Longitudinal relation between structural network efficiency, cognition, and gait in cerebral small vessel disease.

BACKGROUND To investigate changes in gait performance over time and how these changes are associated with the decline in structural network efficiency and cognition in older patients with cerebral small vessel disease (SVD). METHODS In a prospective, single-center cohort with 217 older participants with SVD, we performed 1.5T MRI scans, cognitive tests and gait assessments evaluated by Timed UP and Go (TUG) test twice over 4 years. We reconstructed the white matter network for each subject based on diffusion tensor imaging tractography, followed by graph-theoretical analyses to compute the global efficiency. Conventional MRI markers for SVD, i.e., white matter hyperintensity (WMH) volume, number of lacunes and microbleeds, were assessed. RESULTS Baseline global efficiency was not related to changes in gait performance, while decline in global efficiency over time was significantly associated with gait decline (i.e., increase in TUG time), independent of conventional MRI markers for SVD. Neither baseline cognitive performance nor cognitive decline was associated with gait decline. CONCLUSIONS We found that disruption of the white matter structural network was associated with gait decline over time, while the effect of cognitive decline was not. This suggests that structural network disruption has an important role in explaining the pathophysiology of gait decline in older patients with SVD, independent of cognitive decline.