Digital Biomarkers in Parkinson's Disease: Missing the Forest for the Trees?
Ashwani Jha, Alberto J. Espay, Andrew Lees
Abstract
Recently proposed digital measures of Parkinson's disease are gaining momentum.1, 2 More objective, more precise, and more easily repeated than human expert-based assessments such as the current gold standard Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS),3 these measures—often conceptualized as digital biomarkers—promise a new dawn in personalized medicine. Digital tools are already being used as surrogate markers in clinical trials4 and are advocated to improve clinical decision-making.5 Therefore, is it only a matter of more time, more data, and of course more money before at-home digital assessments become the clinical gold-standard? In this viewpoint we step-back and re-evaluate what it is we are trying to measure and why we are measuring it. From this perspective we argue that the current pursuit of more precise and objective measures may, if unchecked, lead to ever increasing bias in clinical trials and ever decreasing use for individual decision-making. We may improve the statistical power of clinical trials, but at the cost of personalization. We propose a more holistic digital approach as a solution.