Long-term video-EEG monitoring

Last updated

Long-term or "continuous" video-electroencephalography (EEG) monitoring is a diagnostic technique commonly used in patients with epilepsy. It involves the long-term hospitalization of the patient, typically for days or weeks, during which brain waves are recorded via EEG and physical actions are continuously monitored by video. In epileptic patients, this technique is typically used to capture brain activity during seizures. [1] The information gathered can be used for initial prognosis or long-term care management.

Contents

History

Electroencephalograph machine (left) with computer monitor (center) for display and photic device for stimulation. Electroencephalograph Neurovisor-BMM 40.jpg
Electroencephalograph machine (left) with computer monitor (center) for display and photic device for stimulation.

Like standard EEG-testing, long-term video-EEG monitoring techniques developed from techniques in 1875 by Richard Caton in Liverpool. In 1890, his work was expanded upon by Adolf Beck as developments to the technique were enhanced through animal studies of rhythmic oscillations in the brain due to light stimuli. [2] In these studies, electrodes were placed directly on the surface of the brain. Additional developments made using animal subjects persisted through the early 1900s including the work of Vladimir Vladimirovich Pravdich-Neminsky in 1912, Napoleon Cybulski and Jelenska-Macieszyna in 1914, as well as by Hans Berger in 1924 with the first human EEG recording. [3] [4] These developments lead to the modern EEG techniques which allow for non-invasive measurements using externally placed EEG caps and were established by William Grey Walter in the 1950s. From these easy uses and techniques, a longer-term method of EEG monitoring was developed called long-term video-EEG monitoring which applies these same brain-wave monitoring techniques in a long-duration test format. This test format allows at-home or extended monitoring in clinics and hospitals where the standard EEG monitoring was previously unable to be used.

In either case, these EEG measuring techniques allow one to non-invasively measure action potentials of groups of neurons within the brain using transducers called electrodes. The electrical signals from these electrode transducers are then amplified using differential amplifiers to measure potential differences from one area of the scalp or brain to another. The acquired analog signal is then converted to a digital signal to allow processing and storage of the data using an analog-to-digital converter which is then filtered to remove any signal noise not associated with the neuronal activity. The final signal can then be displayed on an external computer screen as a visual representation of the EEG signals measured. Other EEG techniques can sum these cellular responses either temporally or spatially and help determine which areas of the brain are active during specific activities or due to specific stimuli.[ citation needed ]

Medical Uses

Epileptic EEG output collected from a child with childhood absence epilepsy. Spike-waves.png
Epileptic EEG output collected from a child with childhood absence epilepsy.

Long-term video-EEG monitoring is utilized in the localization of epileptogenic zones which are the areas of the cortex of the brain responsible for epileptic seizures. [5] Long-term video-EEG monitoring is similar to EEG in that the brain waves are periodically monitored and analyzed by a neurologist, typically one trained in clinical neurophysiology. The neurologist determines when the monitoring is finished and issues the final report after the compiled data is interpreted.

The results from the EEG and video monitoring are used to characterize episodic disruptions in brain function and its physical manifestations; many recordings show symptoms of epileptic seizures over time and how severe/frequent the seizures become over a given period of time. [6]

The purposes of long-term video-EEG monitoring include discovering where in the brain seizures begin for a given patient, the severity of the seizures (measured according to a scaled order), determining the frequency of the seizures, the duration and prominence of physical activity during the seizure (which may be indicator of status epilepticus, prolonged seizures or increased frequency of seizures without a return to an otherwise normal state), and distinguishing epileptic seizures from psychogenic non-epileptic seizures. Additionally, audio recordings of patients (verbal and nonverbal) may be taken of the subject during those seizures. Each of these topics may then be used to evaluate a subject's candidacy for surgery to treat epilepsy.

In adults, long-term EEG monitoring typically involves one of three procedures which include long-term video-EEG monitoring, sleep-deprived EEG monitoring, and 24-hour ambulatory monitoring. [7] Long-term video-EEG monitoring typically lasts from a few hours to several days. Depending on the needs of the patient where sleep-deprived and ambulatory EEG monitoring are often used to further investigate symptoms of epilepsy when a standard EEG reading returns inconclusive results. Furthermore, sometimes all three procedures of long-term EEG monitoring are utilized for a single patient due to niche results found in each. Video-EEG (LTVER) specializes in recording of seizures for topographic diagnosis as well as for diagnosis of paroxysmal clinical events. Sleep-deprived EEG monitoring diagnoses specific EEG abnormalities for syndromic classification. Lastly, Ambulatory EEG focuses on monitoring/ quantification of EEG abnormalities.

