An electroencephalogram (EEG) reflects the summation of electrical activity arising from excitatory and inhibitory post-synaptic potentials of pyramidal neurons. EEG electrodes are traditionally placed on the scalp according to the International 10–20 system of electrode placement to reproducibly record cortical electrical activity. There are a number of different montages that may be used to best analyze an EEG, and allow for interpretation of the spatial distribution and localization of the EEG activity across the cortex. Neonates may require a reduced montage. Raw EEG data remain the gold standard of neurophysiological monitoring; however, reduced-montage and quantitative EEG techniques have allowed providers, particularly in the neonatal and pediatric intensive care units, to have supplementary data to interpret, in real time, at the patient’s bedside or via remote access. This chapter reviews the technical aspects of neurophysiological monitoring, including the practice and underlying principles of initiating, recording, displaying, and interpreting EEG. Quantitative trends, including CDSA and aEEG, are included.

The abnormal electroencephalogram (EEG) that attracts the most attention is that showing a seizure. In the intensive care unit (ICU), EEG monitoring is most commonly used for seizure detection; however, EEG can provide additional useful information. The background pattern can be used to evaluate encephalopathy and to assess cerebral function in patients who are sedated and paralyzed. EEG background can inform prognostication after hypoxic ischemic injury. EEG can serve as an ancillary investigation in the determination of brain death. Finally, EEG changes guide titration of treatments, such as continuous infusions administered for status epilepticus or increased intracranial pressure. Quantitative EEG (QEEG) is increasingly used by bedside clinicians for rapid assessment of cerebral function and facilitation of rapid interventions for critically ill patients.

Recognizing a normal recording is the first, but not the simplest, step of EEG analysis. Normal EEG patterns evolve in a predictable, age-dependent manner. In reviewing EEG and qEEG trends, clinicians must identify normal patterns and common artifacts that may mimic seizures or other abnormalities. This chapter provides a guide for practitioners reviewing neonatal and pediatric EEG to help recognize normal tracings. Instruction is given for how to systematically approach EEG and QEEG analysis. Age-specific aspects are reviewed with example findings. Common artifacts are shown.

Neonatal onset epilepsies are infrequent compared with neonatal seizures caused by acute symptomatic etiologies. Etiologies of neonatal epilepsies are classified into structural, genetic, and metabolic causes. EEG and amplitude-integrated EEG (aEEG) are essential for the diagnosis and monitoring of these conditions. EEG/aEEG findings often differ substantially among infants; unusual findings, such as downward seizure patterns on aEEG, can be found. Focal-onset seizures are very frequent, and epileptic spasms are infrequently observed. Myoclonic seizures with ictal EEG correlates and generalized tonic seizures are exceptional. Although burst suppression is known as the EEG hallmark of early infantile epileptic encephalopathy (EIEE) and early myoclonic encephalopathy (EME), the definition of “burst suppression” differs among researchers. Additional information is necessary to better understand the EEG/aEEG findings related to neonatal epilepsies and to clarify their utility in the diagnosis of neonatal epilepsies and monitoring the efficacy of treatment.

Neonatal encephalopathy (NE) is the term used to describe persistent neurological dysfunction evident in the first few days after birth. The commonest cause of NE is hypoxia-ischemia, but a similar clinical presentation may occur in other conditions. EEG is essential to grade the severity of neonatal encephalopathy, monitor response to anti-seizure therapy, and to predict outcome early in the neonatal period in infants with NE. Because therapeutic hypothermia is often used in neonatal encephalopathy, the impact of hypothermia on EEG findings is important to consider. EEG evolution and outcome prediction is altered by therapeutic hypothermia. Seizures are common in NE, and seizure burden is also altered by hypothermia. EEG and aEEG can assess severity of NE and predict outcome more accurately than clinical assessment alone. This chapter discusses the various uses of EEG and aEEG in neonatal encephalopathy.