Biomedical subjects

G C Vanderheiden

Publications and source records attributed to G C Vanderheiden.

4 recordsLinked to original sources

PubMed1992

Gain effects on performance using a head-controlled computer input device.

The purpose of this study was to use a Fitts' task to (1) determine how control-display gain influences performance using a head-controlled computer input device; (2) compare relative sensitivity to gain and optimal gain between head control and hand/arm control; and (3) investigate control-display gain interactions with other task factors including target width, movement amplitude and direction. The task was a discrete target acquisition task using circular targets of 2.9 mm, 8.1 mm, and 23.5 mm, movement amplitudes of 24.3 mm and 61.7 mm, and eight radial directions including 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. Each device was operated at four gain levels. Ten subjects participated. The results indicated that gain had a significant effect on movement time for both types of pointing devices and exhibited local minimums. Discrete target acquisition at all gains was aptly described using Fitts' Law for both input devices. The mouse gain resulting in minimum movement time and RMS cursor deviation was between 1.0 and 2.0. The minimum movement time and RMS cursor deviation for the head-controlled pointer occurred at a gain between 0.3 and 0.6. Average movement time at the optimal head-controlled pointer gain had a slope of 169 ms/bit and was more than 76% greater than at the optimal mouse gain with a slope of 135 ms/bit. In addition, average RMS displacement was more than 27% greater for the head-controlled pointer at its optimal gain setting than for the mouse. Gain had the greatest effect for small target widths and long movement amplitudes using the head-controlled pointer. Average movement time increased 37% when increasing the head-controlled pointer gain from 0.6 to 1.2 for the small target width, but only increased 0.3% when increasing gain for the large target width. Average movement time also increased 12% when decreasing the head-controlled pointer gain from 0.3 to 0.15 for the long movement amplitude, but decreased 0.3% when decreasing gain for the short movement amplitude.

Ergonomics↗

PubMed1990

Thirty-something million: should they be exceptions?

There are over 30 million people in the United States with disabilities or functional limitations (of which a major cause is aging), and this number is increasing. An examination of the role of human factors in addressing this population is presented which includes both special designs for disability/aging and the incorporation of disability/aging into mainstream human factors research and education. Statistics regarding the size and characteristics of this population are presented, including the costs of disability. Examples demonstrating the economic and commercial feasibility of incorporating disability/aging considerations in mass-market designs are provided along with a discussion of the benefits to nondisabled users.

Aged↗

PubMed1990

A method for evaluating head-controlled computer input devices using Fitts' law.

The discrete movement task employed in this study consisted of moving a cursor from the center of a computer display screen to circular targets located 24.4 and 110.9 mm in eight radial directions. The target diameters were 2.7, 8.1, and 24.2 mm. Performance measures included movement time, cursor path distance, and root-mean-square cursor deviation. Ten subjects with no movement disabilities were studied using a conventional mouse and a lightweight ultrasonic head-controlled computer input pointing device. Average movement time was 306 ms greater (63%) for the head-controlled pointer than for the mouse. The effect of direction on movement time for the mouse was relatively small compared with the head-controlled pointer, which was lowest at 90 and 270 deg, corresponding to head extension and head flexion, respectively. Average path distance and root mean square displacement was lowest at off-diagonal directions (0, 90, 180, and 270 deg). This methodology was also shown to be useful for evaluating performance using an alternative head-controlled input device for two subjects having cerebral palsy, and measured subtle performance improvements after providing a disabled subject with lateral torso support.

Adult↗

PubMed1987

Service delivery mechanisms in rehabilitation technology.

Rehabilitation technology is a rapidly advancing area involving professionals from multiple disciplines, including engineers, occupational and physical therapists, speech pathologists, computer programmers, and many others. This paper focuses on the use of computers and other personal assistive devices by disabled persons, but the concepts presented apply to all areas of personal rehabilitation technology. The topics covered include a perspective on the use of advanced technology, technological appliances versus tools, skills or special knowledge needed for the effective delivery of rehabilitation technology, new roles for the service delivery team, sources of training in rehabilitation technology, and issues in qualification or certification of rehabilitation technology professionals. The purpose of this paper is to put the use of advanced technology for rehabilitation in its proper perspective and to present ideas for consideration in building more effective service delivery mechanisms for these technologies.

Certification↗