Long-term video-EEG monitoring is typically used in cases of drug-resistant epilepsy to examine symptoms before surgery and is also used to more precisely diagnose a patient when episodes become more frequent. [7]

Risks/Complications

In order to perform long-term video-EEG monitoring appropriately, a patient is admitted into a hospital or clinic, where epileptic seizures may be induced using sleep deprivation techniques or temporarily ceasing the patient's use of antiepileptic drugs. With these techniques, the patient under observation is susceptible to not only experiencing a higher frequency of seizures, but to a change in seizure type or seizure intensity. These changes in seizure behavior can in turn lead to the patient experiencing a higher risk of injuries due to uncontrolled mental behavior such as aggression, psychosis, self-inflicted injury, as well as seizure-related injuries including falls and status epilepticus. Finally, other safety concerns of patients under observation using long-term video-EEG monitoring include technical problems with the equipment used such as electrode degradation and restraints. Each of these safety concerns are negated with staff training and education. [1]

In human use for diagnostic purposes, long-term video-EEG monitoring is a relatively safe procedure compared to other invasive brain-monitoring techniques. However, despite long-term video-EEG monitoring being a generally non-invasive procedure, there still exists the potential for adverse events to occur. These adverse events can mostly prevented with proper test administration. Should an adverse event occur, increased time of hospitalization or death are not likely. [8]

Society and Culture

As seizures have become more easily monitored by neurologists, as well as patients, EEGs and long-term video-EEGs have become the standard for both hospital and home-care. The data and information logs of these EEGs provide insight to a patient's condition that may be otherwise improperly recorded or noticed and can allow for a sense of security and control for the individual/caregiver. The use of long-term EEG thus allows for full episodic events to be recorded so as to give semiological clues that are needed to define the epileptogenic zone in the brain where these events are occurring. [9]

At-home long-term video-EEG monitoring reduces the financial burden, since the individual is no longer at a hospital, or place of care, for long periods of time, as well as allowing for possible epileptic triggers to remain. For example, how an individual has habits at their home, the feeling of their bed when sleeping, or stress levels at home may influence the onset of an episode. [9] Remaining at home will keep the patient under the conditions they would normally be under, when experiencing a seizure. In contrast, long-term video-EEG monitoring may record non-cerebral signals from throughout the body such as biological and extra-physiological artifacts and thus makes the data logs susceptible to displaying false positives that can result in false seizure reports. [10] These false data reports may then impede the neurologist from distinguishing where an episode may begin and end, or if an episode occurred at all. The use of at-home devices also introduces obstacles such as daily visits by a professional to collect the data logs and to take care of the equipment, equipment hazards, and lighting issues for the video recording device. [9] Having long-term video-EEG monitoring sessions in a clinical setting provides a controlled environment that allows the health professional to most efficiently collect data, monitor seizure inducing procedures, and keep the equipment functioning properly.

Research

EEG cap setup. EEG recording.jpg
EEG cap setup.

Research involving the use of long-term video-EEG monitoring has mostly involved animal models which allows for neuronal activity to be better understood by using methods that may involve the use of psychoactive drugs or inducing states that would not be ethical to induce in humans experimentally. These models provide a relatively inexpensive and low risk scenario compared to humans, when testing their effects on the brain in response to events such as pre-clinical and clinical use of pharmaceutical drugs. [11] The use of animal models also allows for variables, that are not as easily related to seizures in humans, to be taken into account such as how status epileptici affect their brain over an individual's life span, familial lineage, and development during maturation. [12] Thus the heritability, prevalence, and general development of seizures over many generations can be closely monitored and studied.

Current research being performed using long-term video-EEG monitoring mostly focuses on the mouse model known as C57BL/6J which can be used to induce behavioral convulsive (CS) and electrographic-nonconvulsive (NCS) seizures. These seizures can then be monitored over a 4-18 week period, which is a much longer period than most humans are normally comfortable with. As these mice are monitored, factors such as the length of the episode, spike amplitude, interspike interval, and spike frequency can all be closely observed to see how CS and NCS develop over the trial. [12] The stages of the status epileptici can then be distinguished by using scales, such as the Racine Stages and CSS indices, to determine the severity of the episode and how they may also change over a given cycle. [12]

Related Research Articles

<span class="mw-page-title-main">Seizure</span> Period of symptoms due to excessive or synchronous neuronal brain activity

An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with loss of consciousness, to shaking movements involving only part of the body with variable levels of consciousness, to a subtle momentary loss of awareness. Most of the time these episodes last less than two minutes and it takes some time to return to normal. Loss of bladder control may occur.

