36 results match your criteria Epileptiform Normal Variants on EEG


EEG Essentials.

Authors:
William O Tatum

Continuum (Minneap Minn) 2022 04;28(2):261-305

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. Read More

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

Zhonghua Er Ke Za Zhi 2022 Apr;60(4):339-344

Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.

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

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

Zhonghua Er Ke Za Zhi 2022 Mar;60(3):232-236

Department of Neurology, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China.

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. Read More

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

Brain 2022 May;145(4):1299-1309

Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre, Dianalund, Denmark.

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. Read More

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

Seizure 2021 Oct 11;91:108-111. Epub 2021 Jun 11.

Research Institute of the McGill University Medical Centre, 1001 Décarie Blvd, Montreal, Quebec, H4A 3J1, Canada; Division of Neurology, Department of Pediatrics, Montreal Children's Hospital, McGill University Health Centre, 1001 Décarie Blvd, Montreal, Quebec, H4A 3J1, Canada; Department of Neurology and Neurosurgery, Montreal Children's Hospital, McGill University Health Centre, 1001 Décarie Blvd, Montreal, Quebec, H4A 3J1, Canada. Electronic address:

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. Read More

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October 2021

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

Epilepsy Res 2021 02 5;170:106539. Epub 2021 Jan 5.

Department of Neurology, Smt. B. K. Shah Medical Institute and Research Center, Sumandeep Vidyapeeth, Vadodara, Gujarat, India.

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. Read More

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February 2021

Normal Variants in Magnetoencephalography.

J Clin Neurophysiol 2020 Nov;37(6):518-536

Epilepsy Center, Cleveland Clinic, Cleveland, Ohio, U.S.A.

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. Read More

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November 2020

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

Clin EEG Neurosci 2021 Sep 3;52(5):371-375. Epub 2020 Sep 3.

Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum, Kerala, India.

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. Read More

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September 2021

The New CIC Mutation Associates with Mental Retardation and Severity of Seizure in Turkish Child with a Rare Class I Glucose-6-Phosphate Dehydrogenase Deficiency.

J Mol Neurosci 2020 Dec 13;70(12):2077-2084. Epub 2020 Jun 13.

Biruni University, Zeytinburnu, Istanbul, Turkey.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive disease that causes acute or chronic hemolytic anemia and potentially leads to severe jaundice in response to oxidative agents. Capicua transcriptional repressor (CIC) is an important gene associated with mental retardation, autosomal dominant 45. Affiliated tissues including skin, brain, bone, and related phenotypes are intellectual disability and seizures. Read More

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December 2020

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

Ital J Pediatr 2020 Mar 27;46(1):36. Epub 2020 Mar 27.

Child Neuropsychiatric Unit - Epilepsy Center, San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Via di Rudinì 8, 20142, Milan, Italy.

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. Read More

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

J Clin Neurophysiol 2021 May;38(3):202-207

Neurosciences and Mental Health Department, Hospital de Santa Maria, CHLN, Lisbon, Portugal.

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. Read More

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

Epilepsia 2019 12;60 Suppl 3:S77-S85

Danish Epilepsy Center, Dianalund, Denmark.

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. Read More

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December 2019

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

Neurol Sci 2020 Mar 16;41(3):631-636. Epub 2019 Nov 16.

Department of Pediatric Metabolism, Faculty of Medicine, Mayıs University, Samsun, Turkey.

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. Read More

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

Clin Neurophysiol 2019 09 21;130(9):1570-1580. Epub 2019 Jun 21.

Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; University of Pittsburgh Comprehensive Epilepsy Center, Pittsburgh, PA, USA.

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). Read More

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September 2019

Normal EEG variants.

Handb Clin Neurol 2019 ;160:143-160

Department of Neurology, Mayo Clinic College of Medicine and Health Sciences, Jacksonville, FL, United States. Electronic address:

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. Read More

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December 2019

Normal Variants Are Commonly Overread as Interictal Epileptiform Abnormalities.

J Clin Neurophysiol 2019 Jul;36(4):257-263

Department of Neurology/Epilepsy Division, Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A.

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. Read More

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Electrographic spikes are common in wildtype mice.

Epilepsy Behav 2018 12 3;89:94-98. Epub 2018 Nov 3.

F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States of America. Electronic address:

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. Read More

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December 2018

Small sharp spikes as EEG markers of mesiotemporal lobe epilepsy.

Clin Neurophysiol 2018 09 28;129(9):1796-1803. Epub 2018 Jun 28.

Department of Neurology, University of Chicago, USA.

Objective: Mesial temporal lobe epilepsy (mTLE) is the most common type of focal epilepsy, but often lacks scalp EEG correlates. We ask if hippocampal epileptiform discharges that are characteristic of mTLE are associated with small sharp spikes (SSS) recorded on scalp EEG. SSS are considered benign waveforms, so are not currently used as markers of epilepsy. Read More

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September 2018

Prevalence of benign epileptiform variants during initial EEG examination in French military aircrew.

Neurophysiol Clin 2018 Jun 21;48(3):171-179. Epub 2018 Apr 21.

Service de neurophysiologie clinique, centre hospitalier Sainte-Anne, 1, rue Cabanis, 75014 Paris, France; Université Paris-Descartes, 12, rue de l'école de médecine, 75006 Paris, France; Inserm UMR S894, centre de psychiatrie et neurosciences, rue de la Santé, 75014 Paris, France.

