Automated Computer Vision Assessment of Hypomimia in Parkinson Disease: Proof-of-Principle Pilot Study.

Background: Facial expressions require the complex coordination of 43 different facial muscles. Parkinson disease (PD) affects facial musculature leading to "hypomimia" or "masked facies."

Objective: We aimed to determine whether modern computer vision techniques can be applied to detect masked facies and quantify drug states in PD.