Presence Of Epileptic Discharges Research Articles

Noise induced quiescence of epileptic spike generation in patients with epilepsy

Clinical scalp electroencephalographic recordings from patients with epilepsy are distinguished by the presence of epileptic discharges i.e. spikes or sharp waves. These often occur randomly on a background of fluctuating potentials. The spike rate varies between different brain states (sleep and awake) and patients. Epileptogenic tissue and regions near these often show increased spike rates in comparison to other cortical regions. Several studies have shown a relation between spike rate and background activity although the underlying reason for this is still poorly understood. Both these processes, spike occurrence and background activity show evidence of being at least partly stochastic processes. In this study we show that epileptic discharges seen on scalp electroencephalographic recordings and background activity are driven at least partly by a common biological noise. Furthermore, our results indicate noise induced quiescence of spike generation which, in analogy with computational models of spiking, indicate spikes to be generated by transitions between semi-stable states of the brain, similar to the generation of epileptic seizure activity. The deepened physiological understanding of spike generation in epilepsy that this study provides could be useful in the electrophysiological assessment of different therapies for epilepsy including the effect of different drugs or electrical stimulation.

A case of Pitt-hopkins Syndrome with de novo mutation in TCF4: Clinical features and treatment for epilepsy

Pitt-Hopkins syndrome (PTHS), belonging to the group of 18q-syndromes, is a rare genetic disorder caused by mutations in TCF4. PTHS is characterized by distinctive facial appearance, intermittent hyperventilation, intellectual disability and developmental delay. Although patients with PTHS generally have various systemic symptoms, most of them with a TCF4 mutation manifest the central nervous system (CNS) disorders. We described the first Chinese case with Pitt-Hopkins syndrome based on clinical presentations and genetic findings. In addition to the typical features of PTHS, the girl also had paroxysms of tachypnea followed by cyanosis and recurrent seizures. Comprehensive medical examinations were performed including metabolic screening, hepatic and renal function evaluation, abdominal and cardiac ultrasounds. The presence of epileptic discharges in electroencephalography and abnormal brain magnetic resonance imaging were found. High-throughput sequencing was used to detect genetic mutations associated with CNS disorders. Sanger sequencing was used to confirm the mutations in the patient. The c.2182C＞T (p.Arg728Ter) mutation was a de novo nonsense mutation at exon 18 in the TCF4 gene of the patient. In conclusion, we have identified a de novo nonsense mutation of TCF4 carried by a Chinese girl with PTHS. The patient underwent anti-epileptic therapy (sodium valproate, levetiracetam, clonazepam), resulting in a reduction of the seizures.

Predictive factors for relapse of epileptic spasms after adrenocorticotropic hormone therapy in West syndrome

PurposeTo investigate whether serial electroencephalographic (EEG) findings can predict relapse of epileptic spasms after synthetic adrenocorticotropic hormone (ACTH) therapy in patients with West syndrome (WS). Subjects and methodsThirty-nine WS patients (8 cryptogenic and 31 symptomatic) were included in this study. These patients received ACTH therapy for the first time and were regularly followed up for more than three years at our hospital. Sixteen patients (41.0%) showed seizure relapse (relapse group) and 23 patients (59.0%) did not show relapse (non-relapse group). We used survival analysis to investigate the influence of etiology and presence of epileptic discharges after the ACTH therapy on seizure outcome. ResultsImmediately after the ACTH therapy, etiology was associated with seizure outcome (p=0.003). In the early stage (1month after the ACTH therapy), only the presence of epileptic discharges (p=0.001) had a significant association with seizure outcome, regardless of etiology. Because all relapsed patients were in the symptomatic group, we performed the same statistical analysis on symptomatic WS patient data only. We found that the group with no epileptic discharges on EEG showed a significantly higher seizure-free rate than those with epileptic discharges in the early stage (p=0.0091). ConclusionThis study demonstrated that serial EEG findings after ACTH therapy are significantly related to relapse of epileptic spasms.

EEG changes associated with autistic spectrum disorders

Autism Spectrum Disorders (ASD) are an etiologically and clinically heterogeneous group of neurodevelopmental disorders. The pathophysiology of ASD remains largely unknown. One essential and well-documented observation is high comorbidity between ASD and epilepsy. Electroencephalography (EEG) is the most widely used tool to detect epileptic brain activity. The EEG signal is characterized by a high temporal resolution (on the order of milliseconds) allowing for precise temporal examination of cortical activity. This review addresses the main EEG findings derived from both the standard or qualitative (visually inspected) EEG and the quantitative (computer analyzed) EEG during resting state in individuals with ASD. The bulk of the evidence supports significant connectivity disturbances in ASD that are possibly widespread with two specific aspects: over-connectivity in the local networks and under-connectivity in the long-distance networks. Furthermore, the review suggested that disruptions appear more severe in later developing parts of the brain (e.g., prefrontal cortex). Based on available information, from both the qualitative and quantitative EEG literature, we postulate a preliminary hypothesis that increased cortical excitability may contribute to the significant overlap between ASD and epilepsy and may be contributing to the connectivity deviations noted. As the presence of a focal epileptic discharge is a clear indication of such hyperexcitability, we conclude that the presence of epileptic discharges is a potential biomarker at least for a subgroup of ASD.