Judgment of duration in individuals with ataxia-telangiectasia

Several clinical investigations with adults suggest that the cerebellum may be critical for judgment of explicit time intervals; however, little work has been done in populations with lesions of the cerebellum acquired during development. We evaluated 17 individuals with ataxia-telangiectasia (AT), an autosomal recessive disorder with on- set in early childhood characteriz ed by diffuse, almost selective, degeneration of the cerebellar cortex, and 21 normal controls, matched for age. Because patients with AT have motor i mpairment, verbal IQ (VIQ) was used to estimate intelligence; VIQ was signi ficantly lower in the group with AT (p < .0001). Participants were tested u sing a test ofjudgment of duration that has been found to be impaired in ad ults with cerebellar lesions and a contrasting auditory control task (not i mpaired in adults with cerebellar lesions) involving judgment of pitch. Aft er statistically controlling for VIQ, the 2 groups did not differ significa ntly on judgment of pitch, but those with AT performed significantly worse than controls on judgment of duration (p = .01). Children and adolescents w ith AT show deficits in judgment of duration but not of pitch, suggesting t hat the cerebellum may be critical for judgment of explicit time intervals at all ages.