Assessment of Gait Symmetry in Elderly Women with Low Bone Mineral Density Using a Portable Trunk Accelerometer: A Pilot Study

BACKGROUND: Convincing evidence regarding gait and balance function in elderly women with low bone mineral density (BMD) and/or osteoporosis is limited. In the present study, we aimed to compare the gait characteristics in elderly women with and without low BMD and to analyze plausible parameter(s) for predicting low BMD. MATERIAL/METHODS: We retrospectively analyzed prospectively collected data of 26 consecutive postmenopausal women aged >65 years who were admitted to our geriatric outpatient service. They were assigned to 2 groups, with (n=14) and without (n=12) low BMD based on T-score (<−1 standard deviation of the mean for healthy adults) of dual-energy X-ray absorptiometry. We compared gait parameters derived from a portable Tri-Axial trunk accelerometer that included cadence, walking speed, average acceleration, horizontal/vertical displacement ratio, and symmetry index of the Lissajous figure (LI) during a 5-meter walk test at comfortably fast speed between groups. RESULTS: Women with low BMD tended to show increased LI compared with healthy subjects (P=0.04). No statistically significant differences were noted in cadence, walking speed, average acceleration, and ratio of horizontal and vertical displacement (P>0.05). Receiver operating characteristic curve analysis demonstrated that LI can predict low BMD in the femur neck with moderate accuracy (area under the curve=0.75, 95% confidence interval 0.55–0.95; P=0.031). The optimal cut-off value was 17%, with 67% specificity and 86% sensitivity. CONCLUSIONS: These results suggest that elderly women with low BMD may walk with asymmetrical trunk movement, but they are able to generate gait patterns similar to healthy peers. The LI may provide valuable quantitative information for preventing fractures in subjects with osteoporosis.