Association between semiologic, autonomic, and electrographic seizure characteristics in children with generalized tonic-clonic seizures

Introduction: Generalized tonic-clonic seizures (GTCS) are associated with elevated electrodermal activ-ity (EDA) and postictal generalized electroencephalographic suppression (PGES), markers that may indi-cate sudden unexpected death in epilepsy (SUDEP) risk. This study investigated the association of GTCS semiology, EDA, and PGES in children with epilepsy. Methods: Patients admitted to the Boston Children's Hospital long-term video-EEG monitoring unit wore a sensor that records EDA. We selected patients with at least one GTCS and reviewed video-EEGs for semiology, tonic and clonic phase duration, total clinical seizure duration, electrographic onset, offset, and PGES. We grouped patients into three semiology classes: GTCS 1: bilateral symmetric tonic arm extension, GTCS 2: no specific tonic arm extension or flexion, GTCS 3: unilateral or asymmetrical arm extension, tonic arm flexion or posturing that does not fit into GTCS 1 or 2. We analyzed the correlation between semiology, EDA, and PGES, and measured the area under the curve (AUC) of the ictal EDA (sei-zure onset to one hour after), subtracting baseline EDA (one-hour seizure-free before seizure onset). Using generalized estimating equation (GEE) and linear regression, we analyzed all seizures and single episodes per patient. Results: We included 30 patients (median age 13.8 +/- 3.6 years, 46.7% females) and 53 seizures. With GEE, GTCS 1 was associated with longer PGES duration compared to GTCS 2 (Estimate (p) =-26.32 s, 95% Confidence Interval (CI):-36.46 to-16.18, p < 0.001), and the presence of PGES was associated with greater EDA change (p = 429604 lS, 95% CI: 3550.96 to 855657.04, p = 0.048). With single-episode anal-ysis, GTCS 1 had greater EDA change than GTCS 2 ((p =-601339 lS, 95% CI:-1167016.56 to-35661.44, p = 0.047). EDA increased with PGES presence (p = 637500 lS, 95% CI: 183571.84 to 1091428.16, p = 0.01) and duration (p = 16794 lS, 95% CI: 5729.8 to 27858.2, p = 0.006). Patients with GTCS 1 had longer PGES duration compared to GTCS 2 (p =-30.53 s, 95% CI:-44.6 to-16.46, p < 0.001) and GTCS 3 (p =-22.07 s, 95% CI:-38.95 to-5.19, p = 0.016). Conclusion: In children with epilepsy, PGES correlates with greater ictal EDA. GTCS 1 correlated with longer PGES duration and may indirectly correlate with greater ictal EDA. Our study suggests potential applications in monitoring and preventing SUDEP in these patients. (C) 2021 The Authors. Published by Elsevier Inc.

Automated summary

This study found that in children with epilepsy, the semiology of generalized tonic-clonic seizures (GTCS) is associated with electrodermal activity (EDA) and postictal generalized electroencephalographic suppression (PGES). GTCS semiology class 1, characterized by bilateral symmetric tonic arm extension, correlated with longer PGES duration. The results suggest potential applications in monitoring and preventing sudden unexpected death in epilepsy (SUDEP) in these patients.