Accuracy of Smartphone Video for Contactless Measurement of Hand Tremor Frequency
Related Experiment Video
Updated: Oct 11, 2025
Video Movement Analysis Using Smartphones ViMAS: A Pilot Study
Published on: March 14, 2017
Stefan Williams1,2, Hui Fang3, Samuel D Relton1
1Leeds Institute of Health Science, University of Leeds Leeds UK.
Background:
Computer vision can measure movement from video without the time and access limitations of hospital accelerometry/electromyography or the requirement to hold or strap a smartphone accelerometer.
Objective:
To compare computer vision measurement of hand tremor frequency from smartphone video with a gold standard measure accelerometer.
Methods:
A total of 37 smartphone videos of hands, at rest and in posture, were recorded from 15 participants with tremor diagnoses (9 Parkinson's disease, 5 essential tremor, 1 functional tremor). Video pixel movement was measured using the computing technique of optical flow, with contemporaneous accelerometer recording. Fast Fourier transform and Bland-Altman analysis were applied. Tremor amplitude was scored by 2 clinicians.
Results:
Bland-Altman analysis of dominant tremor frequency from smartphone video compared with accelerometer showed excellent agreement: 95% limits of agreement -0.38 Hz to +0.35 Hz. In 36 of 37 videos (97%), there was <0.5 Hz difference between computer vision and accelerometer measurement. There was no significant correlation between the level of agreement and tremor amplitude.
Conclusion:
The study suggests a potential new, contactless point-and-press measure of tremor frequency within standard clinical settings, research studies, or telemedicine.
