Neuropsychologic correlates of brain white matter lesions depicted on MR images: 1921 Aberdeen birth cohort

PURPOSE: To examine relationships between brain white matter hyperintensiti es depicted at magnetic resonance (MR) imaging and performance on neuropsyc hologic tests in community-dwelling elderly adults. MATERIALS AND METHODS: The 1921 Aberdeen Birth Cohort is a subsample of sur vivors of the Scottish Mental Survey of 1932 whose mental ability was teste d at 11 years of age. Ninety-five of these subjects agreed to undergo brain MR imaging, an examination of general health, and a neuropsychologic evalu ation. White matter hyperintensities detected at T2-weighted MR imaging wer e rated by using a semi-quantitative method yielding two continuous variabl es: white matter lesions and periventricular lesions. Cognitive ability, in cluding crystallized and fluid intelligence domains, was assessed with stan dard neuropsychologic tests. RESULTS: Rating scores of white matter lesions were normally distributed (o n a devised scale) with means of 1.14 for white matter lesions and 1.28 for periventricular lesions. Intra- and interobserver reliability coefficients for scores were high, generally above 0.7. There were significant correlat ions of medium effect size between the T2-weighted MR imaging-depicted whit e matter lesions and performance on tests of fluid-type intelligence. No si gnificant correlation was demonstrated between white matter lesion ratings and tests of crystallized intelligence. CONCLUSION: Lower fluid-type ("prevailing") intelligence test scores were a ssociated with increased severity of white matter lesion ratings but not cr ystallized type ("remorbid") intelligence test scores. This indicates that MR imaging-depicted white matter lesions are of clinical importance.