The usefulness of sleep and sleep deprivation as activating methods in electroencephalographic recording Contribution to a long-standing discussion

Abstract

Sedated sleep and sleep deprivation are commonly used methods to increase the diagnostic yield of the electroencephalogram (EEG), especially in the evaluation of people with epilepsy, but the rate of activation achieved by them is controversial, as is the issue of whether it is sleep itself, or sleep deprivation which is responsible for their alleged efficacy. We retrospectively studied the EEGs of epileptic patients, examined in our laboratory, who, after having undergone an inconclusive initial routine recording, had then been examined with a second recording. This was after either: (1) sleep deprivation with evidence of drowsiness in the recordings, (2) sleep deprivation without drowsiness (indicative of the effect which sleep deprivation per se has in eliciting abnormal patterns), or (3) drug-induced sedation. The activation rates found were (1) 22.5%, (2) 24% (22.6% for sleep deprivation collectively, regardless of the presence or not of subsequent drowsiness) and (3) 27% respectively. Only the sleep deprivation rate was statistically different from the 9.6% increased rate of abnormal patterns elicited by the simple repeating of a second routine recording, while the rate of drug-induced sleep was not. Although, sleep deprivation appeared to be more effective as an activating method of EEG compared with sedated sleep, no conclusions could be drawn about which stage of sleep, wakefulness or drowsiness, is primarily responsible for the method's efficacy.

What is the role for EEG after sleep deprivation in the diagnosis of epilepsy? Issues, controversies, and future directions

“…In age-matched healthy controls, SD EEG achieved a specificity of 92-100% (Aguglia et al, 1994;Geller et al, 1969;Tartara et al, 1980;Thomaides et al, 1992), whereas 82-100% specificity was obtained for patients with neurological disorders other than epilepsy (Deisenhammer et al, 1984;Mattson et al, 1965;Roupakiotis et al, 2000;Tartara et al, 1980). These data are particularly meaningful, since they confirm the critical role of SD EEG as a diagnostic test for patients with epilepsy.…”

“…1). A more complex protocol was used in selected studies: DeRoos et al (2009) randomized different subjects either to a routine wake EEG or to an SD EEG, while Roupakiotis et al (2000) recorded a routine EEG and subsequently randomized their subjects to a second routine EEG, an SD EEG, or a drug-induced sleep EEG. Gilbert et al (2004) did not acquire a baseline EEG for all their patients, but randomized them to a baseline EEG, an EEG following total SD, or an EEG after partial SD.…”

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

“…Previous studies described a higher sensitivity of SD-EEG in comparison to a S-EEG (Roupakiotis et al, 2000;Leach et al, 2006;Giorgi et al, 2013a,b). This effect was attributed to the higher probability of recording light sleep (Degen and Degen, 1991).…”

“…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.…”

“…As in all trigger maneuvers the question of specificity is to be addressed, because epileptiform changes are also found in healthy controls after sleep deprivation; -according to some studies, up to 12% of healthy subjects showed IEAs after sleep deprivation (Thomaides et al, 1992;Roupakiotis et al, 2000).…”