Glossary
Adverse event
An unfavorable change in health that can occur during a clinical trial or study or within a certain time period after. These can range from mild( e. g., nausea) to serious or life-threatening( e. g., stroke). This change may or may not be related to the intervention being studied. See also: intervention
Alpha-synuclein
A protein normally found in brain cells and the main component of clumps, called Lewy bodies, in the brains of people with Parkinson’ s. Researchers believe that the alpha-synuclein in Lewy bodies is associated with death or damage to brain cells. A mutation in the gene SNCA that directs the production of the alpha-synuclein protein is the basis for a rare, inherited form of Parkinson’ s disease. See also: SNCA
Arm
A specific group of study participants within a clinical trial. For example, in an interventional trial, one“ arm” may receive the investigational treatment and another“ arm” receives placebo. See also: interventional trial
Baseline data
Demographic information( e. g., age and gender) and other information such as symptoms, medications or measurements on specific tests that is collected from participants at the beginning of a clinical trial or study.
Biomarker
A measurable, biological characteristic that can be used to determine the risk, presence or progression of a disease. For example, high blood pressure is a biomarker of potential heart disease. No biomarker of Parkinson’ s has yet been validated, but researchers are working toward such a measure.
Blinding
A clinical trial strategy where the researchers and participants do not know which participants are taking placebo( inactive substance) and which are receiving the intervention. In single blinding, only one group( either researchers or participants) knows which participants are taking placebo or intervention. In double blinding, neither group knows. See also: intervention; placebo
Breakthrough therapy designation
A U. S. FDA process that speeds the development and review of new therapies that may treat a serious condition if early clinical trial data indicate that the drug may be more efficacious than available therapies. See also: efficacy; U. S. Food and Drug Administration
44 Navigating Clinical Trials: A Guide for Parkinson’ s Patients and Families