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{{Short description|Cluster of signs and symptoms that define a unique epileptic condition}}An '''epilepsy syndrome''' is defined as "a characteristic cluster of clinical and ] (EEG) features, often supported by specific ] findings (structural, genetic, metabolic, immune, and infectious)."<ref name="Wirrell22">{{cite journal |vauthors=Wirrell EC, Nabbout R, Scheffer IE, Alsaadi T, Bogacz A, French JA, Hirsch E, Jain S, Kaneko S, Riney K, Samia P, Snead OC, Somerville E, Specchio N, Trinka E, Zuberi SM, Balestrini S, Wiebe S, Cross JH, Perucca E, Moshé SL, Tinuper P |title=Methodology for classification and definition of epilepsy syndromes with list of syndromes: Report of the ILAE Task Force on Nosology and Definitions |journal=Epilepsia |volume=63 |issue=6 |pages=1333–48 |date=June 2022 |pmid=35503715 |doi=10.1111/epi.17237 |url=https://discovery.ucl.ac.uk/id/eprint/10148709/ }}</ref>
Cases of ] may be organized into ] by reliably identified common clinical features. These include typical age of seizure onset, specific seizure types, ] characteristics and others. The diagnose of an epilepsy syndrome is useful as it provides information on which underlying causes should be considered and which ] might be most useful.<ref name = ileasyndromes2014>{{ cite web | url = https://www.epilepsydiagnosis.org/syndrome/epilepsy-syndrome-groupoverview.html | publisher = International league against epilepsy | accessdate = 2014-10-06}}</ref><ref name=NChp9>{{cite book|title=The Epilepsies: The diagnosis and management of the epilepsies in adults and children in primary and secondary care|publisher=National Clinical Guideline Centre|chapter=Chapter 9: Classification of seizures and epilepsy syndromes|pages=119–129|url=http://www.nice.org.uk/nicemedia/live/13635/57784/57784.pdf|author=National Institute for Health and Clinical Excellence|date=January 2012}}</ref>


Syndromes are characterized by ] types and specific findings on EEGs. Epilepsy syndromes often begin, and may remit, at specific ages. Identification of an epilepsy syndrome may provide important clues to the likely cause, the most effective treatment and the risk of ] such as learning problems, intellectual disability, ] (ADHD), or other problems.<ref name="Wirrell22" />
The ability to categorize a case of epilepsy into a specific syndrome occurs more often with children since the onset of seizures is commonly early.<ref name=Nel2012>{{cite journal|last=Neligan|first=A|author2=Hauser, WA |author3=Sander, JW |title=The epidemiology of the epilepsies.|journal=Handbook of clinical neurology|year=2012|volume=107|pages=113–33|pmid=22938966|doi=10.1016/B978-0-444-52898-8.00006-9}}</ref> Benign examples are ] (2.8 per 100,000), ] (0.8 per 100,000) and ] (0.7 per 100,000).<ref name=Nel2012/> Severe syndromes with diffuse brain dysfunction are also referred to as epileptic encephalopathies. These are associated with frequent intractable ] and severe cognitive dysfunction, for instance ] and ].<ref name=jcnnordli2012>{{cite journal | journal = J Clin Neurophysiol | year = 2012 | volume = 29 | issue = 5 | page = 420-4 | doi = 10.1097/WNP.0b013e31826bd961 | title = Epileptic encephalopathies in infants and children | author = Nordli DR jr | pmid = 23027099}}</ref>


Not everyone with ] can be defined as having an epilepsy syndrome.<ref name="Wirrell22" /> Epilepsy syndromes are most commonly found in children with epilepsy onset before 3 years of age and are less common in adult-onset epilepsy.<ref name=Nel2012>{{cite book|vauthors=Neligan A, Hauser WA, Sander JW |chapter=6. The epidemiology of the epilepsies |chapter-url=https://www.sciencedirect.com/science/article/abs/pii/B9780444528988000069 |title=Handbook of Clinical Neurology|series=Epilepsy |year=2012|volume=107|pages=113–133|doi=10.1016/B978-0-444-52898-8.00006-9|isbn=978-0-444-52898-8 |publisher=Elsevier|pmid=22938966 }}</ref>
Epilepsies with onset in childhood are a complex group of diseases with a variety of causes and clinical features. Some have no underlying obvious neuropathology or evident ] disturbance.<ref name = conpandolfo2013>{{cite journal | journal = Curr Opin Neurol | year = 2013 | volume = 26 | issue = 2 | page = 137-45 | title = Pediatric epilepsy genetics | author = Pandolfo M | doi = 10.1097/WCO.0b013e32835f19da | pmid = 23449174}}</ref> They may be associated with variable degrees of intellectual disability, elements of ], other ], and motor impairment. Others have underlying inherited metabolic diseases, ] abnormalities, ], or poor ] development.<ref name = conpandolfo2013/> Some of these epilepsies can be categorized into the traditional epilepsy syndromes. Furthermore, a variety of syndromes exist of which the main feature is not epilepsy but which are associated with a higher risk of epilepsy. For instance between 1 and 10% of those with ] and 90% of those with ] have epilepsy.<ref name=Bh2011>{{Cite journal |last1 = Bhalla | first1 = D. | last2 = Godet | first2 = B. | last3 = Druet-Cabanac | first3 = M. |last4 = Preux | first4 = PM. | title = Etiologies of epilepsy: a comprehensive review. | journal = Expert Rev Neurother | volume = 11 | issue = 6 | pages = 861–76 |date=Jun 2011 | doi = 10.1586/ern.11.51 | PMID = 21651333 }}</ref>


This article reflects the '''2017 ILAE Classification of the Epilepsies''', and its more detailed follow-up papers, produced for the ] by a number of specialist clinicians.<ref>{{cite web |title=Classification and Definition of Epilepsy Syndromes |publisher=ILAE International League Against Epilepsy |url=https://www.ilae.org/guidelines/definition-and-classification/classification-and-definition-of-epilepsy-syndromes}} "", ]</ref> Some syndromes in earlier classifications have been renamed or redefined, but these are retained at the end of the article for convenience.
In general, genetics is believed to play an important role in epilepsies by different mechanisms. Simple and complex modes of ] have been identified for some of them. However, extensive screening failed to identify more single rare ] variants of large effect.<ref>{{cite journal | author = Heinzen EL, Depondt C, Cavalleri GL, Ruzzo EK, Walley NM, Need AC, Ge D, He M, Cirulli ET, Zhao Q, Cronin KD, Gumbs CE, Campbell CR, Hong LK, Maia JM, Shianna KV, McCormack M, Radtke RA, O'Conner GD, Mikati MA, Gallentine WB, Husain AM, Sinha SR, Chinthapalli K, Puranam RS, McNamara JO, Ottman R, Sisodiya SM, Delanty N, Goldstein DB | title = Exome sequencing followed by large-scale genotyping failed to identify single rare variants of large effect in "idiopathic" generalized epilepsy | journal = Am J Hum Genet | year = 2012 | volume = 91 | page = 293–302 | pmid = 22863189 | pmc = 3415540}}</ref> Recent research data suggests that, particularly in the epileptic encephalopathies, de novo ] is an important mechanism.<ref>{{cite journal | journal = Nat Rev Neurol | year = 2014 | volume = 10 | issue = 5 | page = 283-92 | doi = 10.1038/nrneurol.2014.62 | title = The hidden genetics of epilepsy-a clinically important new paradigm | author = Thomas RH, Berkovic SF | pmid = 24733163 | url = http://www.nature.com/nrneurol/journal/v10/n5/full/nrneurol.2014.62.html}}</ref><ref name=n23934111>{{cite journal | journal = Nature | year = 2013 | volume = 501 | issue = 7466 | page = 217-21 | doi = 10.1038/nature12439 | title = De novo mutations in epileptic encephalopathies | pmid = 23934111 | pmc = 3773011}}</ref> De novo means that a child is affected, but the parents do not have the mutation. De novo mutations occur in ] or at a very early stage of ]nic development. In ] a single affected ] has been identified.<ref name=n23934111/>


== Classification of epilepsy syndromes ==
Syndromes in which causes are not clearly identified are difficult to match with categories of the current classification of epilepsy. Categorization for these cases was made somewhat arbitrarily.<ref name="2011rec"/> The ''idiopathic'' (unknown cause) category of the 2011 classification includes syndromes in which the general features and/or age specificity strongly point to a presumed genetic cause.<ref name="2011rec"/> Some childhood epilepsy syndromes are included in the ''idiopathic'' (unknown cause) category in which the cause is presumed genetic, for instance ]. Others are included in ''symptomatic'' despite a presumed genetic cause (in at least in some cases), for instance ].<ref name="2011rec"/> Clinical syndromes in which epilepsy is not the main feature (e.g. ]) were categorized ''symptomatic'' but it was argued to include these within the category ''idiopathic''.<ref name="2011rec"/> Classification of epilepsies and particularly of epilepsy syndromes will change with advances in research."
Epilepsy syndromes are now classified based on the type of epilepsy as well as by the age at onset.<ref name="Wirrell22" />


==Autosomal dominant nocturnal frontal lobe epilepsy== ===Type of epilepsy===
Syndromes are characterized into 4 groups based on epilepsy type:<ref name="Wirrell22" />
:a. Generalized onset epilepsy syndromes. These epilepsy syndromes have only ] and include both the idiopathic generalized epilepsies (specifically childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and epilepsy with generalized tonic- clonic seizures alone), as well as other genetic generalized epilepsies.<ref name="Hirsch22" >{{cite journal |vauthors=Hirsch E, French J, Scheffer IE, Bogacz A, Alsaadi T, Sperling MR, Abdulla F, Zuberi SM, Trinka E, Specchio N, Somerville E, Samia P, Riney K, Nabbout R, Jain S, Wilmshurst JM, Auvin S, Wiebe S, Perucca E, Moshé SL, Tinuper P, Wirrell EC |title=ILAE definition of the Idiopathic Generalized Epilepsy Syndromes: Position statement by the ILAE Task Force on Nosology and Definitions |journal=Epilepsia |volume=63 |issue=6 |pages=1475–99 |date=June 2022 |pmid=35503716 |doi=10.1111/epi.17236 |url=https://eprints.gla.ac.uk/270405/1/270405.pdf }}</ref>

:b. Focal onset epilepsy syndromes. These epilepsy syndromes have only ] and include both the self-limited focal epilepsies in infants and children as well as other focal epilepsy syndromes.

:c. Generalized and focal onset epilepsy syndromes. These syndromes have seizures which can be both of generalized or focal onset.

