Cognitive sequelae of unilateral posteroventral pallidotomy

Objective: To examine the cognitive sequelae of unilateral posteroventral pallidotomy, Design: Single-group pretest and posttest methodologic assessment with baseline evaluation performed 1 to 2 days prior to surgery and follow-up conducted 3 months after pallidotomy. Setting: Movement disorder clinic at a university medical center. Patients: Fourteen patients (age range, 43-82 years) with Parkinson disease (average disease duration, 7.4 years). Intervention: Unilateral posteroventral pallidotomy procedures were performed on the right (n = 8) and left (n = 6) side of the brain. Main Outcome Measures: The protocol consisted of a range of neuropsychological instruments sensitive to subcortical dysfunction, including measures of bimanual coordination, simple-complex reaction time, visual attention, naming, verbal fluency, learning, recognition memory, and problem solving. Results: No significant deterioration in specific cognitive abilities was observed as a function of the procedure. Patients showed a significant improvement in motor coordination speed for both contralateral and ipsilateral upper extremities. Conclusions: Stereotactic unilateral posteroventral pallidotomy is associated with minimal risk of adverse neuropsychological effects or cognitive decline. Additional research is warranted, with an increased sample size and extended follow-up, to assess any potential lateralized effects of the procedure.