WHITE-MATTER CHANGES IN HEALTHY ELDERLY PERSONS CORRELATE WITH ATTENTION AND SPEED OF MENTAL PROCESSING

Objective.-To evaluate the association between white matter changes (l eukoaraiosis [LA]) seen on magnetic resonance imaging and cognitive fu nctions. Design.-Survey of cohorts of neurologically healthy elderly s ubjects derived consecutively from a population-based random sample. S etting.-General community, the Helsinki (Finland) Aging Brain Study. S ubjects.-Cohorts of neurologically healthy subjects aged 55, 60, 65, 7 0, 75, 80, and 85 years (n=20,18,19,18, 1 7, 1 7, and 11 subjects, res pectively; total N=120). Measures.-Leukoaraiosis was rated in the peri ventricular areas (0 to 24) and the centrum semiovale (0 to 24); also, a total LA score was obtained (0 to 48). The neuropsychological test battery covered memory, verbal intellectual and constructional functio ns, language, speed and attention, and speed of mental processing, as well as simple psychomotor speed. Results.-Low age-related LA scores a nd deterioration of cognitive functions were obtained in the normal su bjects. When controlling for age, we found that speed and attention, t ogether with the speed of mental processing measured by the Trail Maki ng A and the Stroop tests, correlated with the total LA score. However , there was wide variation between subjects. Comparing groups with and without LA proved the association of LA with Trail Making A time, Str oop test result (words/time and difference/time), and the compound sco re of speed and attention. Presence of periventricular LA was especial ly related to speed of mental processing. Conclusion.-Leukoaraiosis co uld explain some of the intellectual impairment in the elderly, especi ally that of slowing of distinct motor and attentional functions, as w ell as slowing of mental processing. Mild LA in normal aged subjects c ould also signal brain at risk for further cognitive impairment.