:d. Developmental and epileptic ] (DEEs) or syndromes with progressive neurological deterioration.<ref name="Wirrell22" /> Developmental and epileptic encephalopathies are disorders that typically onset early in life and are associated with developmental impairment that is due to both the underlying cause of the epilepsy (developmental encephalopathy) as well as frequent seizures and/or epileptiform discharges on EEG (epileptic encephalopathy). Epilepsy syndromes associated with ] or other neurological regression that begin after a period of prolonged normal development are termed syndromes with progressive neurological deterioration. Both the DEEs and syndromes with progressive neurological deterioration are amongst the most severe types of epilepsy, with frequent seizures and high rates of ].

===Age at onset===
Epilepsy syndromes are also classified based on age at onset when the syndrome first appears, syndromes with onset in neonates and infancy, beginning prior to 2 years of age,<ref name="Zuberi22">{{cite journal |vauthors=Zuberi SM, Wirrell E, Yozawitz E, Wilmshurst JM, Specchio N, Riney K, Pressler R, Auvin S, Samia P, Hirsch E, Galicchio S, Triki C, Snead OC, Wiebe S, Cross JH, Tinuper P, Scheffer IE, Perucca E, Moshé SL, Nabbout R |title=ILAE classification and definition of epilepsy syndromes with onset in neonates and infants: Position statement by the ILAE Task Force on Nosology and Definitions |journal=Epilepsia |volume=63 |issue=6 |pages=1349–97 |date=June 2022 |pmid=35503712 |doi=10.1111/epi.17239 |url=https://discovery.ucl.ac.uk/id/eprint/10148126/ }}</ref> syndromes with onset in childhood,<ref name="Specchio22">{{cite journal |vauthors=Specchio N, Wirrell EC, Scheffer IE, Nabbout R, Riney K, Samia P, Guerreiro M, Gwer S, Zuberi SM, Wilmshurst JM, Yozawitz E, Pressler R, Hirsch E, Wiebe S, Cross HJ, Perucca E, Moshé SL, Tinuper P, Auvin S |title=International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions |journal=Epilepsia |volume=63 |issue=6 |pages=1398–1442 |date=June 2022 |pmid=35503717 |doi=10.1111/epi.17241 }}</ref> and syndromes that begin at a variable age. This group includes syndromes that can begin either in childhood or adulthood.<ref name="Riney22">{{cite journal |vauthors=Riney K, Bogacz A, Somerville E, Hirsch E, Nabbout R, Scheffer IE, Zuberi SM, Alsaadi T, Jain S, French J, Specchio N, Trinka E, Wiebe S, Auvin S, Cabral-Lim L, Naidoo A, Perucca E, Moshé SL, Wirrell EC, Tinuper P |title=International League Against Epilepsy classification and definition of epilepsy syndromes with onset at a variable age: position statement by the ILAE Task Force on Nosology and Definitions |journal=Epilepsia |volume=63 |issue=6 |pages=1443–74 |date=June 2022 |pmid=35503725 |doi=10.1111/epi.17240 |url=https://eprints.gla.ac.uk/270402/1/270402.pdf }}</ref>
==Epilepsy syndromes with onset in neonates and infants==
Epilepsy syndromes are identified in over half of children with epilepsy onset before 2 years of age.<ref name="Zuberi22" /> Almost two thirds of these syndromes are developmental and epileptic ], which are associated with significant developmental impairment and frequent seizures which often respond poorly to ]. Of the remainder of infants with an epilepsy syndrome, most will have a self-limited focal epilepsy, which will not impact development, and which are typically outgrown by early childhood.<ref name="Zuberi22" />

===Self-limited neonatal, infantile or neonatal-infantile epilepsy===
As their names suggest, these epilepsies begin at specific ages in otherwise healthy babies and are caused by changes (variants) in specific genes. In some cases, the genetic changes are passed on from parent to child, and thus the syndromes are said to be familial. In other cases, the genetic change occurs de novo in the baby and there is no family history of other persons with early life seizures. De novo means that the child is affected but neither parent has the genetic variant. De novo variants typically may occur in the egg or sperm, or in early embryonic life.<ref name="Zuberi22" />

Seizures are focal in onset but less commonly may progress to involve both sides of the body (focal to bilateral convulsive seizure. The babies have a normal examination and attain normal developmental milestones. The MRI, interictal EEG (between seizures) and bloodwork is normal however genetic testing often shows a causal genetic variant (most commonly KCNQ2 or KCNQ3 in self-limited neonatal epilepsy, PRRT2 or less commonly SCN2A or SCN8A in self-limited infantile epilepsy and SCN2A or KCNQ2 in self-limited neonatal-infantile epilepsy. These epilepsies are generally outgrown by the early preschool years and antiseizure medication is not needed after that time.<ref name="Zuberi22" />

===Infantile epileptic spasms syndrome===
Infantile epileptic spasms syndrome is the most common DEE that begins in early life. Infants present with a characteristic seizure type called infantile spasms (repetitive spells of body crunching, each spell lasting less than 2-3 seconds, but which occur in brief clusters). The EEG is always severely abnormal and often shows a pattern called hypsarrhythmia. Many children will have a preceding history of developmental delay and neurological concerns however this syndrome can also affect previously healthy babies. Typically if the seizures are not controlled quickly, infants may have plateauing or even regression of their development. An underlying cause can be found in most babies with infantile epileptic spasms syndrome. In many cases, the ] will show evidence of a prior brain injury or abnormal brain development. Genetic causes are also relatively common and can include a large number of genetic variants. Metabolic causes are less commonly found.<ref name="Zuberi22" />

Infantile spasms are treated with specific types of medication, most commonly either oral steroid, ACTH or ]. The long-term outcome is often worrisome. While infantile spasms often stop with medication, many babies will develop other seizure types over time and most will be left with intellectual disability. The outcome is best predicted by the underlying cause of the spasms and whether the infant's development before onset of spasms. Rapid treatment with effective medication has also been shown to improve longterm developmental outcome.<ref name="Zuberi22" />

===Dravet syndrome===
{{main|Dravet syndrome}}
Dravet syndrome is a DEE beginning in infancy and characterized by severe epilepsy that does not respond well to treatment. This syndrome was described in 1978 by ], a French psychiatrist and epileptologist, while working at the Centre Saint Paul at the ]. The prevalence of this disorder is approximately 1/16,00 live births.<ref name="Wu15">{{cite journal |vauthors=Wu YW, Sullivan J, McDaniel SS, Meisler MH, Walsh EM, Li SX, Kuzniewicz MW |title=Incidence of Dravet Syndrome in a US Population |journal=Pediatrics |volume=136 |issue=5 |pages=e1310–5 |date=November 2015 |pmid=26438699 |pmc=4621800 |doi=10.1542/peds.2015-1807 }}</ref> Seizures begin before 20 months of age and in most cases, the first seizures occur with fever and are generalized tonic-clonic (grand mal) or unilateral (one-sided) convulsions. These seizures are often prolonged, and may lead to status epilepticus, a medical emergency. In time, seizures increase in frequency and begin to occur without fever. Additional seizure types appear, most often these are myoclonic, atypical absence, and focal seizures.<ref name="Cooper16" />

Seizures persist despite treatment with medication, however several medications including ], ], ], ] and pharmaceutical grade ] are often helpful to decrease seizure burden. Development is normal at the time of seizure onset, however developmental typically plateaus around age 2 years, and by adulthood, intellectual disability of varied severity is seen. Additional features that are seen in significant numbers of patients with Dravet syndrome may include a crouch gait, ], sleep problems, ], and problems with growth and nutrition.{{Citation needed|date=April 2024|reason=Part of text saying but did not link to citation}} Persons with Dravet syndrome also have an increased risk of early death, particularly due to ].<ref name="Cooper16">{{cite journal |vauthors=Cooper MS, Mcintosh A, Crompton DE, McMahon JM, Schneider A, Farrell K, Ganesan V, Gill D, Kivity S, Lerman-Sagie T, McLellan A, Pelekanos J, Ramesh V, Sadleir L, Wirrell E, Scheffer IE |title=Mortality in Dravet syndrome |journal=Epilepsy Res |volume=128 |pages=43–47 |date=December 2016 |pmid=27810515 |doi=10.1016/j.eplepsyres.2016.10.006 }}</ref>

==Epilepsy syndromes with onset in childhood==
Epilepsy syndromes can be identified in up to one third of children with epilepsy. Syndromes with onset at this age are divided into the self-limited focal epilepsies, the genetic generalized epilepsies (including childhood absence epilepsy) and the developmental and epileptic encephalopathies.<ref name="Specchio22" />

===A. Self-limited focal epilepsies (SeLFEs)===
SeLFEs account for approximately one quarter of epilepsies that begin in childhood.<ref name="Specchio22"/> They occur in otherwise healthy children with normal development and are not correlated with any brain abnormality on MRI. In most cases, children outgrow this epilepsy type by adolescence and do not need long-term antiseizure medication. These epilepsy syndromes are associated with characteristic seizures and EEG findings, specific for each syndrome.<ref name="Specchio22" />

i. Self-limited epilepsy with centrotemporal spikes (SeLECTS)
SeLECTS, (previously known as benign epilepsy of childhood with centrotemporal spikes or benign Rolandic epilepsy) is a focal epilepsy of unknown cause that most commonly occurs in early to mid school-aged children. Apart from their seizure disorder, these patients are otherwise normal. Seizures usually involve facial muscles and frequently cause drooling and difficulty with speech, although the child is aware throughout the seizure. Although most episodes are brief, seizures that occur in sleep may spread to both sides of the body with convulsive activity. Seizures are typically associated with sleep, most commonly being seen shortly after falling asleep or just before waking. The EEG shows epileptic discharges that occur over the centrotemporal region and are most frequent during drowsiness or light sleep. Seizures are outgrown by puberty. Seizures may require antiseizure medication treatment, but sometimes are infrequent enough to allow physicians to defer treatment.<ref name="Specchio22" />

ii. Self-limitied epilepsy with autonomic seizures (SeLEAS)
SeLEAS (formerly known as benign occipital epilepsy of childhood or Panayiotopoulos syndrome) is a focal epilepsy of unknown cause that most commonly presents in the preschool years. Seizures are typically infrequent although can be prolonged. Seizures typically have a prominent autonomic component, most commonly retching but also including pallor, nausea, abdominal pain or even syncope. Seizures may evolve with head and eye deviation to one side, followed by focal or bilateral convulsive activity. Children often have retained awareness early on, but as the seizure evolves, awareness is often impaired. The EEG shows a normal background with epileptiform discharges that are maximal over the posterior head region and typically occur in sleep. As seizures are not frequent, daily antiseizure medication is not needed in many cases. In most cases, this epilepsy type is outgrown within a few years after onset, and longterm antiseizure medication is not required.<ref name="Specchio22" />

===B. Genetic Generalized Epilepsy===
Childhood absence epilepsy (CAE) is an idiopathic generalized epilepsy that presents in early to mid childhood (age 3–12 years) with typical absence seizures, characterized by abrupt loss of responsiveness, staring, sometimes with subtle motor features such as eye blinking or chewing. Seizures are brief, typically lasting 20 seconds or less, but occur very frequently (up to 20–50 times per day in the untreated child). The EEG shows generalized 3 Hz spike and wave discharges. In most cases, absence seizures are the only seizure type, however a minority will develop generalized tonic-clonic seizures, most commonly in adolescence. Children with CAE do not show cognitive decline or neurological deficits, however have higher rates of learning disorders and ADHD. Children require anti-seizures medication, about 60% will outgrow CAE typically within a few years after onset.<ref name="Hirsch22" />

===C. Developmental and Epileptic Encephalopathies===
i. ] (LGS) is a developmental and epileptic encephalopathy that consists of a triad of developmental delay, mixed seizure types and an EEG demonstrating a pattern of "slow" (<2.5 Hz) spike-wave and generalized paroxysmal fast activity. Onset is most commonly prior to age 8 years but rare cases can onset in adolescence.

