Falls are a significant problem in older adults, resulting from a complex interaction of sensory, motor and cognitive loss. Older adults have been shown to require increased cognitive resources (i.e. attention) for balance. In addition, dynamic regulation of sensory information relative to balance is known to be important in balance function. Environmental changes that alter sensory information about body orientation and motion have a greater impact on balance of older adults compared to young adults, but it is not known to what extent differences in postural control between young and older adults are due to differences in sensory integration. Moreover, the interaction of attention and sensory integration in older adults has not been fully studied or developed. The proposed research will investigate and model the interaction of sensory integration and attention in postural control in healthy older subjects. We plan to quantitatively investigate the interactions of attention and sensory regulation in older subjects by modifying and applying a validated sensory re-weighting postural control model to include the role of higher cognitive function (i.e. attention), and then perform dual-task balance experiments to validate the model. A central hypothesis of our research is that attention-requiring information processing tasks concurrent with moderate postural challenges will divert attention away from balance control in older adults, which can be quantified by time delay and other physiologically relevant parameters in our proposed postural control model. The proposed research is relevant to public health in that falls are a significant problem in older adults compared to young adults. Environmental changes that alter sensory orientation information tend to have a greater destabilizing effect on older adults, and older adults appear to require greater attentional resources for balance control. However, the interaction between attention and sensory integration is an open question. Studying how these two factors interact, and developing a model of that interaction, will lead to better understanding of their impact on balance control and predisposing conditions for falls in older adults.
