CEREBELLUM IN ATTENTION-DEFICIT HYPERACTIVITY DISORDER - A MORPHOMETRIC MRI STUDY

Clinical, neuroanatomic, neurobehavioral, and functional brain-imaging studies suggest a role for the cerebellum in cognitive functions, inc luding attention. However, the cerebellum has not been systematically studied in attention-deficit hyperactivity disorder (ADHD). We quantif ied the cerebellar and vermal volumes, and the midsagittal areas of th ree vermal regions, from MRIs of 46 right-handed boys with ADHD and 47 matched healthy controls. Vermal volume was significantly less in the boys with ADHD. This reduction involved mainly the posterior inferior lobe (lobules VIII to X) but not the posterior superior lobe (lobules VI to VII). These results remained significant even after adjustment for brain volume and IQ. A cerebello-thalamo-prefrontal circuit dysfun ction may subserve the motor control, inhibition, and executive functi on deficits encountered in ADHD.