Management of drug-resistant epilepsy

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Management of drug-resistant epilepsy
Other namesRefractory epilepsy
Specialty neurology

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) (whether as monotherapies or in combination) to achieve sustained seizure freedom. [1] [2] 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%. [3] 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. [4]

Contents

When two AED regimens have failed to produce sustained seizure-freedom, it is important to initiate other treatments to control seizures. Next to indirect consequences like injuries from falls, accidents, drowning and impairment in daily life, seizure control is critical because uncontrolled seizures -specifically generalized tonic clonic seizures- can damage the brain and increase the risk for sudden unexpected death in epilepsy called SUDEP. [5] [6] The first step is for physicians to refer their DRE patients to an epilepsy center.

Diagnostic evaluation

Prolonged EEG/Continuous video EEG/ Epilepsy Monitoring Unit monitoring

One of the first steps in management of drug resistant epilepsy is confirming the diagnosis by EEG. Typically patients are admitted to hospital for prolonged EEG monitoring. [7] Typically patients are taken off their antiseizure medications so that the evolution of seizure symptoms and their relation with changes in electrical activity of brain can be determined; while minimizing adverse consequences of seizures as far as possible. Additional maneuvers to provoke seizures are also frequently performed, like sleep deprivation, photic stimulation, hyperventilation. This study can take 3–14 days. Length of study depends on factors like baseline seizure frequency, number and types of seizure medication patient is taking prior to study, institutional protocols etc. The goal is to record 3-4 typical seizures, though in some cases more or fewer seizures may need to be recorded. After this evaluation some patients may be determined to have non-epileptic causes of their symptoms, eg syncope, psychogenic nonepileptic seizures, cardiac arrhythmia etc. For patients who are confirmed to have epilepsy, this testing helps confirm the type of epilepsy- generalized vs focal. In case of focal epilepsy, this evaluation provides crucial information to determine the area of brain where seizures begin. Information from seizure symptoms and their evolution over the course of the seizure as well changes on EEG in relation to the symptoms is used to hypothesize the likely area of the brain responsible for seizure symptoms (symptomatic zone) and by extrapolation the area where seizure likely starts (seizure onset zone).

In some specific cases, prolonged EEG may be done as an outpatient or ambulatory study where patient goes home with EEG set-up. This type of monitoring is usually limited to 2–3 days and patients are not taken off their medications.

Neuroimaging

MRI of brain is the most common neuroimaging modality to be used in evaluation of epilepsy. A 3 Tesla MRI is generally recommended, as opposed to scanning on lower magnet strengths. MRI for evaluation of epilepsy often include T1 and T2 images with small voxel size, that are optimized to appreciate gray-white matter differentiation and oblique coronal images along the axis of hippocampus. Identification of lesions like focal cortical dysplasia, mesial temporal sclerosis, microencephalocele, heterotopia require thorough review of images by trained clinicians as the changes can be very subtle and easily missed if not specifically evaluated for. There is active research to develop newer ways of processing information from MRI to better identify subtle structural lesions that can be associated with seizures. There is also ongoing quantitative analysis of standard MRI images to identify subtle lesions and use of stronger magnetic fields, like 7Tesla MRI, for better delineation of anatomical details.

Positron emission tomography scan using [18F]DG is often used in evaluation of drug resistant epilepsy as well. Its use in epilepsy evaluation is based on the idea that areas of brain responsible for seizure onset also have persistent metabolic dysfunction. So they do not use glucose at the same rate as normal healthy brain. Areas involved in seizure onset or early propagation are expected to have lower glucose uptake, hence, lower radiotracer uptake, compared to other parts. Other ligands like 11C-flumazenil, 11C-alpha-methyl-L-tryptophan, 11C-methionine, have also been used, mostly on research basis to help identify areas of seizure onset. PET-MRI involves coregisteration of PET and MRI images to better identify areas of cortex with relative hypometabolism.

SPECT scan is another radiotracer based imaging technique that uses oxygen radio-isotope to assess blood flow. This imaging is performed during inpatient video EEG monitoring. The tracer is injected in patient's vein as soon as a seizure starts with the idea that areas of brain associated with seizure onset will have increase blood flow at seizure onset, hence, will show increase uptake of the tracer if injected at an appropriate time. Imaging is performed after seizure is over and patient is medically stable to be taken to the scanner. Post hoc analysis to assess areas showing significant increase in blood flow at seizure onset, compared to resting state, is used to identify areas of onset and early propagation. A major limitation with this technique is early identification of seizure onset for injection of radiotracer to be given well before the seizure discharge has spread widely.

