Placebo effect of medication cost in Parkinson disease: A randomized double-blind study.
Espay, Alberto J. MD, MSc; Norris, Matthew M. MEng; Eliassen, James C. PhD; Dwivedi, Alok PhD; Smith, Matthew S. BS; Banks, Christi CCRC; Allendorfer, Jane B. PhD; Lang, Anthony E. MD, FRCPC; Fleck, David E. PhD; Linke, Michael J. PhD; Szaflarski, Jerzy P. MD, PhD
84(8):794-802, February 24, 2015.
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Objective: To examine the effect of cost, a traditionally "inactive" trait of intervention, as contributor to the response to therapeutic interventions.
Methods: We conducted a prospective double-blind study in 12 patients with moderate to severe Parkinson disease and motor fluctuations (mean age 62.4 /- 7.9 years; mean disease duration 11 /- 6 years) who were randomized to a "cheap" or "expensive" subcutaneous "novel injectable dopamine agonist" placebo (normal saline). Patients were crossed over to the alternate arm approximately 4 hours later. Blinded motor assessments in the "practically defined off" state, before and after each intervention, included the Unified Parkinson's Disease Rating Scale motor subscale, the Purdue Pegboard Test, and a tapping task. Measurements of brain activity were performed using a feedback-based visual-motor associative learning functional MRI task. Order effect was examined using stratified analysis.
Results: Although both placebos improved motor function, benefit was greater when patients were randomized first to expensive placebo, with a magnitude halfway between that of cheap placebo and levodopa. Brain activation was greater upon first-given cheap but not upon first-given expensive placebo or by levodopa. Regardless of order of administration, only cheap placebo increased activation in the left lateral sensorimotor cortex and other regions.
Conclusion: Expensive placebo significantly improved motor function and decreased brain activation in a direction and magnitude comparable to, albeit less than, levodopa. Perceptions of cost are capable of altering the placebo response in clinical studies.
Classification of evidence: This study provides Class III evidence that perception of cost is capable of influencing motor function and brain activation in Parkinson disease.
(C) 2015 American Academy of Neurology