William Szurhaj1, Anne-Cécile Troussière2, Régis Logier2, Philippe Derambure2, Louise Tyvaert2, Franck Semah2, Philippe Ryvlin2, Julien De Jonckheere2. 1. From the Epilepsy Unit (W.S., A.-C.T., P.D., L.T.), INSERM CIC-IT 1403 (R.L., J.D.J.), Department of Nuclear Medicine and Molecular Imaging (F.S.), Lille University Medical Center; INSERM U1171 (W.S., P.D., L.T., F.S.), University of Lille, France; and the Department of Clinical Neuroscience (P.R.), Lausanne, Switzerland. william.szurhaj@chru-lille.fr. 2. From the Epilepsy Unit (W.S., A.-C.T., P.D., L.T.), INSERM CIC-IT 1403 (R.L., J.D.J.), Department of Nuclear Medicine and Molecular Imaging (F.S.), Lille University Medical Center; INSERM U1171 (W.S., P.D., L.T., F.S.), University of Lille, France; and the Department of Clinical Neuroscience (P.R.), Lausanne, Switzerland.
Abstract
OBJECTIVE: To measure changes in parasympathetic tone before, during, and after temporal seizures, and to determine whether changes in high-frequency heart rate variability are correlated with postictal oxygen desaturation. METHODS: We recorded the electrocardiogram and peripheral oxygen saturation during 55 temporal lobe seizures and calculated a high-frequency variability index (HFVI) as a marker of parasympathetic tone for periods of 20 minutes (centered on seizure onset). We then compared HFVI values in seizures with and without postictal hypoxemia, and looked for correlations between HFVI changes and the risk of sudden unexpected death in epilepsy (SUDEP) (as assessed with the SUDEP-7 Inventory). RESULTS: Parasympathetic tone decreased rapidly at the onset of temporal lobe seizures, reached its minimum value at the end of the seizure, and then gradually returned to its preictal value. Changes in parasympathetic tone were more intense and longer-lasting in older patients with a longer duration of epilepsy. The HFVI was significantly lower during seizures with hypoxemia, and remained significantly lower 5 minutes after the end of the seizure. The change in the HFVI slope over the first 30 seconds of the seizure was predictive of postictal oxygen desaturation. Postictal autonomic changes were correlated with the SUDEP-7 scores. CONCLUSION: Our results showed that ictal autonomic dysfunction is correlated with postictal hypoxemia. A prolonged impairment of parasympathetic tone might expose a patient to a greater risk of postictal sudden unexpected death. The real-time measurement of parasympathetic tone in patients with epilepsy may be of value to medical staff as an early warning system.
OBJECTIVE: To measure changes in parasympathetic tone before, during, and after temporal seizures, and to determine whether changes in high-frequency heart rate variability are correlated with postictal oxygen desaturation. METHODS: We recorded the electrocardiogram and peripheral oxygen saturation during 55 temporal lobe seizures and calculated a high-frequency variability index (HFVI) as a marker of parasympathetic tone for periods of 20 minutes (centered on seizure onset). We then compared HFVI values in seizures with and without postictal hypoxemia, and looked for correlations between HFVI changes and the risk of sudden unexpected death in epilepsy (SUDEP) (as assessed with the SUDEP-7 Inventory). RESULTS: Parasympathetic tone decreased rapidly at the onset of temporal lobe seizures, reached its minimum value at the end of the seizure, and then gradually returned to its preictal value. Changes in parasympathetic tone were more intense and longer-lasting in older patients with a longer duration of epilepsy. The HFVI was significantly lower during seizures with hypoxemia, and remained significantly lower 5 minutes after the end of the seizure. The change in the HFVI slope over the first 30 seconds of the seizure was predictive of postictal oxygen desaturation. Postictal autonomic changes were correlated with the SUDEP-7 scores. CONCLUSION: Our results showed that ictal autonomic dysfunction is correlated with postictal hypoxemia. A prolonged impairment of parasympathetic tone might expose a patient to a greater risk of postictal sudden unexpected death. The real-time measurement of parasympathetic tone in patients with epilepsy may be of value to medical staff as an early warning system.
Authors: Siddharth S Sivakumar; Amalia G Namath; Ingrid E Tuxhorn; Stephen J Lewis; Roberto F Galán Journal: J Neurophysiol Date: 2016-02-17 Impact factor: 2.714