Weight gain following unilateral pallidotomy in Parkinson's disease

Objective - To determine the clinical correlates and infer pathogenesis of weight gain following pallidotomy in patients with Parkinson's disease (PD) . Background - Surgical ablation of the globus pallidus internus (GPi) impr oves levodopa induced dyskinesias, moderately improves most other "cardinal " manifestations of PD, and has been noted to result in increased weight. M ethods - We incorporated Unified Parkinson's Disease Rating Scales (UPDRS) subscales, the Beck depression inventory and feeding questionnaire data int o a linear regression model in order to determine which post-surgical chang e(s) may lead to weight gain over the first year following pallidotomy, n = 60. Results - The mean weight gain 1 year after pallidotomy was 4.0 +/- 4. 1 kg. Improvement in "off" motor scores (P < 0.005), especially gait subsco res (P < 0.0001), and to a lesser extent improvement in "on" motor scores ( P < 0.05) predicted weight gain. Changes in dyskinesia ratings, mood, food intake, dysphagia, levodopa dose, weight loss in the year prior to pallidot omy, age, and duration of PD did not correlate with subsequent weight gain. Conclusion - The high correlation between post-pallidotomy weight gain and "off" motor scores, suggests that this phenomenon is related to some chang e in underlying homeostasis associated with changes in the cardinal manifes tations of PD itself, rather than secondary changes resultant from the surg ery.