Neuropsychological testing

This includes a battery of tests to assess higher mental functions like memory, executive function, language functions, overall IQ etc. If there is poor performance in measures of specific cognitive domains like verbal memory, naming, visuo-spatial orientation; it may point to areas of brain that are dysfunctional and likely related to seizure onset. This testing could also indicate poor performance on most measures and suggest more widespread dysfunction in the brain. Besides helping assess the likely area of seizure onset, this testing also informs about cognitive risks from epilepsy surgery.

Language Lateralization

If epilepsy surgery is being considered, often a test is performed to determine the hemisphere of brain that is dominant for language and memory function. This helps inform about potential risks to language and memory with surgery. There are two main tests available for this objective- Wada test and fMRI.

Wada test has been one of the most commonly used tests around the world since the 1960s. This is an invasive procedure that requires neurointerventionalists, neuropsychologists, neurophysiologists, EEG technologists, anesthetists among the team members. A catheter is threaded from wrist or groin into the carotid artery and then the middle cerebral artery. [8] An injection of sodium amytal is then given to temporarily anesthetize 2/3rd of the cerebral hemisphere on one side. Neuropsychological testing is done to assess language and memory function of the other hemisphere. Once patient is fully recovered from the injection on first side, the catheter is withdrawn and threaded up the other middle cerebral artery for transient anesthesia in the other hemisphere and testing of the hemisphere injected first. This testing informs the "reserve" for memory and language function in each hemisphere and potential for decline in these with resective surgery on a given side. In some cases additional testing with selective injection of posterior cerebral artery (that supplies the mesial temporal region including hippoampus) can be done to assess potential change in function with loss of these mesial structures on either side. [9]

Wada is increasingly being replaced by fMRI which is a noninvasive test. Functional MRI or fMRI measure the change in blood flow and oxygenation in different parts of the brain, in response to an activity. Different tasks or paradigms are presented to a patient while they are in an MRI scanner. These tasks are designed to make the patient think of words, meaning of words, read, listen to language stimuli etc and hence, activate areas involved in different language functions while continuous scanning is being done. Post processing of the images helps identify areas that are activated during different language tasks.

Other Tests

MEG

Surgery

In epilepsy surgery, a distinction can be made between resective and disconnective procedures. In a resective procedure the area of the brain that causes the seizures is removed. In a disconnective procedure the neural connections in the brain that allow the seizures to spread are disconnected. In most cases epilepsy surgery is only an option when the area of the brain that causes the seizures - the so-called epileptic focus can be clearly identified and is not responsible for critical functions such as language. Several imaging techniques such as magnetic resonance tomography and functional techniques like electrocorticography are used to demarcate the epileptic focus clearly. [10] Recording fMRI and EEG simultaneously is a noninvasive method detecting cerebral hemodynamic changes related to interictal epileptic discharges (IEDs) on scalp EEG. This has been shown through different studies to help diagnose different types of epilepsy. [10]

Lobe resection

Temporal lobe epilepsy (TLE) in which the epileptic focus is in the temporal lobe, is one of the most common types of epilepsy in adolescents and adults. Hence temporal lobe resection, during which the whole temporal lobe or just a part of the temporal lobe for example the hippocampus or the amygdala is removed, is the most common epilepsy surgery procedure. Between 40 and 60% of patients that undergo temporal lobe resection are continuously seizure free [11] [12] The surgery itself is very safe with a mortality of 0%. [13] [14] The risk for neurologic complications from a temporal lobe resection is around 3 to 7% [15] [16]

Lesionectomy

If the source of seizures is a lesion, for example a scar tissue from a brain injury a tumor or malformed blood vessels, this lesion can be removed surgically in a lesionectomy.[ citation needed ]

Corpus callosotomy

Corpus callosotomy is a palliative procedure for specially severe cases of epilepsy. This corpus callosum is a large bundle of nerve fibers that connects both brain halves with each other. To prevent the spreading of seizures from one brain hemisphere (brain half) to the other the corpus callosum can be split. This procedure is mostly carried out on patients with so-called drop attacks that come with a very high risk of injury and in which the epileptic focus is not clearly delimitable. It is very rare that a corpus callosotomy causes seizure freedom however in half of the patients the dangerous drop attacks are less severe. [17] After a corpus callosotomy among others there is the risk that language is temporarily or permanently impaired. The younger a patient is at the time of the corpus callosotomy, the better the prognosis.[ citation needed ]

