Measuring vibration and shock in power wheelchairs for clinical application.

Research evidence demonstrates the negative effects of Whole-Body Vibration (WBV) and correlation between exposure to WBV and detriment to health. ISO Standard 2631-1 (1997) is the accepted standard for human exposure to WBV in vehicle vibration, and provides vibration guidelines for health and comfort. These standards have not been applied to power wheelchairs (PWC), and no clinical tool exists that measures vibration levels during live power wheelchair driving. This study measures WBV and shock levels during PWC driving, considering the impact of terrains, base configurations, and seat cushions. A sensor tag accelerometer was used to measure vibration and shock in three different PWC configurations driven over seven different terrains. Data was collected for two runs per wheelchair, per terrain type, per cushion type. Differences were significant (p < .001) for overall mean and median peak vibration compared across the seven terrains, and for overall mean vibration for basic and enhanced cushions. Differences were also noted in mean and peak vibration in the three different base configurations (p = .0052). Results were compared with ISO 2631-1 guidelines. Mechanical shock on certain terrains created peak vibration levels with likely health risk. Results from this study can inform PWC prescription process.