Date of Award

8-2009

Degree Name

Doctor of Philosophy

Department

Interdisciplinary Health Sciences

First Advisor

Dr. Amy B. Curtis

Second Advisor

Dr. Robert Wall Emerson

Third Advisor

Dr. Daniel Ashmead

Abstract

The purpose of this dissertation was to examine the three key factors related to drop-off detection with the long cane: (1) cane-technique-related factors, (2) user characteristics, and (3) ergonomic factors. A mixed-measures design with block randomization was used for the study, in which 32 visually impaired adults with no other disabilities attempted to detect the drop-offs using either the two-point touch technique or the constant contact technique.

Participants detected drop-offs at a significantly higher percentage when they used the constant contact technique (78.3%) than when they used the two-point touch technique (62.1%), p < .001. The 50% absolute drop-off detection threshold of the constant contact technique (1.65") was also significantly smaller than that of the two-point touch technique (2.91"), p < .001. Constant contact technique's advantage in overall drop-off detection rate over the two-point touch technique was significantly larger for the less experienced cane users (difference of 26.2%) than for more experienced cane users (difference of 12.9%), p = .001. Constant contact technique's advantage over the two-point touch technique changed little even when the constant contact technique was used with the tip that was perceived to be disadvantageous for drop-off detection (marshmallow roller tip) (76.7% detection rate), while the two-point touch technique was used with the tip that was perceived to be more advantageous for drop-off detection (marshmallow tip) (61.8%), p < .001.

In respect to user characteristics, younger cane users (72.8%) detected drop-offs significantly better than older cane users (60.9%), p = .044. In addition, those who lost their vision early in life (78.0%) performed significantly better than those with later-onset visual impairment (65.5%), p = .012.

The findings of the study may help cane users and orientation and mobility specialists select appropriate cane techniques in accordance with the cane user's characteristics, availability of training time, and the nature of the travel environment. Future studies are needed to examine multiple aspects of long cane performance, which include obstacle detection, texture discrimination, and travel efficiency, as well as drop-off detection, in order to determine the overall effectiveness of cane travel.

Access Setting

Dissertation-Open Access

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