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.