Risk factors of postictal generalized EEG suppression in generalized convulsive seizures

Alexandre, Veriano; Mercedes, Branidia; Valton, Luc; Maillard, Louis; Bartolomei, Fabricē; Szurhaj, William; Hirsch, Édouard; Marchal, Cécile; Chassoux, Francine; Petit, Jérôme; Crespel, Arielle; Nica, Anca; Navarro, Vincent; Kahane, Philippe; Toffol, Bertrand de; Thomas, Pierre; Rosenberg, Sarah; Denuelle, Marie; Jonas, Jacques; Ryvlin, Philippe; Rheims, Sylvain

doi:10.1212/wnl.0000000000001949

Cited by 110 publications

(128 citation statements)

References 18 publications

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“…Seizures were categorized into subclasses as described in 13 : bilateral and symmetric tonic arm extension (Type 1), clonic jerking without tonic extension or flexion (Type 2), and asymmetric tonic extension or flexion (Type 3). Postictal immobility was defined as the patient becoming motionless following cessation of clonic activity 14 and further categorized as flaccid, in which the patient appeared limp with normal or reduced muscle tone, or rigid, characterized by fixed limb posturing, e.g.…”

Section: Methodsmentioning

confidence: 99%

Postictal clinical and electroencephalographic activity following intracranially recorded bilateral tonic–clonic seizures

et al. 2018

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Summary Objective: The dynamics of the postictal period, which may demonstrate such dramatic clinical phenomena as focal neurological deficits, prolonged coma and immobility, and even sudden death, are poorly understood. We sought to classify and characterize postictal phases of bilateral tonic-clonic seizures based on EEG criteria and associated clinical features. Methods: We performed a detailed electroclinical evaluation of the postictal period in a series of 31 bilateral tonic-clonic seizures in 16 patients undergoing epilepsy surgery evaluations for focal pharmacoresistant epilepsy with intracranial electrodes and time-locked video. Results: The postictal EEG demonstrated three clearly differentiated phases: attenuation, a burst-attenuation pattern, and a return to continuous background, with abrupt, synchronized transitions between phases. Postictal attenuation was common, occurring in 84% of seizures in 94% of patients in this study. There was increased power in gamma frequencies (> 25 Hz) during postictal attenuation periods relative to preictal baseline in 88% of seizures demonstrating the attenuation pattern (N=25 seizures, p<0.002). Such increases were seen in more than 90% of channels in 13 seizures (52%), and fewer than 10% of channels in three seizures (12%). Postictal immobility was seen in 87% of seizures, with either a flaccid (58%) or rigid/dystonic (29%) appearance. Clinical motor manifestations, including focal dystonic posturing, automatisms, head and eye deviation, and myoclonic jerking, continued or emerged within the first minute following seizure termination in 48% of seizures, regardless of EEG appearance. Significance: Intracranial postictal attenuation, which may be diffuse or focal, is so common that it should be regarded as an ubiquitous feature of bilateral tonic-clonic seizures, rather than an unusual event. The prominence of high frequency activity coupled with emerging clinical features, including rigid immobility and semiologies such as automatisms, during the postictal period support the presence of ongoing seizure-related neuronal activity in unrecorded brain regions.

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Section: Methodsmentioning

confidence: 99%

Postictal clinical and electroencephalographic activity following intracranially recorded bilateral tonic–clonic seizures

et al. 2018

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“…Seizures induced during either REM or NREM sleep were longer in duration, more severe, and associated with increased respiratory suppression when compared with those induced during wakefulness. 15,21 Oxygen saturation data were not available in either of these studies. 7 The relevance to human epilepsy of the high fatality rates in REM in this animal model is unclear.…”

Section: Epilepsia Ilaementioning

confidence: 99%

“…12 Postictal immobility may be relevant in the pathophysiology of SUDEP. 15 Possible influences of sleep on postictal respiratory dysfunction, seizure characteristics, PGES, and their interactions remain poorly characterized. 13,14 There was no direct analysis of peri-ictal oxygen desaturation and postictal immobility on PGES in a recent study demonstrating that PGES occurred more frequently following GTCS in sleep than wakefulness.…”

mentioning

confidence: 99%

Postictal generalized EEG suppression and respiratory dysfunction following generalized tonic–clonic seizures in sleep and wakefulness

2017

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PGES occurs more commonly after GTCS in sleep than in wakefulness but, in the epilepsy-monitoring unit (EMU), a patient's state at seizure onset does not affect the degree of respiratory dysfunction or duration of postictal immobility. In sleep, outside the hospital setting, GTCS are likely to go unnoticed. Postictal immobility in prone patients prevents head repositioning and unimpeded air exchange. A positive feedback cycle ensues with increasing respiratory distress, potentiating postictal immobility and PGES and eventually leading to asystole. Our findings suggest that the high incidence of nocturnal SUDEP may be related to the unsupervised environment during sleep rather than the severity of sleep-related respiratory dysfunction or PGES duration in the immediate postictal period.

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“…The place of pacemaker or automatic cardioverter-defibrillator implantation to reduce the risk of SUDEP is unclear [24]. Early administration of oxygen during seizures has been found to prevent PGES [32]. Similarly, early nursing interventions including oxygen administration during seizures appear to shorten the duration of PGES [30].…”

Section: Preventionmentioning

confidence: 99%

Sudden unexpected death in epilepsy: a silent killer

Seneviratne

2016

Ceylon Med. J.

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Risk factors of postictal generalized EEG suppression in generalized convulsive seizures

Abstract: The risk of PGES dramatically varied as a function of GCS semiologic characteristics. Whatever the type of GCS, occurrence of PGES was prevented by early administration of oxygen.

Cited by 110 publications

References 18 publications

Postictal clinical and electroencephalographic activity following intracranially recorded bilateral tonic–clonic seizures

Postictal clinical and electroencephalographic activity following intracranially recorded bilateral tonic–clonic seizures

Postictal generalized EEG suppression and respiratory dysfunction following generalized tonic–clonic seizures in sleep and wakefulness

Sudden unexpected death in epilepsy: a silent killer

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