The most characteristic seizure type is a tonic seizure, which consists of brief generalized body stiffening, and often occurs most prominently in sleep. Additionally, patients often have other seizures types including atonic (abrupt, brief events of loss of tone, often leading to falls), atypical absences (staring spells with more gradual onset and offset), myoclonic jerks, generalized tonic-clonic or focal seizures. While many antiseizure medications can reduce seizure burden, patients do not achieve seizure freedom. Epilepsy is very drug resistant and lifelong. Intellectual disability typically worsens with age, and autism, behavior problems, sleep problems, higher rates of SUDEP and other medical comorbidities are common.

ii. Epilepsy with myoclonic-atonic seizures (EMAtS) (formerly known as ] or Doose syndrome) presents in developmentally normal, mid preschool to early school-aged children. The initial presentation is often with a febrile or afebrile generalized tonic-clonic seizure, however shortly thereafter, different seizure types also evolve and seizures become much more frequent. The most characteristic seizure is a myoclonic-atonic seizure, where the child will briefly jerk, often with a vocalization and then lose tone. Other seizure types which commonly co-exist include atypical absences and myoclonic seizures. Tonic seizures are rare early in the course but may present later on. Many children will go through a period of very frequent seizures with developmental stagnation or regression, known as a “stormy course”. The EEG usually shows 3–6 Hz generalized spike-wave discharge, although the frequency is often slower during the stormy phase. Approximately two thirds of children will eventually have remission of seizures and can stop medication, usually within several years after epilepsy onset.

iii. Developmental and epileptic encephalopathy/Epileptic encephalopathy with spike-wave activation in sleep (DEE-SWAS or EE-SWAS). This group of disorders was formerly known by many names, including continuous spike-wave in sleep (CSWS), Electrographic status epilepticus is sleep (ESES), ] or pseudo-Lennox syndrome. In this disorder, there is marked activation of epileptiform discharge in sleep associated with stagnation or regression of development. The term DEE-SWAS is used for children with pre-existing developmental delay while EE-SWAS is used if prior development was normal. This disorder typically presents in preschool or early school-aged children, and the EEG pattern of marked exacerbation of spike-wave discharge in sleep remits by puberty, although the EEG may remain abnormal. Seizures also typically reduce in frequency and often abate by puberty. Persons with DEE-SWAS or EE-SWAS may present with a variety of seizures types including focal seizures or generalized seizures, and rarely seizures may not be seen.<ref name="Specchio22"/>

Certain medications such as steroids or high dose ]s may improve the sleep EEG. Although neurocognitive and behavioral improvement is typically seen after resolution of SWAS, many children are left with learning problems, ] and variable degrees of intellectual disability, depending on the underlying cause and the duration of the abnormal EEG pattern prior to effective treatment and the age at onset.

==Epilepsy syndromes with onset at a variable age==
The majority of syndromes that onset at a variable age can be subdivided into the idiopathic generalized epilepsy syndromes, focal epilepsy syndromes or syndromes with progressive neurological deterioration.

===A. Idiopathic generalized epilepsy syndromes ===
i. Juvenile absence epilepsy (JAE) typically presents in early to mid adolescence in developmentally normal teens with typical absence seizures. JAE is distinguished from CAE as the absence seizures are less frequent (typically up to 10/day at most), age at onset is older (typically >10 years) and higher association with generalized tonic-clonic seizures. The EEG shows generalized 3–4 Hz spike-wave discharge and the background is normal. Approximately 80% of patients will develop generalized tonic-clonic seizures, most commonly within a few years of onset of absence seizures. Persons with JAE do not show cognitive decline or neurological deficits, however have higher rates of learning disorders, depression, anxiety and ADHD. The likelihood of remission is significantly lower than CAE.<ref name="Hirsch22" />

ii. Juvenile myoclonic epilepsy (JME) presents in developmentally normal teens and young adults with myoclonic seizures, that often occur in the morning and can be triggered by sleep deprivation or flashing lights. The majority (over 90%) also will develop generalized tonic-clonic seizures, which are often heralded by a cluster of myoclonic jerks. Approximately 40% also develop typical absence seizures, however these are usually infrequent, very brief and may not have complete impairment in awareness. The EEG shows fast generalized spike-wave or polyspike and wave and the MRI, if done, is normal. Persons with JME do not experience neurocognitive regression but have higher rates of learning problems, depression and anxiety and ADHD.<ref name="Hirsch22" />

===B. Focal epilepsy syndromes===
i. Sleep-related hypermotor epilepsy (SHE) is a focal epilepsy syndrome characterized by clusters of complex motor movements such as hand clenching, arm or leg flailing, abnormal posturing, kicking or vocalizations (shouting, moaning, etc.) that arise during sleep. Seizures are generally brief but often occur multiple times each night. This epilepsy syndrome can occur both in children and adults and is by either a specific gene (including nicotinic acetylcholine receptor subunit genes, genes affecting the GATOR1 complex or KCNT1) or structural brain abnormalities (either developmental brain changes or acquired brain injury). Persons with this epilepsy syndrome are often misdiagnosed as having nightmares.<ref name="Riney22" />

ii. Mesial temporal lobe epilepsy with hippocampal sclerosis is one of the most common causes of drug resistant epilepsy in adults and can also be seen in children. Seizures arise from the mesial temporal structures (e.g., the ], ], and ]) and often begin with autonomic (rising sensation from the abdomen to the chest, nausea, vomiting), cognitive (déjà vu, jamais vu), fear or sensory (bad smell or taste) symptoms. There is often gradual impairment in awareness and oral automatisms (chewing, lip-smacking) are common. With seizures that affect the dominant hemisphere for language, persons often have difficulty with language (inability to speak or garbled language) during and shortly after the seizure. Seizures may evolve to become bilateral convulsive seizures. Seizures most commonly begin in late childhood and adolescence but can occur at any age. The MRI shows evidence of hippocampal sclerosis (scarring of the hippocampus). Often seizures do not sufficiently respond to medical treatment with ]s and epilepsy surgery may be considered.<ref name="Riney22" />

===c. Epilepsy syndromes with progressive neurological impairment===
i. ] is a focal epilepsy that almost always affects only one hemisphere of the brain. It is characterized by focal seizures that progress in frequency and severity over time and often culminate in epilepsia partialis continua (near constant focal seizure activity of one side of the body). With time, the person develops progressive loss of motor control on the side of the body controlled by the affected hemisphere (progressive hemiparesis) and language problems and cognitive regression may also be seen. The MRI is often normal at the time of epilepsy onset but with time shows progressive atrophy of the affected hemisphere. The cause is felt to be immunological/inflammatory. Often, surgery such as a hemispheric disconnection is required to control seizures. Rasmussen encephalitis is most common in children but less commonly begins in adolescence or adult life.<ref name="Riney22" />

ii. Progressive myoclonic epilepsy is a rare syndrome that comprised a group of underlying genetic epilepsies characterized by progressive dementia and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are Unverricht-Lundborg disease, myoclonus epilepsy with ragged red fibers (MERRF syndrome), Lafora disease, neuronal ceroid lipofuscinosis, and sialidosis.<ref name="Riney22" />

==Syndromes not appearing in the 2017 ILAE classification==
The latest 2017 ] classification of epilepsy syndromes no longer includes several syndromes included in earlier classifications. These are now included under other syndromes in the new classification, or are no longer regarded as syndromes, but are retained here for reference.

===Autosomal dominant nocturnal frontal lobe epilepsy===
] (ADNFLE) is an idiopathic localization-related epilepsy that is an inherited epileptic disorder that causes seizures during sleep. Onset is usually in childhood. These seizures arise from the frontal lobes and consist of complex motor movements, such as hand clenching, arm raising/lowering, and knee bending. Vocalizations such as shouting, moaning, or crying are also common. ADNFLE is often misdiagnosed as nightmares. ADNFLE has a genetic basis.<ref name="Bertrand2002">{{cite journal ] (ADNFLE) is an idiopathic localization-related epilepsy that is an inherited epileptic disorder that causes seizures during sleep. Onset is usually in childhood. These seizures arise from the frontal lobes and consist of complex motor movements, such as hand clenching, arm raising/lowering, and knee bending. Vocalizations such as shouting, moaning, or crying are also common. ADNFLE is often misdiagnosed as nightmares. ADNFLE has a genetic basis.<ref name="Bertrand2002">{{cite journal
| author = Bertrand D | author = Bertrand D
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| pmid=12121305 | pmid=12121305
| doi-access = free
}}</ref> These genes encode various ]s.
}}</ref> These genes encode various ]s.{{citation needed|date=July 2021}}


==Rolandic epilepsy== ===Rolandic epilepsy===
Benign centrotemporal lobe epilepsy of childhood or benign ] is an idiopathic localization-related epilepsy that occurs in children between the ages of 3 and 13 years, with peak onset in prepubertal late childhood. Apart from their seizure disorder, these patients are otherwise normal. This syndrome features simple focal seizures that involve facial muscles and frequently cause drooling. Although most episodes are brief, seizures sometimes spread and generalize. Seizures are typically nocturnal and confined to sleep. The ] may demonstrate spike discharges that occur over the centrotemporal scalp over the central sulcus of the brain (the Rolandic sulcus) that are predisposed to occur during drowsiness or light sleep. Seizures cease near puberty.<ref name="BRE1988">{{cite journal Benign centrotemporal lobe epilepsy of childhood or benign ] is an idiopathic localization-related epilepsy that occurs in children between the ages of 3 and 13 years, with peak onset in prepubertal late childhood. Apart from their seizure disorder, these patients are otherwise normal. This syndrome features simple focal seizures that involve facial muscles and frequently cause drooling. Although most episodes are brief, seizures sometimes spread and generalize. Seizures are typically nocturnal and confined to sleep. The ] may demonstrate spike discharges that occur over the centrotemporal scalp over the central sulcus of the brain (the Rolandic sulcus) that are predisposed to occur during drowsiness or light sleep. Seizures cease near puberty.<ref name="BRE1988">{{cite journal
| author = Loiseau P | author = Loiseau P
Line 31: Line 112:
| doi = 10.1111/j.1528-1157.1988.tb03711.x | doi = 10.1111/j.1528-1157.1988.tb03711.x
| pmid = 3371279 | pmid = 3371279
| issue = 3}}</ref> Seizures may require ] treatment, but sometimes are infrequent enough to allow physicians to defer treatment. | issue = 3| s2cid = 13473409
}}</ref> Seizures may require ] treatment, but sometimes are infrequent enough to allow physicians to defer treatment.


