Dynamic Cerebral Autoregulation In Patients With Epilepsy

Background and Objective: Epilepsy and stroke are two of the most common diseases of neurological system.The relationship between epileptic seizures and cerebrovascular disease is intimate but complex.Epilepsy is not only a common neurologic sequela of stroke,but also could sometimes herald a stroke.The potential mechanism for this has not been fully understood.Cerebral autoregulation(CA),a mechanism to maintaincerebral blood flow,is a reliable method to evaluatecerebrovascular function and has been proven to becritical for the occurrence and developmentof ischemic stroke.This study’s purpose is to analyze the dynamic cerebral autoregulation(dCA)in patients with epilepsy and discuss its potential mechanism.Methods: Patients with epilepsy were recruited from the Department of Neurology,First Hospital of Jilin Universitybetween April 2016 and May 2017.Ageandsex-matched healthy controls without epilepsy wererecruited from the same region who otherwise met the sameeligibility criteria as the patients.Noninvasive continuous cerebral blood flow velocity(CBFV)of the bilateral middle artery and arterial blood pressure(ABP)were recorded.Transfer function analyses(TFA)were used to analyze the autoregulatory parameters: phase difference and gain.Phase difference represents the velocity characteristic of dCA,gain represents the damping characteristic of dCA,and coherence represents the linear relationship between CBFV and ABP signals.The data obtained were analyzed statistically.Results: The overall phase difference of patients with epilepsy was significantly lower than that of the healthy control group(p=0.046).Furthermore,patients with interictal slow wave had significant lower phase difference than the slow-wave-free patients(p=0.012).There was no difference in overall phase difference between focal discharges and multifocal discharges in patients with epilepsy.In patients with temporal epilepsy,there was no difference in overall phase difference between unilateral discharges and bilateral discharges.Simultaneously,there was no difference in mean phase difference between the affected and unaffected hemispheres in patients with unilateral discharges.In particular,interictal slow wave was an independent factor that influenced phase difference in patients with epilepsy(p=0.016).Conclusions: Our study documented that dCA is impaired in patients with epilepsy,especially in those with interictal slow wave.The impairment of dCA occurs irrespective of the discharge location and type.Interictal slow wave is an independent factor to predict impaired dCA in patients with epilepsy.