Increased Attentional Focus On Walking By Older Adults Limits Maximum Speed And Dynamic Stability Control

Abstract

Older adults with lower balance confidence demonstrate a reduced willingness to experience instability as the task of walking becomes more challenging. The specific reason why is not known. PURPOSE: To investigate the extent to which performance of a challenging walking task relates to the attentional requirements of walking. METHODS: Fourteen older participants were asked to walk on a treadmill at a range of speeds from 0.4 m/s, increasing 0.2 m/s, up to either 2.0 m/s or a speed they chose to stop. All walking trials included 60 steps. Kinematic data was collected and a measure of margin of stability in the anterior direction at heel strike (MOSAP) was quantified. The timed up and go (TUG) and timed up and go dual task (TUGdual) were performed. An automaticity index (TUG/TUGdual *100) was calculated to evaluate the attentional resources. Individuals were grouped (n=7 in each group) based on whether they could (complete, 70±2.44 years) or could not (incomplete, 67±2.43 years) complete all walking trials. Comparisons between groups were made with Independent T-test and Mann-Whitney U test. Correlations were detected with Spearman rank correlation. RESULTS: Significant differences were detected in the maximum speeds achieved between groups as well as the range of gait stability (p<0.05). Those that could not complete all speeds had a lower automaticity score compared to other group (p=0.019). The fastest speed attempted was correlated with an average of MOSAP (rho=-0.93, p<0.001) and the automaticity index (rho=0.61, p=0.022). The average of MOSAP and the automatic gait index were significantly correlated (rho=-0.71, p=0.004, Fig 1). CONCLUSION: Older adults with lower automaticity of gait appeared to choose to stop limit walking trials before they became dynamically unstable, which may relate with the increased attentional demand required to maintain dynamic stability at higher walking speeds. This should be considered for an assessment to identify stability problems.