Enabling Devices, Empowering People: The Design and Evaluation of Trackball EdgeWrite
By Wobbrock, Jacob O.; Myers, Brad A.; Disability and Rehabilitation: Assistive Technology, Vol. 3, No. 1-2, pp. 35-56Publication Date: January/March 2008
Overview of Trackball EdgeWrite, a design for gesture-based text entry on trackballs developed for computer users with motor impairments. Its design is based on Stylus EdgeWrite, originally developed for text entry on handheld devices such as PDAs. In Trackball EdgeWrite, the user moves a trackball in Roman-letter like patterns along the edges and into the corners of a square bound by impenetrable virtual edges on the computer screen. An iterative design-and-test approach was used to develop the method which includes word-level stroking, which improves the speed and accuracy of the system over its character-level version without altering the way in which character strokes are made. To inform the design process, a field study was conducted with a 46-year-old veteran trackball user with a spinal-cord injury that reduced the dexterity of his arms. Results showed a 46.5% improvement in performance with the word-level version of Trackball EdgeWrite over the character version. Both versions of the method were shown to be better than on-screen keyboards, particularly regarding user preferences. Follow-up correspondence showed that the study participant still used Trackball EdgeWrite on a daily basis two years later. Study limitations and implications for further development of the software are discussed.
Published by: Taylor & Francis, Limited (Website:http://taylorandfrancis.org)
International Society of Physical and Rehabilitation Medicine (Web Site: http://www.isprm.org )
Link to text: http://dx.doi.org/10.1080/17483100701409227
