Full-Length Original Research
Tonic phase of a generalized convulsive seizure is an independent predictor of postictal generalized EEG suppression
Version of Record online: 29 JAN 2013
Wiley Periodicals, Inc. © 2013 International League Against Epilepsy
Volume 54, Issue 5, pages 858–865, May 2013
How to Cite
Tao, J. X., Yung, I., Lee, A., Rose, S., Jacobsen, J. and Ebersole, J. S. (2013), Tonic phase of a generalized convulsive seizure is an independent predictor of postictal generalized EEG suppression. Epilepsia, 54: 858–865. doi: 10.1111/epi.12094
- Issue online: 26 APR 2013
- Version of Record online: 29 JAN 2013
- Manuscript Accepted: 11 DEC 2012
- Sudden unexpected death in epilepsy;
- Prone position;
- Generalized convulsive seizures;
- Postictal generalized EEG suppression
To determine the incidence, duration, risk factors for, and clinical correlates of postictal generalized electroencephalography (EEG) suppression (PGES), and to further delineate the significance of PGES in the pathogenesis of sudden unexpected death in epilepsy (SUDEP).
We retrospectively reviewed the video-EEG studies of 109 consecutive patients with 151 generalized convulsive seizures (GCS) during video-EEG monitoring. We determined the incidence, duration, and clinical correlates of PGES. We also investigated whether factors such as age, sex, seizure type, total seizure duration, and duration of tonic and clonic phases influenced PGES.
PGES was observed in 64 (58.7%) of 109 patients and in 98 (64.9%) of 151 GCS. Average duration of PGES was 42.4 ± 19.1 s. Statistical analysis showed that patients with PGES had no difference in age, gender, total seizure duration, total convulsive duration, clonic phase, seizure type, and seizure termination, as compared to those without PGES. However, tonic phase was significantly prolonged in patients with PGES than in those without PGES (p = 0.00086). A 1 s increase in tonic phase duration was associated with a 0.06 increase in log odds of PGES (odds ratio = 1.1, p = 0.00055). Clinically, 95.3% patients were unresponsive or immobile during PGES, whereas only 26.7% patients without PGES were unresponsive or immobile immediately after seizure termination.
PGES is a common EEG pattern of GCS. Tonic phase of GCS is an independent predictor of PGES, which is well correlated with postictal unresponsiveness or immobile, and may play a significant role in the mechanism of SUDEP.