Influence of Environment and Mobility Aid on Talking Pedometer Accuracy in Adults with Visual Impairment

Abstract

BACKGROUND: Given the efficacy of pedometer-based programs to improve physical activity and health status in various clinical sub-populations, implementation of similar programs for persons with vision loss should be considered. Due to alterations in the gait patterns of persons with vision loss, factors such as environmental familiarity and mobility aids may influence results of pedometer validation trials. PURPOSE: The purpose of this study was to establish validity evidence for the Centrios talking pedometer relative to walking environment and mobility aid use in adults with vision loss. METHODS: Fifteen adults with legal blindness (10 females; age = 38 ± 14 years; BMI = 26.5 ± 4.2 kg·m2) completed two walking sessions over an unfamiliar, quarter-mile walking course while wearing a pedometer at the right and left hip. Walking speed, pedometer-determined step counts, and actual step counts were recorded during the first session, which represented walking in an unfamiliar environment. Following the completion of additional walking trials over the same route, outcome measures were reassessed during a second walking session over the course, which reflected walking in a "familiar environment." To obtain validity evidence for the talking pedometer, absolute percent error (APE) was calculated between actual and pedometer-determined steps. Paired t-tests were used to assess differences in APE relative to mounting position (right hip vs. left hip; mobility aid side vs. non-mobility aid side) across unfamiliar and familiar walking trials. RESULTS: The Centrios pedometer accurately reported step counts during unfamiliar (average speed = 3.2 mph) and familiar (average speed = 3.7 mph) walking trials when mounted at the hip opposite the user's mobility aid (APE = 3.1% and 2.4%, respectively), but was less accurate on the mobility aid side during unfamiliar and familiar walking (APE = 9.2% and 6.3%, respectively). Paired t-tests revealed no significant differences (p >.05) in APE relative to mounting position and familiarity with the environment. CONCLUSIONS: During walking in familiar and unfamiliar settings, the Centrios talking pedometer provides an accurate step count in adults with visual impairment when mounted at the hip opposite of the user's mobility aid.