White Matter Hyperintensities Are Associated with Slower Gait Speed in Older Adults without Dementia.

Introduction: Slow gait speed is associated with poor health outcomes in aging, but the relationship between cerebral small vessel disease (CSVD) pathologies and gait speed in aging is not well understood. We investigated the relationships between CSVD imaging markers and gait speed during simple (normal pace walking [NPW]) and complex (walking while talking [WWT]) as both measures are associated with shared health outcomes such as falls, frailty, disability, mortality, and dementia.

Methods: A total of 113 Ashkenazi Jewish adults over 65 (M age = 78.6 ± 6.3 years, 45.8% women) and without dementia were examined. Established rating systems were used to quantify white matter hyperintensities (WMHs) and lacunes of presumed vascular origin from fluid-attenuated inversion recovery (FLAIR) images. Linear regression models adjusted for age, sex, global health, and total intracranial volume were used to examine associations between CSVD markers and gait speed during NPW and WWT. Student t tests were used to contrast gait speed in those with "confluent-diffuse" WMH and those with "mild or no" WMH.

Results: The number of WMH in the basal ganglia (β = -3.274 cm/s p = 0.047) and temporal lobes (β = -3.113 cm/s p = 0.048) were associated with slower NPW speed in adjusted models. Participants with higher CSVD burden (confluent-diffuse pattern) in the frontal lobe (94.65 cm/s vs. 105.21 cm/s, p = 0.018) and globally (98.98 cm/s vs. 107.24 cm/s, p = 0.028) also had lower NPW speed. WMHs were not associated with WWT speeds. Lacunes were not associated with NPW or WWT speed.

Conclusion: Adjusted models found higher CSVD burden as measured by the presence of WMH in the basal ganglia and temporal lobes were associated with slower normal pace gait speed in older adults, but not with complex walking speeds. Participants with confluent-diffuse WMHs in the frontal lobes were found to have slower average normal gait speed. Further studies are needed to establish the temporality of WMH and gait speed decline as well as mechanistic links between the two.