Age differences in reactive strategies and execution time during choice stepping with visual interference.

Abstract

We aimed to explore the effects of visual interference from a flanker task on a reactive strategy and execution speed of choice stepping among young and older adults. Twenty-two healthy young (21.9±1.4years) and 21 older participants (72.6±4.9years) were instructed to execute forward stepping as quickly and accurately as possible on the side indicated by a central arrow (←left vs. right→) of a visual cue during a neutral condition. During a flanker condition, participants were additionally required to ignore flanker arrows on each side of the central arrow (→→→→→ congruent or incongruent →→←→→). Errors in the direction of the initial weight transfer [anticipatory postural adjustment (APA) errors], step execution time, and divided phases (reaction, APA, and swing phases) were measured from the data of vertical force. Incongruence had larger effects on step execution times and APA phase in older adults than in young adults, while incongruence had smaller effects on reaction phase in older adults than in young adults. Step execution times were prolonged for trials with APA errors relative to trials without those in both groups. Only older adults showed that step execution times during trials with APA errors increased prominently in the incongruent condition as compared to the other conditions. Older adults might have a tendency to make hastier judgments, and might be vulnerable to potential motor program errors caused by an interference effect. Composite measurement of inhibition and stepping in a functional context may increase discriminative ability for age-related deficits in postural control.