The Incidence and Electroencephalographic Features in Brain Tumor-Related Epilepsy

Methods: This retrospective-prospective study included 90 patients with BT. Based on the type of BT, the participants were divided into three groups of 30 patients each: patients with gliomas, with meningiomas and with brain metastasis. Demographic data such as age, sex, alcohol and cigarette consumption were collected. In all three study groups, the time of onset of the first ES, type, characteristics, and frequency were analyzed as well as abnormalities on electroencephalography (EEG). EEG was reviewed for any abnormal background or interictal epileptic discharges. Results: Brain tumor-related epilepsy (BTRE) was present in 46.7% of patients. The incidence of epilepsy secondary to brain tumors was 66.7% in patients with gliomas, 46.6% in those with meningiomas, and 26.7% in those with metastasis. The tumors associated with BTRE were most commonly located in the frontal (40%) and temporal (32.2%) lobes, followed by the parietal (25.6%) and occipital (2.2%) lobes. Focal to bilateral tonic-clonic ES represented the most common seizure type among the studied patients. Abnormalities on the initial EEG recordings were observed in 33 patients with BTRE. Focal EEG abnormalities were identified in 54.7% of patients, while diffuse changes were present in 23.8% of patients (p < 0.005). Conclusions: The highest incidence of BTRE was observed in patients with gliomas, followed by those with meningiomas, while the lowest incidence was recorded in the group with metastases. Smaller and slower growing tumors were associated with higher incidence of seizures than larger, more rapidly growing lesions. Focal to bilateral tonic-clonic seizures were the most common seizure type among patients with BTRE.