Observational study of informative value of routine EEG and nocturnal EEG-video monitoring in adult patients with epilepsy in the real-life setting

The aim was to study the informative value of routine EEG and nocturnal EEG-video monitoring in adult patients with epilepsy. Materials and methods . We examined 1217 patients who were referred to a specialized epilepsy clinic; of those, 589 (48.4%) men and 628 (51.6%) women aged from 22 to 83 years. In these patients, the age of seizure onset varied from I month to 72 years. The inclusion criteria in this study were: an age over 18 years and two or more epileptic seizures in the medical history. The exclusion criteria: a history of non-epileptic seizures of any etiology and/or the inability to perform regular EEG or EEG video monitoring. The examination included medical history records, clinical and neurological examinations, routine EEG and EEG video monitoring, brain MRI, and laboratory tests. In total, 915 routine EEG and 302 nocturnal EEG video monitoring were performed. Results. During the routine EEG procedure, no epileptiform activity was detected in 379 (41.42%) patients. Among other patients, non-epileptic changes were found in 163 (17.81%), focal epileptiform activities - in 203 (22.19%), and generalized epileptiform activities - in 170 (18.58%) patients. During the nocturnal EEG-video monitoring, no epileptiform activity was detected in 34 (11.26%) patients; among other patients, non-epileptic changes were found in 11 (3.64%), focal epileptiform activities - in 167 (55.3%), and generalized epileptiform activities - in 90 (29.8%) patients. Conclusion. Routine EEG and nighttime EEG video monitoring do not always reveal an epileptiform activity. The probability of detecting an epileptiform activity is higher with nocturnal EEG video monitoring due to its longer record duration and an increased epileptiform activity in sleep. The probability of detecting an epileptiform activity also depends on the form of epilepsy. It is advisable to gradually replace a routine EEG procedure with a nocturnal EEG-video monitoring.