Gait and cognition: the relationship between gait stability and variability with executive function in persons with and without dementia.

Besides cognitive decline, dementia is characterized by gait changes and increased fall risk, also in early stages of the disease. The aim of this study was to investigate differences in the relationship between executive function and gait variability and stability during single task and dual task walking in persons with and without dementia. The study sample consisted of three groups: fifteen dementia patients (aged 75-87), fourteen healthy elderly (aged 75-85), and twelve relatively younger elderly (aged 55-70). Participants underwent neuropsychological testing and tests of single and dual task walking while wearing an accelerometer. Outcome measures include stride related measures such as mean and coefficient of variation of stride time, and dynamic measures regarding the magnitude, smoothness, predictability and local stability of trunk accelerations. Patients with dementia exhibited a significantly (p<.05) less variable, but more irregular trunk acceleration pattern than cognitively intact elderly on single and dual task walking. The walking pattern during dual tasking for the whole group became increasingly unstable, even though participants modified their gait pattern by slowing their walking speed, and decreasing the magnitude of trunk accelerations. Moderate to high correlations (r>.51) were found between executive tasks and gait parameters. In conclusion, these findings indicate that decreased executive function plays an important role in increased gait variability in dementia patients; a fact that should be considered when designing fall risk interventions for this population. Furthermore, results indicate that measures of gait variability and stability should be deemed worthwhile in the diagnosis of dementia.