Silent Brain Infarcts and the Risk of Dementia and Cognitive Decline

TLDR

Silent brain infarcts are common on MRI in healthy elderly and have been implicated in dementia and cognitive decline. This study examined whether baseline silent brain infarcts predict incident dementia and cognitive decline in a 60‑90‑year‑old cohort free of dementia and stroke. Participants underwent serial MRI and neuropsychological testing over ~4 years, and Cox proportional‑hazards and linear‑regression models adjusted for age, sex, education, subcortical atrophy, and white‑matter lesions were used. Baseline silent brain infarcts more than doubled dementia risk (HR 2.26) and were linked to poorer neuropsychological performance, steeper global cognitive decline, with thalamic infarcts affecting memory and non‑thalamic infarcts affecting psychomotor speed; decline was limited to those who developed additional infarcts.

Abstract

Silent brain infarcts are frequently seen on magnetic resonance imaging (MRI) in healthy elderly people and may be associated with dementia and cognitive decline.We studied the association between silent brain infarcts and the risk of dementia and cognitive decline in 1015 participants of the prospective, population-based Rotterdam Scan Study, who were 60 to 90 years of age and free of dementia and stroke at base line. Participants underwent neuropsychological testing and cerebral MRI at base line in 1995 to 1996 and again in 1999 to 2000 and were monitored for dementia throughout the study period. We performed Cox proportional-hazards and multiple linear-regression analyses, adjusted for age, sex, and level of education and for the presence or absence of subcortical atrophy and white-matter lesions.During 3697 person-years of follow-up (mean per person, 3.6 years), dementia developed in 30 of the 1015 participants. The presence of silent brain infarcts at base line more than doubled the risk of dementia (hazard ratio, 2.26; 95 percent confidence interval, 1.09 to 4.70). The presence of silent brain infarcts on the base-line MRI was associated with worse performance on neuropsychological tests and a steeper decline in global cognitive function. Silent thalamic infarcts were associated with a decline in memory performance, and nonthalamic infarcts with a decline in psychomotor speed. When participants with silent brain infarcts at base line were subdivided into those with and those without additional infarcts at follow-up, the decline in cognitive function was restricted to those with additional silent infarcts.Elderly people with silent brain infarcts have an increased risk of dementia and a steeper decline in cognitive function than those without such lesions.