EEG normal variants: A prospective study using the SCORE system.

Objective: To determine the prevalence and characteristics of normal variants in EEG recordings in a large cohort, and provide readers with typical examples of all normal variants for educational purposes.

Methods: Using the SCORE EEG system (Standardized Computer-Based Organized Reporting of EEG), we prospectively extracted EEG features in consecutive patients. In this dataset, we analyzed 3050 recordings from 2319 patients (mean age 38.

EEG Essentials.

Purpose Of Review: EEG is the best study for evaluating the electrophysiologic function of the brain. The relevance of EEG is based on an accurate interpretation of the recording. Understanding the neuroscientific basis for EEG is essential.

[Analysis of clinical and genetic characteristics of epilepsy associated with chromosome 16p11.2 microdeletion].

To investigate the clinical and genetic characteristics of epilepsy associated with chromosome 16p11.2 microdeletion. The patients (=10) with 16p11.

Novel mutation of SIK1 gene causing a mild form of pediatric epilepsy in a Chinese patient.

Developmental and Epileptic Encephalopathy (DEE) is a group of disorders affecting children at early stages of infancy, which is characterized by frequent seizures, epileptiform activity on EEG, and developmental delayor regression. Developmental and epileptic encephalopathy-30 (DEE30) is a severe neurologic disorder characterized by onset of refractory seizures soon after birth or in the first months of life. Which was recently found to be caused by heterozygous mutations in the salt-inducible kinase SIK1.

[Clinical characteristics and gene analysis of GRIN2B gene related neurological developmental disorders in children].

To analyse the clinical and gene characteristics of GRIN2B gene related neurological developmental disorders in children. The data of 11 children with GRIN2B gene related neurological developmental disorders from November 2016 to February 2021 were collected from Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health and analyzed retrospectively. The clinical features, electroencephalogram (EEG), brain imaging and gene testing results were summarized.

Gain-of-function variants in GABRD reveal a novel pathway for neurodevelopmental disorders and epilepsy.

A potential link between GABRD encoding the δ subunit of extrasynaptic GABAA receptors and neurodevelopmental disorders has largely been disregarded due to conflicting conclusions from early studies. However, we identified seven heterozygous missense GABRD variants in 10 patients with neurodevelopmental disorders and generalized epilepsy. One variant occurred in two sibs of healthy parents with presumed somatic mosaicism, another segregated with the disease in three affected family members, and the remaining five occurred de novo in sporadic patients.

Age-related evolution of EEG in Dravet syndrome: Meta-analysis of 155 patients.

Purpose: Dravet syndrome is an early-onset developmental and epileptic encephalopathy caused by pathogenic SCN1A variants in 80-90% of patients. EEG is initially normal, but abnormalities, both generalized and focal, may develop later. There is a limited understanding of typical EEG evolution in Dravet syndrome.

Prevalence of benign epileptiform variants from an EEG laboratory in India and frequency of their misinterpretation.

Objective: To prospectively study the prevalence of benign epileptiform variants (BEVs) and their impact on epilepsy misdiagnosis.

Methods: Consecutive patients, older than one year, who underwent EEG from January 2016 to December 2019 were prospectively studied for the presence of BEVs. We used descriptions of Klass and Westmoreland (1985) to categorize the BEVs.

Epilepsy and electroencephalogram evolution in YWHAG gene mutation: A new phenotype and review of the literature.

A male patient with a de novo mutation in the YWHAG gene and mild phenotype is presented. He had normal delivery and normal development, with normal speech and social milestones. At the age of 9 months, myoclonic seizures started, with generalized epileptiform discharges.

Normal Variants in Magnetoencephalography.

Normal variants, although not occurring frequently, may appear similar to epileptic activity. Misinterpretation may lead to false diagnoses. In the context of presurgical evaluation, normal variants may lead to mislocalizations with severe impact on the viability and success of surgical therapy.

The presenting symptoms of Lafora Disease: An electroclinical and genetic study in five Apulian (Southern Italy) families.

Purpose: To elucidate the presenting symptoms of Lafora Disease (LD) to differentiate it from Juvenile Myoclonic Epilepsy (JME).

Methods: We collected and evaluated the early electroclinical data of 5 unrelated Apulian (Southern Italy) LD families, 30 LD patients selected from the literature, and 30 Apulian JME patients.

Results: The Apulian LD patients presented with generalised tonic-clonic and focal visual seizures, followed by myoclonic seizures and action-postural myoclonus.

Electroclinical Phenotype-Genotype Homogeneity in Drug-Resistant "Generalized" Tonic-Clonic Seizures of Early Childhood.

Purpose: Children with refractory focal to bilateral tonic-clonic seizures, despite normal high-resolution imaging, are often not subjected to genetic tests due to the costs involved and instead undergo multimodality presurgical evaluation targeted at delineating a focal onset. The objective of this study was to ascertain genotype-phenotype correlations in this group of patients.

Method: An online hospital database search was conducted for children who presented in 2019 with drug-resistant epilepsy dominated by nonlateralizing focal-onset/rapid generalized (bilateral) tonic-clonic seizures (GTCS), subjected to presurgical evaluation and subsequent genetic testing due to absence of a clear focus hypothesis.

