The use of the sonic pathfinder as a secondary mobility aid for travel in business environments: a single-subject design.

Two studies were conducted using a single subject research design in different business environments to evaluate the efficacy of the Sonic Pathfinder for increasing efficiency in travel with an experienced and accomplished blind traveller. The Sonic Pathfinder is one of eight or nine commercially available electronic travel aids (ETAs) designed for use by blind or visually impaired persons. The use of ETAs are thought to result in more rapid travel and a greater ability to detect and avoid obstacles in one's path. Elapsed time for travel and the number of unintentional contacts made while travelling were used as the dependent variables in both studies. No marked effect was observed for either variable in either study. An additional traveller who was slower and more tenuous in his movements was recruited to participate in the second study to investigate the possibility that a floor effect may have masked the results of the use of the ETA with the first subject. However, no marked effects were observed with this subject either. Yet, both subjects stated that the use of the aid increased their distance for environmental preview over and above that provided by the long cane alone, while providing them with the opportunity to judge the distance of objects approached beyond cane length. Discussion centers on the need to identify other means to evaluate the utility of this aid in light of the positive statements made by the participants of these studies.