The nature and frequency of cognitive deficits in children with neurofibromatosis type 1.

OBJECTIVE: To assess the frequency and severity of specific cognitive deficits in children with neurofibromatosis type 1 (NF1) in a large unbiased cohort.
METHODS: Extensive cognitive assessments were performed in 81 children with NF1 ages 8 to 16 years and their performance was compared with that of 49 unaffected sibling controls.
RESULTS: Eighty-one percent of the children with NF1 had moderate to severe impairment in one or more areas of cognitive functioning. Although 51% of children with NF1 performed poorly on tasks of reading, spelling, and mathematics, specific learning disabilities (as defined by IQ-achievement discrepancies) were present in only 20% of the children. Sustained attention difficulties were present in 63% of children with NF1, with 38% of children with NF1 fulfilling the diagnostic criteria for attention deficit-hyperactivity disorder. The NF1 neuropsychological profile is characterized by deficits in perceptual skills (visuospatial and visuoperceptual), executive functioning (planning and abstract concept formation), and attention (sustained and switching). Interestingly, both verbal and visual memory was unaffected in NF1 children, and their memory skills were in general stronger than their level of general intellectual function. Although both expressive and receptive language skills were significantly impaired in NF1 children, they appeared to be relatively better preserved than visuospatial abilities once IQ is taken into account.
CONCLUSION: There is an extremely high frequency of cognitive problems in children with neurofibromatosis type 1, making cognitive dysfunction the most common complication to affect quality of life in these children.