Assessment of decubitis risk in a test circuit using different wheelchair cushions

The risk of pressure sores is a common problem to wheelchair users. A great variety of wheelchair cushions are produced to reduce this risk. To evaluate wheelchair cushions in most studies the pressure under the ischial tuberosities is measured in a static situation with the subjects seated in one posture. However wheelchair users do interact with their environment and during the day they will drive on different surfaces adopting different postures, leading to continuous pressure variations under the buttocks. Therefore in this study, the pressure under the buttocks of nine spinal cord injured subjects was measured continuously during wheelchair driving, while they were sitting on a standard foam cushion (thickness 5 cm) or a Jay Active® cushion. The results of dynamic pressure measurements correlate with three classes of tissue response under the buttocks (Bar, 1988): severe, moderate and mild. The results from the data showed that a 5 cm thick foam cushion produced only severe responses, while a Jay Active® cushion showed mild responses most of the time.