How children with neurofibromatosis type 1 differ from "typical" learning disabled clinic attenders: nonverbal learning disabilities revisited

To further investigate cognitive deficits in children with Neurofibromatosis Type 1 (NF-1), children with NF-1 were compared to typical learning disabled clinic attenders (LD-clinic), all of whom had reading disabilities, as well as to a group with no disabilities (NoDx). Results indicated that both the NF-1 group and LD-clinic group had reading and reading-related deficits when compared to the NoDx group; however, the NF-1 group was more globally language impaired than the LD-clinic group. In addition, the NF-1 group scored significantly lower than the LD-clinic group, but not the NoDx group, on the visuospatial measures, thus confirming that children with NF-1 have visuospatial deficits not typical of a general LD-clinic population. The NF-1 group was not impaired in comparison to the NoDx group on certain language and visuospatial tasks that were previously found to be deficits in sibling pairwise matched designs; thus, the importance of considering genetic and familial context when studying the impact of genetic disorders on cognition was demonstrated.

Relationship of cognitive functioning, whole brain volumes, and T2-weighted hyperintensities in neurofibromatosis-1

Using quantitative magnetic resonance imaging morphometry, we report that the whole brain volumes of patients with neurofibromatosis-1 are significantly larger than normal, confirm the prevalence of macrocephaly as about 50%, and report that macrocephaly in patients with neurofibromatosis-1 does not appear to be related to the familial or sporadic origin of the neurofibromatosis-1 or to the presence or absence of T2-weighted hyperintensities. No strong relationship emerged between the extent of neurofibromatosis-1-associated impairment of cognitive functions and degree of macrocephaly; however, the macrocephalic neurofibromatosis-1 group did have a significant verbal impairment relative to the nonmacrocephalic neurofibromatosis-1 group in vocabulary (P < .009).