Functional hemispherectomy

This procedure is a modern adaptation of the radical hemispherectomy in which one brain hemisphere is removed to prevent the spread of seizures from one brain hemisphere to the other. In the functional version only a part of the hemisphere is removed but the connections to the other brain hemisphere are cut through. This procedure is only performed on a small group of patients under the age of 13 that have severe damage or malformation of one hemisphere, patients with Sturge Weber syndrome or patients with Rasmussen's encephalitis. Surgical intervention is considered a viable option for infants with drug-resistant epilepsy, particularly when anti-seizure medications fail to achieve seizure control. For this population, surgery can lead to favorable outcomes in a substantial number of cases. [18] The functional hemispherectomy can achieve long-term seizure freedom in over 80% of patients however often at the price of hemiplegia and hemianopsy. The death rate is around 1 to 2% and 5% of patients develop a hydrocephalus that needs to be treated with a shunt. [19]

Multiple subpial transection

Multiple subpial transection (MST) is a palliative procedure that is considered when an epileptic focus can be identified but cannot be removed because it is in a functionally relevant brain region- a so-called eloquent region. In an MST nerve fibers are disconnected so that seizures cannot spread from the epileptic focus into the rest of the brain. Between 60 and 70% of patients experienced a seizure reduction of over 95% after an MST and the risk for neurologic deficits is around 19%. [20]

Vagus nerve stimulation

Vagus nerve stimulation (VNS) involves implanting a pacemaker-like generator below the skin in the chest area that intermittently sends electrical impulses to the left vagus nerve in the neck. The impulses are mediated to the brain by the vagus nerve and thereby help to inhibit electrical disturbances that cause seizures. The antiepileptic effect of vagus nerve stimulation increases over several months: after two years around half of VNS patients experience a reduction of their seizures by at least 50% [21] [22] and after 10 years the average seizure reduction is around 75% [23] Furthermore, in most patients mood (VNS has a significant anti-depressent effect and is approved for depression in some countries), alertness and quality-of-life are increased significantly within the first year of vagus nerve stimulation. [24] [25] VNS patients can induce an extra stimulation themselves with a VNS magnet when they noticed that a seizure is approaching and it has been shown that the majority of seizures can be interrupted this type of on-demand stimulation. [26] [27]

The procedure to implant a vagus nerve stimulator is very safe: no case of death related to VNS implantation surgery has ever occurred. Infection of the tissue pocket in which the generator is located that requires antibiotic treatment occurs in around 3% of patients. [28] [29] The most common side effect is hoarseness or change in voice. Headaches and shortness of breath are less common. In most cases, side effects only occur during activity of the stimulation (mostly every 3 to 5 minutes) and reduce over time. [30] In most cases VNS does not replace antiepileptic medication. Patients must continue their antiepileptic medication however in many cases the dose can be reduced over time so that patients experience fewer side effects of the medication. The battery of the VNS generator can, depending on the model and the settings, last between 3 and 10 years.[ citation needed ]

VNS with cardiac-based seizure detection

In 82% of epilepsy patients the heart rate increases quickly and suddenly upon a seizure [31] This is known as ictal tachycardia. Ictal tachycardia is so characteristic that it can be distinguished from the slow gradual increase of heart rate that occurs during physical activity. This way in the majority of epilepsy patients seizures can be detected in the ECG. In addition to classical VNS, some new VNS generators continuously monitor heart rate and identify fast and sudden heart rate increases associated with seizures with intelligent software. Then an automatic additional stimulation can be triggered to interrupt, prevent or alleviate the seizure. This new generator type was shown to detect and treat at least four out of five seizures and 60% of seizures were shown to be interrupted with this heart-rate triggered stimulation. [32] The earlier in the course of the seizure the stimulation occurred the quicker the seizure ended generally seizures were shown to be reduced by around 35% by stimulation [33] [34]

Diets

For over 100 years it has been known that a diet with a high fat content and a low carbohydrate content can reduce seizures. Radically curbing carbohydrate intake imitates starvation and forces the body to draw energy from ketone bodies that form when fat is metabolized instead of drawing its energy from sugar. This state is called ketosis and it changes several biochemical processes in the brain in a way that inhibits epileptic activity. On this basis there are several diets that are often recommended to children under 12 years old, but are also effective in adults.[ citation needed ]

