Cerebral white matter abnormalities and lifetime cognitive change: A 67-year follow-up of the Scottish Mental Survey of 1932.

Abstract

Cerebral white matter abnormalities relate to cognitive functioning in elders. We examine whether this association is (a) independent of mental ability in youth and (b) related to general and/or specific mental abilities. We retested 83 participants of the Scottish Mental Survey of 1932 on a battery of mental tests. Their brains were scanned by magnetic resonance imaging. Three independent ratings (Fazekas) were made of periventricular, and subcortical and deep white matter abnormalities. Structural equation models showed that, irrespective of brain location, white matter abnormalities contributed about 14% of cognitive function variance in old age. Some of this effect might be due to hypertension. This contribution is independent of mental function in early life and is associated with general cognitive ability.People who retain their cognitive functions in old age tend to have higher quality of life and live longer (Korten et al., 1999; National Research Council, 2000). Therefore, it is important to discover the factors that contribute to individual differences in cognitive functioning among the elderly. Ideally, researchers should establish the extent to which putative determinants of differences in cognitive aging are independent of prior cognitive ability differences, but cognitive data from youth are rarely available for aging cohorts. We discovered a population-wide cohort of individuals who took a validated mental test under standardized conditions in 1932 at 11 years of age (Scottish Council for Research in Education, 1933;Deary, Whalley, Lemmon, Crawford, & Starr, 2000). A measure of early life cognitive ability was available, therefore, for many individuals who were in their late 70s at the time of this investigation.In the present study, we examined the contribution of brain white matter lesions (WML) to cognitive ability differences in old age. Brain white matter abnormalities are important in the study of psychology and aging: (a) They are common, even in people with no dementia or other neurocognitive disorders; (b) they appear to be associated with other factors related to cognitive aging (such as hypertension and other illnesses, e.g., diabetes, that have an impact on vascular function); and (c) they are related to cognitive functioning in old age. In this article, we enquire whether (a) any association between WML and cognitive ability in old age is independent of cognitive ability in youth; (b) WML relate to specific or general cognitive abilities; and (c) hypertension underlies both differences in WML and cognitive function in old age. Brain White Matter AbnormalitiesIn this section, the phenomenon of brain WML is described, and causes of WML are discussed. One possible cause of both WML and cognitive aging is hypertension, which we examine in the present study.White matter abnormalities are frequently observed on T2 weighted magnetic resonance imaging (T2W MRI) of the brain, particularly in adults over the age of 60. They are alternatively referred to as lesions or hyperintensities, which is...

Socioeconomic status is positively correlated with frontal white matter integrity in aging

“…First, the cross-sectional design used in this study is unable to provide definitive information on causeand-effect relationships between SES and WM integrity. Furthermore, the cross-sectional design did not allow us to account for potential cohort effects (Deary et al 2003). Second, SES is considered to be a proxy indicator for other lifestyle variables known to contribute to reserve (such as physical activity, access to health care, and dietary habits).…”

Cognitive Correlates of Cerebral White Matter Lesions and Water Diffusion Tensor Parameters in Community-Dwelling Older People

“…Signifi cant associations have been found previ- ously in the largest studies which include a wide range of WML loads and cognitive ability [4,5] . The main cognitive defi cits were in tasks of processing speed, executive function, memory and global cognitive function rather than general intelligence [6] .…”

“…This rates WML separately for periventricular hyperintensities (PVH) and deep white matter hyperintensities (DWMH) providing a score of 0-3 for each. This scale was used because it was found to be appropriate for capturing a broad range of degrees of white matter abnormalities from mild to severe [4] . The rater (J.M.W.)…”

Early Life Risk Factors for Stroke and Cognitive Impairment

“…Furthermore, higher childhood intelligence is associated with better cognitive ability in older adulthood [17] and may influence later cognitive decline [18], perhaps by influencing peak adult cognitive function and/or the rate of cognitive decline [19].…”