title: Subthalamic stimulation in Parkinson disease: intraoperative predictive factors.
abstract: BACKGROUND
  High-frequency stimulation of the subthalamic nucleus (STN) is an effective treatment for advanced forms of Parkinson disease. Postoperative improvement of motor parkinsonian disability is known to depend on patient selection and surgical targeting.
  
  
  OBJECTIVE
  To determine which clinical and electrophysiological variables evaluated during the operation predict the postoperative clinical outcome of patients with Parkinson disease treated by bilateral high-frequency stimulation of the STN.
  
  
  METHODS
  Intraoperative clinical and electrophysiological data obtained in 41 patients with Parkinson disease who underwent bilateral implantation of electrodes for STN stimulation were correlated with the improvement in parkinsonian disability assessed 6 months after the operation.
  
  
  RESULTS
  The extent of STN neuronal activity recorded along the trajectory of the therapeutic electrode had no effect on the postoperative clinical outcome. The intraoperative improvement in segmental akinesia, but not rigidity, was predictive of the postoperative improvement in parkinsonian motor disability and reduction in daily levodopa-equivalent dosage. Parkinsonian motor disability scores assessed after surgery were lower in patients with intraoperative stimulation-induced dyskinesias than in those without stimulation-induced dyskinesias.
  
  
  CONCLUSIONS
  The improvement of segmental akinesia and the observation of dyskinesias provoked by stimulation during the operation predict the best postoperative effects of bilateral STN stimulation on parkinsonian motor disability.
authors.affiliation: Centre d'Investigation Clinique, Fédération de Neurologie, INSERM Unit 289, Hôpital de la Salpêtrière, Paris, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Houeto
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Welter
authors.forename: Paul-Boulos
authors.initials: PB
authors.lastname: Bejjani
authors.forename: Sophie
authors.initials: S
authors.lastname: Tezenas du Montcel
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Bonnet
authors.forename: Valerie
authors.initials: V
authors.lastname: Mesnage
authors.forename: Soledad
authors.initials: S
authors.lastname: Navarro
authors.forename: Bernard
authors.initials: B
authors.lastname: Pidoux
authors.forename: Didier
authors.initials: D
authors.lastname: Dormont
authors.forename: Philippe
authors.initials: P
authors.lastname: Cornu
authors.forename: Yves
authors.initials: Y
authors.lastname: Agid
mesh_terms: D004185:Disability Evaluation; D020820:Dyskinesias / Q000175:diagnosis / Q000601:surgery / Q000628:therapy; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010300:Parkinson Disease / Q000175:diagnosis / Q000601:surgery* / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D020531:Subthalamic Nucleus / Q000601:surgery*; D016896:Treatment Outcome