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Doctoral Dissertation Announcement
Candidate: Dae Shik Kim
Doctor of Philosophy
Department: Interdisciplinary Health Studies
Title: Analysis of Factors Related to Drop-off Detection with the Long Cane
Dr. Amy Curtis, Chair
Dr. Robert Wall Emerson
Dr. Daniel Ashmead
Date: Monday, June 29, 2009 10:00 a.m. - 12:00 p.m.
2204 College of Health and Human Services
The purpose of this dissertation is 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 is used for the study, in which 32 visually impaired adults with no other disabilities attempt to detect the drop-offs using either the two-point touch technique or the constant contact technique.
Participants detect drop-offs at a significantly higher percentage when they use the constant contact technique (78.3%) than when they use the two-point touch technique (62.1%), p < .001. The 50% absolute drop-off detection threshold of the constant contact technique (1.65”) is also significantly smaller than that of the two-point touch technique (2.91”), p < .001. The advantage of the constant contact technique in overall drop-off detection rate over the two-point touch technique is significantly larger for the less experienced cane users (difference of 26.2%) than for more experienced cane users (difference of 12.9%), p = .001. The advantage over the two-point touch technique changes little even when the constant contact technique is used with the (over) marshmallow roller tip (76.7%) while the two-point touch technique is used with the marshmallow tip (61.8%), p < .001.
In respect to user characteristics, younger cane users (72.8%) detect drop-offs significantly better than older cane users (60.9%), p = .044. In addition, those who lost their vision early in life (78.0%) perform 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 beyond drop-off detection are needed to examine multiple aspects of long cane performance, which include obstacle detection, texture discrimination, and travel efficiency, in order to determine the overall effectiveness of cane travel.