Computer-Assisted Ambulatory Electroencephalography

Computer-assisted ambulatory electroencephalography (CAAEEG) is a useful tool when a diagnosis of paroxysmal events cannot be made on the basis of the clinical history, neurological examination, and routine outpatient awake and asleep EEG studies. CAEEG is uniquely able to monitor EEG and electrocardiography (ECG) in an outpatient environment over one to three days. Its most common use is to support a clinical diagnosis of epileptic seizures by identifying interictal epileptiform discharges. Studies indicate ambulatory EEG provides useful clinical information for patient management in over 70% of recordings. CAAEEG may be particularly useful in the pediatric age group, as well as in diagnosing psychogenic events. CAAEEG can assist in the quantification of seizures or determining seizure frequency. A few centers have used CAAEEG to assist in the presurgical evaluation of epilepsy patients. Its niche involves lower cost and less resource utilization compared with in-patient video-EEG monitoring and is more sensitive than routine outpatient EEG in detecting interictal epileptiform discharges.

The first-hour-of-the-day sleep EEG reliably identifies interictal epileptiform discharges during long-term video-EEG monitoring

Seizure ◽

10.1016/j.seizure.2018.10.015 ◽

2018 ◽

Vol 63 ◽

pp. 48-51 ◽

Cited By ~ 2

Author(s):

Xi Liu ◽

Naoum P. Issa ◽

Sandra Rose ◽

Shasha Wu ◽

Taixin Sun ◽

...

Keyword(s):

Sleep Eeg ◽

Eeg Monitoring ◽

Epileptiform Discharges ◽

TP3-6 Preliminary evaluation of diagnostic home video telemetry (HVT)

Journal of Neurology Neurosurgery & Psychiatry ◽

10.1136/jnnp-2019-abn.61 ◽

2019 ◽

Vol 90 (3) ◽

pp. e19.2-e20

Author(s):

W Stern ◽

G Leschziner ◽

R Howard ◽

M Koutroumanidis

Keyword(s):

Clinical Information ◽

Epileptic Seizures ◽

Preliminary Evaluation ◽

Clinical Question ◽

Home Video ◽

Clinical Events ◽

Idiopathic Hypersomnia ◽

Diagnostic Hypothesis ◽

Generalized Epilepsy ◽

ObjectivesTo assess the clinical usefulness of HVT over the first 2 years.DesignCohort observational.Subjects60 patients (49 F) with epilepsies or non-epileptic paroxysmal clinical events.Methods48–72 hour continuous video EEG at patients’ own environment.ResultsHVT answered the primary clinical question in 45/60 patients (75%), and provided additional clinical information in 5 patients [2 with unsuspected coexistent psychogenic non-epileptic seizures (PNES) and 3 with unsuspected sleep disorders (SD)]. Of the 12 patients with Idiopathic Generalized Epilepsy, absences had been overestimated in 6 and underestimated in 4, while absence status was recorded in 1 of the 2 patients in whom it had been suspected. Valproate was possible to drastically reduce or stop in 3/6 women. Focal seizures were recorded in 19 of 28 patients with focal epilepsies, PNES were the habitual seizures in further 2 patients, while syndrome classification changed in one. In all 4 patients referred for differentiation between SD and epilepsy, HVT confirmed parasomnias in 2, daytime naps in 1 and idiopathic hypersomnia in 1. The diagnosis of PNES was confirmed in 8 of 13 suspected patients. HVT was unhelpful in the 3 patients referred for not witnessed, poorly understood episodes of loss of consciousness. Three patients switched off the video and 2 failed to change battery on day 2.ConclusionsHVT is a useful diagnostic test provided that diagnostic hypothesis and clinical question are appropriate.

Congruence and Discrepancy of Interictal and Ictal EEG With MRI Lesions in Pediatric Epilepsies

Clinical EEG and Neuroscience ◽

10.1177/1550059420921712 ◽

2020 ◽

Vol 51 (6) ◽

pp. 412-419

Author(s):

Jan Rémi ◽

Sophie Shen ◽

Moritz Tacke ◽

Philipp Probst ◽

Lucia Gerstl ◽

...

