Relationship between sleep microstructure and seizure frequency, sleep qualityin patients with focal epilepsy patients

Introduction and Objective: It is known that sleep and epilepsy interact with each other bidirectionally, and it is emphasized that the sleep structures and contents of epilepsy patients differ from normal individuals. Although average data on the sleep macrostructure of epilepsy patients are known, different results are reported on the microstructure. The aim of this study is to compare the differences in sleep macro and microstructure elements and sleep quality between focal epilepsy patients and individuals with similar complaints who applied to the sleep outpatient clinic, and the effect of seizure frequency on sleep microstructure. Materials and Methods: The study was planned as a prospective crosssectional study. 55 patients (41.8% F) with "focal epilepsy" diagnosis followed up at Çukurova University Faculty of Medicine Epilepsy Outpatient Clinic, with complaints of snoring, excessive daytime sleepiness (EDS), and witnessed apnea, were included, along with 55 control group patients (43.6% F) matched for body mass index (BMI), age, gender, and mean apnea/hypopnea index (AHI) and periodic leg movement index (PLMI) who applied to the Sleep Outpatient Clinic with similar complaints and underwent polysomnography (PSG) examination during the same period. Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI) tests were applied. After an all-night PSG recording, sleep scoring and cyclic alternating pattern (CAP) scoring were performed manually. IBM SPSS 25.0 program was used for statistical evaluation and matching. Results: There was no significant difference between the epilepsy and control groups in terms of sleep macrostructures (recording time, sleep efficiency, post-sleep wakefulness duration, N1, N2, N3, PLMI, and AHI). However, sleep latency (p=0.023) and REM percentage ratio were shorter in epilepsy patients (p=0.01). As for sleep microstructure, the CAP rate was higher in epilepsy patients (38.91±17.9% vs. 26.05±13.4%) (p<0.0001). In epilepsy patients, the total A1 phase percentage within the CAP period was higher (p=0.006), while the mean numerical percentage of A2 phase and mean percentage of A2 phase duration were higher in the control group (p=0,036 and p=0,001, respectively), and the mean B phase duration (sec) was longer in epilepsy patients (23.19±4.97 vs. 21.39±3.84) (p=0.037). There was no significant difference in ESS scores (p>0.05), while the global PSQI score was higher in the control group (7.8±3,88 vs. 5.3±2.93) (p=0,0002). Conclusion: When focal epilepsy patients with suspected obstructive sleep apnea syndrome were compared to a control group with similar demographic, AHI, and PLMI characteristics, the significantly higher CAP rate in epilepsy patients supports a significant relationship between epileptic networks and the circuits that modify CAPs. Furthermore, the prominence of the A1 phase in epilepsy patients and the A2 phase in the control group suggest differences in autonomic and sleep/wakefulness-promoting circuits within the CAP.