Electroencephalography spectrum and high frequency oscillation analysis in patients with nrem parasomnia and epilepsy

Introduction: There are clinical and pathophysiological similarities between non-rapid eye movements (non-REM, NREM) parasomnias and sleep-related hypermotor epilepsy. The aim of this study is to examine the spectral electroencephalographic (EEG) features and high frequency oscillations (HFO) in patients with NREM parasomnia and epilepsy, compare them with the healthy control group, and reveal possible similarities and differences. Materials and Methods: Sixteen patients with NREM parasomnia, 14 patients with non-refractory frontotemporal epilepsy, and 10 age- and gender-matched healthy controls were included. Spectral EEG data were obtained from bilateral central areas, HFO analysis was performed in 16-channel EEG in at least one three-minute period each from pre-sleep wakefulness, first and second half of sleep, and NREM and REM sleep stages. Results: Delta power in N2 sleep was lower in patients with parasomnia in the first half of sleep, theta power in N2 sleep, alpha and theta percentage in N3 sleep were higher in the second half. In patients with epilepsy, a decrease in delta power was observed in the second half. In HFO data, it was observed that total fast ripple numbers in sleep and wakefulness were highest in epilepsy, and total fast ripple in all sleep and in the second half of sleep were higher in parasomnia than in controls. Conclusion: Spectral EEG analysis can be used as an indicator of sleep instability in parasomnia. Our study has shown that HFOs can be observed not only in epilepsy but also in parasomnia. New studies examining HFO in sleep disorders are needed.