==Benign occipital epilepsy of childhood== ===Benign occipital epilepsy of childhood===
{{see also|Occipital epilepsy}}
Benign occipital epilepsy of childhood (BOEC) is an idiopathic localization-related epilepsy and consists of an evolving group of syndromes. Most authorities include two subtypes, an early subtype with onset between three and five years, and a late onset between seven and 10 years. Seizures in BOEC usually feature visual symptoms such as scotoma or fortifications (brightly colored spots or lines) or amaurosis (blindness or impairment of vision). Convulsions involving one half the body, hemiconvulsions, or forced eye deviation or head turning are common. Younger patients typically experience symptoms similar to migraine with nausea and headache, and older patients typically complain of more visual symptoms. The ] in BOEC shows spikes recorded from the occipital (back of head) regions. The EEG and genetic pattern suggest an autosomal dominant transmission as described by ], et al.<ref name="Kuzniecky1987">{{cite journal Benign occipital epilepsy of childhood (BOEC) is an idiopathic localization-related epilepsy and consists of an evolving group of syndromes. Most authorities include two subtypes, an early subtype with onset between three and five years, and a late onset between seven and 10 years. Seizures in BOEC usually feature visual symptoms such as scotoma or fortifications (brightly colored spots or lines) or amaurosis (blindness or impairment of vision). Convulsions involving one half the body, hemiconvulsions, or forced eye deviation or head turning are common. Younger patients typically experience symptoms similar to migraine with nausea and headache, and older patients typically complain of more visual symptoms. The ] in BOEC shows spikes recorded from the occipital (back of head) regions. The EEG and genetic pattern suggest an autosomal dominant transmission as described by ], et al.<ref name="Kuzniecky1987">{{cite journal
| author = Kuzniecky R, Rosenblatt B |vauthors=Kuzniecky R, Rosenblatt B | title = Benign occipital epilepsy: a family study
| title = Benign occipital epilepsy: a family study
| journal = Epilepsia | journal = Epilepsia
| volume = 24 | volume = 24
Line 42: Line 124:
| year = 1987 | year = 1987
| doi = 10.1111/j.1528-1157.1987.tb03655.x | doi = 10.1111/j.1528-1157.1987.tb03655.x
| issue = 4}}</ref> Lately, a group of epilepsies termed ]<ref name="Payan2000">{{cite journal | issue = 4| pmid = 3113923
| s2cid = 22014736
}}</ref> Lately, a group of epilepsies termed ]<ref name="Payan2000">{{cite journal
| author = Panayiotopolous CP | author = Panayiotopolous CP
| title = Benign childhood epileptic syndromes with occipital spikes: New classification proposed by the ILAE | title = Benign childhood epileptic syndromes with occipital spikes: New classification proposed by the ILAE
Line 51: Line 135:
| doi = 10.1177/088307380001500810 | doi = 10.1177/088307380001500810
| pmid = 10961795 | pmid = 10961795
| issue = 8| s2cid = 25866946
| issue = 8}}</ref> that share some clinical features of BOEC but have a wider variety of EEG findings are classified by some as BOEC.
}}</ref> that share some clinical features of BOEC.


==Childhood absence epilepsy== ===Childhood absence epilepsy===
] (CAE) is an idiopathic generalized epilepsy that affects children between the ages of 4 and 12 years of age, although peak onset is around five to six years old. These patients have recurrent ], brief episodes of unresponsive staring, sometimes with minor motor features such as eye blinking or subtle chewing. The EEG finding in CAE is generalized 3&nbsp;Hz spike and wave discharges. Some go on to develop generalized tonic-clonic seizures. This condition carries a good prognosis because children do not usually show cognitive decline or neurological deficits, and the seizures in the majority cease spontaneously with ongoing maturation. ] (CAE) is a genetic generalized epilepsy that affects children between the ages of 4 and 12 years of age, although peak onset is around five to six years old. These patients have recurrent ], brief episodes of unresponsive staring, sometimes with minor motor features such as eye blinking or subtle chewing. The EEG finding in CAE is generalized 3&nbsp;Hz spike and wave discharges. Some go on to develop generalized tonic-clonic seizures. This condition carries a good prognosis because children do not usually show cognitive decline or neurological deficits, and the seizures in the majority cease spontaneously with ongoing maturation.{{citation needed|date=July 2021}}


===Epilepsy in females with intellectual disability===
==Dravet's syndrome==
], is characterized by seizure onset in infancy or early childhood (6–36 months) and cognitive impairment in some cases. Seizures are predominantly generalized, including tonic-clonic, tonic and atonic seizures. The spectrum of phenotypes has been extended to include female patients with early onset epileptic encephalopathies resembling Dravet syndrome, FIRES, Generalized epilepsy with febrile seizures plus (GEFS+) or focal epilepsy with or without intellectual disability. The condition is caused by mutations in PCDH19 (protocadherin 19).{{citation needed|date=July 2021}}
], previously known as severe myoclonic epilepsy of infancy (SMEI), is a neurodevelopmental disorder beginning in infancy and characterized by severe epilepsy that does not respond well to treatment. This syndrome was described by Charlotte Dravet, French psychiatrist and ] (born July 14, 1936). Dravet described this syndrome while working at the Centre Saint Paul at the University of ]. At Centre Saint Paul, one of her supervisors was Henri Gastaut, who described the ]. She described this condition in 1978<ref name="Dravet1978">Dravet C (1978) Les epilepsies graves de l'enfant. Vie Médicale 8: 543–548</ref> Estimates of the prevalence of this rare disorder have ranged from 1:20,000 to 1:40,000 births, though the incidence may be found to be greater as the syndrome becomes better recognized and new genetic evidence is discovered. It is thought to occur with similar frequency in both genders, and knows no geographic or ethnic boundaries. The course of Dravet syndrome is highly variable from person to person. Seizures begin during the first year of life and development is normal before their onset. In most cases, the first seizures occur with fever and are generalized tonic-clonic (grand mal) or unilateral (one-sided) convulsions. These seizures are often prolonged, and may lead to status epilepticus, a medical emergency. In time, seizures increase in frequency and begin to occur without fever. Additional seizure types appear, most often these are myoclonic, atypical absence, and focal seizures. Additional features that are seen in significant numbers of patients with Dravet syndrome may include ]s and other ]characteristics, orthopedic or movement disorders, frequent or chronic upper respiratory and ear infections, sleep disturbance, ], and problems with growth and nutrition.<ref>{{cite web|url=http://idea-league.org/dravet-syndrome|title=Dravet Syndrome|accessdate=2010-09-08}}</ref>


===Febrile infection-related epilepsy syndrome===
==Epilepsy in Females with Mental Retardation==
See ] (FIRES)
], is characterized by seizure onset in infancy or early childhood (6–36 months) and cognitive impairment in some cases. Seizures are predominantly generalized, including tonic-clonic, tonic and atonic seizures. The spectrum of phenotypes has been extended to include female patients with early onset epileptic encephalopathies resembling Dravet syndrome, FIRES, Generalized epilepsy with febrile seizures plus (GEFS+) or focal epilepsy with or without mental retardation. EFMR is caused by mutations in PCDH19 (protocadherin 19).


==Febrile infection-related epilepsy syndrome== ===Frontal lobe epilepsy===
] (FIRES)

==Frontal lobe epilepsy==
], usually a symptomatic or cryptogenic localization-related epilepsy, arises from lesions causing seizures that occur in the frontal lobes of the brain. These epilepsies can be difficult to diagnose because the symptoms of seizures can easily be confused with nonepileptic spells and, because of limitations of the EEG, be difficult to "see" with standard scalp ]. ], usually a symptomatic or cryptogenic localization-related epilepsy, arises from lesions causing seizures that occur in the frontal lobes of the brain. These epilepsies can be difficult to diagnose because the symptoms of seizures can easily be confused with nonepileptic spells and, because of limitations of the EEG, be difficult to "see" with standard scalp ].
Juvenile absence epilepsy is an idiopathic generalized epilepsy with later onset than CAE, typically in prepubertal adolescence, with the most frequent seizure type being absence seizures. Generalized tonic-clonic seizures can occur. Often, 3&nbsp;Hz spike-wave or multiple spike discharges can be seen on EEG. The prognosis is mixed, with some patients going on to a syndrome that is poorly distinguishable from JME. Juvenile absence epilepsy is an idiopathic generalized epilepsy with later onset than CAE, typically in prepubertal adolescence, with the most frequent seizure type being absence seizures. Generalized tonic-clonic seizures can occur. Often, 3&nbsp;Hz spike-wave or multiple spike discharges can be seen on EEG. The prognosis is mixed, with some patients going on to a syndrome that is poorly distinguishable from JME.


===Juvenile myoclonic epilepsy===
==Interictal dysphoric disorder==
] (JME) is a genetic generalised epilepsy that occurs in patients aged 8 to 20 years. Patients have normal cognition and are otherwise neurologically intact. The most common seizure is myoclonic jerks, although generalized tonic-clonic seizures and absence seizures may occur as well. Myoclonic jerks usually cluster in the early morning after awakening. The EEG reveals generalized 4–6&nbsp;Hz spike wave discharges or multiple spike discharges. These patients are often first diagnosed when they have their first generalized tonic-clonic seizure later in life, when they experience sleep deprivation (e.g., freshman year in college after staying up late to study for exams). Alcohol withdrawal can also be a major contributing factor in ]s, as well. The risk of the tendency to have seizures is lifelong; however, the majority have well-controlled seizures with anticonvulsant medication and avoidance of seizure precipitants.{{citation needed|date=July 2021}}
] (IDD) is a pleomorphic syndrome characterized by intermittent depression between seizures.


