COGNITIVE DEFICITS IN MACHADO-JOSEPH DISEASE

Cognitive function was examined in 6 patients with genetically confirm ed Machado-Joseph disease (MJD) and 15 age- and ethnically matched con trols using a series of subtests from tile Cambridge Neuropsychologica l Test Automated Battery (CANTAB), a touch screen-based testing system previously validated in a number of movement and neurodegenerative di sorders. The MJD patients had deficits in visual attentional function that were characterized by a slowing of the processing of visual infor mation when task demands were high and an inability to shift attention to previously irrelevant stimulus dimensions to discriminate between complex stimuli. Tests of learning and visual memory were normal. Thes e results demonstrate that specific cognitive deficits occur in patien ts with MJD, independent of motor dysfunction, and these deficits may reflect disruption to frontosubcortical pathways.