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Abstract:
Cognitive assessment and neuroimaging studies were carried
out in a large group of adolescents (n=77, mean age 15y7m) who had
been very low birthweight infants. Two groups were formed from this
cohort. Twelve children had scores on the Numerical Operations
(NOps) subtest of the Wechsler Objectives Numerical Dimensions
(WOND) that were significantly below predictions from the WISC-III
and were assigned to the NOps Deficit Group. A further twelve
children whose NOps scores were IQ appropriate, and who were
matched with the first group for age, gender and verbal IQ, were
assigned to the No Deficit Group. None of the children had deficits
in literacy skills. Neuroimaging studies were conducted on all
children; a voxel-based morphometry study of the 3D MRI data sets
was carried out using Statistical Parametric Mapping (SPM)
software. Both white and grey matter were compared. The area of
greatest difference between the two groups was in the left parietal
lobe in the region of the intraparietal sulcus. This finding is
consistent with both lesion and functional imaging studies in
adults. A third group (n=13) with a selective deficit in WOND
Mathematics Reasoning showed no such difference, indicating that
the difference was specific to calculation and not general
mathematics ability.
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