Measuring autonomic involvement related to seizure onset in Focal Cortical Dysplasia type II

The research here presented aims to the investigation of the Autonomic Nervous System (ANS) and of the sympatho-vagal balance during sleep-related seizures in patients affected by Focal Cortical Dysplasia (FCD) type II. Heart Rate Variability (HRV) signal was recorded during sleep together with S-EEG (stereo EEG) acquisitions performed for pre-surgical evaluation. The sympatho-vagal balance was estimated in pre-ictal, ictal and post-ictal time, by means of parameters in the time and in the frequency domain. The results here presented are related to 10 epileptic seizures occurring during the same night in one patient. The obtained results testify a significant decrease (p < 0.005) in the RR mean value and standard deviation during the ictal and post-ictal periods in respect to the inter-ictal phase, and a significant decrease (p < 0.001) in the HF(%) power between inter-ictal and post-ictal periods. All these findings are associated to a sympathetic activation and to a vagal drive reduction. A deeper knowledge of the correlations between ANS and epilepsy can lead to better understand the causes of SUDEP (Sudden Unexpected Death in Epilepsy); can contribute to the development of methods for the detection and prediction of epileptic seizures and help to evaluate the effects of vagal nerve stimulation used in those cases in which the patient is not an ideal candidate for surgery.