Sintered ag agcl electrodes

Scalp EEG was measured at conceptional age of 42.1 ± 0.9 weeks in AED and 42.2 ± 0.9 weeks in HC groups (or 2.0 ± 1.0 and 2.0 ± 1.1 weeks from birth, respectively; mean ± SD for all) with no significant difference (P = 0.51, Wilcoxon rank-sum test). The EEG recording was performed during daytime sleep with a NicOne EEG amplifier (Cardinal Healthcare/Natus, USA), using initial sampling frequency (Fs) of 250 Hz or 500 Hz. The neonatal Waveguard caps had 20–32 sintered Ag/AgCl electrodes (ANT-Neuro, Germany) placed according to the 10–20 international system. For further analysis, the same 19 channels were selected from all subjects: Fp1, Fp2, F7, F3, Fz, F4, F8, T7, C3, Cz, C4, T8, P7, P3, Pz, P4, P8, O1, and O2.
EEG epochs for the network analyses were selected from both neonatal sleep (vigilance) states, AS and QS. They were identified visually using the standard combination of electrophysiological and behavioral measures (André et al. 2010 (link)), including polygraphic channels (submental electromyogram, electrocardiogram, electrooculogram, and respiration sensor). EEG signal during AS is known to exhibit continuous fluctuations, while polygraphic channels show irregular respiration and occasional eye movements. Conversely, EEG signal during QS is characteristically discontinuous, while respiration is markedly regular.

The multichannel scalp EEG recordings were collected for the HC and AED groups during daytime sleep using a NicOne EEG amplifier (Cardinal Healthcare/Natus, USA) with a sampling frequency of 250 or 500 Hz. The neonatal Waveguard caps had 20–32 sintered Ag/AgCl electrodes (ANT‐Neuro, Germany) placed according to the 10–20 international placement standard. The EEG signals were captured near term age (HC group: 42.2 ± 0.9 weeks; AED group: 42.1 ± 0.9 weeks) for about an hour that included both cardinal sleep states, active (AS), and quiet sleep (QS). Most subjects had clean enough EEG data for both sleep states (N = 53/46 for the HC/AED group), whereas others had only one state (Tokariev et al., 2019 ; Tokariev et al., 2021 ; Tokariev et al., 2022 ). The infants' sleep state was identified, as described in detail before (André et al., 2010 (link)), visually by the standard combination of electrophysiological and behavioral measures. In brief, newborn EEG exhibits continuous fluctuations during AS with irregular respiration and occasional eye movements, and in contrast, it is inherently discontinuous during QS and accompanies distinct regular breathing.