Presurgical cognitive status in patients with low-grade glioma and epilepsy: Testing the effects of seizures, antiseizure medications, and tumor localization.

Background: Low-grade gliomas (LGGs) are frequently associated with epilepsy. There are few studies addressing the impact of seizures, antiseizure medications (ASMs), and lesion localization on presurgery cognitive functioning.
Methods: We tested the relation between the above-mentioned variables in a continuous series of 73 young patients (mean age 38.3 years ± 11.7) affected by LGGs and epilepsy. The anatomical areas, involved in this sample, were the left insula with surrounding cortical and subcortical areas, the right precentral gyrus/rolandic operculum, and the white matter and cortical regions beneath.
Results: Patients' presurgery cognitive status was within the normal range, with borderline performance for some tasks. We tested whether lower scores were related with lesion or with epilepsy-related factors. Multiple regression identified variables that predict test scores. The Token test score was predicted by a model (p = .0078) containing the DT2T1 MRI, corrected for seizure features. Object naming performance was predicted by a model (p = .0113) containing the localization, the DT2T1 MRI, corrected for sex, EEG, and onset. Verbal fluency score was predicted by a model (p = .0056) containing the localization and the DT2T1 MRI, corrected for AEDs and EEG. Working memory score was predicted by a model (p = .0117) containing Engel class, the DT2T1 MRI, corrected for sex. Clock drawing score was predicted by a model (p < .0001) containing the Engel class, AEDs, and EEG. TMT A score was predicted by a model (p = .0022) containing localization, corrected for EEG. TMT B-A score was predicted by a model (p = .0373) containing localization. Voxel Lesion Symptom Mapping analyses carried out on patients' lesion volumes confirmed that patients' level of performance correlated with lesion-related variables.
Conclusion: This preliminary study indicates that the presurgical level of performance for language tasks and for cognitive flexibility and shifting is mainly predicted by lesion-related variables, working memory by both lesion and epilepsy-related variables. Epilepsy clinical and instrumental characteristics predicted performance for visuospatial planning.
(© 2022 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)