Quantitative Movement Testing: Measuring Patient Movements from a Single Smartphone Video
Pranav Mahajan, Amanda Wall, Eleonora Maria Camerone, Julie Stebbins, Eoin Kelleher, Shuangyi Tong, Annina Schmid, Katja Wiech, Anushka Irani, Ben Seymour
Stop requiring patients to visit labs for movement assessment. Deploy smartphone-based kinematic tracking for clinical trials and longitudinal monitoring. Best for tracking treatment response where objective functional measures matter more than perfect precision.
Chronic pain assessment relies on subjective self-reports or expensive lab-based motion capture. Clinicians need objective functional measures that work in real-world settings, not just controlled labs.
Method: A computer vision pipeline extracts 3D kinematic biomarkers from standard smartphone video using deep learning-based pose estimation. After leave-one-subject-out calibration to correct systematic bias, it achieved strong correlations (r > 0.85) with gold-standard optical motion capture and high test-retest reliability (r > 0.86) in fibromyalgia patients. It successfully tracked day-to-day movement fluctuations in chronic sciatica patients and detected group-level differences between patients and healthy controls in remote home recordings.
Caveats: Home environments introduced higher measurement variance than lab settings. Reliability optimization for uncontrolled conditions still needed.
Reflections: What minimum recording quality thresholds ensure clinical-grade reliability in diverse home lighting and space constraints? · Can the pipeline detect clinically meaningful changes in movement quality before patients report symptom improvements? · How does measurement variance in home settings affect statistical power for clinical trial endpoints?