AGE-RELATED EFFECTS OF A COGNITIVE TASK ON FRONTAL PLANE STABILITY DURING NARROW-BASE WALKING.

Abstract

Purpose/Hypothesis: Age-related changes in frontal plane stability during gait are associated with impaired balance and increased fall risk in older adults. Clinically, tandem and narrowbase walking are used to assess dynamic gait stability. Adding a cognitive task to narrow-base walking (i.e. dual tasking) may further challenge stability, allowing identification of early balance deficits not detected under single task conditions. The purpose of this study is to examine age-related effects of a cognitive task on frontal plane stability during narrow-base walking in a population of healthy older adults. Subjects: Thirty subjects categorized by age: <65, 65–74, and 75 years, with 10 subjects per group. Materials/Methods: We examined spatiotemporal and center of mass (COM) parameters during narrow-base walking with and without a cognitive task. Statistical analyses included repeated measures ANOVA's (3 age groups x 2 task conditions). Results: The percent of step errors (i.e. steps outside the narrow-base corridor) did not differ significantly between groups (p=0.29) and was not affected by the performance of a secondary task (p=0.80). On average, about 16% of the steps were outside the narrow-base corridor. Average stride velocity (p<0.001) and step length (p<0.001) decreased with age, while mediolateral COM peak velocity (p<0.001) and displacement (p<0.05) increased. Addition of a cognitive task decreased stride velocity (p<0.001) and step length (p<0.05) for all age groups, but did not affect COM characteristics. Conclusions: Age-related changes in both velocity and frontal plane stability are evident during narrow-base gait. The addition of a secondary task affected stride velocity and stride length but did not affect mediolateral COM control in this group of healthy older adults. Clinical Relevance: The use of a cognitive task during balance and gait activities can help to identify individuals with increased fall risk. Further research is needed to determine if changes in narrow-base walking with versus without a secondary task can be used to predict future falls in older adults. If so, narrow-base walking under single and dual task conditions may be useful in identifying older adults with preclinical instability.