Peter J. McAlindon
McAlindon Enterprises, Inc.
Florian G. Jentsch
University of Central Florida
The de-facto standard QWERTY keyboard was developed over a hundred years ago and is one of the few visual display terminal (VDT) workstation components that has not made the same technological strides as the rest of the workstation components. It is this lack of advancement that has caused the QWERTY keyboard to become suspect in causing repetitive strain injuries (RSIs) such as carpal tunnel syndrome (CTS). Keyboard and mouse operations require unnatural physical positioning of the arms, hands, and fingers; in typical operations elbows are flexed and wrists are ulnarly deviated, pronated, and extended ( Duncan & Ferguson, 1974), Such positions put operators at risk of developing cumulative trauma disorders (CTDs). CTDs are caused from continuous repetitive motions of the hand, wrist, and arm. In extreme cases, these compromising positions can cause severe wrist trauma such as CTS as well as muscle strains in the shoulders, neck, and arms of the typist.
The purpose of this study was to investigate the ergonomic, biomechanical, and typing performances of a newly designed alphanumeric keyboard called the Alphanumeric Input Device for those with Carpal Tunnel Syndrome (AID-CTS keyboard) -- one of the first ergonomically designed keyboards that eliminates finger movement and drastically reduces wrist movement while maximizing typing comfort.
Forty-four touch typists (40 females and 4 males) between the ages of 18 and 55 (mean = 28, s.d. = 9.9) fulfilled the initial requirements to participate in the research. Preexperimental typing performances ranged from 32 to 88 GWPM (mean = 49.9, s.d. = 12). An orthopedic surgeon determined the degree of disability for each participant. Based on this classification, the participants were assigned to cohort groups with similar disabilities. Within each disability cohort group, participants were then separated into performance groups. They were then randomly assigned to the six experimental groups: Two groups used the QWERTY keyboard, two used the ergonomic split keyboard, and