Brian T. Fay

What is interface pressure

The term interface pressure (IP) is used widely in the area of wheelchair seating to describe the physical interaction between the buttocks and the seat surface. Methods of quantifying IP exist even though a formal, research-based definition does not exist. Using a previously proposed definition of IP, issues surrounding the definition are examined relative to research studies to show weaknesses in the definition. Additional concerns relative to current methods of quantifying IF, such as creep and hysteresis, are evaluated. Two alternative methods of considering the seating interface are presented. One involves standardization of IP measurement via an index whereas the other discards IP in favor of quantifying tissue deformation. It is concluded that a new method of considering the seating interface is required which allows for comparison between measurements and individuals.

Wrist kinematics and indicators of carpal tunnel syndrome during manual wheelchair propulsion

This study compared wrist kinematics during manual wheelchair propulsion (MWP) for 22 experienced Manual Wheelchair Users (MWU) with and without evidence of median mononeuropathy (MMN), an indicator of CTS. Thirteen (13) MWUs tested positive for MMN. Analysis found significantly higher peak wrist flexion for MWU who demonstrated CTS via the nerve conduction study. It may be prudent to instruct MWUs to avoid extremes of wrist extension.

Kinematic model of wrist via marker placement during manual wheelchair propulsion

Due to the dynamic nature of MWP, motion analysis via markers placed on bony prominences provides the best approximation of the three dimensional trajectory of the segments of the upper extremity. Previous models which use motion analysis markers have been described in the literature, but these models have not corrected for positioning of the hand in a non-neutral position. The current model provides a standard method for determining the three ranges of motion commonly attributed to the wrist: flexion/extension, radial/ulnar deviation, and pronation/supination. These quantities are calculated via a local coordinate system based at the wrist as described by Shimada (1997), but applies a correction factor to account for non-neutral hand position during calibration.