In children with Neurofibromatosis type 1 (NF1), hamartomatous lesions called FASI (focal areas of signal intensity) on brain MRI are common. The relationship between neurocognitive functions and the presence of cerebellar FASI in NF1 children is a controversial issue. Our aim in this study is to investigate whether there is a difference in fractional anisotropy (FA) and mean diffusivity (MD) values in children with NF1 with and without cerebellum FASI, and to analyze its effect on neurocognitive functions. Twenty-seven patients children were assessed using Diffusion Tensor Imaging (DTI) and MRI. According to MRI features, we classified children with NF1 as group 1 with FASI (n=14) in the cerebellum, group 2 without FASI (n=13). The WISC-R scale (a revised form of the Wechsler intelligence scale for children) was used to analyze cognitive functions. MD and FA values were measured from cerebellar FASI and white matter. The relationship between neurocognitive function test scores and FA and MD values was investigated. There was a significant difference between group 1 and group 2 in terms of MD and FA values of the cerebellum. Verbal and performance test scores were lower in group 1 and group 2. The MD values obtained from the cerebellum were positively correlated with the full-scale intelligence quotient (IQ), Verbal IQ, and Performance IQ. There was a significant difference between group 1 and group 2 in terms of information, vocabulary, digit span, picture arrangement. DTI changes in the cerebellum are associated with demyelination and loss of axonal integrity in the white matter pathways responsible for some neurocognitive functions. We think that the presence of cerebellar FASI in children with NF1 does not contribute to the severity of neurocognitive impairment.
Key words: Neurofibromatosis type 1, cognitive functions, diffusion tensor imaging, fractional anisotropy, mean diffusivity
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