Measurements of preferred walking speed in subjects with central and peripheral vision loss

BACKGROUND: Previous mobility studies have used Preferred Walking Speed (PWS) in order to determine the walking efficiency in terms of the Percent Preferred Walking Speed (PPWS) of visually impaired adults. PWS has been measured in previous studies using the sighted guide (SG) and non-sighted guide (NSG) techniques. This study compared the NSG, SG and string (ST) (subjects walked by holding on lightly to a cardboard tube attached to a piece of string) techniques of measuring PWS in visually impaired subjects. METHODS: Forty visually impaired subjects with central and peripheral vision loss were recruited. PWS was measured using the NSG, SG and ST techniques. For each technique, PWS was determined by recording the time taken for a subject to walk an unobstructed, straight 20-m corridor. RESULTS: There were no significant differences in PWS using the SG, NSG and ST techniques. CONCLUSION: For assessing walking efficiency, either the SG, NSG or ST technique could be employed when measuring PWS in visually impaired subjects.