Preferred walking speed for assessment of mobility performance: sighted guide versus non-sighted guide techniques.

Background: If visually impaired people had their sight fully restored, it is assumed that they would walk at their optimal speeds. Previous mobility studies have used preferred walking speed (PWS) to measure walking efficiency of visually impaired adults. Therefore, the actual speeds that visually impaired people adopt on a route can be expressed as a percentage of their preferred walking speed (PPWS). There have been two approaches used in previous studies for determining preferred walking speed. 1the sighted guide technique (SG), which requires a subject to walk with a sighted guide and regard the latter as a perfect mobility aid, with the subject setting the preferred (optimal) walking pace. 2the non-sighted guide technique (NonSG), which requires a subject to walk alone along an unobstructed straight path for a certain distance, adopting the preferred (optimal) walking speed. There is some debate on which technique is the better. This study was conducted to determine if there is any difference between the two techniques for determining visually impaired subjects' preferred walking speeds. Methods: Fourteen visually impaired adult subjects were recruited. PWS was determined by recording the time taken for a subject to walk an unobstructed, straight 20-metre corridor path using each technique. Results: There was no significant difference in PWS using the sighted guide and non-guided techniques. Conclusions: Either the SG or NonSG techniques can be used to determine PWS for a heterogeneous group of visually impaired subjects.