title: Motor symptoms after deep brain stimulation of the subthalamic nucleus.
abstract: OBJECTIVE
  Stimulation of the subthalamic nucleus (STN-DBS) is an established treatment with long-term beneficial effects on motor symptoms in patients with Parkinson's disease (PD). The efficacy of STN-DBS on non-dopaminergic motor symptoms remains less elucidated. In this study, we have examined short- and long-term impacts of STN-DBS on the development of the postural instability and gait difficulties (PIGD) phenotype, freezing of gait (FOG), and falls.
  
  
  METHODS
  We collected data from a prospectively followed cohort of patients that had been operated with STN-DBS 6-9 years before final examination and compared our findings to the longitudinal development of the same symptoms in a non-operated, historical reference population.
  
  
  RESULTS
  During short-term follow-up after surgery, we observed a marked improvement in mean UPDRS-motor score from 27 to 18. We also found clear improvements in tremor, bradykinesia, rigidity, and PIGD scores. However, 6-9 years after surgery, all patients had a dominating PIGD pattern of parkinsonism and 50% of the patients had developed FOG and/or had become recurrent fallers. The disease development in a group of patients with PD from the presurgery period had a similar trajectory as among the operated patients. In addition, mean annual change of both bradykinesia and PIGD scores was nearly identical in both study groups while tremor and rigidity had a significant better development in the operated patients.
  
  
  CONCLUSIONS
  We found that STN-DBS induces an acute improvement of PIGD symptoms. The following long-term development was however characterized by a marked progression of non-dopaminergic symptoms.
authors.affiliation: The Norwegian Centre for Movement Disorders, Stavanger University Hospital, Stavanger, Norway.
authors.forename: B
authors.initials: B
authors.lastname: Lilleeng
authors.forename: M
authors.initials: M
authors.lastname: Gjerstad
authors.forename: R
authors.initials: R
authors.lastname: Baardsen
authors.forename: I
authors.initials: I
authors.lastname: Dalen
authors.forename: J P
authors.initials: JP
authors.lastname: Larsen
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000009:adverse effects*; D018450:Disease Progression; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000503:physiopathology; D014202:Tremor / Q000209:etiology*
keywords: Parkinson's disease; deep brain stimulation of the subthalamic nucleus; non-dopaminergic