Absence seizures are one of several kinds of generalized seizures. In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures ; however, usage of this terminology is no longer recommended. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy. Absence seizures are most common in children. They affect both sides of the brain.

Landau–Kleffner syndrome (LKS)—also called infantile acquired aphasia, acquired epileptic aphasia or aphasia with convulsive disorder—is a rare childhood neurological syndrome.

Frontal lobe epilepsy (FLE) is a neurological disorder that is characterized by brief, recurring seizures arising in the frontal lobes of the brain, that often occur during sleep. It is the second most common type of epilepsy after temporal lobe epilepsy (TLE), and is related to the temporal form in that both forms are characterized by partial (focal) seizures.

<span class="mw-page-title-main">Electrocorticography</span>

Electrocorticography (ECoG), a type of intracranial electroencephalography (iEEG), is a type of electrophysiological monitoring that uses electrodes placed directly on the exposed surface of the brain to record electrical activity from the cerebral cortex. In contrast, conventional electroencephalography (EEG) electrodes monitor this activity from outside the skull. ECoG may be performed either in the operating room during surgery or outside of surgery. Because a craniotomy is required to implant the electrode grid, ECoG is an invasive procedure.

The postictal state is the altered state of consciousness after an epileptic seizure. It usually lasts between 5 and 30 minutes, but sometimes longer in the case of larger or more severe seizures, and is characterized by drowsiness, confusion, nausea, hypertension, headache or migraine, and other disorienting symptoms.

Epilepsy surgery involves a neurosurgical procedure where an area of the brain involved in seizures is either resected, ablated, disconnected or stimulated. The goal is to eliminate seizures or significantly reduce seizure burden. Approximately 60% of all people with epilepsy have focal epilepsy syndromes. In 15% to 20% of these patients, the condition is not adequately controlled with anticonvulsive drugs. Such patients are potential candidates for surgical epilepsy treatment.

EEG-fMRI is a multimodal neuroimaging technique whereby EEG and fMRI data are recorded synchronously for the study of electrical brain activity in correlation with haemodynamic changes in brain during the electrical activity, be it normal function or associated with disorders.

Racine stages are a categorization of epileptic seizures proposed by Ronald J. Racine in 1972. Prior to Racine's research in epilepsy, a quantifiable means to describe seizure intensities and their causes was not readily available. Racine's work allowed for epilepsy to be understood on a level previously thought impossible.

<span class="mw-page-title-main">Generalized tonic–clonic seizure</span> Type of generalized seizure that affects the entire brain

A generalized tonic–clonic seizure, commonly known as a grand mal seizure or GTCS, is a type of generalized seizure that produces bilateral, convulsive tonic and clonic muscle contractions. Tonic–clonic seizures are the seizure type most commonly associated with epilepsy and seizures in general and the most common seizure associated with metabolic imbalances. It is a misconception that they are the sole type of seizure, as they are the main seizure type in approximately 10% of those with epilepsy.

<span class="mw-page-title-main">Spike-and-wave</span>

Spike-and-wave is a pattern of the electroencephalogram (EEG) typically observed during epileptic seizures. A spike-and-wave discharge is a regular, symmetrical, generalized EEG pattern seen particularly during absence epilepsy, also known as ‘petit mal’ epilepsy. The basic mechanisms underlying these patterns are complex and involve part of the cerebral cortex, the thalamocortical network, and intrinsic neuronal mechanisms.

<span class="mw-page-title-main">Rolandic epilepsy</span> Most common epilepsy syndrome in childhood, usually subsiding with age

Benign Rolandic epilepsy or self-limited epilepsy with centrotemporal spikes is the most common epilepsy syndrome in childhood. Most children will outgrow the syndrome, hence the label benign. The seizures, sometimes referred to as sylvian seizures, start around the central sulcus of the brain.

Panayiotopoulos syndrome is a common idiopathic childhood-related seizure disorder that occurs exclusively in otherwise normal children and manifests mainly with autonomic epileptic seizures and autonomic status epilepticus. An expert consensus has defined Panayiotopoulos syndrome as "a benign age-related focal seizure disorder occurring in early and mid-childhood. It is characterized by seizures, often prolonged, with predominantly autonomic symptoms, and by an EEG [electroencephalogram] that shows shifting and/or multiple foci, often with occipital predominance."

