Comparison of EEG Signal Characteristics Between Polysomnography and Self Applied Somnography Setup in a Pediatric Cohort

Samu Kainulainen,Marta Serwatko,Michael Clausen,Henri Korkalainen,Timo Leppanen,Erna Sif Arnardottir,Sigurveig pora Sigurdardottir,Sigriur Sigurdardottir,Sami Myllymaa

doi:10.1109/access.2021.3099987

Abstract

We aimed to investigate differences in the electroencephalography (EEG) signal characteristics recorded with a type II polysomnography (PSG) setup including the American Academy of Sleep Medicine recommended EEG montage and Self Applied Somnography (SAS) setup. The PSG and SAS monitoring were simultaneously performed in a pediatric cohort ( n=111) with Nox A1 equipment (Nox Medical, Reykjavik, Iceland). The PSG channels F4-M1 and F3-M2 were compared to the SAS channels AF4-E3E4 and AF3-E3E4. The analyses were conducted separately in each sleep stage. The amplitude levels were compared by investigating envelope curves of each epoch and the frequency content by investigating the power spectrums obtained with Welch's method. The EEG spectral morphology was similar between SAS and PSG. However, the SAS had consistently lower median amplitudes in all sleep stages compared to the PSG. In Stage N3 (slow-wave sleep), the lower and upper envelope curves had 42.4-47.4% lower median absolute amplitudes. Similarly, the SAS channels had consistently less power in the whole analysed frequency range of 0.3-35 Hz. In conclusion, the results illustrate that the SAS signals have similar EEG spectral morphology but consistently lower amplitudes and less power across the whole EEG frequency range compared to PSG signals. To achieve scoring corresponding to PSG, either the raw SAS signals should be digitally preprocessed or the amplitude threshold for identifying N3 should be lowered from 75 μV to e.g. 45 μV when using SAS instead of PSG. Further clinical validation studies are required to demonstrate scoring reliability using modified scoring rules.

Highlights

Sleep disorders form a growing global health problem and cause significant economical costs [1]
The results illustrate that the Self Applied Somnography (SAS) signals have similar EEG spectral morphology but consistently lower amplitudes and less power across the whole EEG frequency range compared to PSG signals
We aim to investigate the differences in the EEG signal characteristics obtained via simultaneous type II PSG and SAS recording in a pediatric cohort

Summary

Introduction

Sleep disorders form a growing global health problem and cause significant economical costs [1]. The EEG, EOG, and chin EMG signals are the basis of sleep staging used to provide information on the sleep architecture and the total sleep time [4]. Type II PSGs, where the electrodes are placed at a sleep laboratory and the patient sleeps at home, still require approximately a 1-hour setup by sleep laboratory staff [8]. This can be impractical for the patient and the electrodes are prone to be detached [9]. To diagnose OSA in adults, simpler type III polygraphy can be used [4]; these cannot identify sleep stages due to the absence of the EEG, EOG, and chin EMG recording montage. Type III polygraphy is not accepted internationally for diagnosis of pediatric OSA [4], [10]

Objectives

Methods

Results

Discussion

Conclusion