Effect of sleep deprivation on spike-wave discharges in idiopathic generalised epilepsy: a 4×24 h continuous long term EEG monitoring study

Halász, Péter; Filakovszky, Janos; Vargha, András; Bagdy, György

doi:10.1016/s0920-1211(02)00123-7

Cited by 61 publications

(53 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Only a few reports also examined an additional second baseline EEG or a second SD EEG, to allow for the exclusion of a sampling effect (see Table 1 and Section 6.1). Few other studies also performed an additional EEG during spontaneous sleep, either within a continuous EEG monitoring protocol (Halász et al, 2002a;Malow et al, 2002) or during an afternoon nap (Molaie and Cruz, 1988;Drake et al, 1990). In some reports, the authors compared a routine EEG and/or an SD EEG with a sleep EEG induced by drugs (Fig.…”

Section: Methodological Differencesmentioning

confidence: 99%

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

Giorgi

Guida

Caciagli

et al. 2014

Neuroscience & Biobehavioral Reviews

View full text Add to dashboard Cite

Section: Methodological Differencesmentioning

confidence: 99%

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

Giorgi

Guida

Caciagli

et al. 2014

Neuroscience & Biobehavioral Reviews

View full text Add to dashboard Cite

“…6 Sleep EEG may be achieved by recording natural or drug induced sleep, using hypnotics which have minimal effect on the EEG, such as chloral or melatonin (the latter is not currently licensed in the UK). Whether sleep deprivation has additional value is difficult to establish from reported studies, although there is some evidence that it activates IED in idiopathic generalised epilepsies, 7 and in practice, most patients achieve sleep reduction rather than true sleep deprivation. Standard activation procedures of hyperventilation (up to three minutes) and photic stimulation (using published protocols) should be included in routine EEG recordings, 8 but it is current good practice to warn patients of the small risk of seizure induction and obtain consent to these procedures.…”

Section: Specificity and Sensitivity Of Routine Eeg Cmentioning

confidence: 99%

EEG in the diagnosis, classification, and management of patients with epilepsy

Smith¹

2005

Journal of Neurology, Neurosurgery & Psychiatry

564

433

View full text Add to dashboard Cite

T he human electroencephalogram (EEG) was discovered by the German psychiatrist, Hans Berger, in 1929. Its potential applications in epilepsy rapidly became clear, when Gibbs and colleagues in Boston demonstrated 3 per second spike wave discharge in what was then termed petit mal epilepsy. EEG continues to play a central role in diagnosis and management of patients with seizure disorders-in conjunction with the now remarkable variety of other diagnostic techniques developed over the last 30 or so years-because it is a convenient and relatively inexpensive way to demonstrate the physiological manifestations of abnormal cortical excitability that underlie epilepsy.However, the EEG has a number of limitations. Electrical activity recorded by electrodes placed on the scalp or surface of the brain mostly reflects summation of excitatory and inhibitory postsynaptic potentials in apical dendrites of pyramidal neurons in the more superficial layers of the cortex. Quite large areas of cortex-in the order of a few square centimetres-have to be activated synchronously to generate enough potential for changes to be registered at electrodes placed on the scalp. Propagation of electrical activity along physiological pathways or through volume conduction in extracellular spaces may give a misleading impression as to location of the source of the electrical activity. Cortical generators of the many normal and abnormal cortical activities recorded in the EEG are still largely unknown. Spatial sampling in routine scalp EEG is incomplete, as significant amounts of cortex, particularly in basal and mesial areas of the hemispheres, are not covered by standard electrode placement. Temporal sampling is also limited, and the relatively short duration of routine interictal EEG recording is one reason why patients with epilepsy may not show interictal epileptiform discharge (IED) in the first EEG study.If inappropriate questions are asked of the EEG, diagnostic errors will occur, and there will be poor yield of information that could be useful in the management of patients with seizure disorders. It is crucial to recognise that a normal EEG does not exclude epilepsy, as around 10% of patients with epilepsy never show epileptiform discharges. Secondly, an abnormal EEG demonstrating IED does not in itself indicate that an individual has a seizure disorder, as IED are seen in a small percentage of normal subjects who never develop epilepsy, and IED may also be found in patients with neurological disorders which are not complicated by epilepsy. Table 1 lists the areas in epilepsy diagnosis and management for which interictal and ictal EEG are useful, strongly so in some, but in a more limited way in others. SPECIFICITY AND SENSITIVITY OF ROUTINE EEG cEpileptiform activity is specific, but not sensitive, for diagnosis of epilepsy as the cause of a transient loss of consciousness or other paroxysmal event that is clinically likely to be epilepsy. EEG has relatively low sensitivity in epilepsy, ranging between 25-56%. Specificity is better, but...

show abstract

“…For example, Laufs et al demonstrated that in the absence of IEDs that are normally used to model fMRI data, automated EEG frequency analyses in EEG-fMRI may prove to be useful for planning the placement of intracranial electrodes to map epileptogenic areas (Laufs et al, 2006d). In addition, provocative measures such as sleep deprivation or medication that influences the number of IEDs (Halasz et al, 2002;Mäkiranta et al, 2005) may be relevant to increase the diagnostic yield of EEG-fMRI (Zijlmans et al, 2007). Alternatively, new techniques such as using epilepsy-specific EEG voltage maps (based on long-term EEG, correlated with hemodynamic changes) to help localize the epileptic focus increase the yield of EEGfMRI, allowing better targeting for surgical resection or implantation of intracranial electrodes (Grouiller et al, 2011).…”

Section: Discussionmentioning

confidence: 99%