Sodium Valproate Combined With Topiramate vs. Sodium Valproate Alone for Refractory Epilepsy: A Systematic Review and Meta-Analysis

Background: Among antiepileptic drugs (AEDs), sodium valproate alone or in the combination of topiramate (TPM) for treating refractory epilepsy was controversial. This meta-analysis aimed to systematically evaluate the clinical effects of these two regimens in this population.Methods: Relevant studies up to August 2021 were identified through systematic searches of CNKI, Wanfang, PubMed, and Embase databases. We assessed the effectiveness and the frequency of absence seizures, atonic seizures, and tonic–clonic seizures. The included literature's risk of bias was evaluated using the Cochrane Collaboration's Risk of Bias tool. Sensitivity analysis was conducted to confirm the results' stability. STATA 15.0 was utilized for all pooled analyses in the included studies.Results: Totally 10 articles were determined for our meta-analysis, involving 976 patients with epilepsy in total (combined group, n = 488; monotherapy group, n = 488). The results of this meta-analysis indicated that the total effective rate of sodium valproate combined with TPM was higher than that of sodium valproate alone (random-effect model: OR = 3.52; 95% CI 1.47 to 8.47; p < 0.001; I2 = 73.8%). The frequency of absence seizures in the combined group was lower (fixed-effect model: WMD = −6.02; 95% CI −6.50 to −5.54; I2 = 0.0%) than that in the monotherapy group, with a statistical difference (p < 0.05). The combined group had lower frequency of atonic seizures (WMD = −4.56, 95% CI −6.02 to −3.10; I2 = 82.6%) and lower frequency of tonic–clonic seizures (WMD = −3.32; 95% CI −4.75 to −1.89; I2 = 96.4%). In addition, the distinct difference of adverse events was non-existent between two groups.Conclusions: Sodium valproate combined with TPM was more effective than sodium valproate alone for epilepsy therapy. This meta-analysis provides feasibility data for a larger-scale study on AED therapy of refractory epilepsy and may contribute to better therapy strategies for epilepsy clinically.

Respiratory alkalosis provokes spike-wave discharges in seizure-prone rats

Hyperventilation reliably provokes seizures in patients diagnosed with absence epilepsy. Despite this predictable patient response, the mechanisms that enable hyperventilation to powerfully activate absence seizure-generating circuits remain entirely unknown. By utilizing gas exchange manipulations and optogenetics in the WAG/Rij rat, an established rodent model of absence epilepsy, we demonstrate that absence seizures are highly sensitive to arterial carbon dioxide, suggesting that seizure-generating circuits are sensitive to pH. Moreover, hyperventilation consistently activated neurons within the intralaminar nuclei of the thalamus, a structure implicated in seizure generation. We show that intralaminar thalamus also contains pH-sensitive neurons. Collectively, these observations suggest that hyperventilation activates pH-sensitive neurons of the intralaminar nuclei to provoke absence seizures.

Closed-loop Controller Based on Reference Signal Tracking for Absence Seizures

Deep brain stimulation (DBS) targeting thalamus reticular nucleus (TRN) brain regions has been proven to play an irreplaceable role in the treatment of absence seizures. Compared with open-loop DBS, closed-loop DBS has been recognized by researchers for its advantages of significantly inhibiting seizures and having fewer side effects. However, due to the complexity of the nervous system, the mechanism of DBS control epilepsy is still unclear, which hinders the study of closed-loop DBS. In our study, based on the biophysical model jointly constituted by cortical, thalamic, and basal ganglia, we selected the 2-4 Hz spike and wave discharges (SWDs) of the cortical region as a biomarker for response to absence epilepsy, and the mean firing rate (MFR) of substantia nigra pars reticulata (SNr) was used as a reference signal for modulation of closed-loop DBS. Moreover, to obtain the linear relationship between the stimulus and the response, we adopted an algorithm that combines controlled auto-regressive (CAR) and recursive least squares (RLS), and we built a proportional integral (PI) controller to make the DBS stimulus parameters self-update to control the seizures. The numerical simulation results show that the closed-loop DBS controllers based on frequency modulation and amplitude modulation respectively not only successfully track the firing rate (FR) of SNr, but also significantly destroy the SWDs of cerebral cortex and restore it to the other two normal discharge modes.

Mowat-Wilson syndrome: literature review and case series

Mowat-Wilson syndrome (MWS) is a rare genetic disorder characterized by a combination of the following signs: 1) facial dysmorphism (wide nose, broad medial eyebrows, pronounced chin, and open mouth); 2) mental retardation; 3) abnormalities of internal organs (congenital heart defects, Hirschsprung's disease, hypospadias/cryptorchidism). The disease is associated with a heterozygous pathogenic mutation in the ZEB2 gene. More than 80 % of MWS patients are diagnosed with epilepsy, the onset of which is usually observed in infancy. Patents have focal motor seizures, atypical absence seizures, generalized convulsive seizures. Epileptic seizures are often triggered by fever; some children are resistant to therapy. MWS patients have a specific phenotype (blue eyes, fair hair, wide-based gait, frequent laughter, limited or absent expressive language) that requires differential diagnosis with Angelman syndrome (caused by a mutation in the UBE3A gene). MWS was described in 1998, but there have been no case reports in the Russian literature yet. We report 4 cases of MWS in children aged 2 to 13 years treated in the Svt. Luka's Institute of Neurology and Epilepsy. In all of these patients, we identified a heterozygous de novo deletion in the ZEB2 gene. Epilepsy was observed in all patients. Mean age at onset was 13 months. All children had focal motor seizures and atypical absence seizures. None of them had tonic-clonic seizures or status epilepticus. The analysis of electroencephalograms showed that patients with a lower index of epileptiform activity tend to have better development and vice versa: children with a high index of epileptiform activity during sleep had more severe developmental delay.

Atypical Presentation Of Paediatric Absence Seizure: EEG As A Diagnostic Tool

Absence seizures involve brief, sudden lapses of consciousness and are more common in children than in adults. We report a case of absence seizure in a girl with atypical presentation which was diagnosed by electroencephalogram. She responded well to sodium valproate. Detailed history, clinical examination and use of electroencephalogram for diagnosis is necessary especially when such atypical presentations are encountered.

Regulatory Mechanism for Absence Seizures in Bidirectional Interactive Thalamocortical Model via Different Targeted Therapy Schemes

Recent clinical practice has found that the spike-wave discharge (SWD) scopes of absence seizures change from small cortical region to large thalamocortical networks, which has also been proved by theoretical simulation. The best biophysics explanation is that there are interactions between coupled cortico-thalamic and thalamocortical circuits. To agree with experiment results and describe the phenomena better, we constructed a coupled thalamocortical model with bidirectional channel (CTMBC) to account for the causes of absence seizures which are connected by the principle of two-way communication of neural pathways. By adjusting the coupling strength of bidirectional pathways, the spike-wave discharges are reproduced. Regulatory mechanism for absence seizures is further applied to CTMBC via four different targeted therapy schemes, such as deep brain stimulation (DBS), charge-balanced biphasic pulse (CBBP), coordinated reset stimulation (CRS) 1 : 0, and (CRS) 3 : 2. The new CTMBC model shows that neurodiversity in bidirectional interactive channel could supply theory reference for the bidirectional communication mode of thalamocortical networks and the hypothesis validation of pathogenesis.