When should a sleep-deprived EEG be performed following a presumed first seizure in adults?

Abstract

EDs in the SD-EEG following a first diagnosed seizure occur more commonly when the test is performed within 3 days following a first seizure or when previous seizures are recognized.

The adolescent or adult with generalized tonic-clonic seizures

“…The presence of epileptiform discharges increases the recurrence risk of seizures by 1.7-times.-[32] However, only a third of routine interictal EEGs (20–30-min recording with photic stimulation and 3 min hyperventilation) pick up significant abnormalities. [33] A repeat study probably adds another 20% but, if negative, further routine EEG would add at best about 10% by the 4th recording.…”

“…Sleep deprivation is more physiological and shows discharges in about 50% of the patients with initial normal routine EEG. [3637] This is because of the added effect of sleep deprivation in enhancing cortical excitability. [38] The yield is highest in younger individuals and in the IGE.…”

Controversial Issues on EEG after Sleep Deprivation for the Diagnosis of Epilepsy

“…A residual postictal activation seems to be likely only when performing SD-EEG within 2-3 days after seizure [6, 23], but in the routine clinical practice this rarely occurs, and thus it is not as important as expected [9]. …”

“…Only in a few studies SD-EEGs were performed in de novo patients which had never been treated with AEDs [6, 8, 9, 14, 20, 23], while in most of the remaining ones, also patients taking AEDs were included, and therapy was left unchanged or at least AEDs tapering was performed thus probably significantly affecting occurrence of IIA and, thus, sensitivity and specificity of SD-EEG [47–49]. Furthermore, the number and type of AEDs were not described in detail in most papers (see, e.g., [10, 11, 13, 15, 16, 22, 24, 25, 27, 31, 32, 34, 40, 42, 44]), with some exceptions [17, 41, 46].…”

EEG after sleep deprivation is a sensitive tool in the first diagnosis of idiopathic generalized but not focal epilepsy

“…As the association between sleep itself and epileptiform changes in EEG is well established (Kotagal and Yardi, 2008), some authors came to the conclusion that the higher probability of recording sleep in SD-EEGs invariably leads to a higher likelihood of recording IEAs (Peraita-Adrados et al, 2001;Degen et al, 1987). Others assume that there is an increased frequency of IEAs after sleep deprivation in general -even if no sleep is recorded in SD-EEG (Roupakiotis et al, 2000;Gandelman-Marton and Theitler, 2011). In general, SD-EEG is an inexpensive diagnostic method (Leach et al, 2006) when compared to long term EEG telemetry.…”