Localizing seizure-susceptible brain regions associated with low-grade gliomas using voxel-based lesion-symptom mapping

Background. Patients afflicted with low-grade glioma (LGG) frequently suffer from seizures. The mechanisms of seizure initiation in these patients remain poorly understood. Tumor location has been correlated with seizure initiation. However, these correlative studies relied on dichotomized data analysis based on arbitrary lobe assignments. As a result, the lesion-symptom correlation may be incorrectly interpreted. Here, we present the first study that used a voxel-wise quantitative lesion analysis to investigate the spatial correlation between tumor location and seizure susceptibility. Methods. We collected the medical records and magnetic resonance images of 410 LGG patients. The dataset was divided into a discovery set and a validation set. A voxel-based lesion-symptom correlative analysis was performed to determine whether tumor location was associated with seizure risk and could be related to the specific type of seizure. Results. For all seizure types, increased seizure risks were identified for LGGs that involved the left premotor area. The LGGs that involved the posterior portion of the left inferior and middle frontal gyrus were associated with increased risk of simple partial seizures. LGGs that involved the right temporal-insular region were associated with an increased risk of complex partial seizures. LGGs that involved the left premotor area were more likely to be associated with seizures that generalize. These correlations were consistently observed in both the discovery and the validation datasets. Conclusions. Our quantitative neuroimaging analyses support the concept that the anatomic location of an LGG is a contributing factor in tumor-related seizure.