The Effectiveness of a Simple Approach to the Assessment of the Risk of Falls in the Elderly-Probe Reaction Time and the Dispersion of the Time for a Single Step during Marking Time-

Abstract

This paper discusses the relationship of the probe reaction time (P-RT), the number of steps, and the step rhythm to the risk of falls. These three factors were measured while subjects marked time at a self-determined rate. The subjects were divided into three groups including 18 young subjects (Young group; 15 males, 3 females), 11 elderly subjects who had not experienced falls (Old no-fall group; 1 male, 10 females) and 8 elderly subjects who had experienced falls (Old fall group; 3 males, 5 females). Using a digital audio player (for sonic stimulation) and sound recording equipment, the probe reaction time and the sound of the foot touching the ground was measured. One-way analysis of the variance of the probe reaction time showed a significant effect in all groups, and post-hoc comparison of the means confirmed that the probe reaction time scores were significantly longer in the Old fall group than in the Young group or the Old no-fall group. The coefficient of variation (CV) of the time for a single step was calculated once for the right foot and once for the left foot, and revealed that the effect was significant for all groups. Two-way analysis of the variance was significant, and a post-hoc comparison of the means confirmed the differences between the groups. It was thus found that the probe reaction time and the coefficient of variation of the time for a single step are reliable and useful for evaluation of the risk of falls.