EEG abormalities after antiepileptic drug cutting in patients with epilepsy

Purpose: Epilepsy is one of the most common neurological disorders of childhood. The prevalence of epilepsy in the world is approximately 5-10%. The incidence of epilepsy in childhood is approximately 1.5-8% (1). EEG is used to diagnose epilepsy, to support the diagnosis, to classify epilepsy and to follow up patients. Antiepileptic drugs (AEDs) used in the treatment of epilepsy patients reduce morbidity and mortality by providing seizure control, but treatment should be terminated at the appropriate time due to the increased possibility of side effects in long-term use of antiepileptic drugs. In this study we aimed to investigate EEG abnormalities at the time of diagnosis, during drug withdrawal and after drug discontinuation in epilepsy patients who had a 2-year seizure-free history under antiepileptic drug therapy and to contribute to the literature in this sense. Materials and Methods: This study was initiated with the approval decision of the Fırat University Faculty of Medicine Non-Invasive Research Ethics Committee dated 28/12/2021 and numbered 125865. The file information of 650 patients who were admitted to the Fırat University Hospital Pediatric Neurology Policlinic with the diagnosis of epilepsy (ICD code G40.0-G40.9) between 01.01.2020 and 01.12.2021 were analyzed from the hospital records. Patients who were younger than 3 months, had deficiencies in file data, had no EEG, had no brain MRI, had a diagnosis of metabolic disease, and had electrolyte imbalances that could cause seizures in their examinations were excluded from the study. The data obtained from the files of 152 patients who met the inclusion criteria in the study were recorded. Results: A total of 152 patients 57 (37.5%) female and 95 (62.5%) male were included in the study. When the diagnosis age groups of the patients were examined, it was determined that the most common age group was under the age of 6 years. The mean age at diagnosis of the patients was 4.0±3.5 years (median:3 years; min=0.3 years-; max=14 years). Generalized tonic-clonic (JTC) seizures were the most common in the patients included in the study and this was different from other studies. We think that this is due to the evaluation of seizure types according to the ILAE 2017 classification according to the information obtained from the hospital medical record system, the narratives of the families or the videos they took. EEG records were taken from the patients at the time of diagnosis, during drug reduction and after drug discontinuation. EEG results were normal in 18 (11.8%) patients, abnormal in 127 (83.6%) and non-epileptic paroxysmal activity in 7 (4.6%) patients at diagnosis. After drug discontinuation EEG results of 137 (90.1%) patients were reported as normal, 12 (7.9%) abnormal, and 3 (2%) non-epileptic paroxysmal activity. Recurrence was observed in 13.2% of the cases included in our study after all AEDs were discontinued. Recurrence was observed in 45.5% of the cases within the first 6 months, in 27.3% within 6-12 months, and in 27.3% after 12 months. AEDs were started again in 19 of the patients with recurrence, the same AED was continued in 6 (31.6%) of them and different AEDs were preferred in 13 (68.4%) patients. Conclusion: Each patient should be evaluated individually before deciding on AED treatment. Antiepileptic drug discontinuation may be considered in patients with a 2-year seizure-free history under antiepileptic drug therapy. This study shows that abnormal findings in the EEG obtained after drug reduction or discontinuation increase the risk of seizure recurrence. In addition it shows that closer follow-up should be done in this process, since the risk of seizure recurrence is high in the first 6 months after drug discontinuation in patients.