Attentional demands and postural control: the effect of sensorycontext

Abstract

BACKGROUND: This study used a dual task design to examine the effect ofsensory context on postural stability during the concurrent performance ofan attentionally demanding cognitive task in young and older adults withand without a history of imbalance and falls. METHODS: A choice reactiontime auditory task was used to produce changes in attention during quietstance in six different sensory conditions that changed the availability ofaccurate visual and somatosensory cues for postural control. Posturalstability was quantified by using forceplate measures of center of pressurein 18 young adults, 18 healthy older adults, and 18 older adults withbalance impairments and a history of recent falls. Reaction time andaccuracy of verbal response to the auditory task were quantified by using arepeated measures analysis of variance. RESULTS: In young adults theauditory task did not affect postural stability in any of the sensoryconditions. However, in the older adults the effect of the auditory taskdepended on sensory context. For healthy older adults, the addition of anauditory tone task significantly affected sway only when both visual andsomatosensory cues for postural control were removed. In thebalance-impaired older adults, the addition of the auditory tasksignificantly affected postural stability in all sensory conditions. Inaddition, as sensory conditions became more difficult, older adults who hadbeen able to maintain stability in a single task context lost balance whenperforming a secondary task. CONCLUSION: Results suggest that with aging,attentional demands for postural control increase as sensory informationdecreases. In addition, the inability to allocate sufficient attention topostural control under multitask conditions may be a contributing factor toimbalance and falls in some older adults.