While there is some degree of independence between physical and mental capability among older adults, the ageing process is associated with an average decline in both.

We examined whether gait speed is related equally strongly to two aspects of cognition: memory and executive function.

If gait speed is related more strongly to executive function than to memory this would provide some evidence for a causal link between executive processes and gait speed. If memory and executive function are related equally strongly to gait speed this is more consistent with a common cause hypothesis.