Comparative analysis of background EEG activity based on MRI findings in neonatal hypoxic-ischemic encephalopathy: a standardized, low-resolution, brain electromagnetic tomography (sLORETA) study

Abstract

Background It is important to assess the degree of brain injury and predict long-term outcomes in neonates diagnosed with hypoxic-ischemic encephalopathy (HIE). However, routine studies, including magnetic resonance imaging (MRI) and conventional encephalography (EEG) or amplitude-integrated EEG (aEEG), have their own limitations in terms of availability and accuracy of evaluation. Recently, quantitative EEG (qEEG) has been shown to improve the predictive reliability of neonatal HIE and has been further refined with brain mapping techniques. Methods We investigated background EEG activities in 29 neonates with HIE who experienced therapeutic hypothermia, via qEEG using a distributed source model. MRI images were evaluated and classified into two groups (normal-to-mild injury vs moderate-to-severe injury), based on a scoring system. Non-parametric statistical analysis using standardized low-resolution brain electromagnetic tomography was performed to compare the current density distribution of four frequency bands (delta, theta, alpha, and beta) between the two groups. Results Electrical neuronal activities were significantly lower in the moderate-to-severe injury group compared with the normal-to-mild injury group. Background EEG activities in moderate-to-severe HIE were most significantly reduced in the temporal and parietal lobes. Quantitative EEG also revealed a decrease in background activity at all frequency bands, with a maximum in decrease in the delta component. The maximum difference in current density was found in the inferior parietal lobule of the right parietal lobe for the delta frequency band. Conclusions Our study demonstrated quantitative and topographical changes in EEG in moderate-to-severe neonatal HIE. They also suggest possible implementation and evaluation of conventional EEG and aEEG in neonatal HIE. The findings have implications as biomarkers in the assessment of neonatal HIE.

Epileptic Seizures in Neonates Treated with Hypothermia for Hypoxo-Ischemic Encephalopathy in Brazzaville, Congo: Types and Evolution

“…Similarly, the study by Nash et al [23] also distinguished three types of background EEG activity: improved activity in 49% of neonates, unchanged ac-tivity in 38% of neonates, and worsened activity in 13% of neonates. Other investigators have reported changes in background EEG activity in neonates during TH [25] [37]. The duration and severity of cerebral anoxia, the location, extent, and number of cerebral lesions could explain the occurrence of the 3 types of background EEG activity [38]- [44].…”

Quantitative EEG in the neonatal intensive care unit: Current application and future promise

“…55 Spectral analysis incorporating spatial distribution of changes has recently demonstrated that changes in the temporal lobes may be particularly predictive. 56 Similarly, functional connectivity, a quantitative measure of the functional connection between brain regions, which is impossible to assess on visual review of the raw EEG, has been associated with outcomes in to severe NE. 57 Overall, these findings support that the excitotoxicity and metabolic stress of hypoxicischemic injury leads to abnormal neurovascular regulation and impairment in functional connectivity, with some regions of the growing brain being particularly vulnerable to injury.…”

“…Similar techniques were applied prospectively to 36 neonates with hypoxic–ischemic encephalopathy, and determined measurements of poor neurovascular coupling had an AUC of 80% for predicting brain MRI abnormalities 55 . Spectral analysis incorporating spatial distribution of changes has recently demonstrated that changes in the temporal lobes may be particularly predictive 56 . Similarly, functional connectivity, a quantitative measure of the functional connection between brain regions, which is impossible to assess on visual review of the raw EEG, has been associated with outcomes in moderate to severe NE 57 .…”

High-beta oscillations at EEG resting state and hyperconnectivity of pain circuitry in fibromyalgia: an exploratory cross-sectional study

“…Brain activity studies have explored the correlation effects with the BDNF. Theta and beta power positively correlate with serum BDNF levels in the right temporoparietal region in gambling disorder ( Kim et al, 2022 ). Brain connectivity areas involved in pain processing, particularly functional connectivity between the thalamic subregions with the PFC, have been found to be associated with BDNF in individuals with long-term primary dysmenorrhea ( Han et al, 2019 ).…”

“…It uses a three-dimensional head model and EEG recordings to estimate electrical activity in different brain regions. This method was validated through correlations with other imaging techniques, such as functional magnetic resonance imaging (fMRI) and MRI ( Mulert et al, 2004 ; Kim et al, 2022 ). Despite the use of a limited number of electrodes, sLORETA has provided valuable insights into the underlying sources of brain activity ( Michel and Brunet, 2019 ).…”