title: Changes in intracortical inhibition and clinical symptoms after STN-DBS in Parkinson's disease.
abstract: OBJECTIVE
  To examine effects of subthalamic nucleus deep brain stimulation (STN-DBS) on intracortical inhibition in Parkinson's disease (PD) and the correlation between intracortical inhibition and clinical symptoms after alteration of STN-DBS status.
  
  
  METHODS
  Nine PD patients treated by STN-DBS were compared with eight age-matched controls. Antiparkinsonian medication was withdrawn 12h before the study. Short-interval intracortical inhibition (SICI) with a 3-ms interval and silent period (SP) were examined using transcranial magnetic stimulation. SP duration, SICI and motor symptoms (rigidity and tremor) were evaluated with STN-DBS ON, and over 120 min during STN-DBS OFF.
  
  
  RESULTS
  Even during STN-DBS, PD patients showed a shortened SP and reduced SICI relative to normal controls. SICI decreased further throughout STN-DBS OFF, resulting in facilitation rather than inhibition; SP shortened only after 120 min STN-DBS OFF. Both rigidity and tremor worsened throughout STN-DBS OFF, with a time course similar to SICI.
  
  
  CONCLUSIONS
  Even during STN-DBS, both SICI and SP in PD patients remain impaired without medication. Changes in SICI, but not SP, show a time course similar to those of motor symptoms.
  
  
  CONCLUSIONS
  The dissimilarity of SICI and SP changes suggests differences in mediation of inhibitory mechanisms and/or superimposition of exaggerated intracortical facilitation on SICI.
authors.affiliation: Dept. of Neurosurgery, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan; Department of Neurology, Mihara Memorial Hospital, 366 Otamachi, Isesaki, Gunma 370-0006, Japan. Electronic address: mkob@saitama-med.ac.jp.
authors.forename: Masahito
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Dept. of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo 165-8582, Japan. Electronic address: tak@med.keio.ac.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohira
authors.affiliation: Department of Neurology, Mihara Memorial Hospital, 366 Otamachi, Isesaki, Gunma 370-0006, Japan. Electronic address: mmh-kenkyu@mihara-ibbv.jp.
authors.forename: Ban
authors.initials: B
authors.lastname: Mihara
authors.affiliation: Dept. of Neurosurgery, Saitama Medical University, 38 Morohongo, Moroyama-machi, Iruma-gun, Saitama 350-0495, Japan. Electronic address: tfujimak@saitama-med.ac.jp.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Fujimaki
mesh_terms: D000368:Aged; D046690:Deep Brain Stimulation / Q000639:trends*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009127:Muscle Rigidity / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D009433:Neural Inhibition / Q000502:physiology*; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000639:trends*; D014202:Tremor / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy
keywords: Intracortical inhibition; Parkinson’s disease; Subthalamic nucleus deep brain stimulation