Keyword(s):

Pediatric Patients ◽

Pediatric Epilepsy ◽

Resonance Imaging ◽

Epileptiform Discharges ◽

Ictal Eeg ◽

Magnetic Resonance Imaging Mri ◽

Surface Eeg ◽

Frontal Lesions ◽

Purpose. To evaluate the congruence or discrepancy of the localization of magnetic resonance imaging (MRI) lesions with interictal epileptiform discharges (IEDs) or epileptic seizure patterns (ESPs) in surface EEG in lesional pediatric epilepsy patients. Methods. We retrospectively analyzed presurgical MRI and video-EEG monitoring findings of patients up to age 18 years. Localization of MRI lesions were compared with ictal and interictal noninvasive EEG findings of patients with frontal, temporal, parietal, or occipital lesions. Results. A total of 71 patients were included. Localization of ESPs showed better congruence with MRI in patients with frontal lesions (n = 21, 77.5%) than in patients with temporal lesions (n = 24; 40.7%) ( P = .009). No significant IED distribution differences between MRI localizations could be found. Conclusions. MRI lesions and EEG findings are rarely fully congruent. Congruence of MRI lesions and ESPs was highest in children with frontal lesions. This is in contrast to adults, in whom temporal lesions showed the highest congruency with the EEG localization of ESP. Lesional pediatric patients should be acknowledged as surgical candidates despite incongruent findings of interictal and ictal surface EEG.

Criteria for defining interictal epileptiform discharges in EEG

Neurology ◽

10.1212/wnl.0000000000009439 ◽

2020 ◽

Vol 94 (20) ◽

pp. e2139-e2147 ◽

Cited By ~ 4

Author(s):

Mustafa Aykut Kural ◽

Lene Duez ◽

Vibeke Sejer Hansen ◽

Pål G. Larsson ◽

Stefan Rampp ◽

...

Keyword(s):

Clinical Neurophysiology ◽

High Specificity ◽

Class Iii ◽

Clinical Implementation ◽

Accurate Identification ◽

Epileptiform Discharges ◽

Space Method ◽

ObjectiveTo define and validate criteria for accurate identification of EEG interictal epileptiform discharges (IEDs) using (1) the 6 sensor space criteria proposed by the International Federation of Clinical Neurophysiology (IFCN) and (2) a novel source space method. Criteria yielding high specificity are needed because EEG over-reading is a common cause of epilepsy misdiagnosis.MethodsSeven raters reviewed EEG sharp transients from 100 patients with and without epilepsy (diagnosed definitively by video-EEG recording of habitual events). Raters reviewed the transients, randomized, and classified them as epileptiform or nonepileptiform in 3 separate rounds: in 2, EEG was reviewed in sensor space (scoring the presence/absence of each IFCN criterion for each transient or classifying unrestricted by criteria [expert scoring]); in the other, review and classification were performed in source space.ResultsCutoff values of 4 and 5 criteria in sensor space and analysis in source space provided high accuracy (91%, 88%, and 90%, respectively), similar to expert scoring (92%). Two methods had specificity exceeding the desired threshold of 95%: using 5 IFCN criteria as cutoff and analysis in source space (both 95.65%); the sensitivity of these methods was 81.48% and 85.19%, respectively.ConclusionsThe presence of 5 IFCN criteria in sensor space and analysis in source space are optimal for clinical implementation. By extracting these objective features, diagnostic accuracy similar to expert scorings is achieved.Classification of evidenceThis study provides Class III evidence that IFCN criteria in sensor space and analysis in source space have high specificity (>95%) and sensitivity (81%–85%) for identification of IEDs.

Influence of Sleep and Sleep Deprivation on Ictal and Interictal Epileptiform Activity

Epilepsy Research and Treatment ◽

10.1155/2013/492524 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Antonio Díaz-Negrillo

Keyword(s):

Sleep Deprivation ◽

Epileptiform Activity ◽

Epileptic Seizures ◽

Future Research ◽

Reciprocal Relation ◽

Physiological Factors ◽

Rigorous Approach ◽

Epileptiform Discharges ◽

The Relationship

Sleep is probably one of the most important physiological factors implicated both in epileptic seizures and interictal epileptiform discharges. The neurophysiology concerning the relationship between sleep and epilepsy is well described in the literature; however, the pathological events that culminate in the seizures are poorly explored. The present paper intends to make a rigorous approach to the main mechanisms involved in this reciprocal relation. Knowledge of sleep and sleep deprivation effects in epilepsy stands as crucial in the understanding of how seizures are produced, their possible lines of treatment, and future research.

Spontaneous EEG-Functional MRI in Mesial Temporal Lobe Epilepsy: Implications for the Neural Correlates of Consciousness

Epilepsy Research and Treatment ◽

10.1155/2012/385626 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Zheng Wang ◽

Loretta Norton ◽

R. Matthew Hutchison ◽

John R. Ives ◽

Seyed M. Mirsattari

Keyword(s):

Temporal Lobe ◽

Animal Studies ◽

Brain Activity ◽

Epileptic Seizures ◽

Mesial Temporal Lobe Epilepsy ◽

Unified Framework ◽

Epileptiform Discharges ◽

Mesial Temporal Lobe ◽

Hemodynamic Processes

The combination of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) has been shown to have great potential for providing a greater understanding of normal and diseased states in both human and animal studies. Simultaneous EEG-fMRI is particularly well suited for the study of epilepsy in that it may reveal the neurobiology of ictal and interictal epileptiform discharges and noninvasively localize epileptogenic foci. Spontaneous, coherent fluctuations of neuronal activity and the coupled hemodynamic responses have also been shown to provide diagnostic markers of disease, extending our understanding of intrinsically structured ongoing brain activity. Following a short summary of the hardware and software development of simultaneous EEG-fMRI, this paper reviews a unified framework of integrating neuronal and hemodynamic processes during epileptic seizures and discusses the role and impact of spontaneous activity in the mesial temporal lobe epilepsies with particular emphasis on the neural and physiological correlates of consciousness.

The long-term course of temporal lobe epilepsy: From unilateral to bilateral interictal epileptiform discharges in repeated video-EEG monitorings

Epilepsy & Behavior ◽

10.1016/j.yebeh.2016.12.027 ◽

2017 ◽

Vol 68 ◽

pp. 17-21 ◽

Cited By ~ 7

Author(s):

Stephanie Gollwitzer ◽

Catherine A. Scott ◽

Fiona Farrell ◽

Gail S. Bell ◽

Jane de Tisi ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epileptiform Discharges ◽

Interictal Epileptiform Discharge Dynamics in Peri-sylvian Polymicrogyria Using EEG-fMRI

Frontiers in Neurology ◽

10.3389/fneur.2021.658239 ◽

2021 ◽

Vol 12 ◽

Author(s):

Noa Cohen ◽

Yoram Ebrahimi ◽

Mordekhay Medvedovsky ◽

Guy Gurevitch ◽

Orna Aizenstein ◽

...

Keyword(s):

Case Series ◽

Epileptic Seizures ◽

Epileptic Activity ◽

Scalp Eeg ◽

Epileptiform Discharges ◽

Malformation Of Cortical Development ◽

Interictal Epileptiform Discharge ◽

Drug Resistant Epilepsy ◽

Patients With Epilepsy

Polymicrogyria (PMG) is a common malformation of cortical development associated with a higher susceptibility to epileptic seizures. Seizures secondary to PMG are characterized by difficult-to-localize cerebral sources due to the complex and widespread lesion structure. Tracing the dynamics of interictal epileptiform discharges (IEDs) in patients with epilepsy has been shown to reveal the location of epileptic activity sources, crucial for successful treatment in cases of focal drug-resistant epilepsy. In this case series IED dynamics were evaluated with simultaneous EEG-fMRI recordings in four patients with unilateral peri-sylvian polymicrogyria (PSPMG) by tracking BOLD activations over time: before, during and following IED appearance on scalp EEG. In all cases, focal BOLD activations within the lesion itself preceded the activity associated with the time of IED appearance on EEG, which showed stronger and more widespread activations. We therefore propose that early hemodynamic activity corresponding to IEDs may hold important localizing information potentially leading to the cerebral sources of epileptic activity. IEDs are suggested to develop within a small area in the PSPMG lesion with structural properties obscuring the appearance of their electric field on the scalp and only later engage widespread structures which allow the production of large currents which are recognized as IEDs on EEG.