ABSTRACT
A randomized clinical trial is the “gold standard” through which potential new therapies are tested. The purpose of clinical trials is to demonstrate the effects, both good and bad, of a given intervention in an objective manner and ultimately to improve clinical care. In the case of Parkinson’s disease (PD), results from trials may be used for several purposes, including
1. To compare treatment choices for existing therapies 2. To demonstrate the efficacy of new symptomatic treatments 3. To evaluate potentially neuroprotective therapies
In the first part of this chapter, we review the role of clinical trials. We discuss the conditions that should exist to justify conducting a trial; the process by which, after a trial is completed, the knowledge gained is adopted by physicians and applied to individual patients; and the eth ically sensitive relationship between clinical trials and clinical practice. In the second part of the chapter, we describe design paradigms for clinical trials in PD and review some frequently used outcome measures. The chapter may serve as a starting point for interpreting existing trials and possibly for designing new trials for emerging therapies for PD.
