Cognitive functioning after subthalamic nucleotomy for refractory Parkinson's disease

Objective-To evaluate whether subthalamic nucleotomy produces adverse cogni tive effects in patients with Parkinson's disease. Method-Twelve patients with Parkinson's disease underwent stereotactic surg ery to the subthalamic nucleus. Presurgical and postsurgical neuropsycholog ical assessment of attention, memory, executive function, language, and ver bal intellect were undertaken with a battery of tests designed to minimise potential contamination of cognitive effects by motor symptoms. Results-There was no statistically significant difference in the cognitive tests results after operation for the group as a whole. Reliable change ind exes were generated for the cognitive tests. Reliable change postoperativel y was found on specific tests of verbal memory, attention, and planning. Le ft sided operations were associated with greater incidence of deterioration postsurgery. Conclusions-Preliminary data on the first reported cognitive changes after subthalamic nucleotomy suggested few adverse cognitive effects of the surge ry although discrete neuropsychological changes were seen in some patients. These effects were consistent with current theories on the cognitive funct ions of the basal ganglia.