title: Subthalamic stimulation improves the cerebral hemodynamic response to the cold pressure test in patients with Parkinson's disease.
abstract: OBJECTIVE
  Disturbances of the autonomic nervous system are common in patients with Parkinson's disease (PD) but the effect of deep brain stimulation of the subthalamic nucleus on cerebrovascular reactivity is not entirely known.
  
  
  METHODS
  Seven patients in an advanced stage of the disease and seven healthy age-matched controls participated in the study, which took place after one night of drug withdrawal. Cerebral blood flow velocity was continuously monitored on both sides with transcranial Doppler ultrasound, and cerebrovascular reactivity (CR) was evaluated with the cold pressure test. The measurements were repeated and compared during the stimulation-on and -off phases.
  
  
  RESULTS
  The PD patients had significantly higher CR values in the stimulation-on than -off conditions (15.1% ± 6.9 versus 9.4% ± 6.2; p = 0.03). CR values were higher in controls than in patients in the stimulation-off condition (20.4% ± 12.5 versus 9.4% ± 6.2; p = 0.007) without a significant difference with the stimulation-on phase.
  
  
  CONCLUSIONS
  CR, evaluated by the response to the cold pressure test, is impaired in patients with advanced PD and improved by subthalamic nucleus.
authors.affiliation: Department of Neurology and Neurosurgery, University of Tartu, Estonia.
authors.forename: Tõnu
authors.initials: T
authors.lastname: Rätsep
authors.forename: Toomas
authors.initials: T
authors.lastname: Asser
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D003080:Cold Temperature; D046690:Deep Brain Stimulation / Q000379:methods*; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D011312:Pressure; D020531:Subthalamic Nucleus / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods