This paper presents an assistive device for wheelchair users with severe disability. It consists of several sensors deployed on a wheelchair, able to sense pressure relief habits, activity level, vital signs, and ambient conditions. A pilot study was conducted to evaluate the potential capabilities of the system and the feasibility of implementing alarms. During a period of two weeks, six full-time wheelchair users were monitored. Results show that the system is able to capture pressure relief patterns and tilt-in-space usage, a mechanism required to avoid pressure ulcers. Data analysis shows that none of the volunteers fully complied with the tilting recommendations. It also shows varied activity levels, both within and between patients, indicating their engagement in daily activities. The system is also able to estimate heart and respiration rate during passive activities (e.g., watching TV and/or resting). Also, high temperatures in summer were monitored while patients were outside, to prevent heatstroke events. All the monitored variables are acquired with unobtrusive sensors, producing no discomfort to the patient and providing valuable information for better care. The final recommendation and alarm system is implemented in a single board computer, to be embedded in the wheelchair.
Telehealth monitor to measure physical activity and pressure relief maneuver performance in wheelchair users