title: Central pain modulation after subthalamic nucleus stimulation: A crossover randomized trial.
abstract: OBJECTIVE
  To investigate the acute effect of subthalamic nuclei deep brain stimulation (STN-DBS) and levodopa on pain and tolerance thresholds in patients with Parkinson disease. We hypothesized that a modification of pain threshold after STN-DBS would suggest a central modification of pain perception, whereas the absence of pain threshold change after STN-DBS would correspond to a peripheral mechanism via a decrease of painful stimuli.
  
  
  METHODS
  Nineteen patients with Parkinson disease were included in this double-blind, randomized, crossover study. Postoperatively, we evaluated pain thresholds (thermal and mechanical) and motor symptoms under 3 acute conditions: stimulation on/medication off; stimulation off/medication on; and stimulation off/medication off. We also conducted a retrospective analysis of the data prospectively recorded during the follow-up of the cohort pre- and postoperatively (Unified Parkinson's Disease Rating Scale [UPDRS] score, Hoehn and Yahr stage, equivalent levodopa daily dose, and tapping test score).
  
  
  RESULTS
  We found a significant increase of pain and tolerance mechanical thresholds not only after acute STN-DBS but also after acute levodopa administration. We did not find any significant correlation between postoperative clinical pain improvement and UPDRS-III improvement after acute levodopa or STN-DBS, nor with motor complications improvement assessed with UPDRS-IV after chronic STN-DBS. No correlation was found between postoperative clinical pain improvement and mechanical pain threshold modification.
  
  
  CONCLUSIONS
  Clinical pain alleviation after STN-DBS cannot be considered merely as a consequence of motor complications improvement and could be attributable to a direct central modulation of pain perception, via increased mechanical pain and tolerance thresholds.
authors.affiliation: Neurology Department, CHU Clermont-Ferrand; University Clermont 1, CH Vichy, Vichy, France. ar_marques@chu-clemontferrand.fr
authors.forename: Ana
authors.initials: A
authors.lastname: Marques
authors.forename: Olivier
authors.initials: O
authors.lastname: Chassin
authors.forename: Dominique
authors.initials: D
authors.lastname: Morand
authors.forename: Bruno
authors.initials: B
authors.lastname: Pereira
authors.forename: Bérengère
authors.initials: B
authors.lastname: Debilly
authors.forename: Philippe
authors.initials: P
authors.lastname: Derost
authors.forename: Miguel
authors.initials: M
authors.lastname: Ulla
authors.forename: Jean Jacques
authors.initials: JJ
authors.lastname: Lemaire
authors.forename: Franck
authors.initials: F
authors.lastname: Durif
mesh_terms: D000978:Antiparkinson Agents / Q000627:therapeutic use; D018592:Cross-Over Studies; D046690:Deep Brain Stimulation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000502:physiology
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa