title: Effect of motor improvement on quality of life following subthalamic stimulation is mediated by changes in depressive symptomatology.
abstract: OBJECTIVE
  Subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease (PD) improves motor symptoms and quality of life (QOL). Because depression is a potent correlate of QOL, and STN-DBS may be associated with changes in mood, this study sought to determine whether QOL improvement is a direct or indirect consequence of motor improvement.
  
  
  METHODS
  26 patients with PD, free of dementia and major depression, who consecutively underwent bilateral, microelectrode-guided STN-DBS, underwent preoperative and 3-month postoperative neuropsychological evaluation, including measures of QOL (PD Questionnaire -39) and depressive symptoms (Beck Depression Inventory).
  
  
  RESULTS
  Motor score in the Unified Parkinson's Disease Rating Scale (UPDRS Part III) improved significantly with STN-DBS relative to preoperative 'on' and 'off' scores, as did QOL and depressive symptoms. Extent of QOL improvement tended to be associated with improvement in motor score from presurgical on to postsurgical on stimulation and on medication state. QOL improvement was significantly related to amelioration of depressive symptoms. Partial correlations revealed that the association between QOL improvement and depression remained significant when influence of motor improvement on QOL and depression was controlled for. The motor-QOL association was no longer significant when effects of depression were controlled for.
  
  
  CONCLUSIONS
  Significant QOL improvements after STN-DBS are associated with improved motor 'on' state and depressive symptoms. The influence of motor improvement on QOL may be largely indirect by reducing depression.
authors.affiliation: Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, USA. trostera@glial.med.unc.edu
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Tröster
authors.forename: Julie A
authors.initials: JA
authors.lastname: Fields
authors.forename: Steven
authors.initials: S
authors.lastname: Wilkinson
authors.forename: Rajesh
authors.initials: R
authors.lastname: Pahwa
authors.forename: William C
authors.initials: WC
authors.lastname: Koller
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Lyons
mesh_terms: D000368:Aged; D003863:Depression / Q000628:therapy*; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000523:psychology* / Q000601:surgery / Q000628:therapy*; D011584:Psychology; D011788:Quality of Life; D020531:Subthalamic Nucleus / Q000502:physiology*