Neuropsychological outcome following unilateral pallidotomy

Despite the findings of significantly improved motor functioning following pallidotomy for the treatment of Parkinson's disease, the cognitive sequela e following surgery have yet to be clearly defined. With increasing knowled ge of the surgery's effect on frontostriatal circuits, the cognitive proces ses potentially affected by the procedure require further exploration to ev aluate fully the efficacy of the treatment. We reviewed 10 studies on the n europsychological outcome after pallidotomy that were published in peer-rev iewed journals, A general agreement exists that pallidotomy is a relatively safe and effective treatment for ameliorating the motor symptoms of Parkin son's disease, with relatively few cognitive changes reported following sur gery. However, a number of conceptual and methodological concerns, includin g diverse selection criteria, small sample sizes and short follow-up period s, limit the interpretation and generalizability of these findings. These c oncerns are discussed in detail, along with a summary of the current neurop sychological literature, suggested guidelines for the conduct of research a nd future research directions. The neuropsychological findings are critical ly reviewed and tabulated by study, cognitive domain and follow-up period, with particular emphasis on hemisphere-specific cognitive changes.