Investigation of Vibratory Detection Thresholds on Proximal Phalange and Wrist in Blind and Visually Impaired Teenagers

摘要

The paper presents results concerning vibratory detection thresholds measured on a wrist and proximal phalange and fingertips of the index, middle and ring fingers for blind and visually impaired teenagers. Subjects with vision dysfunctions were divided into two groups: congenitally blind and visually impaired. The study tested 10 handicapped individuals (5 congenitally blind and 5 visually impaired) and 10 sighted persons making reference groups chosen to be adequate in terms of age, gender, body mass and height. To date, no study has described results of such experiments for blind/visually handicapped teenagers. Vibratory perception thresholds were tracked using the Bekesy algorithm. The thresholds were investigated as a function of stimulating force frequency and magnitude or an area of a stimulating probe. Threshold values obtained for the wrist were higher than values obtained for proximal phalange and fingertips. It was shown that the performance of blind/visually impaired teenagers was not better than their sighted counterparts. Suggestions about technical form and physical parameters of a vibrating device signalling places particularly dangerous for blind/visually handicapped people were formulated.