Severe autonomic nervous system imbalance in Lennox-Gastaut syndrome patients demonstrated by heart rate variability recordings

S Hödl; E Olbert; C Mahringer; E Carrette; A Meurs; S Gadeyne; I Dauwe; L Goossens; R Raedt; P Boon; K Vonck

doi:10.1016/j.eplepsyres.2021.106783

Severe autonomic nervous system imbalance in Lennox-Gastaut syndrome patients demonstrated by heart rate variability recordings

Epilepsy Res. 2021 Nov:177:106783. doi: 10.1016/j.eplepsyres.2021.106783. Epub 2021 Oct 5.

Authors

S Hödl¹, E Olbert², C Mahringer³, E Carrette⁴, A Meurs⁴, S Gadeyne⁴, I Dauwe⁴, L Goossens⁴, R Raedt⁴, P Boon⁴, K Vonck⁴

Affiliations

¹ Department of Neurology, 4Brain, Institute for Neuroscience, Reference Center for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium. Electronic address: stephanie.hoedl@uzgent.be.
² Department of Neurology, University Hospital Tulln, Karl Landsteiner University of Health Sciences, Austria.
³ Institute of Signal Processing, Kepler University Hospital, Med Campus III., Linz, Austria.
⁴ Department of Neurology, 4Brain, Institute for Neuroscience, Reference Center for Refractory Epilepsy, Ghent University Hospital, Ghent, Belgium.

PMID: 34626869
DOI: 10.1016/j.eplepsyres.2021.106783

Abstract

Objective: Patients diagnosed with Lennox Gastaut syndrome (LGS), an epileptic encephalopathy characterized by usually drug resistant generalized and focal seizures, are often considered as candidates for vagus nerve stimulation (VNS). Recent research shows that heart rate variability (HRV) differs in epilepsy patients and is related to VNS treatment response. This study investigated pre-ictal HRV in generalized onset seizures of patients with LGS in correlation with their VNS response.

Methods: In drug resistant epilepsy (DRE) patients diagnosed with LGS video-electroencephalography recording was performed during their pre-surgical evaluation. Six HRV parameters (time and-, frequency domain, non-linear parameters) were evaluated for every seizure in epochs of 10 min at baseline (60 to 50 min before seizure onset) and pre-ictally (10 min prior to seizure onset). The results were correlated to VNS response after one year of VNS therapy.

Results: Seven patients and 31 seizures were included, two patients were classified as VNS responders (≥ 50 % seizure reduction). No difference in pre-ictal HRV parameters between VNS responders and VNS non-responders could be found, but high frequency (HF) power, reflecting the parasympathetic tone increased significantly in the pre-ictal epoch in both VNS responders and VNS non-responders (p = 0.017, p = 0.004).

Significance: In this pilot data pre-ictal HRV did not differ in VNS responders compared to VNS non-responders, but showed a significant increase in HF power - a parasympathetic overdrive - in both VNS responders and VNS non-responders. This sudden autonomic imbalance might have an influence on the cardiovascular system in the ictal period. Generalized tonic-clonic seizures are regarded as the main risk factor for SUDEP and severe seizure-induced autonomic imbalance may play a role in the pathophysiological pathway.

Keywords: Autonomic imbalance; Central autonomic network; Generalized seizures; SUDEP.

MeSH terms

Autonomic Nervous System
Electroencephalography
Heart Rate / physiology
Humans
Lennox Gastaut Syndrome*
Treatment Outcome
Vagus Nerve Stimulation* / methods