EVALUATION OF CEREBELLAR SIZE IN ATTENTION-DEFICIT HYPERACTIVITY DISORDER

Evidence from animal and human research suggests that the cerebellum m ay play a role in cognition. This includes domains of executive functi on that are normally attributed to the prefrontal cortex and are typic ally deficient in individuals with attention-deficit hyperactivity dis order (ADHD), To investigate cerebellar structure in ADHD, magnetic re sonance imaging morphometry was used to measure the area of the cerebe llar vermis in 12 males with ADHD and 23 male controls matched for age and Wechsler Full-Scale IQ, Analyses were conducted to evaluate group differences, as well as differences between matched pairs of subjects with ADHD and those without ADHD. All measurements were corrected for overall brain size. Both analyses revealed that the size of the poste rior vermis was significantly decreased in males with ADHD (P < .05 in both analyses), and that within the posterior vermis, the: inferior p osterior lobe (lobules VIII-X) was involved in this reduction (P < .05 for group analysis, P < .005 for matched pair analysis), while the su perior posterior lobe (lobules VL/VII) was not involved in the reducti on. The finding of abnormal inferior posterior vermal size suggests th at dysfunction within this region of the cerebellum may underlie clini cal deficits seen in individuals with ADHD.