ABSTRACT
BACKGROUND: In community-dwelling older adults, global cognitive function predicts longitudinal gait speed decline. Few prospective studies have evaluated whether specific executive cognitive deficits in aging may account for gait slowing over time. METHODS: Multiple cognitive tasks were administered at baseline in 909 participants in the Health, Aging, and Body Composition Study Cognitive Vitality Substudy (mean age 75.2 ± 2.8 years, 50.6% women, 48.4% black). Usual gait speed (m/s) over 20 minutes was assessed at baseline and over a 5-year follow-up. RESULTS: Poorer performance in each cognitive task was cross-sectionally associated with slower gait independent of demographic and health characteristics. In longitudinal analyses, each 1 SD poorer performance in global function, verbal memory, and executive function was associated with 0.003-0.004 m/s greater gait speed decline per year (p =.03-.05) after adjustment for baseline gait speed, demographic, and health characteristics. CONCLUSIONS: In this well-functioning cohort, several cognitive tasks were associated with gait speed cross-sectionally and predicted longitudinal gait speed decline. These data are consistent with a shared pathology underlying cognitive and motor declines but do not suggest that specific executive cognitive deficits account for slowing of usual gait in aging.
Subject(s)
Aging/physiology , Executive Function/physiology , Gait/physiology , Memory/physiology , Aged , Analysis of Variance , Cross-Sectional Studies , Female , Health Status , Humans , Linear Models , Longitudinal Studies , Male , Neuropsychological Tests , Risk Factors , Statistics, NonparametricABSTRACT
Issues arising in the graphics simulation of bone grafting and in the use of commercial libraries to create custom-designed models revolve on the ability to combine data defined in Volume Representation--as that generated by Computed Tomography scans--and user-defined data introduced in Boundary Representation--as vertices of polygons, for instance. To address these issues the authors propose a hybrid filling technique, which also processes conflicting adjacency information created by subsampling or digitization errors. A graphics experiment has been designed to illustrate the problems arising in the presence of objects defined partially in Volume and partially in Boundary Representation, and a method to handle them.