Epilepsy Syndromes

What is a Syndrome?
Defining Groups - different syndromes
Idiopathic Partial Epilepsies
Idiopathic Generalised Epilepsies
Symptomatic Partial Epilepsies
Symptomatic Generalised Epilepsies
Special Syndromes

What is a Syndrome?
There are many different types of epilepsy classifications. Nowadays, most people are given a specific diagnosis or name for their epilepsy, rather than just to told that ‘you have epilepsy’. Some epilepsy disorders are classified as syndromes. A seizure syndrome is a type of epilepsy that depends upon:

• Family history
• Age of onset of the condition
• Seizure type(s)
• Cause, and other underlying diseases/conditions
• Rate of progression or development over time
• Presence or absence of neurologic abnormalities
• EEG findings
• Structural and functional neuroimaging findings (such as CT, MRI, PET)
• Response to medication

A diagnosis of a particular epilepsy syndrome is useful in deciding the possible treatment options, what course of the condition may take, and the possible genetic risk of passing it on to offspring.

In the following sections, we outline some of the more common epilepsy syndromes.

Seizures and syndromes are divided into several groups:

Partial and Generalised
Idiopathic and Symptomatic

Idiopathic means a condition of unknown cause. With epilepsy, idiopathic epilepsies are presumed to be inherited and have no apparent structural cause, with seizures as the only sign of the condition.

It may indicate normal development and intellect, EEG shows normal a background, usually seizures are easy to control and there is often a good prognosis.

Symptomatic means there is a known cause for the condition. This may mean there is abnormal brain tissue causing the seizures. There are usually localised abnormalities seen on diagnostic tests. Sometimes these seizures can be more difficult to control.

There are many more syndromes than are mentioned here. We will discuss some of the more common syndromes.

Idiopathic Partial Epilepsies

• The onset of seizures is between 2 and 14 years of age, most commonly between 5 and 10 years of age.
• These conditions account for about 10–15% of people with epilepsy in this age group.
• About 30% of these children will have a family history of epilepsy.
• Intellectual or developmental abnormalities are not usually associated with idiopathic partial epilepsies, and people almost always outgrow the condition by puberty.

• Normal intelligence and development
• Genetic tendency/ family history
• Onset above infancy and below puberty, usually between 3-13 years
• Partial seizures, usually brief and infrequent, with or without secondary generalisation
• Seizures may involve face, mouth and tongue.Sensation changes such as numbness and tingling occur, facial twitching and sometimes gurgling or grunting noises can be heard. The child is unable to speak and may drool. The child usually has an awareness of some or all of the seizure
• Seizures may spread to become a generalised tonic-clonic seizure
• 70-80% of seizures occur during sleep
• Medication is not often prescribed, but if it is given there is usually a good response
• Remission occurs around the time of puberty
• Specific characteristics are found on EEG
• Good prognosis

• Age at onset of epilepsy varies from 15 months to 17 years.
• Most children have normal intelligence and development. Although a small number of children may have neurological, developmental, behavioural or visual problems
• Adversive seizures (rotation of eyes, head and body) are the most common seizures seen.
• They usually follow visual symptoms such as hallucinations, blindness or flashing lights.
• Visual symptoms are usually brief, and consciousness is preserved or only slightly impaired.
• Migraine, nausea and vomiting are usually seen after seizures. Sometimes confusion is present
• There are two peaks: the early type seen between 3 and 5 years, and the late type between 7 and 9 years. Their characteristics are:
  Early onset
  The early-onset variant of this syndrome can involve brief or prolonged, infrequent partial seizures marked by deviation of the eyes to one side and vomiting. The seizures are usually during sleep and frequently develop into jerking of one side of the body and generalised tonic-clonic seizures. It is more prevalent in females and the prognosis is good
  Late onset
  The late-onset variant is more so characterised by visual seizures often followed by jerking or repetitive movements of one side the body. Visual seizures that can include symptoms of blindness, visual illusions of hallucinations, usually occur in the daytime. In 25% of cases, seizures are followed by migraine.

