Primer on Neonatal Electroencephalograms for the Neonatologist

Objectives

After completing this article, readers should be able to:

1. List indications for obtaining an electroencephalogram (EEG) in a neonate.

2. Define electrographic seizures.

3. Describe normal patterns in the EEG reading that correlate with conceptional age.

4. List EEG background patterns associated with encephalopathies and their prognostic significance.

Introduction

The electroencephalogram (EEG) is a valuable noninvasive tool for assessing neonatal brain function. It has the unique property of providing functional information about the brain, rather than simply the anatomic information that is provided by neuroimaging studies. The major areas in which an EEG can provide unique information in the assessment of newborns are: 1) diagnosis and treatment of seizures, 2) evaluation of severity of cerebral dysfunction from primary neurologic disorders (eg, hypoxic-ischemic encephalopathy) or systemic diseases, 3) identification of specific neurologic entities (eg, periventricular leukomalacia, congenital brain malformations, viral encephalitis, and metabolic encephalopathies), and 4) determination of prognosis and long-term neurologic outcome. Serial EEGs provide information about the effectiveness of treatment and disturbances in brain maturation.

Indication for the EEG

An EEG should be considered in the neonate when questions arise regarding the cause of the child’s abnormal neurologic status. There are many situations in which the EEG provides much-needed information that is either unavailable or difficult to obtain. For example, it is difficult to obtain an adequate neurologic assessment of a neonate who is heavily sedated or paralyzed with neuromuscular blocking agents. Neuroimaging studies are difficult to obtain in infants who are unstable and mechanically ventilated. The EEG can be obtained at the bedside.

Another situation in which the EEG is particularly useful is when there is a question about seizures. Neonatal seizures often are subtle, which makes their clinical identification challenging. An EEG can discriminate easily between epileptic seizures and nonepileptic events in the neonate. In the case of the paralyzed or sedated infant, sudden and …