Silent Brain Infarcts in 1015 people and the Risk of Dementia and Cognitive Decline

1015 people 60 to 90 of age was studied by cerebral mri and neuropsychological testing with interesting results

In USA and many other countries, neurologists often neglect the importance as well as the monitoring of silent brain infarcts. Sarah Vermeer’s study gives them and us a proportion of the problem. Silent brain infarcts are frequently seen on magnetic resonance imaging (MRI) in healthy elderly people and sometimes incidentally revealed by CT-scan executed for other purposes, yet the real incidence of cognitive impairment or decline related to the pathology is still largely unknown. The prospective population-based Rotterdam Scan Study, including 1015 people 60 to 90 years of age and free of dementia and stroke at baseline (Sarah E. Vermeer et al., Silent Brain Infarcts and the Risk of Dementia and Cognitive Decline, New England Journal of Medicine, March 27 issue, Number 13, Vol. 348, 1215-1222, 2003) found a more than doubled risk of dementia (hazard ratio, 2.26; 95 percent confidence interval, 1.09 to 4.70) in people with silent brain infarct at the baseline MRI.

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. The authors performed Cox proportional-hazards and multiple linear-regression analyses, adjusted for age, sex, and level of education and for the presence of white matter lesions and the presence-absence of subcortical atrophy. 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 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 non-thalamic 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.

Sarah Vermeer and her colleagues concluded that silent brain infarct represents a defined increased risk of dementia and accelerates cognitive decline in elderly people.

BM&L-March 2003

Source Information. From the Departments of Epidemiology and Biostatistics (S.E.V., N.D.P., T.H., A.H., M.M.B.B.), and Neurology (S.E.V., N.D.P., T.H., P.J.K.), Erasmus Medical Center, Rotterdam, the Netherlands. Address reprint requests to Dr. Breteler at the Department of Epidemiology and Biostatistics, Erasmus Medical Center, P.O. Box 1738, 3000 DR Rotterdam, the Netherlands, or at m.breteler@erasmusmc.nl.