Posture control, aging, and attention resources: models and posture-analysis methods.

This paper reviews the literature on balance and cognitive function in normal aging. The first part provides a general background of dual tasking (postural performance under a concurrent cognitive activity) and summarizes the main relevant models capable of explaining the poorer postural performance of older-healthy adults compared to younger-healthy adults: the cross-domain competition model, the nonlinear interaction model, and the task-prioritization model. In the second part, we discuss the main limitations of the traditional-posturographic analyses used in most of the dual-task investigations and explain how these can account for some discrepancies found in the literature. New methods based on the stabilogram-diffusion analysis and the wavelet transform are proposed as better approaches to understand posture control. The advantages of these new methods are illustrated in young adults and elderly people performing a simple postural task (quiet standing) simultaneously with a mental or a spatial task.