title: Meta-analysis comparing deep brain stimulation of the globus pallidus and subthalamic nucleus to treat advanced Parkinson disease.
abstract: OBJECTIVE
  Deep brain stimulation (DBS) is the surgical procedure of choice for patients with advanced Parkinson disease (PD). The globus pallidus internus (GPi) and the subthalamic nucleus (STN) are commonly targeted by this procedure. The purpose of this meta-analysis was to compare the efficacy of DBS in each region.
  
  
  METHODS
  MEDLINE/PubMed, EMBASE, Web of Knowledge, and the Cochrane Library were searched for English-language studies published before April 2013.
  
  
  RESULTS
  of studies investigating the efficacy and clinical outcomes of DBS of the GPi and STN for PD were analyzed.
  
  
  RESULTS
  Six eligible trials containing a total of 563 patients were included in the analysis. Deep brain stimulation of the GPi or STN equally improved motor function, measured by the Unified Parkinson's Disease Rating Scale Section III (UPDRSIII) (motor section, for patients in on- and off-medication phases), within 1 year postsurgery. The change score for the on-medication phase was 0.68 (95% CI - 2.12 to 3.47, p > 0.05; 5 studies, 518 patients) and for the off-medication phase was 1.83 (95% CI - 3.12 to 6.77, p > 0.05; 5 studies, 518 patients). The UPDRS Section II (activities of daily living) scores for patients on medication improved equally in both DBS groups (p = 0.97). STN DBS allowed medication dosages to be reduced more than GPi DBS (95% CI 129.27-316.64, p < 0.00001; 5 studies, 540 patients). Psychiatric symptoms, measured by Beck Depression Inventory, 2nd edition scores, showed greater improvement from baseline after GPi DBS than after STN DBS (standardized mean difference -2.28, 95% CI -3.73 to -0.84, p = 0.002; 3 studies, 382 patients).
  
  
  CONCLUSIONS
  GPi and STN DBS improve motor function and activities of daily living for PD patients. Differences in therapeutic efficacy for PD were not observed between the 2 procedures. STN DBS allowed greater reduction in medication for patients, whereas GPi DBS provided greater relief from psychiatric symptoms. An understanding of other symptomatic aspects of targeting each region and long-term observations on therapeutic effects are needed.
authors.affiliation: Department of Neurology, the Second Affiliated Hospital of Chong Qing Medical University, YuZhong, Chong Qing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Weina
authors.initials: W
authors.lastname: Li
authors.forename: Changhong
authors.initials: C
authors.lastname: Tan
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Yuejiang
authors.initials: Y
authors.lastname: Gui
authors.forename: Lu
authors.initials: L
authors.lastname: Qin
authors.forename: Fen
authors.initials: F
authors.lastname: Deng
authors.forename: Changlin
authors.initials: C
authors.lastname: Hu
authors.forename: Lifen
authors.initials: L
authors.lastname: Chen
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D005917:Globus Pallidus / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D011569:Psychiatric Status Rating Scales; D020531:Subthalamic Nucleus / Q000503:physiopathology*; D016896:Treatment Outcome
keywords: ADLs = activities of daily living; BDI-II = Beck Depression Inventory, 2nd edition; DBS = deep brain stimulation; GPi = globus pallidus internus; LED = levodopa-equivalent dosage; MPTP = 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; PD = Parkinson disease; Parkinson disease; RCT = randomized controlled trial; SMD = standardized mean difference; STN = subthalamic nucleus; UPDRS = Unified Parkinson's Disease Rating Scale; UPDRSII, -III = UPDRS Sections II (ADLs) and III (motor section); Unified Parkinson's Disease Rating Scale; deep brain stimulation; functional neurosurgery; globus pallidus; subthalamic nucleus