Electroclinical Findings of Epileptic Encephalopathy.

Introduction: Early-onset epileptic encephalopathies are among the most severe early-onset epilepsies, leading to progressive neurodegeneration. An increasing number of novel genetic causes continue to be uncovered as the primary etiology.

Results: We report a girl infant of Semitic (Saudi Arabian) descent who presented with multifocal seizures and later developed intractable infantile spasms and myoclonic seizures.

Electro-clinical and neurodevelopmental outcome in six children with early diagnosis of tuberous sclerosis complex and role of the genetic background.

Background: Seizures in individuals affected by tuberous sclerosis complex (TSC) commonly develop in the first year of life, are often preceded by a progressive deterioration of the electroencephalogram (EEG), and likely influence developmental outcome. Although early diagnosis of TSC has offered a tremendous opportunity to monitor affected patients before seizure onset, reports of the neurological manifestations of TSC in infants before seizure onset are still scarce. Here we describe early EEG activity, clinical and genetic data and developmental assessment in a group of TSC infants, with the aim of identifying possible prognostic factors for neurodevelopmental outcome.

Etiology and Clinical Impact of Interictal Periodic Discharges on the Routine Outpatient Scalp EEG.

Purpose: Periodic discharges (PDs) are common in acute structural or metabolic brain lesions, but their occurrence during follow-up of epileptic patients in an outpatient setting is rare. Aim of this article was to study whether PDs on the routine outpatient scalp EEG of patients with epilepsy, as compared with nonperiodic epileptiform discharges, are associated with drug refractoriness and the decompensation of epilepsy and particular etiologies.

Methods: A retrospective case-control study.

Phenotypic and genetic spectrum of SCN8A-related disorders, treatment options, and outcomes.

Pathogenic variants in SCN8A have originally been described in patients with developmental and epileptic encephalopathy (DEE). However, recent studies have shown that SCN8A variants can be associated with a broader phenotypic spectrum, including the following: (1) Patients with early onset, severe DEE, developing severe cognitive and motor regression, pyramidal/extrapyramidal signs, and cortical blindness. Severe SCN8A-DEE is characterized by intractable seizures beginning in the first months of life.

Interictal epileptiform discharges on electroencephalography in children with methylenetetrahydrofolate reductase (MTHFR) polymorphisms.

Objective: Methylenetetrahydrofolate reductase (MTHFR) is an important enzyme involved in folate metabolism. MTHFR C677T and A1298C polymorphisms are best-defined variants of MTHFR that were reported to be associated with epilepsy development. The aim of the study was to determine the incidence of interictal epileptiform discharges on electroencephalography (EEG) in asymptomatic children with C677T and A1298C polymorphisms who had no history of seizure.

The intracranial correlate of the 14&6/sec positive spikes normal scalp EEG variant.

Objective: To investigate the intracranial correlate of the 14&6/sec positive spikes normal variant of scalp EEG.

Methods: Out of 35 adult refractory focal epilepsy patients who underwent intracranial electrode implantation with simultaneous scalp EEG electrodes, the 14&6/sec positive spikes variant was found in 4. We used three methods to identify and quantify intracranial correlates to the variant: visual inspection, time-referenced waveform averaging and 3D brain volume spectrum-based statistical parametric mapping (SPM).

Normal EEG variants.

Understanding common variations of normal EEG and benign variants of uncertain significance is essential to discern the boundary between normal and abnormal EEG. Wide variation and fluctuation can occur with normal signals generated by the brain, and these can be a pitfall for less-experienced electroencephalographers in accurately interpreting the EEG. Normal EEG variants are benign and do not portend specific pathological conditions.

Normal Variants Are Commonly Overread as Interictal Epileptiform Abnormalities.

Electroencephalographers may misclassify benign variant EEG patterns as epileptiform discharges, resulting in delays in the diagnosis and appropriate treatment of other paroxysmal disorders, such as psychogenic nonepileptic seizures, anxiety/panic disorders, and near syncope. These benign variant patterns include wicket spikes, small sharp spikes, and rhythmic mid-temporal theta of drowsiness. Cautious interpretations of semi-rhythmic sharp transients, usually gradually rising from the EEG background in drowsiness, can help avoid misdiagnosing patients as having seizures.

Ryanodine receptor 2 (RYR2) mutation: A potentially novel neurocardiac calcium channelopathy manifesting as primary generalised epilepsy.

Purpose: Ryanodine receptor 2 (RYR2) mutation is well-established in the aetiology of an inherited cardiac disorder known as catecholaminergic polymorphic ventricular tachycardia (CPVT). The RYR2 receptor is expressed in cardiomyocytes, and also in the hippocampus. The RYR2 mutation has not been reported as a potential cause of adult-onset genetic generalised epilepsy (GGE).

Electrographic spikes are common in wildtype mice.

High-voltage rhythmic electroencephalographic (EEG) spikes have been recorded in wildtype (WT) rats during periods of light slow-wave sleep and passive wakefulness. The source of this activity is unclear but has been attributed to either an inherent form of absence epilepsy or a normal feature of rodent sleep EEG. In contrast, little is known about epileptiform spikes in WT mice.