title: Effect of chronic pallidal deep brain stimulation on off period dystonia and sensory symptoms in advanced Parkinson's disease.
abstract: OBJECTIVE
  To investigate the efficacy of chronic pallidal deep brain stimulation (DBS) on off period dystonia, cramps, and sensory symptoms in advanced Parkinson's disease (PD).
  
  
  METHODS
  16 patients (6 women, 10 men; mean age at surgery 65 years) suffering from advanced PD were followed up prospectively for one year after implantation of a monopolar electrode in the posteroventral lateral globus pallidus internus. Unilateral DBS was performed in 9 patients. 10 patients had bilateral procedures (contemporaneous bilateral surgery in 7 and staged bilateral surgery in 3 instances). The decision whether to perform unilateral or bilateral surgery depended on the clinical presentation of the patient. Patients were formally assessed preoperatively, at 3-5 days, 3 months, and 12 months after surgery.
  
  
  RESULTS
  In patients who underwent unilateral surgery, pain was present in 7 (78%), off dystonia in 5 (56%), cramps in 6 (67%), and dysaesthesia in 4 (44%). In patients who underwent bilateral surgery, pain was present in 7 (70%), off dystonia in 6 (60%), cramps in 7 (70%), and dysaesthesia in 4 (40%). With unilateral DBS, contralateral off period dystonia was improved by 100% at 1 year postoperatively, pain by 74%, cramps by 88%, and dysaesthesia by 100%. There was less pronounced amelioration of ipsilateral off period dystonia and sensory symptoms. With bilateral DBS, total scores for dystonia were improved by 86%, for pain by 90%, for cramps by 90%, and for dysaesthesia by 88%. The benefit appeared early at the first evaluation 3-5 days after surgery and was stable throughout the follow up period.
  
  
  CONCLUSIONS
  Pallidal DBS yields major improvement of off period dystonia, cramps, and sensory symptoms in patients with advanced PD.
authors.affiliation: Department of Neurology, Inselspital, University of Berne, Berne, Switzerland.
authors.forename: T J
authors.initials: TJ
authors.lastname: Loher
authors.forename: J-M
authors.initials: JM
authors.lastname: Burgunder
authors.forename: S
authors.initials: S
authors.lastname: Weber
authors.forename: R
authors.initials: R
authors.lastname: Sommerhalder
authors.forename: J K
authors.initials: JK
authors.lastname: Krauss
mesh_terms: D000328:Adult; D000368:Aged; D004421:Dystonia / Q000209:etiology* / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D005917:Globus Pallidus / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009120:Muscle Cramp / Q000209:etiology / Q000628:therapy; D010300:Parkinson Disease / Q000150:complications*; D011446:Prospective Studies; D012678:Sensation Disorders / Q000209:etiology* / Q000628:therapy*; D012720:Severity of Illness Index; D016896:Treatment Outcome