Ketogenic diet

In Europe the ketogenic diet is the diet that is most commonly recommended by doctors for patients with epilepsy. In this diet the ratio of fat to carbohydrates and proteins is 4:1. That means that the fat content of the consumed food must be around 80%, the protein content must be around 15%, and the carbohydrate content must be around 5%. For comparison the average western diet consists of a carbohydrate content of over 50%. After one year on the ketogenic diet the success rate (seizure reduction over 50%) is between 30 and 50% and the dropout rate is around 45%. [35] [36] Although the ketogenic diet can be very effective some families report that it's not compatible with daily life on the long run because it's too restrictive as bread pasta and sweets are forbidden in the ketogenic diet. In puberty with increasing autonomy it can be difficult for adolescents to follow the diet strictly. For this reason a fat ratio of 3: 1 instead of 4: 1 can be recommended to make meals more palatable. Side effects of the ketogenic diet can be constipation, tiredness and after a long term diet, in one out of 20 patients, kidney stones. [37]

MCT-Ketogenic diet

In the 1960s it was discovered that when medium-chain triglycerides (MCT) fats are metabolized in the body more ketone bodies are produced then from metabolizing any other fat. Based on this mechanism the MCT ketogenic diet a modification of the ketogenic diet was developed and it has nearly replaced the classic ketogenic diet in the USA. In the MCT ketogenic diet MCT oil is added to ketogenic meals, [38] which allows the carbohydrate content to be increased to around 15 to 20%. This way some patients find the meals more enjoyable. The success rate of the MCT ketogenic diet does not differ from the classic ketogenic diet however not all children can tolerate the necessary large amounts of MCT oil which is also very expensive.[ citation needed ]

Modified Atkins

A modified Atkins diet describes the long term practice of the first phase of the popular Atkins diet the so-called induction phase to reduce seizures through ketosis. In this diet the fat content of the nutrition is slightly lower than in the ketogenic diet at around 60%, the protein content is around 30% and the carbohydrate content is around 10% rendering the diet less restrictive and more compatible with the daily life compared to the ketogenic diet. Several studies show that the modified Atkins diet produces a similar or slightly lower seizure reduction to the ketogenic diet. [39] Some physicians, especially in the US, recommend the modified Atkins diet because they assume that patients will adhere to it on the long-term because it is more compatible with daily life and the meals are more enjoyable. It has also been concluded in another study that the diet is well tolerated and effective in hard to treat childhood epilepsy. [40]

Other

Deep brain stimulation of the anterior nuclei of the thalamus is approved for DRE in some countries in Europe, but has been and continues to only be used in a very few patients. After 5 years of DBS a seizure reduction of 69% and a 50%-responder rate of 68% was reported in a randomized-double blinded trial. [41] The rate of serious device related events was 34% in this study.

Responsive neurostimulation (RNS) is approved for DRE in the US and involves stimulation directly to 1 or 2 seizure foci when abnormal electrocorticographic activity is detected by the devices software. After 2 years of RNS a seizure reduction of 53% was reported in a randomized-double blinded trial as well as a rate of serious device related events of 2.5%. [42]

Transcutaneous vagus nerve stimulation (tVNS) is approved for DRE in some European countries and involves externally stimulating the auricular branch of the vagus nerve in the ear. tVNS failed to demonstrate efficacy in a first randomized-double blinded trial: responder rates did not differ between active and control groups potentially indicating a placebo effect behind the 34% seizure reduction seen in the patients who completed the full follow-up period. [43]

Related Research Articles

<span class="mw-page-title-main">Epilepsy</span> Group of neurological disorders causing seizures

Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. An epileptic seizure is the clinical manifestation of an abnormal, excessive, and synchronized electrical discharge in the neurons. The occurrence of two or more unprovoked seizures defines epilepsy. The occurrence of just one seizure may warrant the definition in a more clinical usage where recurrence may be able to be prejudged. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain. These episodes can result in physical injuries, either directly, such as broken bones, or through causing accidents. In epilepsy, seizures tend to recur and may have no detectable underlying cause. Isolated seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to the alarming nature of their symptoms.

<span class="mw-page-title-main">Ketogenic diet</span> High-fat dietary therapy for epilepsy

The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate dietary therapy that in conventional medicine is used mainly to treat hard-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates.

