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Dissertation
Use of a joystick by people with cerebral palsy in performing screen positioning tasks
Doctor of Philosophy (Ph.D.), Drexel University
1998
DOI:
https://doi.org/10.17918/00010200
Abstract
Study of the interaction between individuals with disability and the computer has implications in the design of input devices, such as the mouse and keyboard, and in expanding knowledge about movement control. The present work evaluated the performance of non-disabled individuals and those with cerebral palsy in the use of a position-controlled spring-centered position joystick versus a position-controlled isometric joystick. The subjects acquired differently sized targets at different distances by positioning a cursor on the target. Performance with the position joystick was superior when compared with the performance with the isometric joystick. It was found that due to the high stiffness of the isometric joystick, physiological noise was recorded. This led to uncontrolled movement of the cursor on the screen, which added to the distance traversed by the cursor and increased the time needed to reach the target. With the position joystick, the inertial load due to the displacement of the stick and the elastic action of the spring provides damping of the physiological noise. Arm movement generates signals from the joint receptors, providing additional propioceptive feedback in controlling the cursor movement. Movement time was directly proportional to the cursor-target distance, and indirectly proportional to the target size. The phase-plane plot and trajectory of the cursor movement revealed the presence of one primary movement that accounts for the peak velocity, and several submovements. Fitts' paradigm was a good predictor of cursor positioning task for the non-disabled individuals. Subjects chose to move more slowly towards the smaller and closer targets, and they increased speed for larger and more distant targets. Fur individuals with disability, a linear relationship was found between the movement time and accuracy when a force joystick was used.
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Details
- Title
- Use of a joystick by people with cerebral palsy in performing screen positioning tasks
- Creators
- Raghavendra Shankar Rao
- Contributors
- Rahamim Seliktar (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xiii, 153 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 991021889109704721