methods have yet to be implemented for the assessment of FCDs in individuals with ASDs. The research team lead by Ruth Carper aims to address this issue by acquiring high-resolution anatomical and diffusion MRI scans from individuals with ASDs, from matched, typically developing individuals and from a population with known FCDs but without ASD.
Specifically, the team will: (1) test for the presence of previously unidentified FCDs in a seizure-free population with ASD, (2) test whether the addition of advanced diffusion measures improves detection sensitivity for FCDs and (3) examine the overall impact of location and extent of FCDs on cognition and behaviors in ASDs. Subject-specific surface maps reflecting deviation from norms will be generated for multiple measures (e.g., cortical thickness), and cumulative load scores will be calculated in order to account for individual variability. If increased rates of FCDs are found in individuals with ASD without a history of seizures, this could improve the ability to detect ASD subtypes and to understand variability of cognitive phenotypes. Improvements in FCD detection would have benefits for both clinicians and researchers.