Peri‐ictal heart rate variability parameters as surrogate markers of seizure severity

Abstract

This study aims at defining objective parameters reflecting the severity of peri‐ictal autonomic changes and their relation to post‐ictal generalized electroencephalography (EEG) suppression (PGES), with the view that such changes could be detected by wearable seizure detection systems and prove useful to assess the risk of sudden unexpected death in epilepsy (SUDEP). To this purpose, we assessed peri‐ictal changes in heart rate variability (HRV) and correlated them with seizure duration, intensity of electromyography‐based ictal muscle activity, and presence and duration of post‐ictal generalized EEG suppression (PGES). We evaluated 75 motor seizures from 40 patients, including 61 generalized tonic‐clonic seizures (GTCS) and 14 other major motor seizure types. For all major motor seizures, HRV measurements demonstrated a significantly decreased parasympathetic activity and increased sympathetic activity in the post‐ictal period. The post‐ictal increased sympathetic activity was significantly higher for GTCS as compared with non‐GTCS. The degree of peri‐ictal decreased parasympathetic activity and increased sympathetic activity was associated with longer PGES (>20 s), longer seizure duration, and greater intensity of ictal muscle activity. Mean post‐ictal heart rate (HR) was an independent predictor of PGES duration, seizure duration, and intensity of ictal muscle contraction. Our results indicate that peri‐ictal changes in HRV are potential biomarkers of major motor seizure severity.

Biomarkers of seizure severity derived from wearable devices

“…Heart rate variability (HRV) measures in patients who later died of SUDEP suggested a significant decrease 38–41 or increase 35,39 in the parasympathetic activity (root mean square of successive differences) during the interictal period. The postictal decrease in parasympathetic activity and increase in sympathetic activity were correlated with PGES 42–44 . Postictal mean heart rate (a combination of sympathetic increase and parasympathetic decrease) was an independent predictor of PGES, suggesting that this could be a useful parameter for monitoring severity in the postictal period 44 .…”

“…[42][43][44] Postictal mean heart rate (a combination of sympathetic increase and parasympathetic decrease) was an independent predictor of PGES, suggesting that this could be a useful parameter for monitoring severity in the postictal period. 44 Using automated R-peak detection algorithms, 45 these HRV parameters can be recorded with wearable electrocardiographic (ECG) devices originally designed for seizure detection. 46,47 In addition, ECG monitoring in patients at risk can provide valuable information on cardiac repolarization anomalies (prolonged or shortened QTc interval), which have been suggested to contribute to the development of SUDEP.…”

“…The postictal decrease in parasympathetic activity and increase in sympathetic activity were correlated with PGES 42–44 . Postictal mean heart rate (a combination of sympathetic increase and parasympathetic decrease) was an independent predictor of PGES, suggesting that this could be a useful parameter for monitoring severity in the postictal period 44 . Using automated R‐peak detection algorithms, 45 these HRV parameters can be recorded with wearable electrocardiographic (ECG) devices originally designed for seizure detection 46,47 .…”

Seizure detection and mobile health devices in epilepsy: Recent developments and future perspectives

“…This supplement tackles several of the above issues, including the physicians' and patients' assessment of current seizure detection and wearable devices, 1,2 with a specific focus on video-based automated detection of nocturnal motor seizures 3 and home video-EEG telemetry. 4 The supplement also addresses the issues of quantifying GTCS severity 5,6 and detecting the various forms of focal seizures, 7,8 with emphasis on heart rate variability. 5,7 The selected papers provide an overview of the stateof-the-art while delineating a roadmap for future research © 2020 International League Against Epilepsy…”

“…4 The supplement also addresses the issues of quantifying GTCS severity 5,6 and detecting the various forms of focal seizures, 7,8 with emphasis on heart rate variability. 5,7 The selected papers provide an overview of the stateof-the-art while delineating a roadmap for future research © 2020 International League Against Epilepsy…”