Concurrent Validity of the use of an Accelerometer to Record Distance Travelled by Manual Wheelchairs
Kim Parkera, Karen Pahlavanb, R. Lee Kirbyc
aAssistive Technology, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
bDepartment of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia, Canada
cDepartment of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
ABSTRACT
The objective was to assess the concurrent validity of a commercially available tri-axial accelerometer (GT3X +) to record distance travelled by manual wheelchairs in comparison with fixed-distance trials and GPS tracking. Indoor and outdoor validation tests were performed with occupied manual wheelchairs. A measurement wheel was used to measure the true distance. The accelerometer was secured to the rear wheel spokes of the wheelchair. A global positioning device (GPS) data logger was used to record the outdoor distance travelled. The radial and tangential acceleration output was used to derive the distance travelled using two techniques. The accelerometer-derived and GPS distances both over-estimated the actual distance travelled by the wheelchair by an average of 3%. The accelerometer appears to be a valid method of tracking both indoor and outdoor wheelchair movements.