Highlights
- •PGES is common after GCS and the incidence of PGES in GCS varies from 23% to 86%.
- •Longer tonic phase duration in GCS increases the likelihood of having PGES in GCS.
- •Sleep state at GCS onset and age of epilepsy onset show significant association with PGES occurrence in GCS.
- •The presence of postictal immobility and oxygen desaturation nadir are also related to PGES occurrence in GCS.
Abstract
Background and purpose
Postictal generalized EEG suppression (PGES) has been suggested as a pathophysiological
hallmark for sudden unexpected death in epilepsy (SUDEP). We aimed to characterize
the clinical determinants for PGES occurrence after generalized convulsive seizures
(GCS).
Methods
We systematically searched Pubmed, Embase and Medline databases up to 30 August 2021.
Eligibility screening, data extraction, and quality assessment of the retrieved articles
were conducted by two independent reviewers. Studies reporting potential risk factors
of PGES occurrence in GCS were included for subsequent meta-analysis and PGES was
defined as a generalized EEG attenuation of any duration >1s below 10μV, immediately
or within 30s after an ictal EEG pattern has terminated. A fixed-effects model was
applied when the heterogeneity is low (I2 values < 50%). Otherwise, a random-effects model was used (I2 values ≥ 50%). We assessed the odds ratio (OR) as outcome measure for dichotomous
variables and the STD Mean Difference (SMD) for continuous variables. The Begg test
and the Egger test was applied in the assessment of publication bias.
Results
A total of 15 relevant studies were identified, enrolling 2057 GCSs. The incidence
of PGES in GCS from 15 studies varied from 23% to 86%. The longer tonic phase duration
(SMD, 0.26; 95%CI, 0.13 to 0.39; p < 0.001), sleep state at GCS onset (OR,1.63; 95%CI, 1.24 to 2.16; p = 0.001), older age of epilepsy onset (SMD, 0.48; 95%CI, 0.21 to 0.75; p = 0.001), the presence of postictal immobility (OR, 78.05; 95%CI, 32.31 to 188.53;
p < 0.001) and oxygen desaturation nadir (SMD, -0.54; 95%CI, -0.76 to -0.33; p < 0.001) showed significant association with the likelihood of having PGES in GCS,
but not total seizure duration (SMD, -0.06; 95%CI, -0.20 to 0.08; p = 0.385), tonic-clonic duration (SMD, -0.12; 95%CI, -0.26 to 0.01; p = 0.071), clonic phase duration (SMD, -0.09; 95%CI, -0.27 to 0.08; p = 0.293), epilepsy duration of patients (SMD, -0.09; 95%CI, -0.27 to 0.08; p = 0.293) or lack of early O2 administration (OR, 1.59; 95%CI, 0.80 to 3.17; p = 0.184).
Conclusion
The current study informed that PGES is common after GCS. Early identification should
be considered among individuals with GCS at high risk of PGES through clinical screening.
Further studies with larger sample size are required for individualized evaluation
of the risk of PGES in GCS and more effort is needed to further evaluate the risk
of SUDEP.
Keywords
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Article info
Publication history
Published online: March 27, 2022
Accepted:
March 26,
2022
Received in revised form:
March 23,
2022
Received:
October 7,
2021
Identification
Copyright
© 2022 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.
