When should we obtain a routine EEG while managing people with epilepsy?

Abstract

More than eight decades after its discovery, routine electroencephalogram (EEG) remains a safe, noninvasive, inexpensive, bedside test of neurological function. Knowing when a routine EEG should be obtained while managing people with epilepsy is a critical aspect of optimal care. Despite advances in neuroimaging techniques that aid diagnosis of structural lesions in the central nervous system, EEG continues to provide critical diagnostic evidence with implications on treatment. A routine EEG performed after a first unprovoked seizure can support a clinical diagnosis of epilepsy and differentiate those without epilepsy, classify an epilepsy syndrome to impart prognosis, and characterize seizures for antiseizure management. Despite a current viral pandemic, EEG services continue, and the value of routine EEG is unchanged.

Keywords: ASM; EEG; Electrodes; Epilepsy; ILAE; Montage; Routine; Stat; Taper; Video.

Fig. 1

When should we perform and repeat a routine electroencephalogram?. ASM = antiseizure medication; CNS = central nervous system; EEG = electroencephalogram; IED = interictal epileptiform discharge; PNES = psychogenic nonepileptic seizures. Copyright William O. Tatum.

Fig. 2

Electroencephalogram was performed in a 12-year-old female for academic decline. Note the 4 second burst of 4-Hz generalized spike-and-waves. During this time, no clinical signs were observed, though treatment was initiated for juvenile absence epilepsy. Copyright William O. Tatum.

Fig. 3

Routine electroencephalogram was performed in a college student for episodes witnessed by others manifesting as behavior unbefitting her personality. During this time, she would spit but then deny that it occurred. Copyright William O. Tatum.