<span class="mw-page-title-main">Electroencephalography</span> Electrophysiological monitoring method to record electrical activity of the brain

Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp using the International 10–20 system, or variations of it. Electrocorticography, involving surgical placement of electrodes, is sometimes called "intracranial EEG". Clinical interpretation of EEG recordings is most often performed by visual inspection of the tracing or quantitative EEG analysis.

Jeavons syndrome is a type of epilepsy. It is one of the most distinctive reflex syndromes of idiopathic generalized epilepsy characterized by the triad of eyelid myoclonia with and without absences, eye-closure-induced seizures, EEG paroxysms, or both, and photosensitivity. Eyelid myoclonia with or without absences is a form of epileptic seizure manifesting with myoclonic jerks of the eyelids with or without a brief absence. These are mainly precipitated by closing of the eyes and lights. Eyelid myoclonia is the defining seizure type of Jeavons syndrome.

People with epilepsy may be classified into different syndromes based on specific clinical features. These features include the age at which seizures begin, the seizure types, and EEG findings, among others. Identifying an epilepsy syndrome is useful as it helps determine the underlying causes as well as deciding what anti-seizure medication should be tried. Epilepsy syndromes are more commonly diagnosed in infants and children. Some examples of epilepsy syndromes include benign rolandic epilepsy, childhood absence epilepsy and juvenile myoclonic epilepsy. Severe syndromes with diffuse brain dysfunction caused, at least partly, by some aspect of epilepsy, are also referred to as epileptic encephalopathies. These are associated with frequent seizures that are resistant to treatment and severe cognitive dysfunction, for instance Lennox-Gastaut syndrome and West syndrome.

A neonatal seizure is a seizure in a baby younger than age 4-weeks that is identifiable by an electrical recording of the brain. It is an occurrence of abnormal, paroxysmal, and persistent ictal rhythm with an amplitude of 2 microvolts in the electroencephalogram,. These may be manifested in form of stiffening or jerking of limbs or trunk. Sometimes random eye movements, cycling movements of legs, tonic eyeball movements, and lip-smacking movements may be observed. Alteration in heart rate, blood pressure, respiration, salivation, pupillary dilation, and other associated paroxysmal changes in the autonomic nervous system of infants may be caused due to these seizures. Often these changes are observed along with the observance of other clinical symptoms. A neonatal seizure may or may not be epileptic. Some of them may be provoked. Most neonatal seizures are due to secondary causes. With hypoxic ischemic encephalopathy being the most common cause in full term infants and intraventricular hemorrhage as the most common cause in preterm infants.

<span class="mw-page-title-main">Amplitude integrated electroencephalography</span> Technique for monitoring brain function in intensive care settings

Amplitude integrated electroencephalography (aEEG), cerebral function monitoring (CFM) or continuous electroencephalogram (CEEG) is a technique for monitoring brain function in intensive care settings over longer periods of time than the traditional electroencephalogram (EEG), typically hours to days. By placing electrodes on the scalp of the patient, a trace of electrical activity is produced which is then displayed on a semilogarithmic graph of peak-to-peak amplitude over time; amplitude is logarithmic and time is linear. In this way, trends in electrical activity in the cerebral cortex can be interpreted to inform on events such as seizures or suppressed brain activity. aEEG is useful especially in neonatology where it can be used to aid in diagnosis of hypoxic ischemic encephalopathy (HIE), and to monitor and diagnose seizure activity.

Drug-resistant epilepsy (DRE), also known as refractory epilepsy, intractable epilepsy, or pharmacoresistant epilepsy, is diagnosed following a failure of adequate trials of two tolerated and appropriately chosen and used antiepileptic drugs (AEDs) to achieve sustained seizure freedom. The probability that the next medication will achieve seizure freedom drops with every failed AED. For example, after two failed AEDs, the probability that the third will achieve seizure freedom is around 4%. Drug-resistant epilepsy is commonly diagnosed after several years of uncontrolled seizures, however, in most cases, it is evident much earlier. Approximately 30% of people with epilepsy have a drug-resistant form.

EEG analysis is exploiting mathematical signal analysis methods and computer technology to extract information from electroencephalography (EEG) signals. The targets of EEG analysis are to help researchers gain a better understanding of the brain; assist physicians in diagnosis and treatment choices; and to boost brain-computer interface (BCI) technology. There are many ways to roughly categorize EEG analysis methods. If a mathematical model is exploited to fit the sampled EEG signals, the method can be categorized as parametric, otherwise, it is a non-parametric method. Traditionally, most EEG analysis methods fall into four categories: time domain, frequency domain, time-frequency domain, and nonlinear methods. There are also later methods including deep neural networks (DNNs).

