Review of Noninvasive Neuromonitoring Modalities in Children II: EEG, qEEG

Abstract

Critically ill children with acute neurologic dysfunction are at risk for a variety of complications that can be detected by noninvasive bedside neuromonitoring. Continuous electroencephalography (cEEG) is the most widely available and utilized form of neuromonitoring in the pediatric intensive care unit. In this article, we review the role of cEEG and the emerging role of quantitative EEG (qEEG) in this patient population. cEEG has long been established as the gold standard for detecting seizures in critically ill children and assessing treatment response, and its role in background assessment and neuroprognostication after brain injury is also discussed. We explore the emerging utility of both cEEG and qEEG as biomarkers of degree of cerebral dysfunction after specific injuries and their ability to detect both neurologic deterioration and improvement.

Keywords: Continuous electroencephalography; Critical care neuromonitoring; Encephalopathy; Quantitative electroencephalography; Seizure; Status epilepticus.

Fig. 1

Periodic and rhythmic patterns in pediatric critical care EEG. EEG electroencephalography, GPD generalized periodic discharges, GRDA generalized rhythmic delta activity, LPD lateralized periodic discharges, LRDA lateralized rhythmic delta activity

Fig. 2

Summary of quantitative EEG trends used in the pediatric ICU. *CDSA color density spectral array, CSA compressed spectral array, EEG electroencephalography, FFT Fast Fourier Transform. *Trends, color schematics, axes, and scales may vary by quantitative EEG software

Fig. 3

A 9-year-old boy with a left frontotemporal tumor and new onset left hemispheric onset seizures (black arrows). Trend description from top to bottom: rhythmicity spectrogram for left then right hemisphere demonstrates increased rhythmicity over the left hemisphere during seizures. Fast Fourier Transform spectrogram left over right hemisphere shows solid flames best formed over the left during seizures. Asymmetry spectrogram shows greater power over the left hemisphere during seizures (blue color change). Asymmetry indices for slower frequencies (1–5 Hz) over faster frequencies (6–14 Hz) show discrete graph trend toward less positive values during seizures, indicating greater relative power of the left hemisphere. Amplitude-integrated electroencephalography (EEG) shows classic arched pattern during seizures (Color figure online)

Fig. 4

A 9-year-old with a left hemispheric-onset seizures. Levetiracetam 40 mg/kg (black arrow) slowed seizures but did not resolve them. Lacosamide 5 mg/kg (red arrow) provided definitive seizure suppression (Color figure online)

Fig. 5

A 13-year-old with acute liver failure and progression from stage II to stage III hepatic encephalopathy. Dashed blue arrow notes gradual decline in the alpha/delta ratio, which is confirmed to be due to both loss of alpha power and increase in delta power as demonstrated by the Fast Fourier Transform (FFT) spectrogram trends for the left and right hemispheres. This change in quantitative electroencephalography (EEG) trends corresponded to the patient no longer following commands and progressing to extensor posturing of arms and legs, sustained clonus at the ankles, hyperreflexia, and positive Babinski sign bilaterally (Color figure online)

Fig. 6

A 10-year-old with metastatic brain tumor in the right hemisphere who developed progressive cerebral herniation and loss of cortical activity. There was a right hemispheric onset seizure prior to herniation (black arrow)

Fig. 7

A 10-year-old boy with at-home cardiac arrest requiring extracorporeal membrane oxygenation (ECMO). Hypotension and arrhythmias resulted in hypoperfusion injury around the time of ECMO cannulation (black arrow). The right hemisphere lost delta power, increasing the alpha/delta ratio (ADR), whereas the left hemisphere lost fast frequencies and gained slow frequencies, resulting in a decrease in ADR (red arrow). Asymmetry spectrogram reflects the increase in delta power over the left hemisphere after cannulation (Color figure online)

Fig. 8

Macroperiodic oscillations (MOs) observed in a 6-month-old with traumatic brain injury are visualized on segments of 12-hour and 1-hour time scales on color density spectral array (CDSA). This MOs pattern oscillated over 2 minutes from peak to peak (black arrows). There was a modest change in voltage observed on raw electroencephalography (EEG) during this time, but the periodic invariant quality was only appreciated on the CDSA (Color figure online)

Fig. 9

a Artifact in the 13- to 14-Hz frequency range from a high-frequency chest wall oscillation vest (black arrow) in a 13-year-old. b Quantitative electroencephalography (EEG) in a 3-month-old with congenital heart disease status post surgical repair. Asymmetry indices and spectrograms demonstrate shifting impact of scalp edema on the EEG signal, with changing asymmetric power at regular intervals, reflecting timed repositioning of the patient by the bedside nurses