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Updated: Jun 10, 2025
Preterm EEG: A Multimodal Neurophysiological Protocol
Published on: February 18, 2012
Haemodynamic Responses to Spontaneous Neural Activity on the Electroencephalogram in Preterm Infants
Anna Shiraki1,2, Hiroyuki Kidokoro3, Hama Watanabe4
1Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Insights
Delta brushes, early brain activity in preterm infants, show widespread hemodynamic responses. These responses, particularly in temporal areas, increase with infant age, suggesting the insula
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Neonatal Physiology
Background:
- Delta brushes are spontaneous neural activities in preterm electroencephalograms (EEGs), linked to subplate neuron function.
- Understanding the hemodynamic correlates of delta brushes is crucial for assessing early brain development.
Purpose of the Study:
- To investigate hemodynamic responses associated with delta brushes in preterm infants using simultaneous EEG-NIRS.
- To analyze the spatial distribution and temporal patterns of these hemodynamic responses in relation to infant age.
Main Methods:
- Simultaneous electroencephalography (EEG) and functional near-infrared spectroscopy (NIRS) were used in five preterm infants.
- An automated algorithm detected delta brushes; NIRS measured oxy- and deoxy-hemoglobin changes.
- Hemodynamic responses were classified into five patterns and analyzed based on location and infant postmenstrual age.
Main Results:
- Predominant positive hemodynamic responses (oxy-hemoglobin increases) were observed, extending beyond local areas.
- Notable responses were detected in bilateral temporal regions.
- The proportion of anti-phase positive responses increased significantly from 12% at 33-34 weeks to 54% at 36 weeks postmenstrual age.
Conclusions:
- Localized neuronal activity (delta brushes) elicits widespread hemodynamic responses in the developing brain.
- The increasing anti-phase responses with age suggest maturational changes in neural network communication.
- Findings support the hypothesis of the insula as a highly interconnected hub in the developing brain.
Abstract:
Delta brushes are spontaneous neural activities observed in preterm electroencephalograms (EEGs) and are thought to reflect the activities of subplate neurons in the developing brain. We investigated the haemodynamic responses associated with delta brushes in five preterm infants at two time points (at 33 or 34, and 36 weeks of postmenstrual age), using simultaneous EEG-functional near-infrared spectroscopy (NIRS). An automated detection algorithm was developed to identify the brush components of delta brushes in the bipolar EEG envelope; we placed eight EEG electrodes. An eight-channel NIRS device was placed around the head of each infant to measure changes in oxy- and deoxy-haemoglobin (Hb) concentrations. Haemodynamic grand averages were calculated for local brushes in each NIRS channel. We classified the responses into five patterns based on changes in oxy- and deoxy-Hb signals (positive in-phase/anti-phase, negative in-phase/anti-phase, and unclassified) and evaluated the relationship between the locations of NIRS measurements and those of brushes, as well as the haemodynamic response patterns and infant age at the time of recording. In all the 10 recordings, we found that positive responses (oxy-Hb increases) predominated, not only in the corresponding areas but also in remote areas. Particularly, notable responses were observed in the bilateral temporal areas. Among the positive responses, the proportion exhibiting an anti-phase pattern was 12% at 33 to 34 weeks of postmenstrual age and 54% at 36 weeks of postmenstrual age. Our unexpected finding of remarkable temporal responses to localised neuronal activity supports the hypothesis that the insula is the most strongly interconnected hub in the developing brain.
