Researchers and clinicians are learning that Parkinson’s disease (PD) is an umbrella term that covers similar but distinct variants of the disease that may result from differences in biology. Symptoms may be similar, but each person’s disease may have different features, rate of progression, needs, and treatments connected to the specific underlying cause. In this era of “personalized” medicine, a goal is to treat each person’s condition according to their unique disease. To do so, neurologists will need to be able to define and identify those differences (“biomarkers”) that will allow a truly personalized approach to treatment. A biomarker is a measurable indicator of a normal or abnormal bodily function. Examples are imaging such as MRI, chemicals in the blood or brain, brain wave patterns, sleep cycles, or even specific signs and symptoms. 

Having biomarkers indicative of specific variants of the disease could help to design clinical trials to test therapies. It would allow researchers to include individuals with similar underlying biology when they test a potential new drug to be able to understand if it works for that form of PD. In a trial that included people falling under the umbrella term of “PD,” for example, researchers could see who benefited from the drug and then examine them to see what biomarkers they had in common. In this podcast, Dr. Anthony Lang, Director of the Edmond J. Safra Program in Parkinson’s Disease at the Toronto Western Hospital in Canada, discusses the need for biomarkers when searching for disease-modifying therapies – those treatments that can actually modify the course of PD and not just treat its symptoms. And he tells us why it is sometimes hard to tell the two apart.