Purpose: The peri-ictal autonomic disturbances have been studied as predictors of seizure outcome and as markers of seizure onset. We studied the changes in heart rate (HR), HRV, oxygen saturation and blood pressure (BP) in the peri-ictal period in patients with drug-resistant localization-related epilepsy.
Methodology: Ninety one subjects undergoing video-EEG monitoring, underwent continuous HR, SpO2, BP and Lead II ECG monitoring. The changes during the preictal, ictal and postictal periods were analyzed for 57 seizures in 42 patients with artifact-free recordings and correlated with VEEG ictal onset and MRI characteristics.
Results: Ictal tachycardia was noted in 15 (26.3%) seizures, of which, 60% had temporal lobe onset. HR increased by an average of 20.1% from pre-ictal to ictal phases (p=0.04). Ictal bradycardia was noted in one event with right temporal seizure onset. Heart rate variability (HRV) analysis of the preictal, ictal and postictal phases showed an increase in the sympathetic and decrease in parasympathetic activity during the ictus with relatively preserved total power. Ictal oxygen desaturation (84.1%±3.5%) was noticed in 10 (17.5%) seizures. Ictal hypertension was observed in 15 (26.3%); ictal hypotension was noted in 5 (8.7%) seizures. Both the systolic BP and diastolic BPs increased from the pre-ictal to ictal phase (p=0.01).
Conclusions: Peri-ictal dysautonomia can present in variable patterns and can be measured and compared over different modalities such as BP, HR and HRV. Though degree of tachycardia and increase in BP were higher during extratemporal onset of seizures, a fall in variability was noted in seizures of temporal lobe origin. Oxygen desaturation is not an uncommon event during the peri-ictal period in localization related epilepsy.
Keywords: Autonomic dysfunction; Epilepsy; Localization related epilepsy; Peri-ictal.
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