title: Deep brain stimulation in Parkinson disease: a metaanalysis of patient outcomes.
abstract: OBJECTIVE
  Deep brain stimulation (DBS) to treat advanced Parkinson disease (PD) has been focused on one of two anatomical targets: the subthalamic nucleus (STN) and the globus pallidus internus (GPI). Authors of more than 65 articles have reported on bilateral DBS outcomes. With one exception, these studies involved pre- and postintervention comparisons of a single target. Despite the paucity of data directly comparing STN and GPI DBS, many clinicians already consider the STN to be the preferred target site. In this study the authors conducted a metaanalysis of the existing literature on patient outcomes following DBS of the STN and the GPI.
  
  
  METHODS
  This metaanalysis includes 31 STN and 14 GPI studies. Motor function improved significantly following stimulation (54% in patients whose STN was targeted and 40% in those whose GPI was stimulated), with effect sizes (ESs) of 2.59 and 2.04, respectively. After controlling for participant and study characteristics, patients who had undergone either STN or GPI DBS experienced comparable improved motor function following surgery (p = 0.094). The performance of activities of daily living improved significantly in patients with either target (40%). Medication requirements were significantly reduced following stimulation of the STN (ES = 1.51) but did not change when the GPI was stimulated (ES = -0.02).
  
  
  CONCLUSIONS
  In this analysis the authors highlight the need for uniform, detailed reporting of comprehensive motor and nonmotor DBS outcomes at multiple time points and for a randomized trial of bilateral STN and GPI DBS.
authors.affiliation: Midwest Center for Health Services and Policy Research, Edward Hines Jr. VA Hospital, IL 60141-5000, USA. Frances.Weaver@va.gov
authors.forename: Frances
authors.initials: F
authors.lastname: Weaver
authors.forename: Kenneth
authors.initials: K
authors.lastname: Follett
authors.forename: Kwan
authors.initials: K
authors.lastname: Hur
authors.forename: Dolores
authors.initials: D
authors.lastname: Ippolito
authors.forename: Matthew
authors.initials: M
authors.lastname: Stern
mesh_terms: D000203:Activities of Daily Living; D000978:Antiparkinson Agents / Q000627:therapeutic use; D046690:Deep Brain Stimulation; D005917:Globus Pallidus / Q000503:physiopathology; D006801:Humans; D009068:Movement; D010300:Parkinson Disease / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy*; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents