Neonatal EEG- an overview

Abstract

Electro-encephalogram (EEG) is the best non-invasive modality for brain monitoring. As brain continues to develop and mature in neonatal period, EEG of a normal newborn varies from time to time. Wave patterns may be normal at one developmental stage and abnormal at another stage. There are many types of EEG waves like alpha, beta, gamma & delta waves. Burst suppression occurs in very sick neonates following brain damage due to asphyxia & predicts poor prognosis. Isoelectric pattern occurs in severe asphyxia, circulatory collapse, massive intracerebral hemorrhage, severe inborn metabolic deficits, CNS bacterial or viral infections, drug-induced state, hypothermia, postictal recording and in malformations like hydranencephaly or massive hydrocephalus. Grading of severity of disease condition can be done based on EEG. They can be vital in arriving etiological diagnosis. EEG distinguishes between normal paroxysmal movements from epileptic seizures. Nearly 90% of abnormal movements mimiking seizures may be nonepileptic after EEG study. Early recordings, prolonged recordings at different activity states, serial short interval EEGs increase the prognostic value of EEGs. Long-time bedside monitoring of brain function can be done by amplitude-integrated EEG (aEEG). Some rare neonatal epilepsy syndromes have characteristic EEG features. Artifacts mimicking electrical seizures include environmental interference, electrode impedence abnormalities, motion artifacts and endogenous non-cerebral potentials which can be distinguished by Polygraphy. Drugs can alter background activity. EEG is a boon for noninvasive bedside continuous monitoring of the brain. Judicious application of this technique can help in prompt management of various pathologies like seizures , encephalopathies, epilepsy and asphyxia.