Dynamic Stability in the Elderly: Identifying a Possible Measure

Background: The purpose of this research was to assess the ability of trunk acceleration measures to discriminate between the walking patterns of elderly individuals with and without stability problems.

Methods: Twenty volunteers, aged 65 and over, and 19 younger volunteers, all of whom were free of abnormalities or problems that could affect their gait, were recruited for this study. A triaxial accelerometry system was mounted directly over the spine of the upper trunk. Forty seconds of walking data were collected. Using a heel contact switch to define the beginning of the gait cycle, harmonic analyses of each of the 3 acceleration measures were performed on 10 strides. The ratio of summed amplitudes of the even and odd harmonics (index of smoothness) was calculated for each stride and averaged across 10 strides. One-way analyses of variance were used to compare harmonic ratios between groups. Relationships between variables were tested using a correlation analysis.

Results: The scores of individuals with stability problems were shown to be significantly different from the younger controls and the older individuals without stability problems for the anterior/posterior and vertical harmonic ratio and peak acceleration measures.

Conclusion: The results from this research demonstrate that trunk acceleration measures offer the possibility of being able to identify unstable elderly individuals.