===Ohtahara syndrome===
==Juvenile myoclonic epilepsy==
] is a rare but severe epilepsy syndrome usually starting in the first few days or weeks of life. The seizures are often in the form of stiffening spasms but other seizures including unilateral ones may be seen. The electroencephalogram (EEG) is characteristic. The prognosis is poor with about half of the infants dying in the first year of life; most if not all surviving infants are severely intellectually disabled and many have cerebral palsy. There is no effective treatment. A number of children have underlying structural brain abnormalities.<ref>{{cite book |vauthors=Aicardi J, Ohtahara S |chapter=Severe neonatal epilepsies with suppression-burst pattern |chapter-url= |veditors=Roger J, Bureau M, Dravet C, Genton P, Tassinari C, Wolf P |title=Epileptic Syndromes in Infancy, Childhood and Adolescence |publisher=J. Libbey Eurotext |edition=4th |date=2005 |isbn=2-7420-0569-2 |pages= |oclc=171296692}}</ref>
] (JME) is an idiopathic generalized epilepsy that occurs in patients aged 8 to 20 years. Patients have normal cognition and are otherwise neurologically intact. The most common seizure is myoclonic jerks, although generalized tonic-clonic seizures and absence seizures may occur as well. Myoclonic jerks usually cluster in the early morning after awakening. The EEG reveals generalized 4–6&nbsp;Hz spike wave discharges or multiple spike discharges. These patients are often first diagnosed when they have their first generalized tonic-clonic seizure later in life, when they experience sleep deprivation (e.g., freshman year in college after staying up late to study for exams). Alcohol withdrawal can also be a major contributing factor in ]s, as well. The risk of the tendency to have seizures is lifelong; however, the majority have well-controlled seizures with anticonvulsant medication and avoidance of seizure precipitants.


===Reflex epilepsies===
==Lennox-Gastaut syndrome==
About 6% of those with epilepsy have seizures that are often triggered by specific events, known as ].<ref name=Reflex2008>{{cite book|title=Behavioral aspects of epilepsy: principles and practice|year=2008|publisher=Demos |isbn=978-1-933864-04-4|page=125|url=https://books.google.com/books?id=a6Ygv5_RKKsC&pg=PA125 |editor-first=Steven C. |editor-last=Schachter}}</ref> A number of epilepsy syndromes, known as ], have seizures that are only triggered by specific stimuli.<ref>{{cite journal|last=Xue|first=LY|author2=Ritaccio, AL |title=Reflex seizures and reflex epilepsy.|journal=American Journal of Electroneurodiagnostic Technology|date=March 2006|volume=46|issue=1|pages=39–48|pmid=16605171|doi=10.1080/1086508X.2006.11079556|s2cid=10098600 }}</ref> Common triggers include: flashing lights and sudden noises.<ref name=Reflex2008/>
] (LGS) is a generalized epilepsy that consists of a triad of developmental delay or childhood dementia, mixed generalized seizures, and ]demonstrating a pattern of approximately 2&nbsp;Hz "slow" spike-waves. Onset occurs between two and 18 years.


Those with ] can have seizures triggered by flashing lights. Other precipitants can trigger an epileptic seizure in patients who otherwise would be susceptible to spontaneous seizures. For example, children with ] may be susceptible to ]. In fact, flashing lights and hyperventilation are activating procedures used in clinical ] to help trigger seizures to aid diagnosis. Finally, other precipitants can facilitate, rather than obligately trigger, seizures in susceptible individuals. Emotional stress, sleep deprivation, sleep itself, heat stress, alcohol and febrile illness are examples of precipitants cited by patients with epilepsy. Notably, the influence of various precipitants varies with the epilepsy syndrome.<ref name="Frucht2000">{{cite journal|vauthors=Frucht MM, Quigg M, Schwaner C, Fountain NB | title =Distribution of seizure precipitants among epilepsy syndromes | journal = Epilepsia | volume = 41 | issue = 12|pages = 1534–9 | year = 2000 | doi = 10.1111/j.1499-1654.2000.001534.x | pmid = 11114210| doi-access = free }}</ref> Likewise, the ] in women with epilepsy can influence patterns of seizure recurrence. ] is the term denoting seizures linked to the menstrual cycle.<ref name="Herzog2004">{{cite journal | author = Herzog AG|title = Frequency of catamenial seizure exacerbation in women with localization-related epilepsy | journal = Annals of Neurology | volume = 56 | issue = 3 | pages = 431–34| pmid = 15349872| year = 2004 | doi = 10.1002/ana.20214 | author2 = Harden CL | author3 = Liporace J | author4 = Pennell P | author5 = Schomer DL | author6 = Sperling M | display-authors = 6 | last7 = Fowler | first7 = Kristen | last8 = Nikolov|first8 = Blagovast | last9 = Shuman | first9 = Sevie|s2cid = 2124572 }}</ref>
Epilepsy is consider a chronic (meaning it lasts for a long time) condition that is defined by seizures. is a rare and severe form of epilepsy.2

As in West syndrome, LGS result from idiopathic, symptomatic, or cryptogenic causes, and many patients first have ]. Authorities emphasize different seizure types as important in LGS, but most have astatic seizures (drop attacks), tonic seizures, tonic-clonic seizures, atypical absence seizures, and sometimes, focal seizures. Anticonvulsants are usually only partially successful in treatment.

==Ohtahara syndrome==
] is a rare but severe epilepsy syndrome usually starting in the first few days or weeks of life. The seizures are often in the form of stiffening spasms but other seizures including unilateral ones may be seen. The electroencephalogram (EEG) is characteristic. The prognosis is poor with about half of the infants dying in the first year of life; most if not all surviving infants are severely intellectually disabled and many have cerebral palsy. There is no effective treatment. A number of children have underlying structural brain abnormalities.<ref>(Aicardi J and Ohtahara S. Severe neonatal epilepsies with suppression-burst pattern. Epileptic Syndromes in Infancy, Childhood and Adolescence (4th edition) Eds Roger J, Bureau M, Dravet C,Genton P, Tassinari C, and Wolf P. John Libbey Eurotext 2005 ISBN 2-7420-0569-2.</ref>

==Reflex epilepsy==
About 6% of those with epilepsy have seizures that are often triggered by specific events, known as ].<ref name=Reflex2008>{{cite book|title=Behavioral aspects of epilepsy : principles and practice|year=2008|publisher=Demos|location=New York|isbn=9781933864044|page=125|url=http://books.google.ca/books?id=a6Ygv5_RKKsC&pg=PA125|edition=.|editor=Steven C. Schachter}}</ref> A number of epilepsy syndromes, known as ], have seizures that are only triggered by specific stimuli.<ref>{{cite journal|last=Xue|first=LY|author2=Ritaccio, AL |title=Reflex seizures and reflex epilepsy.|journal=American journal of electroneurodiagnostic technology|date=March 2006|volume=46|issue=1|pages=39–48|pmid=16605171}}</ref> Common triggers include: flashing lights and sudden noises.<ref name=Reflex2008/>

Those with ] can have seizures triggered by flashing lights. Other precipitants can trigger an epileptic seizure in patients who otherwise would be susceptible to spontaneous seizures. For example, children with ] may be susceptible to ]. In fact, flashing lights and hyperventilation are activating procedures used in clinical ] to help trigger seizures to aid diagnosis. Finally, other precipitants can facilitate, rather than obligately trigger, seizures in susceptible individuals. Emotional stress, sleep deprivation, sleep itself, heat stress, alcohol and febrile illness are examples of precipitants cited by patients with epilepsy. Notably, the influence of various precipitants varies with the epilepsy syndrome.<ref name="Frucht2000">{{cite journal|author = Frucht MM, Quigg M, Schwaner C, Fountain NB. | title =Distribution of seizure precipitants among epilepsy syndromes | journal = Epilepsia | volume = 41 | issue = 12|pages = 1534–1539. | year = 2000 | doi = 10.1111/j.1499-1654.2000.001534.x | pmid = 11114210}}</ref> Likewise, the ] in women with epilepsy can influence patterns of seizure recurrence. ] is the term denoting seizures linked to the menstrual cycle.<ref name="Herzog2004">{{cite journal | author = Herzog AG|title = Frequency of catamenial seizure exacerbation in women with localization-related epilepsy | journal = Annals of Neurology | volume = 56 | issue = 3 | pages = 431–34| pmid = 15349872| year = 2004 | doi = 10.1002/ana.20214 | author-separator = , | author2 = Harden CL | author3 = Liporace J | author4 = Pennell P | author5 = Schomer DL | author6 = Sperling M | display-authors = 6 | last7 = Fowler | first7 = Kristen | last8 = Nikolov|first8 = Blagovast | last9 = Shuman | first9 = Sevie}}</ref>


Primary reading epilepsy is a ] classified as an idiopathic localization-related epilepsy. Reading in susceptible individuals triggers characteristic seizures.<ref name="Koutroumanidid1998">{{cite journal Primary reading epilepsy is a ] classified as an idiopathic localization-related epilepsy. Reading in susceptible individuals triggers characteristic seizures.<ref name="Koutroumanidid1998">{{cite journal
Line 95: Line 167:
| journal = Brain | journal = Brain
| volume = 121 | volume = 121
| pages = 1409–1427 | pages = 1409–27
| year = 1998 | year = 1998
| doi = 10.1093/brain/121.8.1409 | doi = 10.1093/brain/121.8.1409
| pmid = 9712004 | pmid = 9712004
| issue = 8}}</ref> | issue = 8| doi-access = free
}}</ref>
] (CE) is when seizures cluster around certain phases of a woman's menstrual cycle. ] (CE) is when seizures cluster around certain phases of a woman's menstrual cycle.
*] * ]


==Progressive myoclonic epilepsis== ===Progressive myoclonic epilepsies===
Progressive myoclonic epilepsies define a group of symptomatic generalized epilepsies characterized by progressive ] and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are ], myoclonus epilepsy with ragged red fibers (]), ], neuronal ceroid lipofucinosis, and sialdosis. Progressive myoclonic epilepsies define a group of symptomatic generalized epilepsies characterized by progressive ] and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are ], myoclonus epilepsy with ragged red fibers (]), ], neuronal ceroid lipofuscinosis, and sialidosis.


