Electrode Challenges in Amplitude-Integrated Electroencephalography (aEEG): Research Application of a Novel Noninvasive Measure of Brain Function in Preterm Infants

Continuous real-time brain function monitoring of preterm infants offers a novel way to evaluate neurological development in neonatal intensive care. Direct measurement of brain function is difficult and complicated by vulnerabilities of the preterm infant population. This study illustrates the feasibility of using noninvasive hydrogel electrodes with amplitude-integrated electroence-phalography (aEEG) as a simplified brain monitor in preterm infants. This article presents a systematic exploration of factors influencing the accuracy of aEEG measurement, especially skin preparation procedures and skin condition after electrode placement. The authors conducted aEEG recordings on 16 medically stable preterm infants at 31-36 weeks postmenstrual age in the neonatal intensive care unit between feedings and caregiving for approximately 3 hr. The authors systematically performed several strategies to improve electrode placement procedures and reduce skin impedance, including (a) examination of possible influences of environmental electrical equipment, (b) comparison of different hydrogel electrode types, (c) modification of skin preparation procedures, and (d) assessment of impacts of different skin conditions. The authors achieved improvements in the impedance value, length of uninterrupted recording, and percentage of the recording duration with measured impedance < 20 k Omega (recommended acceptable limit). There was no report of skin irritation during or after the recording. The aEEG measurement at the bedside using hydrogel electrodes is noninvasive and feasible for reliable brain monitoring in preterm infants. This study demonstrated the importance of establishing systematic methods to ensure the accuracy and feasibility of physiologic measurements for nurse researchers.