Reliability of cushion construction for a low-cost pressure-reducing wheelchair cushion for less-resourced settings

Purpose: In less-resourced settings, 80% of people with spinal cord injuries die from pressure ulcer complications within two years. Appropriately constructed wheelchair cushions are effective in reducing incidence and severity of pressure ulcers. The Tuball is an inexpensive wheelchair cushion designed for users in less-resourced settings, which can be reproduced by local clinicians using locally sourced materials. This paper aimed to assess whether different individuals with limited knowledge of cushion construction could reliably construct the Tuball cushion.

Materials and Methods: A convenience sample of eleven occupational therapy students were randomly assigned to one of two groups. Six participants constructed a Tuball and completed a subjective workload assessment. Five different participants sat on each cushion while pressure distributions were mapped. Intraclass correlation coefficients (ICC) with 95% confidence intervals were calculated for reliability of construction of each cushion using data from a range of pressure indices: dispersion index (primary outcome), peak pressure index, contact area, and seat pressure index (secondary outcomes) across all six cushions.

Results and Conclusions: The ICC across all cushions was 0.745 (95% CI 0.103-0.970) for dispersion index. ICCs across cushions for secondary outcomes ranged from 0.879 to 0.951. Good-moderate reliability was found for the reliability in cushion construction as measured by the dispersion index. Excellent reliability in cushion construction was found as measured by peak pressure index, contact area, and seat pressure index. Data indicates individuals can reliably construct the Tuball given equivalent materials and instructions.