Journal of Rehabilitation Research & Development (JRRD)

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Volume 48 Number 3, 2011
   Pages 225 — 234

Abstract —  Interface shear and pressure characteristics of wheelchair seat cushions

Jonathan S. Akins;1* Patricia E. Karg, MS;2 David M. Brienza, PhD1-2

1Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA; 2Department of Rehabilitation Sciences and Technology, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA

Abstract — Pressure ulcer incidence rates have remained constant despite advances in support surface technology. Interface shear stress is recognized as a risk factor for pressure ulcer development and is the focus of many shear reduction technologies incorporated into wheelchair cushions; however, shear reduction has not been quantified in the literature. We evaluated 21 commercial wheelchair seat cushions using a new methodology developed to quantify interface shear stress, interface pressure, and horizontal stiffness. Interface shear stress increased significantly with applied horizontal indenter displacement, while no significant difference was found for interface pressure. Material of construction resulted in significant differences in interface shear stress, interface pressure, and horizontal stiffness. This study shows that the existing International Organization for Standardization (ISO) 16840-2 horizontal stiffness measure provides similar information to the new horizontal stiffness measure. The lack of a relationship between interface shear stress and the overall horizontal stiffness measure, however, suggests that a pressure and shear force sensor should be used with the ISO 16840-2 horizontal stiffness measure to fully quantify a cushion's ability to reduce interface shear stress at the patient's bony prominences.

Key words: decubitus ulcer, interface, pressure, pressure sore, pressure ulcer, shear force, shear stress, stiffness, support surface, wheelchair seat cushion.

View HTML  ¦  View PDF  ¦  Contents Vol. 48, No. 3
This article and any supplementary material should be cited as follows:
Akins JS, Karg PE, Brienza DM. Interface shear and pressure characteristics of wheelchair seat cushions. J Rehabil Res Dev. 2011;48(3):203-12.

Last Reviewed or Updated  Tuesday, March 22, 2011 11:36 AM

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