title: Effects of deep brain stimulation of the subthalamic nucleus on freezing of gait in Parkinson's disease: a prospective controlled study.
abstract: BACKGROUND
  Freezing of gait (FOG) is a debilitating gait disorder in Parkinson's disease (PD) with partial responsiveness to dopaminergic medication. To date, notions about the effects of subthalamic deep brain stimulation (STN-DBS) on FOG remain controversial.
  
  
  OBJECTIVE
  To compare the effects of bilateral STN-DBS and continued best medical treatment (BMT) on FOG occurrence, FOG severity and clinical outcomes in PD patients at 6 and 12 months follow-up.
  
  
  METHODS
  In this prospective, controlled study, 41 PD patients with at least 5 years disease duration participated. Twenty-four subjects (20 with FOG) were treated with STN-DBS and seventeen (15 with FOG) continued BMT. The primary outcome was the New Freezing of Gait Questionnaire (NFOGQ) at 6 months postsurgery. Other outcomes were the NFOGQ at 12 months and clinical outcomes (Unified Parkinson's Disease Rating Scale III (UPDRS III), timed gait, falls and quality of life) at both time points.
  
  
  RESULTS
  STN-DBS increased the likelihood to convert from being a freezer to a non-freezer at 6 and 12 months follow-up (relative risk reduction=0.4). However, 45% of baseline freezers still experienced FOG 6 and 12 months postsurgery although with reduced severity. Three baseline non-freezers (1/2 BMT-treated, 2/4 STN-DBS-treated) developed FOG during follow-up. STN-DBS-induced benefits on FOG were mostly mediated by baseline levodopa equivalent dose, altered medication-intake and reduced motor fluctuations.
  
  
  CONCLUSIONS
  In contrast to continued BMT, STN-DBS reduced FOG occurrence and severity at 6 months postsurgery with largely sustained effects at 12 months follow-up. Longer follow-up periods are needed to test whether FOG improvements after STN-DBS persist with disease progression.
authors.affiliation: Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Vercruysse
authors.affiliation: Department of Neurology, University Hospitals Leuven, Leuven, Belgium.
authors.forename: W
authors.initials: W
authors.lastname: Vandenberghe
authors.affiliation: Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Münks
authors.affiliation: Department of Neurosurgery, University Hospitals Leuven, Leuven, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Nuttin
authors.affiliation: Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: H
authors.initials: H
authors.lastname: Devos
authors.affiliation: Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Nieuwboer
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D015331:Cohort Studies; D046690:Deep Brain Stimulation / Q000379:methods*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000628:therapy*; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000628:therapy*; D011446:Prospective Studies; D020531:Subthalamic Nucleus / Q000502:physiology*; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Gait; Motor Control; Movement Disorders; Neurosurgery; Parkinson's Disease