title: Differential effects of deep brain stimulation target on motor subtypes in Parkinson's disease.
abstract: OBJECTIVE
  The Veterans Administration Cooperative Studies Program #468, a multicenter study that randomized Parkinson's disease (PD) patients to either subthalamic nucleus (STN) or globus pallidus internus (GPi) deep brain stimulation (DBS), found that stimulation at either target provided similar overall motoric benefits. We conducted an additional analysis of this data set to evaluate whether PD motor subtypes responded differently to the 2 stimulation targets.
  
  
  METHODS
  We classified 235 subjects by motor subtype: tremor dominant (TD), intermediate (I), or postural instability gait difficulty (PIGD), based on pre-DBS baseline Unified Parkinson's Disease Rating Scale (UPDRS) scores off-medication. The primary outcome was change in UPDRS part III (UPDRS-III) off-medication scores from baseline to 24 months post-DBS, compared among subjects with particular PD motor subtypes and by DBS target (STN vs GPi). Changes in tremor, rigidity, akinesia, and gait scores were also assessed using the UPDRS.
  
  
  RESULTS
  TD patients had greater mean overall motor improvement, measured by UPDRS-III, after GPi DBS, compared to STN DBS (17.5 ± 13.0 vs 14.6 ± 14.9, p = 0.02), with improvement in gait accounting for this difference. Regardless of stimulation target, PIGD subjects had lower mean overall improvement in UPDRS-III scores compared with I or TD subjects (8.7 ± 12.2 vs 21.7 ± 11.2 vs 16.3 ± 13.8, p = 0.001).
  
  
  CONCLUSIONS
  Our results suggest that responsiveness to both GPi and STN DBS is similar among different PD motor subtypes, although the TD motor subtype may have a greater response to GPi DBS with respect to gait. PIGD patients obtained less overall benefit from stimulation.
authors: Department of Neurology, University of California, San Francisco and Parkinson's Disease Research, Education, and Clinical Center, San Francisco Veterans Affairs Medical Center, San Francisco, CA.
authors: Maya
authors: M
authors: Katz
authors: Marta San
authors: MS
authors: Luciano
authors: Kimberly
authors: K
authors: Carlson
authors: Ping
authors: P
authors: Luo
authors: William J
authors: WJ
authors: Marks
authors: Paul S
authors: PS
authors: Larson
authors: Philip A
authors: PA
authors: Starr
authors: Kenneth A
authors: KA
authors: Follett
authors: Frances M
authors: FM
authors: Weaver
authors: Matthew B
authors: MB
authors: Stern
authors: Domenic J
authors: DJ
authors: Reda
authors: Jill L
authors: JL
authors: Ostrem
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D005917:Globus Pallidus; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000145:classification* / Q000175:diagnosis / Q000628:therapy*; D016037:Single-Blind Method; D020531:Subthalamic Nucleus; D016896:Treatment Outcome