<span class="mw-page-title-main">Lennox–Gastaut syndrome</span> Rare form of childhood-onset epilepsy

Lennox–Gastaut syndrome (LGS) is a complex, rare, and severe childhood-onset epilepsy syndrome. It is characterized by multiple and concurrent seizure types including tonic seizure, cognitive dysfunction, and slow spike waves on electroencephalogram (EEG), which are very abnormal. Typically, it presents in children aged 3–5 years and most of the time persists into adulthood with slight changes in the electroclinical phenotype. It has been associated with perinatal injuries, congenital infections, brain malformations, brain tumors, genetic disorders such as tuberous sclerosis and numerous gene mutations. Sometimes LGS is observed after infantile epileptic spasm syndrome. The prognosis for LGS is marked by a 5% mortality in childhood and persistent seizures into adulthood.

<span class="mw-page-title-main">Vagus nerve stimulation</span> Medical treatment that involves delivering electrical impulses to the vagus nerve.

Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy, cluster headaches, treatment-resistant depression and stroke rehabilitation.

<span class="mw-page-title-main">Aura (symptom)</span> Symptom of epilepsy and migraine

An aura is a perceptual disturbance experienced by some with epilepsy or migraine. An epileptic aura is actually a minor seizure.

<span class="mw-page-title-main">Temporal lobe epilepsy</span> Chronic focal seizure disorder

In the field of neurology, temporal lobe epilepsy is an enduring brain disorder that causes unprovoked seizures from the temporal lobe. Temporal lobe epilepsy is the most common type of focal onset epilepsy among adults. Seizure symptoms and behavior distinguish seizures arising from the medial temporal lobe from seizures arising from the lateral (neocortical) temporal lobe. Memory and psychiatric comorbidities may occur. Diagnosis relies on electroencephalographic (EEG) and neuroimaging studies. Anticonvulsant medications, epilepsy surgery and dietary treatments may improve seizure control.

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.

Anterior temporal lobectomy (ATL) is the complete or partial removal of the anterior portion of the temporal lobe of the brain. The exact boundaries for removal can vary slightly in practice and between neurosurgeons. It is a treatment option for temporal lobe epilepsy for those in whom anticonvulsant medications do not control epileptic seizures, and who have frequent seizures, and who additionally qualify based on a WADA test to localize the dominant hemisphere for language module.

Abdominal epilepsy is a rare condition most frequently found in children, consisting of gastrointestinal disturbances caused by epileptiform seizure activity. Though a few cases of it have been reported in adults too. It has been described as a type of temporal lobe epilepsy. Responsiveness to anticonvulsants can aid in the diagnosis. Distinguishing features of abdominal epilepsy include (1) Abnormal laboratory, radiographic, and endoscopic findings revealing paroxysmal GI manifestations of unknown origin (2) CNS symptoms (3) Abnormal EEG. Most published medical literature dealing with abdominal epilepsy is in the form of individual case reports. A 2005 review article found a total of 36 cases described in the medical literature.

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.

Ohtahara syndrome (OS), also known as Early Infantile Developmental & Epileptic Encephalopathy (EIDEE) is a progressive epileptic encephalopathy. The syndrome is outwardly characterized by tonic spasms and partial seizures within the first few months of life, and receives its more elaborate name from the pattern of burst activity on an electroencephalogram (EEG). It is an extremely debilitating progressive neurological disorder, involving intractable seizures and severe intellectual disabilities. No single cause has been identified, although in many cases structural brain damage is present.

<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.

<span class="mw-page-title-main">Epilepsy in children</span>

Epilepsy is a neurological condition of recurrent episodes of unprovoked epileptic seizures. A seizure is an abnormal neuronal brain activity that can cause intellectual, emotional, and social consequences. Epilepsy affects children and adults of all ages and races, and is one of the most common neurological disorders of the nervous system. Epilepsy is more common among children than adults, affecting about 6 out of 1000 US children that are between the age of 0 to 5 years old. The epileptic seizures can be of different types depending on the part of the brain that was affected, seizures are classified in 2 main types partial seizure or generalized seizure.

Febrile infection-related epilepsy syndrome (FIRES), is onset of severe seizures following a febrile illness in someone who was previously healthy. The seizures may initially be focal; however, often become tonic-clonic. Complications often include intellectual disability, behavioral problems, and ongoing seizures.

An epilepsy syndrome is defined as "a characteristic cluster of clinical and Electroencephalography (EEG) features, often supported by specific etiological findings ."

