Adult EEG

2016 ◽  
pp. 97-109
Author(s):  
Katherine H. Noe ◽  
Joseph F. Drazkowski
Keyword(s):  
Epileptiform Activity ◽  
Sharp Waves ◽  
Epileptiform Discharges ◽  
Inappropriate Treatment ◽  
Delta Activity ◽  
Epilepsy Diagnosis ◽  
Interictal Eeg ◽  
Eeg Recordings ◽  
Rhythmic Delta Activity ◽  
Normal Background

Epileptiform discharges present on routine EEG recordings highly correlate with a tendency for clinical seizures. When present, they can help confirm a diagnosis of epilepsy and classify epilepsy type, localization, and syndrome. EEG’s sensitivity for detecting epileptiform activity depends on many factors, including the site of seizure origin and seizure frequency. Even in persons with known epilepsy, a routine EEG can often be normal; thus a normal interictal EEG should not be used to exclude an epilepsy diagnosis. Misinterpretation or “over-reading” of artifacts and normal background activity on the EEG as epileptiform is common by inexperienced readers. Unfortunately, this can lead to misdiagnosis and inappropriate treatment. The EEG reader should be familiar with the commonly encountered epileptiform patterns of generalized spike and wave, generalized slow spike and wave, generalized paroxysmal fast activity, focal spike and sharp waves, and temporal intermittent rhythmic delta activity.

scholarly journals EEG in genetic generalized epilepsies

2020 ◽  
Vol 12 (1S) ◽  
pp. 23-40
Author(s):  
V. Yu. Nogovitsyn ◽  
A. A. Sharkov
Keyword(s):  
Differential Diagnosis ◽  
Juvenile Myoclonic Epilepsy ◽  
Absence Epilepsy ◽  
Night Time ◽  
Epileptiform Discharges ◽  
Atypical Features ◽  
Delta Activity ◽  
Ictal Activity ◽  
Rhythmic Delta Activity ◽  
Generalized Epilepsy

Genetic, or idiopathic, generalized epilepsies (GGEs or IGEs) includes childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and epilepsy with generalized tonic-clonic seizures alone (GTCS-a).Aim. to characterize the capabilities of electroencephalography (EEG) for the diagnosis of various forms of genetic generalized epilepsyMaterials and methods. Literature data in Pubmed, Google Scholar was analyzed. In addition, own observations and clinical cases were systematized.Results. The article presents the data of morphology and topography of spike-wave discharges, as well as other patterns of EEG in the GGE – poly-spike activity, photoparoxysmal response, occipital intermittent rhythmic delta activity (OIRDA), fixation-off sensitivity and generalized paroxysmal fast activity (GPFA), as well as epileptiform K-complexes, the allocation of which in an independent pattern is questioned by a number of neurophysiologists. The differences between interictal and ictal activity in the GGE are discussed in detail; electroencephalogram (EEG) informativity modifiers are considered. The morphology of atypical features in the GGE is considered. The role of EEG in the differential diagnosis of CAE, JAE, JME, GTCS alone with the description of typical, atypical features, study scenarios and diagnostic criteria for each form are considered.Conclusions. Typical EEG features of GGE significantly simplify the differential diagnosis of electroclinical syndromes. There are “non-classical” features of EEG in the GGE, which do not contradict the diagnosis. To reveal the peculiarities of epileptiform discharges distribution, video EEG monitoring with night-time sleep and the use of several modality stimuli is preferable. Incorrect interpretation of EEG is dangerous for the patient. 

scholarly journals Lateralized Rhythmic Delta Activity Synchronous with Hippocampal Epileptiform Discharges on Intracranial EEG

2020 ◽  
Vol 83 (2) ◽  
pp. 225-227 ◽  
Author(s):  
Pia De Stefano ◽  
Serge Vulliémoz ◽  
Margitta Seeck ◽  
Pierre Mégevand
Keyword(s):  
Intracranial Eeg ◽  
Epileptiform Discharges ◽  
Delta Activity ◽  
Rhythmic Delta Activity

scholarly journals Quantitative Measure to Differentiate Wicket Spike from Interictal Epileptiform Discharges

2021 ◽  
Vol 4 (1) ◽  
pp. 14-22
Author(s):  
Suryani Gunadharma ◽  
Ahmad Rizal ◽  
Rovina Ruslami ◽  
Tri Hanggono Achmad ◽  
See Siew Ju ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Linear Discriminant Analysis ◽  
Quantitative Measure ◽  
Linear Discriminant ◽  
Sharp Waves ◽  
Epileptiform Discharges ◽  
Interictal Epileptiform Discharges ◽  
Temporal Location ◽  
Eeg Recordings ◽  
Excellent Accuracy

