The association of motoric cognitive risk with incident dementia and neuroimaging characteristics: The Atherosclerosis Risk in Communities Study.

INTRODUCTION Motoric cognitive risk (MCR), a clinical syndrome characterized by slow gait speed and subjective cognitive complaints, has been associated with dementia risk. The neuropathological features underlying MCR remain poorly understood. METHODS The Atherosclerosis Risk in Communities (ARIC) community-based cohort study classified participants using standardized criteria as MCR+/- and mild cognitive impairment (MCI)+/- at study baseline (2011-2013). We examined the 5-year dementia risk and baseline brain structural/molecular abnormalities associated with MCR+ and MCI+ status. RESULTS Of 5023 nondemented participants included, 204 were MCR+ and 1030 were MCI+. Both MCR+ and MCI+ participants demonstrated increased dementia risk. The pattern of structural brain abnormalities associated with MCR+ differed from that of MCI+. Whereas MCI+ was associated with comparatively smaller volumes in brain regions vulnerable to Alzheimer's disease pathology, MCR+ status was associated with smaller volumes in frontoparietal regions and greater white matter abnormalities. DISCUSSION MCR may represent a predementia syndrome characterized by prominent white matter abnormalities and frontoparietal atrophy.