title: Neuropsychological effects of bilateral STN stimulation in Parkinson disease: a controlled study.
abstract: OBJECTIVE
  To evaluate the cognitive and behavioral effects of bilateral subthalamic nucleus (STN) stimulation in patients with Parkinson disease (PD).
  
  
  METHODS
  The authors included 103 patients; 99 patients were evaluated 6 months after surgery. A control group of 39 patients with PD was formed and 36 patients were evaluated 6 months later. At baseline and at follow-up we administered neuropsychological tests of language, memory, visuospatial function, mental speed, and executive functions. A depression rating scale, a quality of life scale, self and proxy ratings of memory and dysexecutive symptoms, and a neuropsychiatric interview were also administered.
  
  
  RESULTS
  Six months after surgery, the STN group showed a larger decline than the control group on measures of verbal fluency, color naming, selective attention, and verbal memory. Moreover, the STN group showed a decrease in positive affect, and an increase in emotional lability and cognitive complaints. On the other hand, the STN group showed an increase in quality of life and a slight decrease in depressive symptoms. Nine percent of the STN patients had psychiatric complications (vs 3% of controls).
  
  
  CONCLUSIONS
  Bilateral subthalamic nucleus stimulation has an adverse effect on executive functions with implications for daily life of the patients and their relatives.
authors.affiliation: Department of Neurology, Academic Medical Center, Amsterdam, the Netherlands. h.m.smeding@amc.uva.nl
authors.forename: H M M
authors.initials: HM
authors.lastname: Smeding
authors.forename: J D
authors.initials: JD
authors.lastname: Speelman
authors.forename: M
authors.initials: M
authors.lastname: Koning-Haanstra
authors.forename: P R
authors.initials: PR
authors.lastname: Schuurman
authors.forename: P
authors.initials: P
authors.lastname: Nijssen
authors.forename: T
authors.initials: T
authors.lastname: van Laar
authors.forename: B
authors.initials: B
authors.lastname: Schmand
mesh_terms: D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D015897:Comorbidity; D046690:Deep Brain Stimulation / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017063:Outcome Assessment, Health Care; D010300:Parkinson Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy*; D011788:Quality of Life; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D020531:Subthalamic Nucleus; D016896:Treatment Outcome