[Cognitive function in patients with parkinsonism--in relationship with frontal lobe symptoms]

Whether the basal ganglia have a cognitive function or not is a worldwide dispute. We have examined 13 parkinsonian patients and 12 age-matched non-parkinsonian controls using the Modified Wisconsin Card Sorting Test (MCST). All 12 controls could achieve all 6 sets of categories which were successively changed. On the other hand, in the parkinsonians, 9 patients could achieve all 6 sets, but 4 patients could do only 4 to 0 sets. The difference between the two groups was statistically significant. These 4 patients who showed poor achievement on MCST had tendency showing higher percentage of perseverative errors. Taking the proportion of perseverative error (PE) to total error (TE) revealed that the parkinsonian group had a peak ranged from 55% to 65% which meant higher occurrence of perseverative errors. When the 4 parkinsonians whose proportion of PE/TE on MCST was over 55% were excluded, a comparison of the parkinsonians with the controls showed no significant difference statistically in both groups. There were no clinical differences based upon Yahr's classification between the 4 parkinsonians with poor MCST score and those with the normal score. Among these parkinsonians whose proportion of PE/TE ranged from 55% to 65%, 3 cases showed apparent frontal lobe signs and 3 mild dementia on Wechsler Intelligence Scale for Adults. Two patients with chorea-acanthocytosis and showing a marked atrophy of the caudate nucleus were also examined. They showed excellent results on MCST.(ABSTRACT TRUNCATED AT 250 WORDS)