A number of benign EEG patterns are often misinterpreted as interictal epileptiform discharges (IEDs) because of their epileptiform appearances, one of them is wicket spike. Differentiating wicket spike from IEDs may help in preventing epilepsy misdiagnosis. The temporal location of IEDs and wicket spike were chosen from 143 EEG recordings. Amplitude, duration and angles were measured from the wave triangles and were used as the variables. In this study, linear discriminant analysis is used to create the formula to differentiate wicket spike from IEDs consisting spike and sharp waves. We obtained a formula with excellent accuracy. This study emphasizes the need for objective criteria to distinguish wicket spike from IEDs to avoid misreading of the EEG and misdiagnosis of epilepsy.

scholarly journals EEG findings in patients with angelman syndrome. Notched slow waves and age-specific characteristics of the main EEG patterns

2021 ◽  
Vol 16 (1-2) ◽  
pp. 42-57
Author(s):  
G. V. Kuzmich ◽  
M. Yu. Bobylova ◽  
K. Yu. Mukhin ◽  
O. A. Pylaeva ◽  
L. Yu. Glukhova ◽  
...  
Keyword(s):  
Slow Wave ◽  
Angelman Syndrome ◽  
Activity Index ◽  
Genetic Disorder ◽  
Epileptiform Activity ◽  
Wave Activity ◽  
Theta Activity ◽  
Slow Wave Activity ◽  
Epileptiform Discharges ◽  
Delta Activity

Angelman syndrome (AS) is a genetic disorder caused by a mutation in the maternal copy of the UBE3A gene and characterized by typical clinical manifestations (such as mental retardation, difficulty walking, and laughter) and specific changes on the electroencephalogram (EEG).The aim of this study was to analyze age-specific characteristics of the main EEG patterns, including high-amplitude frontal delta activity with spikes, slow-wave delta-theta activity with spikes in the posterior regions, and diffuse continuous rhythmic theta activity. In addition to that, we assessed the frequency of a rare and highly specific for AS EEG pattern: notched slow waves.We have identified and described additional criteria for EEG during sleep: high index of pathological slow-wave activity and the ratio of pathological slow-wave activity index to epileptiform activity index during sleep. We also analyzed all EEG patterns at the age most significant for the detection of this syndrome (up to 3 years) and their age-specific dynamics.We covered the frequency and characteristics of EEG patterns rare in AS patients, such as three-phase bifrontal delta waves, reactive pathological activity in the posterior areas, EEG patterns of focal seizures originating from the posterior areas, benign epileptiform discharges of childhood, and migrating continuous slow-wave activity.We analyzed the differences between main EEG patterns in AS and frontal and occipital intermittent rhythmic delta activity (fIRDA and OIRDA patterns).

scholarly journals P.052 Benign spasms of infancy - a mimicker of infantile epileptic disorders

2019 ◽  
Vol 46 (s1) ◽  
pp. S28
Author(s):  
J Ghossein ◽  
D Pohl
Keyword(s):  
Epileptiform Activity ◽  
Positive Family History ◽  
Myoclonic Epilepsy ◽  
First Year ◽  
Neurodevelopmental Outcomes ◽  
Epileptic Spasms ◽  
Ictal Eeg ◽  
Interictal Eeg ◽  
Eeg Recordings ◽  
First Year Of Life

Background: Benign spasms of infancy (BSI), previously described as benign non-epileptic infantile spasms or benign myoclonus of early infancy, are non-epileptic movements manifesting during the first year of life and spontaneously resolving in the second year of life. BSI are characterized by spasms typically lasting 1-2 seconds, involving to varying degrees the head, neck, trunk, shoulders and upper extremities. Ictal and interictal EEG recordings are normal. BSI are not associated with developmental retardation and do not require treatment. Distinction between BSI and infantile epileptic disorders, such as epileptic spasms or myoclonic epilepsy of infancy, can be challenging given the clinical similarities. Moreover, interictal EEGs can be normal in all conditions. Epileptic spasms and myoclonic epilepsy require timely treatment to improve neurodevelopmental outcomes. Methods: We describe a 6-month old infant presenting with spasm-like movements. His paroxysms as well as a positive family history for epileptic spasms were in keeping with a likely diagnosis of West syndrome. Results: Surprisingly, ictal video EEG did not reveal epileptiform activity, and suggested a diagnosis of BSI. Conclusions: We emphasize that ictal EEG is the gold standard for classification of infantile paroxysms as either epileptic or non-epileptic, thereby avoiding overtreatment of BSI and facilitating timely targeted treatment of infantile epilepsies.

scholarly journals Hyperperfusion in the thalamus on arterial spin labeling indicates non-convulsive status epilepticus

2020 ◽  
Author(s):  
Satoru Ohtomo ◽  
Hiroshi Otsubo ◽  
Hiroaki Arai ◽  
Yoshiteru Shimoda ◽  
Yoichiro Homma ◽  
...  
Keyword(s):  
Status Epilepticus ◽  
Critically Ill Patients ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Convulsive Status Epilepticus ◽  
Impaired Consciousness ◽  
Periodic Discharges ◽  
Epileptiform Discharges ◽  
Delta Activity ◽  
Rhythmic Delta Activity

Abstract Non-convulsive status epilepticus describes the syndrome of unexplained impaired consciousness in critically ill patients. Non-convulsive status epilepticus is very likely to lead to delayed diagnosis and poor outcomes because of the absence of convulsive symptoms. EEG is essential for the diagnosis of non-convulsive status epilepticus to establish the association between periodic discharges and rhythmic delta activity in addition to ictal epileptiform discharges according to the Salzburg criteria. Arterial spin labeling, a type of perfusion MRI, has been applied for rapid and non-invasive evaluation of the ictal state. Ictal cerebral cortical hyperperfusion is the most common finding to demonstrate focal onset seizures. Hyperperfusion of the thalamus on single photon emission computed tomography was found in patients with impaired awareness seizures. We hypothesized that thalamocortical hyperperfusion on arterial spin labeling identifies non-convulsive status epilepticus and such thalamic hyperperfusion specifically associates with periodic/rhythmic discharges producing impaired consciousness without convulsion. We identified 27 patients (17 females; age 58-91 years) who underwent both arterial spin labeling and EEG within 24 hours of suspected non-convulsive status epilepticus. We analyzed 28 episodes of suspected non-convulsive status epilepticus and compared hyperperfusion on arterial spin labeling with periodic/rhythmic discharges. We evaluated 21 episodes as a positive diagnosis of non-convulsive status epilepticus according to the Salzburg criteria. We identified periodic discharges in 15 (12 lateralized and three bilateral independent) episodes and rhythmic delta activity in 13 (10 lateralized, one bilateral independent, two generalized) episodes. Arterial spin labeling showed thalamic hyperperfusion in 16 (11 unilateral, 5 bilateral) episodes and cerebral cortical hyperperfusion in 24 (20 unilateral, 4 bilateral) episodes. Thalamic hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0007; sensitivity, 76.2%; specificity, 100%), periodic discharges (P < 0.0001; 93.3%; 84.6%), and rhythmic delta activity (P = 0.0006; 92.3%; 73.3%). Cerebral cortical hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0017; 100%; 57.1%) and periodic discharges (P = 0.0349; 100%; 30.8%), but not with rhythmic delta activity. Thalamocortical hyperperfusion could be a new biomarker of non-convulsive status epilepticus according to the Salzburg criteria in critically ill patients. Specific thalamic hyperexcitability might modulate the periodic discharges and rhythmic delta activity associated with non-convulsive status epilepticus. Impaired consciousness without convulsions could be caused by predominant thalamic hyperperfusion together with cortical hyperperfusion but without ictal epileptiform discharges.

scholarly journals Automatic detection of generalized paroxysmal fast activity in Lennox-Gastaut syndrome using a bi-modal EEG time-frequency feature

2020 ◽  
Author(s):  
Amir Omidvarnia ◽  
Aaron E.L. Warren ◽  
Linda J. Dalic ◽  
Mangor Pedersen ◽  
John S. Archer ◽  
...  
Keyword(s):  
Automatic Detection ◽  
Time Frequency ◽  
Scalp Eeg ◽  
Epileptiform Discharges ◽  
Fast Activity ◽  
Brain Maps ◽  
Detection Approach ◽  
Interictal Eeg ◽  
Eeg Recordings ◽  
Frequency Feature

AbstractObjectiveMark-up of generalized interictal epileptiform discharges (IEDs) on EEG is an important step in the diagnosis and characterization of epilepsy. However, manual EEG mark-up is a time-consuming, subjective, and highly specialized task where the human reviewer needs to visually inspect a large amount of data to facilitate accurate clinical decisions. The objective of this study was to develop a framework for automated detection of generalized paroxysmal fast activity (GPFA), which is a characteristic type of generalized IED seen in scalp EEG recordings of patients with Lennox-Gastaut syndrome (LGS), a severe form of drug-resistant generalized epilepsy.MethodsWe studied 13 children with LGS who had GPFA events in their interictal EEG recordings. Time-frequency information derived from manually marked IEDs across multiple EEG channels was used to automatically detect similar events in each patient’s interictal EEG. We validated true positives and false positives of the proposed spike detection approach using both standalone scalp EEG and simultaneous EEG-functional MRI (EEG-fMRI) recordings.ResultsGPFA events displayed a consistent low-high frequency arrangement in the time-frequency domain. This ‘bi-modal’ spectral feature was most prominent over frontal EEG channels. Our automatic detection approach using this feature identified likely epileptic events with similar time-frequency properties to the manually marked GPFAs. Brain maps of EEG-fMRI signal change during these automatically detected IEDs were comparable to the EEG-fMRI brain maps derived from manual IED mark-up.ConclusionGPFA events have a characteristic bi-modal time-frequency feature that can be automatically detected from scalp EEG recordings in patients with LGS. Validity of this time-frequency feature is demonstrated by EEG-fMRI analysis of automatically detected events, which recapitulates the brain maps we have previously shown to underlie generalized IEDs in LGS.SignificanceThis study provides a novel methodology that paves the way for quick, automated, and objective inspection of generalized IEDs in LGS. The proposed framework may be extendable to a wider range of epilepsy syndromes in which monitoring the burden of epileptic activity can aid clinical decision-making. For example, automated quantification of generalized discharges may permit faster assessment of treatment response and estimation of future seizure risk.

scholarly journals Excitatory GABAergic signalling is associated with acquired benzodiazepine resistance in status epilepticus

2018 ◽  
Author(s):  
Richard J. Burman ◽  
Joshua S. Selfe ◽  
John Hamin Lee ◽  
Maurits van den Burg ◽  
Alexandru Calin ◽  
...  
Keyword(s):  
Status Epilepticus ◽  
Epileptiform Activity ◽  
Brain Slices ◽  
Medical Emergency ◽  
Dependent Manner ◽  
High Concentration ◽  
Cellular Mechanisms ◽  
Epileptiform Discharges ◽  
Threatening Condition ◽  
Eeg Recordings

AbstractStatus epilepticus (SE) is defined as a state of unrelenting seizure activity. Generalised convulsive SE is associated with a rapidly rising mortality rate, and thus constitutes a medical emergency. Benzodiazepines, which act as positive modulators of chloride (Cl-) permeable GABAA receptors, are indicated as first-line treatment, but this is ineffective in many cases. We found that 48% of children presenting with SE were unresponsive to benzodiazepine treatment, and critically, that the duration of SE at the time of treatment is an important predictor of non-responsiveness. We therefore investigated the cellular mechanisms that underlie acquired benzodiazepine resistance, using rodent organotypic and acute brain slices. Removing Mg2+ ions leads to an evolving pattern of epileptiform activity, and eventually to a persistent state of repetitive discharges that strongly resembles clinical EEG recordings of SE. We found that diazepam loses its antiseizure efficacy and conversely exacerbates epileptiform activity during this stage of SE-like activity. Interestingly, a low concentration of the barbiturate phenobarbital had a similar exacerbating effect on SE-like activity, whilst a high concentration of phenobarbital was effective at reducing or preventing epileptiform discharges. We then show that the persistent SE-like activity is associated with a reduction in GABAA receptor conductance and Cl- extrusion capability. We explored the effect on intraneuronal Cl- using both gramicidin, perforated-patch clamp recordings and Cl- imaging. This showed that during SE-like activity, reduced Cl- extrusion capacity was further exacerbated by activity-dependent Cl- loading, resulting in a persistently high intraneuronal Cl-. Consistent with these results, we found that optogenetic stimulation of GABAergic interneurons in the SE-like state, actually enhanced epileptiform activity in a GABAAR dependent manner. Together our findings describe a novel potential mechanism underlying benzodiazepine-resistant SE, with relevance to how this life-threatening condition should be managed in the clinic.

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