Figure 1. Conceptual Framework of Slow Gait Speed With Future Risk of Alzheimer Disease (AD).

This simplified model indicates that slow gait is multifactorial and can be manifested as central nervous system (CNS) impairment, non-CNS impairment (musculoskeletal or cardiopulmonary conditions), or a combination. Specifically, among individuals with slow walking speed, failing to use compensation strategies to main physical function, operationalized as lower activity fragmentation, indicates compromised cognition and high risk of developing AD. Among individuals with slow walking speed, using compensation strategies to main physical function, operationalized as increased activity fragmentation, indicates conserved cognition. Their slow walking speed is likely owing to non–CNS-related deficits and is not associated with AD. CVD indicates cardiovascular disease.