Factors Associated with Electroencephalographic Epileptiform Abnormalities in Epilepsy Patients: A Cross-sectional Study

Electroencephalogram (EEG) is one of the diagnostic tools in epilepsy. We studied the factors associated with epileptiform abnormalities in epilepsy patients. This was a single-centre cross-sectional study conducted in Hospital Canselor Tuanku Muhriz, Malaysia. The study population was epilepsy patients without underlying neurodegenerative diseases, psychiatric illnesses, progressive neurological disorders and drug abuse or intoxication. Their demographic data, type and aetiology of epilepsy, comorbidities, anti-seizure medications and EEG data were collected. A total of 183 patients diagnosed with epilepsy were recruited in this study. The mean age was 41.6 years (SD + 17.8) with 94 (51.4%) male and 89 (48.6%) female. The mean age of epilepsy onset was 30.4 years (SD + 21.2). The most common aetiology was structural abnormalities (134, 73.2%). 134 patients (73.2%) had abnormal EEG results which consisted of focal epileptic discharges (103, 57.3%) and generalised epileptic discharges (31, 16.8%). The risk factors associated with abnormal EEG were focal epilepsy, uncontrolled seizures, abnormal brain imaging, the number of anti-seizure medications and the usage of carbamazepine and levetiracetam. The use of EEG in epilepsy patients has assisted in the diagnosis, localisation and management aspects. We reported a high proportion of abnormal EEG in our epilepsy patients. The risk factors associated with abnormal EEG were comparable to the Western literature. The data highlights the importance of performing the EEG as part of the routine investigations. The identification of the risk factors of abnormal EEG may help to determine the recurrence risk, prognosis of the patients and subsequent management.