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Weaver FM, Follett K, Stern M, Hur K, Ippolito D. Deep brain stimulation in Parkinson's disease: A meta-analysis of patient outcomes. Poster session presented at: Movement Disorder Society International Annual Congress; 2005 Mar 1; New Orleans, LA.
Objective: To perform a meta-analysis of the relative effectiveness of bilateral deep brain stimulation (DBS) of the subthalamic nucleus and globus pallidus on patient outcomes. Background: DBS to treat advanced Parkinsons disease (PD) has involved two anatomical targets; the subthalamic nucleus (STN) and the globus pallidum interna (GPi). Despite the paucity of data directly comparing STN and GPi DBS, many clinicians already consider STN the preferred site. Methods: We conducted a Medline search using Parkinsons disease, deep brain stimulation, subthalamic nucleus, globus pallidum MESH terms, supplemented with an FDA report bibliography that reviewed bilateral DBS of STN and GPi literature. We also reviewed references from these articles for additional articles. Inclusion criteria included: idiopathic Parkinsons disease, DBS of STN or GPi, UPDRS motor function scores off medications at baseline and off medications/on stimulation at follow-up, and follow-up at least 3 months post-DBS. 31 STN and 14 GPi studies meet these criteria. The primary outcome of interest was UPDRS Part-III off medication/on stimulation state. Other outcomes included UPDRS activities of daily living subscale (ADL; part II) and levodopa equivalents before and after DBS.Results: Motor function improved significantly following stimulation (54% for STN; 40% for GPi), with effect sizes of 2.59 and 2.04, respectively. After controlling for participant and study characteristics, STN and GPi subjects had comparable improved motor function following surgery (p = 0.094). Activities of daily living also improved significantly for both targets (40%). Medication requirements were significantly reduced for STN (ES = 1.51), but did not change for GPi subjects (ES = -0.02).Conclusions: Motor function improves significantly after DBS, regardless of site, although the effect was greater, but not statistically significant in STN vs. GPi. Medication was reduced following STN DBS but did not change for GPi subjects. These results should be interpreted cautiously because they are based on non-randomized studies with small sample sizes and limited follow-up. This analysis highlights the need for a large randomized controlled trial of STN and GPi DBS to evaluate the effectiveness of DBS targets on multiple patient outcomes over time.