EEG Neonatal Visual Analysis

Excerpt

A conventional electroencephalogram (EEG) is a useful ancillary and diagnostic test that detects the electrical activity of the brain. Electrodes are placed in the scalp and connected to the EEG recording instrument, with a standard set consisting of 21 recording electrodes and one ground (reference) electrode. Odd numbers refer to left-sided and even numbers to right-sided electrodes. The letter designations refer to the different cortical areas (F-frontal, C-central, T-temporal, O-occipital, Z-midline).

The neonatal EEG is useful for determining brain development, identify cortical hyperexcitability, epileptiform activity, or seizures. The analysis can be quite challenging and may require additional skills and training, given that benign variants exist within the different stages of development and must be differentiated from abnormal discharges. For a neonatal EEG, equipment modifications include eight scalp electrodes (FP1, C3, T3, O1, FP2, C4, T4, O2) and lower recording speed. Visual analysis is the gold standard for clinical interpretation of the neonatal EEG.

Individual variability is an essential factor when extracting clinically relevant features by visual analysis of the EEG signals. Although automated software can identify EEG signals, human extraction, and analysis of the clinical information by visual analysis is an essential part of the overall recording. The visual analysis will provide a complete description of the most salient features of the EEG to give an interpretation, a conclusion, and a clinical correlation. This article describes the visual analysis technique in neonates.