Investigate the impact of focal areas of signal intensity (FASI) and gliomas located in the corpus callosum (CC) on neuropsychological profiles of NF1 patients.

NF1 is a genetic disorder with increased risk of central and peripheral nervous system tumors. MRIs often reveal areas of increased T2 signal intensity, called FASI. Many NF1 patients have increased cognitive and motor impairments compared to the general population, with a leftward IQ shift. CC lesions have been associated with lower executive functioning and cognitive processing but remain unstudied in a large NF1 cohort.

We performed a retrospective chart review of 63 NF1 patients (aged 4 to 25 years) followed at NYU who underwent neuropsychological testing. Patients with CC gliomas or FASI were identified and their results were compared across multiple domains including FSIQ, attention, language, academic, visual, and executive functioning.

Among 63 patients, 10 had CC FASI or gliomas. Of the remaining 53, 33.9% had FASI and 54.7% had gliomas of other locations, while 11.3% had no lesions. Overall FSIQ scores were not significantly different between NF1 patients with a CC lesion versus lesions elsewhere, or between patients with and without CC lesions. However, patients with CC lesions had significantly lower verbal comprehension index scores than all other patients (8.5% vs. 19.0%, p=0.028). Those with CC FASI had significantly lower Verbal Comprehension (7% vs 58%, p=0.046), Visual-Spatial (9% vs 37%, p=0.05), Working Memory (16% vs 50%, p=0.046), and Beery VMI (1% vs 18.5%, p=0.02) scores than those without lesions. 

While the presence of CC FASI or gliomas do not significantly impact NF1 patients’ overall FSIQ, they are associated with lower verbal comprehension, visual-spatial skills, and working memory index scores.