Postictal generalized electroencephalographic suppression is associated with generalized seizures
Surges R, Strzelczyk A, Scott CA, et al. (2011) Postictal generalized electroencephalographic suppression is associated with generalized seizures. Epilepsy Behav. 2011 Jul;21(3):271-4.
Abstract: Postictal generalized electroencephalographic suppression (PGES) may be involved in sudden unexpected death in epilepsy (SUDEP). We examined whether the occurrence of PGES depends on seizure type and whether PGES occurs more frequently in people with epilepsy who died suddenly. EEG recordings of people with pharmacoresistant focal epilepsies who died from SUDEP after presurgical video/EEG telemetry were compared with recordings of living controls. To test if PGES depends on seizure type, EEG recordings of people with temporal lobe epilepsy who had complex partial seizures (CPS) and secondarily generalized tonic-clonic seizures (GTCS) were reviewed. A total of 122 seizures in 57 individuals have been included. PGES was observed in 15% of all seizures in 26% of all individuals. Secondarily GTCS were significantly associated with PGES. Neither presence nor duration of PGES differed between the SUDEP and control groups. In conclusion, PGES is facilitated by secondarily GTCS, but does not seem to be an independent risk factor for SUDEP.
Keywords:
Context
- A major proposed mechanism of SUDEP is the concept of electro-cerebral shutdown, seen on scalp EEG as prolonged post-ictal generalized EEG suppression (PGES). Lhatoo et al reports that prolonged PGES (>50 seconds) appears to identify refractory epilepsy patients who are at risk of SUDEP and risk of SUDEP may be increased in direct proportion to duration of PGES. This study by Surges failed to reproduce such findings.There seems to be intra-individual variability in both the occurrence and duration of PGES after seizures. For instance, this study reported that PGES was observed after one seizure out of six in one individual and after all four seizures in another with the duration varying from 63 to 128 seconds. In addition, the level of inconsistency increased with the number of seizures recorded from any one individual see Lamberts et al 2013
The role of PGES in the pathophysiology of SUDEP has yet been established.