title: The influence of a concurrent cognitive task on the compensatory stepping response to a perturbation in balance-impaired and healthy elders.
abstract: This study investigated the influence of a concurrent cognitive task on the compensatory stepping response in balance-impaired elders and the attentional demand of the stepping response. Kinetic, kinematic and neuromuscular measures of a forward recovery step were investigated in 15 young adults, 15 healthy elders and 13 balance-impaired elders in a single task (postural recovery only) and dual task (postural recovery and vocal reaction time task) situation. Results revealed that reaction times were longer in all subjects when performed concurrently with a compensatory step, they were longer for a step than an in-place response and longer for balance-impaired older adults compared with young adults. An interesting finding was that the latter group difference may be related to prioritization between the two tasks rather than attentional demand, as the older adults completed the step before the reaction time, whereas the young adults could perform both concurrently. Few differences in step characteristics were found between tasks, with the most notable being a delayed latency and reduced magnitude of the early automatic postural response in healthy and balance-impaired elders with a concurrent task.
authors.affiliation: Department of Physiotherapy, University of Queensland and Princess Alexandra Hospital, Qld. 4072, St. Lucia, Australia. s.brauer@shrs.uq.edu.au
authors.forename: S G
authors.initials: SG
authors.lastname: Brauer
authors.forename: M
authors.initials: M
authors.lastname: Woollacott
authors.forename: A
authors.initials: A
authors.lastname: Shumway-Cook
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D005528:Foot / Q000502:physiology; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D011930:Reaction Time; D012678:Sensation Disorders / Q000503:physiopathology*; D018709:Statistics, Nonparametric; D014743:Videotape Recording