<span class="mw-page-title-main">Fabrice Bartolomei</span> French neurophysiologist

Fabrice Bartolomei is a French neurophysiologist, and University Professor at Aix-Marseille University (AMU), leading the Service de Neurophysiologie Clinique of the Timone Hospital at the Assistance Publique - Hôpitaux de Marseille, and he is the medical director of the ‘Centre Saint-Paul - Hopital Henri Gastaut’. He is the coordinator of the clinical network CINAPSE that is dedicated to the management of adult and pediatric cases of severe epilepsy and leader of the Federation Hospitalo-Universitaire Epinext. He is also member of the research unit Institut de Neurosciences des Systèmes.

Musicogenic seizure, also known as music-induced seizure, is a rare type of seizure, with an estimated prevalence of 1 in 10,000,000 individuals, that arises from disorganized or abnormal brain electrical activity when a person hears or is exposed to a specific type of sound or musical stimuli. There are challenges when diagnosing a music-induced seizure due to the broad scope of triggers, and time delay between a stimulus and seizure. In addition, the causes of musicogenic seizures are not well-established as solely limited cases and research have been discovered and conducted respectively. Nevertheless, the current understanding of the mechanism behind musicogenic seizure is that music triggers the part of the brain that is responsible for evoking an emotion associated with that music. Dysfunction in this system leads to an abnormal release of dopamine, eventually inducing seizure.

Computational models in epilepsy mainly focus on describing an electrophysiological manifestation associated with epilepsy called seizures. For this purpose, computational neurosciences use differential equations to reproduce the temporal evolution of the signals recorded experimentally. A book published in 2008, Computational Neuroscience in Epilepsy. summarizes different works done up to this time. The goals of using its models are diverse, from prediction to comprehension of underlying mechanisms.

Malignant migrating partial seizures of infancy (MMPSI) is a rare epileptic syndrome that onsets before 6 months of age, commonly in the first few weeks of life. Once seizures start, the site of seizure activity repeatedly migrates from one area of the brain to another, with few periods of remission in between. These seizures are 'focal' (updated term for 'partial'), meaning they do not affect both sides of the brain at the same time. These continuous seizures cause damage to the brain, hence the descriptor 'malignant.'

References

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  15. ↑ Salanova, V.; Markand, O.; Worth, R. (2002-02-01). "Temporal Lobe Epilepsy Surgery: Outcome, Complications, and Late Mortality Rate in 215 Patients". Epilepsia. 43 (2): 170–174. doi: 10.1046/j.1528-1157.2002.33800.x . ISSN   1528-1167. PMID   11903464.
  16. ↑ Fisch, Bruce (2011-11-01). "Anterior Temporal Lobectomy – How Safe Is It?". Epilepsy Currents. 11 (6): 186–188. doi:10.5698/1535-7511-11.6.186. ISSN   1535-7597. PMC   3220424 . PMID   22129637.
  17. ↑ Maehara, Taketoshi; Shimizu, Hiroyuki (2001-01-23). "Surgical Outcome of Corpus Callosotomy in Patients with Drop Attacks". Epilepsia. 42 (1): 67–71. doi: 10.1046/j.1528-1157.2001.081422.x . ISSN   1528-1167. PMID   11207787.
  18. ↑ Tsou, Amy Y.; Kessler, Sudha Kilaru; Wu, Mingche; Abend, Nicholas S.; Massey, Shavonne L.; Treadwell, Jonathan R. (2023-01-03). "Surgical Treatments for Epilepsies in Children Aged 1–36 Months: A Systematic Review". Neurology. 100 (1): e1–e15. doi:10.1212/WNL.0000000000201012. ISSN   0028-3878. PMC   9827129 . PMID   36270898.
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  21. ↑ Elliott, Robert E.; Morsi, Amr; Kalhorn, Stephen P.; Marcus, Joshua; Sellin, Jonathan; Kang, Matthew; Silverberg, Alyson; Rivera, Edwin; Geller, Eric (January 2011). "Vagus nerve stimulation in 436 consecutive patients with treatment-resistant epilepsy: Long-term outcomes and predictors of response". Epilepsy & Behavior. 20 (1): 57–63. doi:10.1016/j.yebeh.2010.10.017. PMID   21144802. S2CID   17965529.
  22. ↑ Orosz, Iren; McCormick, David; Zamponi, Nelia; Varadkar, Sophia; Feucht, Martha; Parain, Dominique; Griens, Roger; Vallée, Louis; Boon, Paul (2014-10-01). "Vagus nerve stimulation for drug-resistant epilepsy: A European long-term study up to 24 months in 347 children". Epilepsia. 55 (10): 1576–1584. doi: 10.1111/epi.12762 . ISSN   1528-1167. PMID   25231724. S2CID   25790247.
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