A biotech firm is using the Apple Watch to study its Parkinson's disease drug in a clinical trial.[1] The MM4PD system uses the accelerometer and gyroscope of the Apple Watch to detect motor symptoms such as resting tremors and dyskinesias.[1][4] Apple researchers, in collaboration with specialists, identified characteristic "on" and "off" patterns of drug effects.[1] MM4PD measurements correlate with clinical ratings of tremor severity (r = 0.80) and detect the presence of dyskinesias (P < 0.001).[4] The system captured changes in symptoms in response to treatment in 94% of 225 participants for up to 6 months.[4] A pilot study included 118 patients with Parkinson's disease, where data were compared to the gold standard MDS-UPDRS.[4] Neurologists at the University of Rochester followed patients with early Parkinson's disease for a year using an Apple Watch and iPhone, revealing a decrease in walking, an increase in tremors, changes in speech, and a reduction in arm swing.[2] The StridePD app has received FDA approval for movement, sleep, and tremor monitoring.[3][5]