Introduction: In France, a systematic EEG is performed during initial examination in military aircrew applicants, which may provide an estimation of the prevalence of benign epileptiform variants in healthy adults.

Methods: We analyzed standard EEG (21 scalp electrodes, 20minutes, 400Hz sampling rate) of military aircrew applicants examined in the French Main Aeromedical Center in 2016. EEGs were analyzed using both bipolar and referential montages. Read More

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Positive interictal epileptiform discharges in adults: A case series of a rare phenomenon.

Clin Neurophysiol 2018 05 8;129(5):952-955. Epub 2018 Feb 8.

Epilepsy Center, Department of Neurology, Ludwig Maximilians University, Munich, Germany.

Objective: Positive interictal epileptiform discharges (IEDs) are rarely recorded from surface EEG, due to the orientation of the cortex and its neurons. Their frequency and significance in adults is unknown, and has only been studied as a phenomenon of the neonatal period and childhood. We aimed to evaluate the frequency and characteristics of positive epileptiform discharges in a large cohort of patients. Read More

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Normal "suspicious" EEG.

Authors:
William O Tatum

Neurology 2013 Jan;80(1 Suppl 1):S4-11

Department of Neurology, Mayo College of Medicine, Mayo Clinic, Jacksonville, FL, USA.

The EEG is a unique measure of electrical brain function and is widely used in patients with seizures. Many normal variants and variations of normal EEG have a predilection for the temporal lobe and mimic epileptiform discharges. The high prevalence of temporal lobe epilepsy and the propensity for normal variants to occupy the temporal lobe may result in an undesired bias, leading to misidentification of normal waveforms. Read More

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January 2013

Artifact-related epilepsy.

Authors:
William O Tatum

Neurology 2013 Jan;80(1 Suppl 1):S12-25

Department of Neurology, Mayo College of Medicine, Mayo Clinic, Jacksonville, FL, USA.

Potentials that do not conform to an expected electrical field generated by the brain characterize an extracerebral source or artifact. Artifact is present in virtually every EEG. It is an essential component for routine visual analysis, yet it may beguile the interpreter into falsely identifying waveforms that simulate epileptiform discharges (ED). Read More

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January 2013

[Electroencephalographic normal variants or with uncertain significance].

Rev Neurol 2012 Apr;54(7):435-44

Instituto Nacional de Ciencias Medicas y de la Nutricion Salvador Zubiran, Tlalpan, Mexico.

Electroencephalography is an important tool in the diagnosis of primary or secondary disorders of central nervous system, epilepsy is one of the most important. Sometimes normal electroencephalographic activity simulates epileptiform activity. This activity does not have pathological value and is considered a variant of normal brain activity. Read More

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[Significance of the EEG in the diagnosis of epilepsy].

Authors:
J Rémi S Noachtar

Nervenarzt 2012 Feb;83(2):172-80

Epilepsie-Zentrum, Neurologische Klinik und Poliklinik, Klinikum der Universität München-Großhadern, Marchioninistr. 15, 81377, München, Deutschland.

The electroencephalogram (EEG) is a specific diagnostic method for the evaluation of patients with epilepsies. Interictal epileptiform discharges (IED) recorded in the seizure interval have a high association with the clinical diagnosis of epilepsy. IEDs have to be differentiated from normal variants that resemble IEDs. Read More

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February 2012

Physiologic pseudoseizures: an EEG case report of mistake in identity.

J Clin Neurophysiol 2011 Jun;28(3):308-10

Mayo College of Medicine, Mayo Clinic, Jacksonville, Florida, USA.

The misdiagnosis of epilepsy may occur from the misinterpretation of a routine scalp EEG. Typically, interictal epileptiform discharges are misidentified on EEGs because of the overinterpretation of normal variants or variations in normal electrocerebral activity. Most reports of misinterpretation have arisen from patients diagnosed with psychogenic nonepileptic attacks using in-patient video-EEG monitoring. Read More

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Web-based collection of expert opinion on routine scalp EEG: software development and interrater reliability.

J Clin Neurophysiol 2011 Apr;28(2):178-84

Department of Neurosciences, Medical University of South Carolina, 96 Jonathan Lucas Street, Charleston, SC 29425, USA.

Computerized detection of epileptiform transients (ETs), characterized by interictal spikes and sharp waves in the EEG, has been a research goal for the last 40 years. A reliable method for detecting ETs would assist physicians in interpretation and improve efficiency in reviewing long-term EEG recordings. Computer algorithms developed thus far for detecting ETs are not as reliable as human experts, primarily due to the large number of false-positive detections. Read More

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Audit of EEG reporting temporal abnormalities.

Can J Neurol Sci 2010 Nov;37(6):819-25

Service de neurologie, Centre hospitalier de l'Université de Montréal - Hôpital Notre-Dame, Montréal, Québec, Canada.

Background: To ensure the overall quality of our electroencephalogram (EEG) laboratory, we decided to perform an audit of EEGs interpreted at our institution, focusing initially on EEGs reporting temporal abnormalities.

Methods: Reports of all EEGs performed between January 1st and June 30th, 2006 were reviewed in order to identify tracings mentioning abnormalities in the temporal regions. These records were then independently reviewed by two epileptologists on two distinct occasions, separated by an interval of at least six months. Read More

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November 2010