A Review of the Surgical Procedures for the Treatment of Drug-Resistant Epilepsy and Their Seizure Control Outcomes

Background: Drug-resistant epilepsy can be defined as the existence of seizures within 6 months, despite adequate therapy regimens with one or more antiepileptic drugs. Epilepsy surgery has been the standard therapy to help those patients who suffer from drug-resistant epilepsy. The goal of this surgery is to halt or reduce the intensity of seizures. This literature review aims to provide an overview of existing surgical procedures for the treatment of drug-resistant epilepsy and the degree of seizure control they provide based on available literature. Methods: Data were collected from medical journal databases, aggregators, and individual publications. The most used databases were PubMed, Medline and NCBI. Some of the keywords used to search these databases include: “drug resistant epilepsy”, “seizure control”, and “neurosurgery”. Results: Epileptic surgery is divided into resective and non-resective procedures. Studies have shown that a full resection of the epileptogenic brain area increases the probability of seizure eradication, however, the risks of postoperative impairments grow as the resection area is extended. On the other hand, patients who are unsuitable for seizure focus removal by resective surgery, such as those with multifocal seizures or overlapping epileptogenic zone with a functional cortex, may benefit from non-resective surgical options such as Vagus Nerve Stimulation and Responsive Neurostimulation. Conclusion: This literature review discusses the comprehensive treatment of epilepsy, especially the surgical treatment of drug-resistant epilepsy. The reviewed studies have shown that epilepsy surgery has promising outcomes in achieving seizure freedom/reducing seizure frequency with minimal adverse effects when performed correctly with the appropriate choice of surgical candidates.

Improving control effects of absence seizures using single-pulse alternately resetting stimulation (SARS) of corticothalamic circuit

Presently,we develop a simplified corticothalamic(SCT)model and propose a single-pulse alternately resetting stimulation(SARS)with sequentially applying anodic(A,“+”)or cathodic(C,“−”)phase pulses to the thalamic reticular(RE)nuclei,thalamus-cortex(TC)relay nuclei,and cortical excitatory(EX)neurons,respectively.Abatement effects of ACC-SARS of RE,TC,and EX for the 2 Hz-4 Hz spike and wave discharges(SWD)of absence seizures are then concerned.The m∶n on-off ACC-SARS protocol is shown to effectively reduce the SWD with the least current consumption.In particular,when its frequency is out of the 2 Hz-4 Hz SWD dominant rhythm,the desired seizure abatements can be obtained,which can be further improved by our proposed directional steering(DS)stimulation.The dynamical explanations for the SARS induced seizure abatements are lastly given by calculating the averaged mean firing rate(AMFR)of neurons and triggering averaged mean firing rates(TAMFRs)of 2 Hz-4 Hz SWD.

Regulating absence seizures by tri-phase delay stimulation applied to globus pallidus internal

In this paper,a reduced globus pallidus internal(GPI)-corticothalamic(GCT)model is developed,and a tri-phase delay stimulation(TPDS)with sequentially applying three pulses on the GPI representing the inputs from the striatal D_(1)neurons,subthalamic nucleus(STN),and globus pallidus external(GPE),respectively,is proposed.The GPI is evidenced to control absence seizures characterized by 2 Hz–4 Hz spike and wave discharge(SWD).Hence,based on the basal ganglia-thalamocortical(BGCT)model,we firstly explore the triple effects of D_(1)-GPI,GPE-GPI,and STN-GPI pathways on seizure patterns.Then,using the GCT model,we apply the TPDS on the GPI to potentially investigate the alternative and improved approach if these pathways to the GPI are blocked.The results show that the striatum D_(1),GPE,and STN can indeed jointly and significantly affect seizure patterns.In particular,the TPDS can effectively reproduce the seizure pattern if the D_(1)-GPI,GPE-GPI,and STN-GPI pathways are cut off.In addition,the seizure abatement can be obtained by well tuning the TPDS stimulation parameters.This implies that the TPDS can play the surrogate role similar to the modulation of basal ganglia,which hopefully can be helpful for the development of the brain-computer interface in the clinical application of epilepsy.

Seizure frequency and obstetric complications at advanced maternal age:a preliminary observational study in women with epilepsy

Background:Seizure control during pregnancy and obstetric outcomes are of important concerns for women with epilepsy(WWE)and their families.Advanced maternal age(≥35 years)shows a growing trend in the society with changes of lifestyle,which also occurs in diseased populations.The advanced maternal age is an independent factor for some unsatisfying obstetric outcomes.In this study we explored the seizure control and obstetric complications associated with advanced maternal age in WWE.Methods:This study was based on the epilepsy pregnancy registry at West China Hospital.Patients with epilepsy in this registry who were aged 35 or older when starting pregnancy were included in this study.Their basic demographics and detailed information on epilepsy management and obstetric issues in all trimesters and during 1-year follow-up after birth were documented and reviewed.Data were processed by IBM SPSS version 22.0.The demographic characteristics,seizure frequency,treatment change,obstetric complications,and outcomes were analyzed and compared.Results:Fifteen patients were included in this study,with an average age of 36.32±2.39 years at pregnancy,and 73.33%of them were primiparas.The change of seizure frequency during pregnancy was not in a clear pattern,but there was an increased incidence of tonic-clonic seizures during the mid-and last trimesters.More than 20%of the patients had obstetric complications throughout the trimesters,including vaginal bleeding,hypothyroidism,and pre-eclampsia.The pre-eclampsia seemed extraordinarily complicated with other conditions.However,none of the complications were related with malformations or poor outcome of babies after 1-year follow-up.Conclusion:Advanced maternal age combined with WWE is associated with frequent common obstetric complications.Future controlled studies with large sample sizes are needed to explore the related risks in comparison with other WWE and non-epileptic populations.