Subclinical seizures detected in eeg, relation to sleep stages and clinical value in patients with partial epilepsy

Subclinical seizures are defined as electrographic seizures of rhythmic ictal discharges that spread over time, which do not lead to objective or subjective changes in consciousness or behavior. Subclinical seizures are known to help diagnose and localize patients with epilepsy. Detection of subclinical seizures also helps the prognosis in many diseases. Subclinical seizures have been shown to be related of progression and prognosis in patients diagnosed with Gliomas and Alzheimer's disease. Patients with subclinical seizures are reported to have a higher frequency of refractory epilepsy and a longer duration of illness. The relationship between sleep and epilepsy has been investigated for a long time. It is known that epileptiform changes in deep sleep are more frequently seen due to the underlying electrophysiological pathways. In our study, a retrospective EEG study of patients with partial epilepsy who applied to our clinic between November 2016 and June 2017 was performed. Patients with subclinical seizures were selected, and the presence of sleep in EEGs and the presence of subclinical seizures in sleep were examined. A total of 140 patients with a twenty minute EEG and 28 patients with a 24 hour EEG were included in the study. The age, sex, medication by number and names, duration of illness and epileptic foci of the patients taken into the study were added to the data by screening from the hospital software system. In the statistical study, two groups were evaluated within themselves and comparatively. In cases where significant statistical relationship was established, the odds ratio was calculated by further analysis. There was no significant difference between age, duration of illness and subclinical seizure. Patients with frontal lobe epilepsy had subclinical seizures more frequently. There was a 2.2 times greater risk than patients with temporal lobe epilepsy. When the sleep stages were examined, 41 times more subclinical seizures were observed in NREM2 and NREM3 stages. A significant statistical difference was obtained for these two cases. For both groups, 3.1 times more subclinical seizures were observed in patients with refractory epilepsy. With the number of drugs used were not significantly different in two groups, elevated risk was detected with the use of levetiracetam and the use of older generation, broad spectrum antiepileptic drugs. In our study; we tried to show the relationship between clinical value of subclinical seizures and sleep. The reason for taking these two groups is to demonstrate the detectability of these seizures with short-term EEG monitorization, which can be done even in small clinics where it is not possible to do longer monitorization, and to try to obtain meaningful statistical results. In conclusion, our recommendation in the study is to choose short-term sleep EEG in patients with suspected frontal lobe epilepsy and a narrower spectrum new generation antiepileptic when the choice of medication is made, even though there is no possibility of 24-hour EEG monitoring in clinics. This study showed that increasing the number of patients and investigating the relationship between sleep disturbances and subclinical seizures in wider centers will allow us to better understand our patients with partial epilepsy and to better control seizures.