Seat Interface Pressure Mapping to Improve Weight Shift Performance in Spinal Cord Injured Wheelchair Users

University of Minnesota Ph.D. dissertation. September 2018. Major: Rehabilitation Science. Advisors: Virgil Mathiowetz, John Ferguson. 1 computer file (PDF); xiii, 159 pages.Objectives. This dissertation investigated the effects of using of a smartphone-based, on-demand seat interface pressure map on trunk activity, weight shifts, and self-efficacy in spinal cord injured wheelchair users in their home environments. We hypothesized that daily trunk activity and time spent in partial and full weight shift positions would increase with daily pressure map access and that self-efficacy for performing weight shifts would increase when education for pressure injury prevention included use of the pressure map and also when using the pressure map in one’s daily routine. Method. This longitudinal, within-subject, repeated measures study of 23 wheelchair users with complete spinal cord injury included an educational component grounded in social cognitive theory. Following education for pressure injury prevention and performance of weight shifts, each participant was provided with a mobile pressure mapping system to take home to use for week-long periods of time, alternated with periods without using the mapping system. Their trunk movement over a 4-week period was monitored with an accelerometer. Self-efficacy for performing weight shifts was evaluated with a 4-item scale before education, after education, after education using the pressure map for feedback and during each of the week-long periods of time at home. Results. A statistically significant increase in trunk activity occurred with access to mobile, on-demand, seat interface pressure mapping in power and manual wheelchair users with spinal cord injury. The results suggested, but did not confirm with statistical significance, that there is a difference related to use of pressure map for time spent in partial and full weight shift zones, however, 81% of the participants had a positive change in at least one movement-related variable while using the pressure map when compared with not using the pressure map. The results also suggest that self-efficacy for performing weight shifts is higher when pressure injury prevention includes pressure mapping as a guide when learning how to perform weight shifts. Finally, self-efficacy for movements that relieve pressure is significantly higher during periods of access to the pressure map than without. Conclusions. We learned from this study that access to visual feedback from pressure mapping increases the types of movements that are protective against pressure injuries. Just as importantly, use of the pressure map improves self-efficacy for performing weight shifts in wheelchair users with spinal cord injury. Future research needs to explore who might benefit from this technology the most, when it should be introduced as an intervention strategy, and the effect of adding other features such as alerts, reminders, and the ability to self-track pressure-relieving behaviors over time