Brain MRI changes were studied in relation to intelligence in a group of 28 children, aged 4 to 16 years, with neurofibromatosis 1. The mean FS IQ on the Wechsler scales (WPPSI, WISC-R) was 89 (range 54-148), mean VS was 95 and PS 84. Eight children who had neurological disease (epilepsy, hydrocephalus, tumor, or post-irradiation) scored significantly lower on IQ tests than the 20 without neurological disease. Eighteen children with hyperintense T2 weighted foci had a mean FS IQ comparable with the 10 without spots. In the group without neurologic disease, the 10 showing hyperintense spots had a higher mean FS IQ than 10 without. There was no significant relation between the number or location of T2 weighted foci and FS IQ. 
COMMENT. Previous studies have shown that the mean full scale IQ in children with neurofibromatosis 1 is shifted to the left, between 88 and 94. T2 weighted hyperintense foci in the brain MRI were not correlated with intelligence of children with neurofibromatosis 1 in the present study, and similar results have been reported from other centers. (see Progress in Pediatric Neurology I, PNB Publishers, 1991, pp376-77). However, the authors cite two recent reports showing a significant correlation between a lowered IQ and the presence of T2 weighted hyperintensities in the MRI of 52 affected children who had no major neurologic complication or frank retardation. Further studies are needed to define the significance of these hyperintense foci.