title: Pallidal stimulation in Parkinson's disease patients with a prior unilateral pallidotomy.
abstract: OBJECTIVE
  To evaluate, in a double-blind fashion, the efficacy of deep brain stimulation of the internal segment of the globus pallidus (GPi) contralateral to a previous unilateral medial pallidotomy (MP).
  
  
  METHODS
  This pilot study involved 4 patients with a previous MP and one previously unoperated patient unable to tolerate any antiparkinsonian drugs. One of the patients with a prior unilateral MP had two electrodes implanted in the contralateral side, one in GPi and one in Vim thalamus. Detailed neurologic assessments were performed after overnight drug withdrawal and in the drug "on" state at baseline, 1 week and 3 months (in all), and 9 and 12 months (one) with patients and evaluators blinded to the status of stimulation.
  
  
  RESULTS
  GPi stimulation resulted in improvements in "off-period" contralateral bradykinesia, rigidity and tremor in all patients. Dyskinesias and freezing episodes were ameliorated in one patient each but dyskinesias were transiently induced in another. The patient with GPi + Vim electrodes had complete resolution of contralateral tremor with thalamic stimulation but less benefit from acute GPi stimulation. One patient experienced a single seizure one week post-op and no other surgical complications were observed.
  
  
  CONCLUSIONS
  Deep brain stimulation can be applied safely and effectively in patients who have already had a pallidotomy on the contralateral side. The effect of stimulation at different sites on different symptom profiles and levodopa-induced dyskinesias requires further evaluation.
authors.affiliation: Morton and Gloria Shulman Movement Disorders Centre, Division of Neurology, Toronto, Ontario, Canada.
authors.forename: N
authors.initials: N
authors.lastname: Gálvez-Jiménez
authors.forename: A
authors.initials: A
authors.lastname: Lozano
authors.forename: R
authors.initials: R
authors.lastname: Tasker
authors.forename: J
authors.initials: J
authors.lastname: Duff
authors.forename: W
authors.initials: W
authors.lastname: Hutchison
authors.forename: A E
authors.initials: AE
authors.lastname: Lang
mesh_terms: D000328:Adult; D000368:Aged; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000009:adverse effects; D005260:Female; D005917:Globus Pallidus / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000601:surgery* / Q000628:therapy*; D010865:Pilot Projects; D011182:Postoperative Care; D011183:Postoperative Complications; D012640:Seizures / Q000209:etiology; D013788:Thalamus / Q000503:physiopathology