===Temporal lobe epilepsy===
==Rasmussen's encephalitis==
] (TLE) is not a classic syndrome but mentioned here because it is the most common epilepsy of adults. It is a symptomatic localization-related epilepsy and in most cases the epileptogenic region is found in the midline (]) temporal structures (e.g., the ], ], and ]). Seizures begin in late childhood and adolescence. Most of these patients have focal seizures sometimes preceded by an ], and some TLE patients also have secondary generalized ]. Often seizures do not sufficiently respond to medical treatment with ]s and ] may be considered.<ref name="Bell 2009 2053–2060">{{cite journal|last=Bell|first=Michael |author2=Rao S |author3=So EL |author4=Trenerry M |author5=Kazemi N |author6=Stead SM |author7=Cascino G |author8=Marsh R |author9=Meyer FB |author10=Watson RE |author11=Giannini C |author12=Worrell GA|title=Epilepsy surgery outcomes in temporal lobe epilepsy with a normal MRI|journal=Epilepsia|year=2009|volume=50|issue=9|pages=2053–60|doi=10.1111/j.1528-1167.2009.02079.x|pmid=19389144|pmc=2841514}}</ref>
] is a symptomatic localization-related epilepsy that is a progressive, inflammatory lesion affecting children with onset before the age of 10. Seizures start as separate focal seizures and may progress to ] (simple partial status epilepticus). Neuroimaging shows inflammatory encephalitis on one side of the brain that may spread if not treated. Dementia and hemiparesis are other problems. The cause is hypothesized to involve an immulogical attack against glutamate receptors, a common neurotransmitter in the brain.<ref name="Rogers1994">{{cite journal
| author = Rogers
| title = Autoantibodies to glutamate receptor GluR3 in Rasmussen's encephalitis
| journal = Science
| volume = 265
| pages = 648–651
| year = 1994
| doi = 10.1126/science.8036512
| pmid = 8036512
| issue=5172}}</ref>


==Ring chromosome 20 syndrome== ===West syndrome===
] is a triad of developmental delay, seizures termed ], and ] demonstrating a pattern termed ]. Onset occurs between three months and two years, with peak onset between eight and nine months. West syndrome may arise from idiopathic, symptomatic, or cryptogenic causes. The most common cause is tuberous sclerosis. The prognosis varies with the underlying cause. In general, most surviving patients remain with significant cognitive impairment and continuing seizures and may evolve to another eponymic syndrome, Lennox-Gastaut syndrome. It can be classified as idiopathic, syndromic, or cryptogenic depending on cause and can arise from both focal or generalized epileptic lesions.
The genetic component to epilepsy is receiving interest with conditions such as ] (r(20)) gaining acknowledgment, although only 60 cases have been reported in the literature since 1976, "more widespread cytogenetic chromosomal karyotyping in nonetiological cases of epilepsy" is likely.<ref>http://www.ring20.org/what-is-r20.php</ref>
Symptomatic localization-related epilepsies are divided by the location in the brain of the epileptic lesion, since the symptoms of the seizures are more closely tied to the brain location rather than the cause of the lesion. Tumors, atriovenous malformations, cavernous malformations, trauma, and cerebral infarcts can all be causes of epileptic foci in different brain regions.


==Temporal lobe epilepsy== ==Based on symptoms==
Some forms of epilepsy or seizures have been defined based on symptoms, such as ], ], and ].<ref name="Benson1991">{{cite journal | vauthors = Benson DF | title = The Geschwind syndrome | journal = Adv Neurol | volume = 55 | issue = | pages = 411–421 | date = 1991 | pmid = 2003418 | doi = | url = }}</ref><ref name="GschwindPicard2016">{{cite journal | vauthors = Gschwind M, Picard F | title = Ecstatic Epileptic Seizures: A Glimpse into the Multiple Roles of the Insula | journal = Front Behav Neurosci | volume = 10 | issue = | pages = 21 | date = 2016 | pmid = 26924970 | pmc = 4756129 | doi = 10.3389/fnbeh.2016.00021 | doi-access = free | url = }}</ref><ref name="Arias2019">{{cite journal | vauthors = Arias M | title = Neurology of ecstatic religious and similar experiences: Ecstatic, orgasmic, and musicogenic seizures. Stendhal syndrome and autoscopic phenomena | journal = Neurologia (Engl Ed) | volume = 34 | issue = 1 | pages = 55–61 | date = 2019 | pmid = 27340019 | doi = 10.1016/j.nrl.2016.04.010 | url = | doi-access = free }}</ref>
] (TLE) is not a classic syndrome but mentioned here because it is the most common epilepsy of adults. It is a symptomatic localization-related epilepsy and in most cases the epileptogenic region is found in the midline (]) temporal structures (e.g., the ], ], and ]). Seizures begin in late childhood and adolescence. Most of these patients have focal seizures sometimes preceded by an ], and some TLE patients also have secondary generalized ]. Often seizures do not sufficiently respond to medical treatment with ]s and ] may be considered.<ref name="Bell 2009 2053–2060">{{cite journal|last=Bell|first=Michael|coauthors=Rao S, So EL, Trenerry M, Kazemi N, Stead SM, Cascino G, Marsh R, Meyer FB, Watson RE, Giannini C, Worrell GA|title=Epilepsy surgery outcomes in temporal lobe epilepsy with a normal MRI|journal=Epilepsia|year=2009|volume=50|issue=9|pages=2053–2060|doi=10.1111/j.1528-1167.2009.02079.x|pmid=19389144|pmc=2841514}}</ref>


==Tuberous sclerosis== ==See also==
* ]
] (TSC) is a genetic disorder that causes tumors to form in many organs, primarily in the brain, eyes, heart, kidney, skin and lungs. Several types of brain lesions can occur in individuals with TSC and 60% - 90% of people with TSC develop epilepsy.

==West syndrome==
] is a triad of developmental delay, seizures termed ], and ] demonstrating a pattern termed ]. Onset occurs between three months and two years, with peak onset between eight and 9 months. West syndrome may arise from idiopathic, symptomatic, or cryptogenic causes. The most common cause is tuberous sclerosis. The prognosis varies with the underlying cause. In general, most surviving patients remain with significant cognitive impairment and continuing seizures and may evolve to another eponymic syndrome, Lennox-Gastaut syndrome. It can be classified as idiopathic, syndromic, or cryptogenic depending on cause and can arise from both focal or generalized epileptic lesions.


==References== ==References==
{{reflist}} {{reflist|32em}}




] ]
]

Latest revision as of 01:47, 6 September 2024

Cluster of signs and symptoms that define a unique epileptic condition

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

Syndromes are characterized by seizure types and specific findings on EEGs. Epilepsy syndromes often begin, and may remit, at specific ages. Identification of an epilepsy syndrome may provide important clues to the likely cause, the most effective treatment and the risk of comorbidities such as learning problems, intellectual disability, Attention Deficit Hyperactivity Disorder (ADHD), or other problems.

Not everyone with epilepsy can be defined as having an epilepsy syndrome. Epilepsy syndromes are most commonly found in children with epilepsy onset before 3 years of age and are less common in adult-onset epilepsy.

This article reflects the 2017 ILAE Classification of the Epilepsies, and its more detailed follow-up papers, produced for the International League Against Epilepsy by a number of specialist clinicians. Some syndromes in earlier classifications have been renamed or redefined, but these are retained at the end of the article for convenience.

Classification of epilepsy syndromes

Epilepsy syndromes are now classified based on the type of epilepsy as well as by the age at onset.

Type of epilepsy

Syndromes are characterized into 4 groups based on epilepsy type:

a. Generalized onset epilepsy syndromes. These epilepsy syndromes have only generalized-onset seizures and include both the idiopathic generalized epilepsies (specifically childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and epilepsy with generalized tonic- clonic seizures alone), as well as other genetic generalized epilepsies.
b. Focal onset epilepsy syndromes. These epilepsy syndromes have only focal onset seizures and include both the self-limited focal epilepsies in infants and children as well as other focal epilepsy syndromes.
c. Generalized and focal onset epilepsy syndromes. These syndromes have seizures which can be both of generalized or focal onset.
d. Developmental and epileptic encephalopathies (DEEs) or syndromes with progressive neurological deterioration. Developmental and epileptic encephalopathies are disorders that typically onset early in life and are associated with developmental impairment that is due to both the underlying cause of the epilepsy (developmental encephalopathy) as well as frequent seizures and/or epileptiform discharges on EEG (epileptic encephalopathy). Epilepsy syndromes associated with cognitive impairment or other neurological regression that begin after a period of prolonged normal development are termed syndromes with progressive neurological deterioration. Both the DEEs and syndromes with progressive neurological deterioration are amongst the most severe types of epilepsy, with frequent seizures and high rates of drug resistance.

Age at onset

Epilepsy syndromes are also classified based on age at onset when the syndrome first appears, syndromes with onset in neonates and infancy, beginning prior to 2 years of age, syndromes with onset in childhood, and syndromes that begin at a variable age. This group includes syndromes that can begin either in childhood or adulthood.

Epilepsy syndromes with onset in neonates and infants

Epilepsy syndromes are identified in over half of children with epilepsy onset before 2 years of age. Almost two thirds of these syndromes are developmental and epileptic encephalopathies, which are associated with significant developmental impairment and frequent seizures which often respond poorly to antiseizure medication. Of the remainder of infants with an epilepsy syndrome, most will have a self-limited focal epilepsy, which will not impact development, and which are typically outgrown by early childhood.

Self-limited neonatal, infantile or neonatal-infantile epilepsy

As their names suggest, these epilepsies begin at specific ages in otherwise healthy babies and are caused by changes (variants) in specific genes. In some cases, the genetic changes are passed on from parent to child, and thus the syndromes are said to be familial. In other cases, the genetic change occurs de novo in the baby and there is no family history of other persons with early life seizures. De novo means that the child is affected but neither parent has the genetic variant. De novo variants typically may occur in the egg or sperm, or in early embryonic life.

Seizures are focal in onset but less commonly may progress to involve both sides of the body (focal to bilateral convulsive seizure. The babies have a normal examination and attain normal developmental milestones. The MRI, interictal EEG (between seizures) and bloodwork is normal however genetic testing often shows a causal genetic variant (most commonly KCNQ2 or KCNQ3 in self-limited neonatal epilepsy, PRRT2 or less commonly SCN2A or SCN8A in self-limited infantile epilepsy and SCN2A or KCNQ2 in self-limited neonatal-infantile epilepsy. These epilepsies are generally outgrown by the early preschool years and antiseizure medication is not needed after that time.

Infantile epileptic spasms syndrome

Infantile epileptic spasms syndrome is the most common DEE that begins in early life. Infants present with a characteristic seizure type called infantile spasms (repetitive spells of body crunching, each spell lasting less than 2-3 seconds, but which occur in brief clusters). The EEG is always severely abnormal and often shows a pattern called hypsarrhythmia. Many children will have a preceding history of developmental delay and neurological concerns however this syndrome can also affect previously healthy babies. Typically if the seizures are not controlled quickly, infants may have plateauing or even regression of their development. An underlying cause can be found in most babies with infantile epileptic spasms syndrome. In many cases, the MRI scan will show evidence of a prior brain injury or abnormal brain development. Genetic causes are also relatively common and can include a large number of genetic variants. Metabolic causes are less commonly found.

