Impact of sitting time on seat-interface pressure and on pressure mapping with multiple sclerosis patients

Objective: To examine changes in seat-interface pressure with multiple sclerosis (MS) patients. Design: Case series. Setting: Multiple Sclerosis Society's Resource Centre and community. Participants: Convenience sample of 15 MS wheelchair users and 12 MS non-wheelchair users. Intervention: Interface pressure was measured for 8 minutes using the Force Sensing Array pressure mapping system. Main Outcome Measures: Number of activated sensors, standard deviation, average and maximum pressures. Results: With the wheelchair users, significant decreases were found in the standard deviation and average and maximum pressures during 0 to 2 minutes of sitting (P <.01). Average pressure was the only parameter to show a significant decrease in the non-wheelchair users (P <.01) during 0 to 2 minutes. Significant increases were found in all output parameters during 2 to 4 minutes with both groups (P <.05). Non-wheelchair users showed no significant changes in the output parameters after 4 minutes, but wheelchair users showed significant continued increases in the output parameters from 4 to 8 minutes (P <.05).