ABSTRACT
Clinical trials are the means by which new therapies are tested. The purpose of trials is to demonstrate the effects, both good and bad, of an intervention with the ultimate goal of better patient outcomes. In the case of Parkinson’s disease (PD), results from trials may be used for several purposes including (1) to demonstrate the efcacy of new symptomatic treatments, (2) to inform choices between existing therapies, and (3) to evaluate potentially neuroprotective therapies. In the rst part of this chapter, we review the role of clinical trials in the context of research and clinical care. We discuss the conditions that justify conducting a trial, the process of integrating the knowledge gained from a trial into the care of individual patients and the distinctions 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, including biomarkers in clinical trials.