Infantile spasms are treated with specific types of medication, most commonly either oral steroid, ACTH or vigabatrin. The long-term outcome is often worrisome. While infantile spasms often stop with medication, many babies will develop other seizure types over time and most will be left with intellectual disability. The outcome is best predicted by the underlying cause of the spasms and whether the infant's development before onset of spasms. Rapid treatment with effective medication has also been shown to improve longterm developmental outcome.

Dravet syndrome

Main article: Dravet syndrome

Dravet syndrome is a DEE beginning in infancy and characterized by severe epilepsy that does not respond well to treatment. This syndrome was described in 1978 by Charlotte Dravet, a French psychiatrist and epileptologist, while working at the Centre Saint Paul at the University of Marseille. The prevalence of this disorder is approximately 1/16,00 live births. Seizures begin before 20 months of age and in most cases, the first seizures occur with fever and are generalized tonic-clonic (grand mal) or unilateral (one-sided) convulsions. These seizures are often prolonged, and may lead to status epilepticus, a medical emergency. In time, seizures increase in frequency and begin to occur without fever. Additional seizure types appear, most often these are myoclonic, atypical absence, and focal seizures.

Seizures persist despite treatment with medication, however several medications including valproic acid, stiripentol, clobazam, fenfluramine and pharmaceutical grade cannabidiol are often helpful to decrease seizure burden. Development is normal at the time of seizure onset, however developmental typically plateaus around age 2 years, and by adulthood, intellectual disability of varied severity is seen. Additional features that are seen in significant numbers of patients with Dravet syndrome may include a crouch gait, autism spectrum disorder, sleep problems, dysautonomia, and problems with growth and nutrition. Persons with Dravet syndrome also have an increased risk of early death, particularly due to SUDEP.

Epilepsy syndromes with onset in childhood

Epilepsy syndromes can be identified in up to one third of children with epilepsy. Syndromes with onset at this age are divided into the self-limited focal epilepsies, the genetic generalized epilepsies (including childhood absence epilepsy) and the developmental and epileptic encephalopathies.

A. Self-limited focal epilepsies (SeLFEs)

SeLFEs account for approximately one quarter of epilepsies that begin in childhood. They occur in otherwise healthy children with normal development and are not correlated with any brain abnormality on MRI. In most cases, children outgrow this epilepsy type by adolescence and do not need long-term antiseizure medication. These epilepsy syndromes are associated with characteristic seizures and EEG findings, specific for each syndrome.

i. Self-limited epilepsy with centrotemporal spikes (SeLECTS) SeLECTS, (previously known as benign epilepsy of childhood with centrotemporal spikes or benign Rolandic epilepsy) is a focal epilepsy of unknown cause that most commonly occurs in early to mid school-aged children. Apart from their seizure disorder, these patients are otherwise normal. Seizures usually involve facial muscles and frequently cause drooling and difficulty with speech, although the child is aware throughout the seizure. Although most episodes are brief, seizures that occur in sleep may spread to both sides of the body with convulsive activity. Seizures are typically associated with sleep, most commonly being seen shortly after falling asleep or just before waking. The EEG shows epileptic discharges that occur over the centrotemporal region and are most frequent during drowsiness or light sleep. Seizures are outgrown by puberty. Seizures may require antiseizure medication treatment, but sometimes are infrequent enough to allow physicians to defer treatment.

ii. Self-limitied epilepsy with autonomic seizures (SeLEAS) SeLEAS (formerly known as benign occipital epilepsy of childhood or Panayiotopoulos syndrome) is a focal epilepsy of unknown cause that most commonly presents in the preschool years. Seizures are typically infrequent although can be prolonged. Seizures typically have a prominent autonomic component, most commonly retching but also including pallor, nausea, abdominal pain or even syncope. Seizures may evolve with head and eye deviation to one side, followed by focal or bilateral convulsive activity. Children often have retained awareness early on, but as the seizure evolves, awareness is often impaired. The EEG shows a normal background with epileptiform discharges that are maximal over the posterior head region and typically occur in sleep. As seizures are not frequent, daily antiseizure medication is not needed in many cases. In most cases, this epilepsy type is outgrown within a few years after onset, and longterm antiseizure medication is not required.

B. Genetic Generalized Epilepsy

Childhood absence epilepsy (CAE) is an idiopathic generalized epilepsy that presents in early to mid childhood (age 3–12 years) with typical absence seizures, characterized by abrupt loss of responsiveness, staring, sometimes with subtle motor features such as eye blinking or chewing. Seizures are brief, typically lasting 20 seconds or less, but occur very frequently (up to 20–50 times per day in the untreated child). The EEG shows generalized 3 Hz spike and wave discharges. In most cases, absence seizures are the only seizure type, however a minority will develop generalized tonic-clonic seizures, most commonly in adolescence. Children with CAE do not show cognitive decline or neurological deficits, however have higher rates of learning disorders and ADHD. Children require anti-seizures medication, about 60% will outgrow CAE typically within a few years after onset.

C. Developmental and Epileptic Encephalopathies

i. Lennox-Gastaut syndrome (LGS) is a developmental and epileptic encephalopathy that consists of a triad of developmental delay, mixed seizure types and an EEG demonstrating a pattern of "slow" (<2.5 Hz) spike-wave and generalized paroxysmal fast activity. Onset is most commonly prior to age 8 years but rare cases can onset in adolescence.

The most characteristic seizure type is a tonic seizure, which consists of brief generalized body stiffening, and often occurs most prominently in sleep. Additionally, patients often have other seizures types including atonic (abrupt, brief events of loss of tone, often leading to falls), atypical absences (staring spells with more gradual onset and offset), myoclonic jerks, generalized tonic-clonic or focal seizures. While many antiseizure medications can reduce seizure burden, patients do not achieve seizure freedom. Epilepsy is very drug resistant and lifelong. Intellectual disability typically worsens with age, and autism, behavior problems, sleep problems, higher rates of SUDEP and other medical comorbidities are common.

ii. Epilepsy with myoclonic-atonic seizures (EMAtS) (formerly known as Myoclonic-Atonic Epilepsy or Doose syndrome) presents in developmentally normal, mid preschool to early school-aged children. The initial presentation is often with a febrile or afebrile generalized tonic-clonic seizure, however shortly thereafter, different seizure types also evolve and seizures become much more frequent. The most characteristic seizure is a myoclonic-atonic seizure, where the child will briefly jerk, often with a vocalization and then lose tone. Other seizure types which commonly co-exist include atypical absences and myoclonic seizures. Tonic seizures are rare early in the course but may present later on. Many children will go through a period of very frequent seizures with developmental stagnation or regression, known as a “stormy course”. The EEG usually shows 3–6 Hz generalized spike-wave discharge, although the frequency is often slower during the stormy phase. Approximately two thirds of children will eventually have remission of seizures and can stop medication, usually within several years after epilepsy onset.

iii. Developmental and epileptic encephalopathy/Epileptic encephalopathy with spike-wave activation in sleep (DEE-SWAS or EE-SWAS). This group of disorders was formerly known by many names, including continuous spike-wave in sleep (CSWS), Electrographic status epilepticus is sleep (ESES), Landau-Kleffner syndrome or pseudo-Lennox syndrome. In this disorder, there is marked activation of epileptiform discharge in sleep associated with stagnation or regression of development. The term DEE-SWAS is used for children with pre-existing developmental delay while EE-SWAS is used if prior development was normal. This disorder typically presents in preschool or early school-aged children, and the EEG pattern of marked exacerbation of spike-wave discharge in sleep remits by puberty, although the EEG may remain abnormal. Seizures also typically reduce in frequency and often abate by puberty. Persons with DEE-SWAS or EE-SWAS may present with a variety of seizures types including focal seizures or generalized seizures, and rarely seizures may not be seen.

Certain medications such as steroids or high dose benzodiazepines may improve the sleep EEG. Although neurocognitive and behavioral improvement is typically seen after resolution of SWAS, many children are left with learning problems, Attention Deficit Hyperactivity Disorder and variable degrees of intellectual disability, depending on the underlying cause and the duration of the abnormal EEG pattern prior to effective treatment and the age at onset.

Epilepsy syndromes with onset at a variable age

The majority of syndromes that onset at a variable age can be subdivided into the idiopathic generalized epilepsy syndromes, focal epilepsy syndromes or syndromes with progressive neurological deterioration.

A. Idiopathic generalized epilepsy syndromes

i. Juvenile absence epilepsy (JAE) typically presents in early to mid adolescence in developmentally normal teens with typical absence seizures. JAE is distinguished from CAE as the absence seizures are less frequent (typically up to 10/day at most), age at onset is older (typically >10 years) and higher association with generalized tonic-clonic seizures. The EEG shows generalized 3–4 Hz spike-wave discharge and the background is normal. Approximately 80% of patients will develop generalized tonic-clonic seizures, most commonly within a few years of onset of absence seizures. Persons with JAE do not show cognitive decline or neurological deficits, however have higher rates of learning disorders, depression, anxiety and ADHD. The likelihood of remission is significantly lower than CAE.

ii. Juvenile myoclonic epilepsy (JME) presents in developmentally normal teens and young adults with myoclonic seizures, that often occur in the morning and can be triggered by sleep deprivation or flashing lights. The majority (over 90%) also will develop generalized tonic-clonic seizures, which are often heralded by a cluster of myoclonic jerks. Approximately 40% also develop typical absence seizures, however these are usually infrequent, very brief and may not have complete impairment in awareness. The EEG shows fast generalized spike-wave or polyspike and wave and the MRI, if done, is normal. Persons with JME do not experience neurocognitive regression but have higher rates of learning problems, depression and anxiety and ADHD.

