Cognitive correlates of ventricular enlargement and cerebral white matter lesions on magnetic resonance imaging. The Rotterdam Study.

TLDR

Ventricular enlargement and white matter lesions are common MRI findings in the elderly, and while they correlate with dementia severity in demented subjects, their clinical relevance in nondemented individuals remains uncertain. The study examined how the size of the lateral ventricles and the extent of white matter lesions relate to cognitive performance in a population‑based sample of nondemented older adults. Ninety nondemented participants aged 65–84 from the Rotterdam Study underwent MRI to quantify white matter lesions and ventricle‑to‑brain ratio, and completed a comprehensive neuropsychological battery covering a broad range of cognitive functions. Both ventricular enlargement and white matter lesions were independently linked to poorer performance on all cognitive tests; after adjusting for age and sex, ventricular enlargement predicted worse global cognition, memory, and executive control, whereas white matter lesions mainly impaired executive control, mental speed, verbal fluency, and memory.

Abstract

Ventricular enlargement and white matter lesions are frequent findings on cerebral magnetic resonance imaging scans of elderly subjects. In demented subjects they seem related to the severity of the dementia, but in nondemented subjects their clinical significance is less clear. We investigated the relation of size of the lateral ventricles and white matter lesions with cognitive function in a population-based random sample of nondemented elderly persons. The study population consisted of 90 subjects, aged 65 to 84 years, who were randomly selected from the cohort of the Rotterdam Study, and who were not demented. The presence of white matter lesions and the ventricle-to-brain ratio were assessed on magnetic resonance scans. Participants were tested with a neuropsychological battery that covered a broad range of cognitive functions. Ventricular enlargement and white matter lesions were both and independently associated with poorer performance on all tests. After adjustment for age and sex, ventricular enlargement was significantly associated with worse scores on tests assessing global cognitive function (Mini-Mental State Examination, P = .02; Groninger Intelligence Test, P = .01), memory (Word List Learning delayed recall, P = .03), and executive control functions (Stroop part II, P = .02; Trial Making Test B, P < .01); for white matter lesions the differences were significant for tests measuring executive control functions and mental speed (Trail Making Test A and B, P = .01 and P < .01, respectively; verbal fluency, P = .01), and memory (Word List Learning delayed recall, P = .04). This study suggests that white matter lesions are primarily related to impairment of subcorticofrontal functions, whereas enlargement of the lateral ventricles is associated with disturbances of cortical functions as well.