The relationship between cognitive impairment, fine motor deficits, and T2-weighted MRI intensities in neurofibromatosis type 1 (NF1) was investigated in 100 patients and 100 healthy controls in a study at University Hospital of Munster, Germany. T2 hyperintensities (T2H) were found in 66% of 56 patients younger than 16 and in 48% of 44 patients older than 16. As a group, patients with NF1 had normal scores on the WISC-R and WAIS-R. Patients with normal MRI had close to the mean IQ of the normal population whereas those who showed T2H (n=58) had significantly depressed verbal, performance, and full-scale IQ scores. On a test of fine motor skills, patients with T2H on MRI showed lower scores than those with normal MRI. Cognitive and motor performances of patients with T2H were not significantly correlated with the number of cerebral regions affected by T2H. Foci of T2H affected a single cerebral region in 40% of patients with T2H, 2 or 3 regions in 48%, and 12% had 4 or more regions affected. Hyperintensities on T2-weighted MRI represent a biological marker for impaired cognitive and fine motor performance in patients with NF1. [1]

COMMENT. This study demonstrates a strong relation between cognitive and fine motor performance and the presence of T2 hyperintensities on the MRI of patients with NF1. The number of cerebral regions affected by T2H is not correlated with cognitive and motor performances. Previous reports have shown variable results. In a study of 12 families reported from Johns Hopkins Hospital, Baltimore, children with NF1 compared to unaffected siblings had a lower !Q, multifocal cognitive deficits, and reading and neuromotor disabilities. In this study, cognitive differences correlated with the number of MRI “unidentified bright objects” (T2H) [2]. Patients identified with T2H should be considered for special education services.