Objective changes in motor function during placebo treatment in PD.

OBJECTIVE: To examine the frequency, temporal development, and stability of objectively derived motor changes during placebo treatment in PD and to define the clinical domains and demographic groups most affected.

BACKGROUND: Placebo effects are documented in neurology, but the timing and specific disabilities most susceptible to changes during placebo treatment in PD have not been examined.

METHODS: The authors examined the placebo-treated group from a randomized, multicenter, placebo-controlled clinical trial of monotherapy ropinerole in PD patients without motor fluctuations.

In 105 patients, they evaluated placebo-associated effects on the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS), dividing the motor examination into four categories: tremor, bradykinesia, rigidity, and gait/balance/midline functions.

The motor UPDRS and its subscales were compared over time (at baseline and at 4, 12, and 24 weeks) using Wilcoxon's signed rank test.

They applied a rigorous definition of placebo-associated improvement as an improvement over baseline score in motor UPDRS of at least 50% or a change in at least two motor items at any one visit by > or =2 points.

RESULTS: During the 6-month study, 16% of subjects improved on placebo treatment.

The prevalence of response was steady (8 to 9%) at any one visit without a predominance of an early effect.

No patient showed a placebo-associated improvement on all visits.

All domains of parkinsonian disability were subject to placebo-associated improvement, with a trend toward more response in bradykinesia and rigidity than in tremor or gait/balance/midline function.

Gender, age, disease duration, and baseline disability score did not influence the likelihood of improvement in association with placebo treatment.

CONCLUSION: Based on a rigorous definition of placebo-associated improvement, prominent improvements in objective measures of PD disability occur during clinical trials.

Because placebo-associated improvements occur throughout a 6-month trial, placebo-controlled studies in PD should be at least 6 months to capture early as well as late improvements.


Neurology 2000 Feb 8;54(3):710-4
Goetz CG, Leurgans S, Raman R, Stebbins GT
Rush University, Rush Presbyterian St. Luke's Medical Center, Chicago, Illinois, 60612, USA.
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PMID: 10680808, UI: 20143001

<http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10680808&dopt=Abstract>

janet paterson
52 now / 41 dx / 37 onset
a new voice: http://www.geocities.com/janet313/
613 256 8340 PO Box 171 Almonte Ontario Canada K0A 1A0