Dynamic Seating Interface Pressures during Wheelchair Locomotion: Influence of Cushion Type

Abstract

Seat interface pressure distribution is measured statically in a clinical or research environment with the patient in a fixed position (static) if measured at all. The purpose of this study was to compare the dynamic seat interface pressures between three cushion types [2″ foam, Roho Low Profile (air), and Jay Active (gel)] during wheelchair locomotion. A total of 9 volunteer subjects (7 males, 2 females) participated in a study to determine seat interface pressure fluctuations between each of the 3 different wheelchair cushions. Seat interface pressures were measured with the Novel Pliance System, consisting of a 320×32 sensor matrix mat interfaced with a PC. Each sensor had an area of 1.5 cm². Sampling rate was fixed at 10 Hz. Average pressures under the ischial tuberosities were determined and the average maxima and minima were calculated from 3 wheelchair locomotion cycles of 3 trials. Wheelchair locomotion speed was constant across trials and conditions (±107). A repeated measures analysis of variance (RM ANOVA) exhibited a main effect for cushion type [F(2, 16)=16.6, p < .05]. A Newman-Keuls pairwise multiple comparison found differences between the 2” foam cushion and both the air and gel cushions, but no differences between the gel and air cushions during wheelchair locomotion. It is important that clinicians and cushion designers understand the dynamic performance characteristics of specific cushion types. Cushion performance may enhance the effectiveness of seating systems in minimizing pressure fluctuations.