Neurofibromatosis type 1 - Motor and cognitive function and T2-weighted MRI hyperintensities

Background: Cognitive impairment and fine motor deficits are frequent manifestations in patients with neurofibromatosis type 1 (NF1). More than 50% of patients with NF1 show focal areas of high signal intensity (T2H) on T2-weighted MRI of the brain. It has been hypothesized that T2H may be associated with the cognitive and motor problems. Methods: The authors investigated 100 patients with NF1 and 100 healthy control subjects matched for age, sex, and socioeconomic status for their IQ (Wechsler Intelligence Scale for Children-Revised [WISC-R] and Wechsler Adult Intelligence Scale-Revised [WAIS-R]), fine motor abilities (Motorische Leistungs-Serie [motor performance task]), and T2H (MRI). Results: As a group, the 100 patients performed within normal limits of WISC-R and WAIS-R scores. However, the scores for the NF1 patients with normal MRI were at the mean, whereas those for the patients who had T2H (n = 58) were significantly depressed. On measures of fine motor skills, patients with T2H performed poorer than patients with normal MRI. Conclusion: Hyperintensities on T2-weighted MRI represent a biological marker for impaired cognitive and fine motor performance in patients with NF1.