Methods for Analysis of Daily Wheelchair Activity Data

INTRODUCTION Recent advances in technology, including accessibility of wireless sensors, improved memory size, low power consumption and longer battery life have resulted in the increased portability of activity monitors. Numerous commercial and custom products including pedometers, wheelchair odometers and accelerometer-based activity monitors allow research to take place beyond the laboratory. It is possible to monitor a subject in their home environment for weeks at a time. Although many medical interventions are meant to improve mobility and physical activity, improved gait in the laboratory does not necessarily translate to improved mobility at home. Therefore, the characterization of daily mobility is very important and raises many new questions including: How much data should be collected? How should it be analyzed? While common measures such as mean and standard deviation successfully describe the magnitude of the data, the temporal spread of activity may also be important. For example, 30-minute bouts of moderate to vigorous physical activity are recommended for health benefits. Alternatively, short bouts of movement may indicate environmental interactions and stationary activities. In wheelchair activity, long durations without activity may be detrimental to tissue loading and pressure ulcer outcomes.