Table 2.

When Should We Repeat a Routine EEG?

Indications		Conclusions
Diagnosis & Classification	Normal EEG	Serial EEGs increase the likelihood of recording an IED
	IEDs on prior EEG	May aid in the classification of IEDs versus seizures to be used for ASM management
	People with epilepsy syndrome (e.g., GGE, absence, or frequent seizures)	Clarification of the diagnosis and classification of epilepsy syndromes
	Behavioral disorders and those with impaired communication	May be used to differentiate seizures from cognitive impairment when IEDs are captured and/or psychogenic nonepileptic seizures from epileptic seizures if events are captured during provocation
Management	Considering a trial of ASM taper in patients who are prolonged seizure-free	IEDs suggests a greater risk for seizure recurrence
	Monitoring ASM response and effectiveness	The IED/seizure burden will suggest adjustment to the ASM regimen in effort to obtain better seizure control
	Hospitalized patients with change in mental status or spells	May suggest unrecognized seizures or subclinical seizures and warrant ASMs
	Change in seizure semiology	Facilitates identifying whether a change in prevalence, frequency, or duration of IEDs may influence ASM management
	After epilepsy surgery	IEDs suggest greater likelihood of seizure recurrence and further need for ASMs

Abbreviations: ASM = antiseizure medication; EEG = electroencephalogram; GGE = generalized genetic epilepsy; IED = interictal epileptiform discharges.