Validation of Dyskinesia Rating Scales

Objective/Rationale: Dyskinesias, or involuntary jerking movements, are troublesome problems for many Parkinson's disease patients. Chemical studies have led to the development of several new treatment strategies. However, because dyskinesias are cause various degrees of difficulty for patients and are often perceived by patients and caregivers differently than by doctors, the rating of dyskinesias remains a scientific challenge. This program will examine a wide gamut of available rating scales to determine which one(s) detect change during dyskinesia treatment. Establishing excellent measurement tools of dyskinesias will allow future treatments to be evaluated in a uniform and maximally effective manner. Project Description: An team of experts will test several dyskinesia scales in a group of Parkinson's disease patients with dyskinesia. Patients will be treated with either amantadine or placebo (an inactive product). The study will be "blinded" so that the raters and the patients do not know if a given patient is receiving amantadine or placebo. Amantadine is selected for this trial, because it is the only drug that has received the designation of Efficacious for dyskinesia by the Movement Disorder Society. This conclusion was based however, on small studies and no large clinical trial of this drug has been conducted in dyskinetic patients. The scales will assess dyskinesia before and after several weeks of treatment. Relevance to Diagnosis/Treatment of Parkinson's Disease: This study will establish a "gold standard" for rating dyskinesia in future trials of treatments in Parkinson's disease patients. It will allow physicians to know the level of change that occurs with a standard and available treatment (amantadine) and to compare that level with changes that occur with newer treatments. Patients will benefit from this new international standard, because they can compare the likelihood and magnitude of anticipated improvement from different dyskinesia treatments, whether medical or surgical. Anticipated Outcome: The anticipated outcomes of this study are: * The impact of amantadine treatment on dyskinesia will be clearly defined. * The effect that participation in a clinical program, even if no amantadine is given ("placebo improvements") will be delineated. * A hierarchy of numerous scales will be determined based on their absolute and relative capability to detect change during treatment. * The best scale(s) to evaluate dyskinesia in clinical practice and research efforts will be identified.