A robust wheelchair pressure relief monitoring system.

It is essential to prevent pressure ulcers for people with spinal cord injuries (SCI). Pressure ulcer is likely to develop when there is excessive pressure on the body tissue for lengthy durations. Therefore, persons with SCI, who usually spend long time sitting in wheelchairs, are advised to perform regular pressure reliefs in their daily lives. This paper proposes a system for the monitoring of wheelchair users' pressure relief behaviors. The system utilizes piezo resistive sensors beneath a wheelchair cushion to monitor pressure, and employs supervised learning techniques to classify a wheelchair user's pressure relief status. Key features of the system include robustness and not interfering with cushion performance or the daily activities of wheelchair users. The system works well on different types of cushions, and achieves 91% sensitivity and 89% specificity based on tests on different wheelchair users.