Original Paper

Immediate Placebo Effect in Parkinson's Disease - Is the Subjective Relief Accompanied by Objective Improvement?
Felipe Fregni^a, Paulo S. Boggio^b, Felix Bermpohl^{a, c}, Fernanda Maia^b, Sergio P. Rigonatti^b, Egberto R. Barbosa^b, Alvaro Pascual-Leone<sup>a

a</sup>Harvard Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass., USA;
^bDepartments of Psychology, Psychiatry and Neurology, University of Sao Paulo, Sao Paulo, Brazil;
^cDepartment of Psychiatry and Psychotherapy, Charité Campus Mitte, University Medicine Berlin, Berlin, Germany

Address of Corresponding Author

Eur Neurol 2006;56:222-229 (DOI: 10.1159/000096490)

  Key Words

• Parkinson's disease
• Transcranial magnetic stimulation
• Levodopa

  Abstract

Background: A recent well-conducted meta-analysis showed that placebo effect is associated with a possible small benefit for subjective outcomes, but has no significant effects on objective outcomes. Objective: Herein, we aimed to investigate the immediate effects of two different types of placebo [placebo pill and sham transcranial magnetic stimulation (TMS)] in Parkinson's disease (PD) patients and compared them to the standard treatment (levodopa) in a proper randomized, double-blind, crossover clinical trial. Methods: PD patients received three different interventions on different days: levodopa, placebo pill, and sham TMS. The motor function was assessed using simple and choice reaction time, Unified Parkinson's Disease Rating Scale (UPDRS), finger tapping, Purdue Pegboard test, time to button up, walking time and supination-pronation. The subjective motor function was measured by a visual analogue scale (VAS). Results: The results showed that there was a significant motor function in the motor function only after the treatment with levodopa, but not after treatment with placebo pills or sham TMS. However, patients reported a similar subjective improvement in motor function indexed by VAS following these three treatments. Conclusion: These results suggest that placebo interventions in PD may have an immediate subjective sensation of improvement but result in no significant objective motor changes compared with levodopa treatment. Although physiological changes are possible after a placebo intervention, our findings suggest that the acute placebo effect in PD may be the result of the subjective change in the motor rating only.

Copyright © 2006 S. Karger AG, Basel

  Author Contacts

Felipe Fregni, MD, PhD
Harvard Center for Non-Invasive Brain Stimulation
Beth Israel Deaconess Medical Center, Harvard Medical School
330 Brookline Ave, KS 452, Boston, MA 02215 (USA)
Tel. +1 617 667 5272, Fax +1 617 975 5322, E-Mail ffregni@bidmc.harvard.edu

  Article Information

Received: April 5, 2006
Accepted: July 31, 2006
Published online: October 20, 2006
Number of Print Pages : 8
Number of Figures : 4, Number of Tables : 1, Number of References : 22