Egocentric Video: A New Tool for Capturing Hand Use of Individuals with Spinal Cord Injury at Home

TL;DR

This paper introduces a wearable egocentric camera system that uses computer vision to quantitatively assess hand use of individuals with spinal cord injury in home settings, providing valuable functional data outside clinical environments.

Contribution

The study presents a novel computer vision-based system for monitoring hand activity in real-world home environments of individuals with cSCI, validated with promising accuracy and correlation to manual labels.

Findings

F1-scores of approximately 0.74 for hand-object interaction detection.

Significant correlations (up to 0.55) between automated measures and manual labels.

Demonstrated potential for quantitative assessment of hand use at home.

Abstract

Current upper extremity outcome measures for persons with cervical spinal cord injury (cSCI) lack the ability to directly collect quantitative information in home and community environments. A wearable first-person (egocentric) camera system is presented that can monitor functional hand use outside of clinical settings. The system is based on computer vision algorithms that detect the hand, segment the hand outline, distinguish the user's left or right hand, and detect functional interactions of the hand with objects during activities of daily living. The algorithm was evaluated using egocentric video recordings from 9 participants with cSCI, obtained in a home simulation laboratory. The system produces a binary hand-object interaction decision for each video frame, based on features reflecting motion cues of the hand, hand shape and colour characteristics of the scene. This output was compared with a manual labelling of the video, yielding F1-scores of 0.74 $\pm$ 0.15 for the left hand and 0.73 $\pm$ 0.15 for the right hand. From the resulting frame-by-frame binary data, functional hand use measures were extracted: the amount of total interaction as a percentage of testing time, the average duration of interactions in seconds, and the number of interactions per hour. Moderate and significant correlations were found when comparing these output measures to the results of the manual labelling, with $\rho$ = 0.40, 0.54 and 0.55 respectively. These results demonstrate the potential of a wearable egocentric camera for capturing quantitative measures of hand use at home.