Postictal generalized EEG suppression after generalized convulsive seizures: A double-edged sword

Objective: The aim of this study is to investigate the key facilitating factors for postictal generalized EEG suppression (PGES) in a large cohort of patients with generalized convulsive seizures (GCSs). Methods: We retrospectively reviewed the data of consecutive patients who had GCSs in the epilepsy monitoring units of two epilepsy centers. Statistical analysis was performed to assess specific variables as potential risk factors for PGES. Results: Among the 208 enrolled patients with 366 seizures, PGES was observed in 109 (51.9%) patients and 168 (45.9%) GCSs. The mean duration of PGES was 33.2 +/- 12.0 s (34 s, 3-70 s). PGES or severe PGES (>20 s) was associated with more severe postictal coma and temporal lobe epilepsy. Moreover, PGES was independently associated with a longer tonic duration, shorter total seizure duration, and lower habitual seizure frequency. Conclusions: PGES is strongly correlated not only with longer tonic duration, but also with shorter total seizure duration and lower habitual seizure frequency. Significance: PGES may represent a switch-off inhibitory mechanism in seizure termination; moreover, it may indicate the efficacy of a long-lasting inhibitory network that suppresses GCS ictogenesis. (C) 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.