B. Focal epilepsy syndromes

i. Sleep-related hypermotor epilepsy (SHE) is a focal epilepsy syndrome characterized by clusters of complex motor movements such as hand clenching, arm or leg flailing, abnormal posturing, kicking or vocalizations (shouting, moaning, etc.) that arise during sleep. Seizures are generally brief but often occur multiple times each night. This epilepsy syndrome can occur both in children and adults and is by either a specific gene (including nicotinic acetylcholine receptor subunit genes, genes affecting the GATOR1 complex or KCNT1) or structural brain abnormalities (either developmental brain changes or acquired brain injury). Persons with this epilepsy syndrome are often misdiagnosed as having nightmares.

ii. Mesial temporal lobe epilepsy with hippocampal sclerosis is one of the most common causes of drug resistant epilepsy in adults and can also be seen in children. Seizures arise from the mesial temporal structures (e.g., the hippocampus, amygdala, and parahippocampal gyrus) and often begin with autonomic (rising sensation from the abdomen to the chest, nausea, vomiting), cognitive (déjà vu, jamais vu), fear or sensory (bad smell or taste) symptoms. There is often gradual impairment in awareness and oral automatisms (chewing, lip-smacking) are common. With seizures that affect the dominant hemisphere for language, persons often have difficulty with language (inability to speak or garbled language) during and shortly after the seizure. Seizures may evolve to become bilateral convulsive seizures. Seizures most commonly begin in late childhood and adolescence but can occur at any age. The MRI shows evidence of hippocampal sclerosis (scarring of the hippocampus). Often seizures do not sufficiently respond to medical treatment with anticonvulsants and epilepsy surgery may be considered.

c. Epilepsy syndromes with progressive neurological impairment

i. Rasmussen's encephalitis is a focal epilepsy that almost always affects only one hemisphere of the brain. It is characterized by focal seizures that progress in frequency and severity over time and often culminate in epilepsia partialis continua (near constant focal seizure activity of one side of the body). With time, the person develops progressive loss of motor control on the side of the body controlled by the affected hemisphere (progressive hemiparesis) and language problems and cognitive regression may also be seen. The MRI is often normal at the time of epilepsy onset but with time shows progressive atrophy of the affected hemisphere. The cause is felt to be immunological/inflammatory. Often, surgery such as a hemispheric disconnection is required to control seizures. Rasmussen encephalitis is most common in children but less commonly begins in adolescence or adult life.

ii. Progressive myoclonic epilepsy is a rare syndrome that comprised a group of underlying genetic epilepsies characterized by progressive dementia and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are Unverricht-Lundborg disease, myoclonus epilepsy with ragged red fibers (MERRF syndrome), Lafora disease, neuronal ceroid lipofuscinosis, and sialidosis.

Syndromes not appearing in the 2017 ILAE classification

The latest 2017 ILAE classification of epilepsy syndromes no longer includes several syndromes included in earlier classifications. These are now included under other syndromes in the new classification, or are no longer regarded as syndromes, but are retained here for reference.

Autosomal dominant nocturnal frontal lobe epilepsy

Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is an idiopathic localization-related epilepsy that is an inherited epileptic disorder that causes seizures during sleep. Onset is usually in childhood. These seizures arise from the frontal lobes and consist of complex motor movements, such as hand clenching, arm raising/lowering, and knee bending. Vocalizations such as shouting, moaning, or crying are also common. ADNFLE is often misdiagnosed as nightmares. ADNFLE has a genetic basis. These genes encode various nicotinic acetylcholine receptors.

Rolandic epilepsy

Benign centrotemporal lobe epilepsy of childhood or benign Rolandic epilepsy is an idiopathic localization-related epilepsy that occurs in children between the ages of 3 and 13 years, with peak onset in prepubertal late childhood. Apart from their seizure disorder, these patients are otherwise normal. This syndrome features simple focal seizures that involve facial muscles and frequently cause drooling. Although most episodes are brief, seizures sometimes spread and generalize. Seizures are typically nocturnal and confined to sleep. The EEG may demonstrate spike discharges that occur over the centrotemporal scalp over the central sulcus of the brain (the Rolandic sulcus) that are predisposed to occur during drowsiness or light sleep. Seizures cease near puberty. Seizures may require anticonvulsant treatment, but sometimes are infrequent enough to allow physicians to defer treatment.

Benign occipital epilepsy of childhood

See also: Occipital epilepsy

Benign occipital epilepsy of childhood (BOEC) is an idiopathic localization-related epilepsy and consists of an evolving group of syndromes. Most authorities include two subtypes, an early subtype with onset between three and five years, and a late onset between seven and 10 years. Seizures in BOEC usually feature visual symptoms such as scotoma or fortifications (brightly colored spots or lines) or amaurosis (blindness or impairment of vision). Convulsions involving one half the body, hemiconvulsions, or forced eye deviation or head turning are common. Younger patients typically experience symptoms similar to migraine with nausea and headache, and older patients typically complain of more visual symptoms. The EEG in BOEC shows spikes recorded from the occipital (back of head) regions. The EEG and genetic pattern suggest an autosomal dominant transmission as described by Ruben Kuzniecky, et al. Lately, a group of epilepsies termed Panayiotopoulos syndrome that share some clinical features of BOEC.

Childhood absence epilepsy

Childhood absence epilepsy (CAE) is a genetic generalized epilepsy that affects children between the ages of 4 and 12 years of age, although peak onset is around five to six years old. These patients have recurrent absence seizures, brief episodes of unresponsive staring, sometimes with minor motor features such as eye blinking or subtle chewing. The EEG finding in CAE is generalized 3 Hz spike and wave discharges. Some go on to develop generalized tonic-clonic seizures. This condition carries a good prognosis because children do not usually show cognitive decline or neurological deficits, and the seizures in the majority cease spontaneously with ongoing maturation.

Epilepsy in females with intellectual disability

Epilepsy in females with intellectual disability, is characterized by seizure onset in infancy or early childhood (6–36 months) and cognitive impairment in some cases. Seizures are predominantly generalized, including tonic-clonic, tonic and atonic seizures. The spectrum of phenotypes has been extended to include female patients with early onset epileptic encephalopathies resembling Dravet syndrome, FIRES, Generalized epilepsy with febrile seizures plus (GEFS+) or focal epilepsy with or without intellectual disability. The condition is caused by mutations in PCDH19 (protocadherin 19).

Febrile infection-related epilepsy syndrome

See Febrile infection-related epilepsy syndrome (FIRES)

Frontal lobe epilepsy

Frontal lobe epilepsy, usually a symptomatic or cryptogenic localization-related epilepsy, arises from lesions causing seizures that occur in the frontal lobes of the brain. These epilepsies can be difficult to diagnose because the symptoms of seizures can easily be confused with nonepileptic spells and, because of limitations of the EEG, be difficult to "see" with standard scalp EEG. Juvenile absence epilepsy is an idiopathic generalized epilepsy with later onset than CAE, typically in prepubertal adolescence, with the most frequent seizure type being absence seizures. Generalized tonic-clonic seizures can occur. Often, 3 Hz spike-wave or multiple spike discharges can be seen on EEG. The prognosis is mixed, with some patients going on to a syndrome that is poorly distinguishable from JME.

Juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is a genetic generalised epilepsy that occurs in patients aged 8 to 20 years. Patients have normal cognition and are otherwise neurologically intact. The most common seizure is myoclonic jerks, although generalized tonic-clonic seizures and absence seizures may occur as well. Myoclonic jerks usually cluster in the early morning after awakening. The EEG reveals generalized 4–6 Hz spike wave discharges or multiple spike discharges. These patients are often first diagnosed when they have their first generalized tonic-clonic seizure later in life, when they experience sleep deprivation (e.g., freshman year in college after staying up late to study for exams). Alcohol withdrawal can also be a major contributing factor in breakthrough seizures, as well. The risk of the tendency to have seizures is lifelong; however, the majority have well-controlled seizures with anticonvulsant medication and avoidance of seizure precipitants.

Ohtahara syndrome

Ohtahara syndrome is a rare but severe epilepsy syndrome usually starting in the first few days or weeks of life. The seizures are often in the form of stiffening spasms but other seizures including unilateral ones may be seen. The electroencephalogram (EEG) is characteristic. The prognosis is poor with about half of the infants dying in the first year of life; most if not all surviving infants are severely intellectually disabled and many have cerebral palsy. There is no effective treatment. A number of children have underlying structural brain abnormalities.

Reflex epilepsies

About 6% of those with epilepsy have seizures that are often triggered by specific events, known as reflex seizures. A number of epilepsy syndromes, known as reflex epilepsies, have seizures that are only triggered by specific stimuli. Common triggers include: flashing lights and sudden noises.

Those with photosensitive epilepsy can have seizures triggered by flashing lights. Other precipitants can trigger an epileptic seizure in patients who otherwise would be susceptible to spontaneous seizures. For example, children with childhood absence epilepsy may be susceptible to hyperventilation. In fact, flashing lights and hyperventilation are activating procedures used in clinical EEG to help trigger seizures to aid diagnosis. Finally, other precipitants can facilitate, rather than obligately trigger, seizures in susceptible individuals. Emotional stress, sleep deprivation, sleep itself, heat stress, alcohol and febrile illness are examples of precipitants cited by patients with epilepsy. Notably, the influence of various precipitants varies with the epilepsy syndrome. Likewise, the menstrual cycle in women with epilepsy can influence patterns of seizure recurrence. Catamenial epilepsy is the term denoting seizures linked to the menstrual cycle.

Primary reading epilepsy is a reflex epilepsy classified as an idiopathic localization-related epilepsy. Reading in susceptible individuals triggers characteristic seizures. Catamenial epilepsy (CE) is when seizures cluster around certain phases of a woman's menstrual cycle.

Progressive myoclonic epilepsies

Progressive myoclonic epilepsies define a group of symptomatic generalized epilepsies characterized by progressive dementia and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are Unverricht-Lundborg disease, myoclonus epilepsy with ragged red fibers (MERRF syndrome), Lafora disease, neuronal ceroid lipofuscinosis, and sialidosis.

Temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is not a classic syndrome but mentioned here because it is the most common epilepsy of adults. It is a symptomatic localization-related epilepsy and in most cases the epileptogenic region is found in the midline (mesial) temporal structures (e.g., the hippocampus, amygdala, and parahippocampal gyrus). Seizures begin in late childhood and adolescence. Most of these patients have focal seizures sometimes preceded by an aura, and some TLE patients also have secondary generalized tonic-clonic seizures. Often seizures do not sufficiently respond to medical treatment with anticonvulsants and epilepsy surgery may be considered.

West syndrome

West syndrome is a triad of developmental delay, seizures termed infantile spasms, and EEG demonstrating a pattern termed hypsarrhythmia. Onset occurs between three months and two years, with peak onset between eight and nine months. West syndrome may arise from idiopathic, symptomatic, or cryptogenic causes. The most common cause is tuberous sclerosis. The prognosis varies with the underlying cause. In general, most surviving patients remain with significant cognitive impairment and continuing seizures and may evolve to another eponymic syndrome, Lennox-Gastaut syndrome. It can be classified as idiopathic, syndromic, or cryptogenic depending on cause and can arise from both focal or generalized epileptic lesions.

Based on symptoms

Some forms of epilepsy or seizures have been defined based on symptoms, such as Geschwind syndrome, ecstatic seizures, and orgasmic seizures.

See also

References

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