Dual-task cost of the Enhanced Gait Variability Index in community-dwelling older adults.

Background: Gait variability is associated with brain abnormalities, falls, and disability in older adults. The Enhanced Gait Variability Index (EGVI), a composite measure of gait variability, offers advantages over traditional measures of variability for individual spatiotemporal parameters (STPs). Gait assessment under complex conditions may reveal additional information about performance and provide insight into potential abnormalities. The EGVI has not been investigated in older adults while performing a concurrent motor task.

Research Question: To examine dual-task cost of the EGVI and STPs in a sample of community-dwelling older adults.

Methods: Thirty-eight community-dwelling older adults (mean age = 72.5 years) walked at self-selected speeds on an instrumented walkway under a single-task (ST) and a motor dual-task (DT) condition. Descriptive statistics were calculated for the EGVI, STPs included in the EGVI, and several other common STPs (cadence, stride width, percent double-support). Wilcoxon signed-rank tests assessed differences in each gait variable between conditions. Dual-task cost (DTC) was calculated for each gait variable.

Results: Going from ST to DT walking, EGVI scores increased significantly (104.5 ± 8.4 to 125.1 ± 10.8, p < .001). Participants also increased double-support (p < .001) and stance time (p < .01), while decreasing stride velocity (p < .001), step length (p < .001), and single-support time (p < .05). Significant changes were not observed for cadence, stride width, or step time. Stride velocity and EGVI showed the greatest DTC.

Significance: When confronted with a concurrent motor dual-task, older adults responded by increasing their EGVI and altering several STPs. The EGVI is a single composite measure that may have utility under ST and DT conditions to enhance understanding of gait variability in older adults. Further research should examine if DTC of EGVI scores predict meaningful constructs such as falls, participation, and self-rated health in older adults.