References

  1. 1 2 Sanders, P. T.; Cysyk, B. J.; Bare, M. A. (1996-10-01). "Safety in long-term EEG/video monitoring". The Journal of Neuroscience Nursing. 28 (5): 305–313. doi:10.1097/01376517-199610000-00004. ISSN   0888-0395. PMID   8950695. S2CID   2853491.
  2. ↑ Coenen, Anton; Fine, Edward; Zayachkivska, Oksana (2014-07-03). "Adolf Beck: A Forgotten Pioneer in Electroencephalography". Journal of the History of the Neurosciences. 23 (3): 276–286. doi:10.1080/0964704X.2013.867600. ISSN   0964-704X. PMID   24735457. S2CID   205664545.
  3. ↑ Pravdich-Neminsky, Vladimir Vladmirovch (1913). "Ein Versuch der Registrierung der elektrischen Gehirnerscheinungen". Zentralblatt für Physiologie. 27: 951–60.
  4. ↑ Haas, L. F. (2003-01-01). "Hans Berger (1873–1941), Richard Caton (1842–1926), and electroencephalography". Journal of Neurology, Neurosurgery & Psychiatry. 74 (1): 9. doi:10.1136/jnnp.74.1.9. ISSN   0022-3050. PMC   1738204 . PMID   12486257.
  5. ↑ Asano, E; Pawlak, C; Shah, A; Shah, J; Luat, AF; Ahn-Ewing, J; Chugani, HT (2005). "The diagnostic value of initial video-EEG monitoring in children--review of 1000 cases". Epilepsy Res. 66 (1–3): 129–35. doi:10.1016/j.eplepsyres.2005.07.012. PMID   16157474. S2CID   22132928.
  6. ↑ Lagerlund, TD; Cascino, GD; Cicora, KM; Sharbrough, FW (1996). "Long-term electroencephalographic monitoring for diagnosis and management of seizures". Mayo Clinic Proceedings. 71 (10): 1000–1006. doi:10.1016/S0025-6196(11)63776-2. PMID   8820777.
  7. 1 2 Michel, V; Mazzola, L; Lemesle, M; Vercueil, L (2015). "Long-term EEG in adults: sleep-deprived EEG (SDE), ambulatory EEG (Amb-EEG) and long-term video-EEG recording(LTVER)". Neurophysiologie Clinique. 45 (1): 47–64. doi:10.1016/j.neucli.2014.11.004. PMID   25638591. S2CID   12350619.
  8. ↑ Noe, Katherine, H.; Drazkowski, Joseph, F. (2009). "Safety of Long-term Video-Electroencephalographic Monitoring for Evaluation of Epilepsy". Mayo Clinic Proceedings. 84 (6): 495–500. doi:10.4065/84.6.495. PMC   2688622 . PMID   19483165.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  9. 1 2 3 Whittaker RG (2015). "Video telemetry: current concepts and recent advances". Practical Neurology. 15 (6): 445–50. doi:10.1136/practneurol-2015-001216. PMID   26271266. S2CID   24387954.
  10. ↑ Van de Vel, A; Cuppens, K; Bonroy, B; Milosevic, M; Jansen, K; Van Huffel, S; Vanrumste, B; Lagae, L; Ceulemans, B (2013). "Non-EEG seizure-detection systems and potential SUDEP prevention: state of the art". Seizure. 22 (5): 345–55. doi: 10.1016/j.seizure.2013.02.012 . PMID   23506646.
  11. ↑ Drinkenburg, Wilhelmus; Ahnaou, Abdallah; Ruigt, Gé (February 23, 2016). "Pharmaco-EEG Studies in Animals: A History-Based Introduction to Contemporary Translational Applications". Neuropsychobiology. 72 (3–4): 139–150. doi: 10.1159/000443175 . PMID   26901675.
  12. 1 2 3 Puttachary, S; Sharma, S; Tse, K; Beamer, E; Sexton, A; Crutison, J; Thippeswamy, T (2015). "Immediate Epileptogenesis after Kainate-Induced Status Epilepticus in C57BL/6J Mice: Evidence from Long Term Continuous Video-EEG Telemetry". PLOS ONE. 10 (7): e0131705. doi: 10.1371/journal.pone.0131705 . PMC   4498886 . PMID   26161754.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.