Abstract A112: Gait Speed as the Earliest Functional Marker of Covert Cerebrovascular Disease in Community-Dwelling Older Adults

Background: Cerebral small vessel disease (CSVD) and intracranial atherosclerosis (ICAS) are two major etiologies of stroke and dementia, yet silent in their covert stage. Advances in neuroimaging permit their detection at this stage, providing a critical window to identify functional correlates that may serve as sensitive clinical markers and mechanistic insights into the initial pathophysiology of cerebrovascular injury. This study aimed to determine the associations of covert CSVD and asymptomatic ICAS with cognitive and physical performance in community-dwelling older adults. Methods: We analyzed data from the Longitudinal Aging Study of Taipei (LAST) cohort, an urban community-based prospective cohort of adults aged ≥ 50 without stroke or dementia, recruited between Feb 2023 and Mar 2025. All participants underwent 3T MRI (T1w,T2w, T2-FLAIR, SWI, TOF) to assess (1) covert CSVD, defined as a simplified CSVD score of 2–3 based on white matter hypderintensities (WMH), lacunes, and cerebral microobleeds (CMBs), and (2) ICAS, defined as ≥50% stenosis in any intracranial artery. Cognitive functions, including memory, language, executive, and visuospatial domains were evaluated with standardized tests while physical functions were assessed by gait speed, handgrip strength, and time to complete 5 chair-stand cycles. Multivariate linear regression tests were used to study the independent associations of covert CSVD and asymptomatic ICAS with functional outcomes, adjusted for age, sex, and education in cognitive models, and for age and sex in physical models. Results: Among 216 participants without history of stroke or dementia (median age 70.93, IQR 68.00–73.45, 32% male), 28% (n=61) had covert CSVD and 7% (n=16) had asymptomatic ICAS. After adjustment, CSVD was independently associated with slower gait speed (β= –0.163, p = 0.041), while no associations were observed with cognitive outcomes. Asymptomatic ICAS showed no association with either cognitive or physical functions at this early stage. Conclusions: In community-dwelling older adults, mobility decline emerges as an earlier manifestation of covert CSVD than cognitive impairment. By contrast, asymptomatic ICAS had limited impact on cognition or mobility. These findings highlight gait speed as a sensitive early clinical marker of CSVD and emphasize the importance of distinguishing the functional trajectories of different cerebrovascular pathologies in aging populations.