Prevalence and cognitive performances of vascular cognitive impairment no dementia in Japan: the Osaki-Tajiri Project

Prevalence, magnetic resonance imaging (MRI) findings, cognitive function and depression are four major aspects of vascular cognitive impairment no dementia (vascular CIND). We performed a community-based study to examine these using 497 community-residents aged 65 years or older. Vascular CIND was defined as a clinical dementia rating (CDR) 0.5 with cerebrovascular disease. Several neuropsychological tests were performed, including MMSE, Geriatric Depression Scale (GDS), and Trail Making Test (TMT). Cerebrovascular disease and white matter lesions were visually assessed using MRI. Prevalence of vascular CIND, localization of cerebrovascular disease, and the relationships amongst MRI findings, white matter lesions, cognitive impairment and depression were analyzed. The prevalence of vascular CIND was 8.5% amongst the total population, corresponding to the rate being 37.2% amongst the CDR 0.5 participants. Compared with the CDR 0, the CDR 0.5 group had more subjects with strategic cerebrovascular disease in the thalamus, etc. No effects of cerebrovascular disease on MMSE and GDS scores were found, but the CDR 0.5/strategic cerebrovascular disease group showed impaired TMT-B scores. In the CDR 0 group, only anterior periventricular hyperintensity was associated with TMT-A score independent of cerebrovascular disease. A vascular CIND population was identified, and executive dysfunction in this population is probably based on an impaired fronto-subcortical circuit.