title: Expectation and the placebo effect in Parkinson's disease patients with subthalamic nucleus deep brain stimulation.
abstract: To determine whether the degree to which a patient with Parkinson's disease expects therapeutic benefit from subthalamic nucleus-deep brain stimulation (STN-DBS) influences the magnitude of his or her improved motor response, 10 patients with idiopathic Parkinson's and bilateral STN-DBS were tested after a 12-hour period off medication and stimulation. Four consecutive UPDRS III scores were performed in the following conditions: (a) stimulation OFF, patient aware; (b) stimulation OFF, patient blind; (c) stimulation ON, patient aware; and (d) stimulation ON, patient blind. Statistical significance (P = 0.0001) was observed when comparing main effect ON versus OFF (mean ON: 32.55; mean OFF: 49.15). When the stimulation was OFF, patients aware of this condition had higher UPDRS motor scores than when they were blinded (mean: 50.7 vs. 47.6). With the stimulation ON, UPDRS motor scores were lower when the patients were aware of the stimulation compared with when they were blinded (mean: 30.6 vs. 34.5). The interaction between these levels was significant (P = 0.049). This variation was important for bradykinesia and was not significant for tremor and rigidity. The authors conclude that the information about the condition of the stimulation enhanced the final clinical effect in opposite directions. The results presented support the role of expectation and placebo effects in STN-DBS in Parkinson's disease patients.
authors.affiliation: Surgical Centre for Movement Disorders, University of British Columbia, British Columbia, Canada.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Mercado
authors.forename: Constantine
authors.initials: C
authors.lastname: Constantoyannis
authors.forename: Tomasz
authors.initials: T
authors.lastname: Mandat
authors.forename: Ajit
authors.initials: A
authors.lastname: Kumar
authors.forename: Michael
authors.initials: M
authors.lastname: Schulzer
authors.forename: A Jon
authors.initials: AJ
authors.lastname: Stoessl
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Honey
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage; D001364:Awareness; D003131:Combined Modality Therapy; D046690:Deep Brain Stimulation / Q000523:psychology*; D004292:Dominance, Cerebral / Q000502:physiology; D018491:Dopamine Agonists / Q000008:administration & dosage; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D018476:Hypokinesia / Q000503:physiopathology / Q000523:psychology / Q000534:rehabilitation; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000503:physiopathology / Q000523:psychology* / Q000534:rehabilitation*; D015990:Placebo Effect; D012718:Set, Psychology; D020531:Subthalamic Nucleus / Q000503:physiopathology*
chemical_list: D000978:Antiparkinson Agents; D018491:Dopamine Agonists; D007980:Levodopa