• Normal intelligence and development.
• Genetic tendency
• Onset ranges from infancy to adulthood. About 80% of people develop this syndrome in the first two decades of life.
• The symptoms and seizures may vary considerably within a family.
• These seizures are characterised by clusters of nocturnal seizures, which often follow the same pattern and are brief (from five seconds to five minutes in duration).
• The seizures vary from simple arousals from sleep to dramatic, often bizarre, excessive movements with stiffening (tonic), twisting (dystonic) or abnormal posturing features.
• People may experience an aura (warning or a simple partial seizure).
• Awareness is usually retained during a seizure.
• It is lifelong but does not worsen.
• The seizures can mimic some sleep disorders.
• It may be difficult to obtain full seizure control in up to 30% of cases.
• Upon reaching middle age, attacks may become milder and less frequent.

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The types of seizures affecting people with idiopathic generalised epilepsy may include myoclonic, absence and generalised tonic-clonic seizures, with usually one type being more prominent that the other types of seizures. These types of epilepsy are usually successfully treated with medications and mostly outgrown, but not always.

Some of the common syndromes include:

1. Benign familial neonatal convulsions
These convulsions typically present on days 2 or 3 of life in an otherwise well baby. Characteristics include:

• Bilateral jerking (clonic) or stiffening (tonic) seizures with or without breathing changes
• Seizures generally resolve after about a week
• Approximately 5% of these children later develop febrile convulsions and about 11% may later develop seizures without fever, although these generally have a benign course
• Intelligence and development is usually normal

2. Benign idiopathic neonatal convulsions
These convulsions typically present on day 5 of life in an otherwise well baby. Characteristics include:

• They are more likely to occur in males than females
• Usually jerking (clonic) seizures are only seen, mostly of a limb or small area of the body (eg side of face). May spread from one side to the other side
• Seizures usually lasting 1-3 minutes, frequently repeated and could lead to status epilepticus
• Seizures generally resolve within 20 hours
• Normal intelligence and development

3. Childhood absence epilepsy (CAE)
Childhood absence epilepsy is commonly mistaken for daydreaming and in-attentiveness.
Some of the features include:

• Age of onset in children is between 3-12 years, usually around 6–8 years
• There is often a strong genetic predisposition in otherwise healthy children
• Normal intelligence and development is seen - although there may be gaps in learning if not diagnosed promptly and seizures continue
• More frequently seen in girls than in boys
• There is often a family history
• These seizures can occur very frequently (tens to hundreds per day)
• The seizures are characterised by brief periods of staring, loss of facial expression, unresponsiveness, suddenly stopping activity and sometimes eye blinking or upward eye movements. Other automatic behaviour may be present. They start and end abruptly, last approximately 2-20 seconds. There is usually an immediate recovery of mental function and resumption of previous activity, with no memory of the event, and the person may not be aware that they have had a seizure
• Diagnosis is relatively easy as the EEG shows characteristic waveforms
• Responds well to medication treatment
• During adolescence, some children may develop infrequent Generalised Tonic-Clonic Seizures
• Otherwise, the child will grow out of the absence seizures (approximately 80%) or more rarely, persist as the only seizure type, later in adult life.

4. Juvenile absence epilepsy (JAE)
Because the number of absence seizures are low, and the seizures are relatively subtle, this disorder may go unnoticed until generalised tonic-clonic seizures appear. Some of the features include:

• Age at onset is usually between 7 and 16 years, with a peak between 10 and 12 years
• Normal intellect and development
• Males and females are equally affected
• The frequency of absences are much less than childhood absence epilepsy, however they can occur in clusters, and tend to be a longer duration. Some people have absence status epilepticus
• There is a possible family history
• Greater than 75% have infrequent generalised tonic-clonic seizures. Sometimes infrequent myoclonic jerks are seen
• Good response to medications, but lifelong therapy is usually needed

5. Juvenile myoclonic epilepsy (JME)
Although this condition is common and usually responds well to treatment with appropriate antiepileptic medications, it is frequently misdiagnosed until the person is asked specifically about the leading symptom, jerky movements occurring in the morning. They often complain of morning clumsiness.

• This is the most common idiopathic generalised epilepsy
• There is normal intelligence and development
• Seizures may begin between late childhood and early adulthood, usually around the time of puberty
• The condition is sometimes not diagnosed until a generalised tonic-clonic seizure occurs
• Seizures generally occur shortly after awakening
• The most prominent seizures are myoclonic jerks which are often mistaken for clumsiness first thing in the morning. Generalised tonic-clonic seizures can also occur, and sometimes absence seizures
• EEG is characteristic and background activity is normal
• Seizures respond well to medication
• Although people usually require lifelong treatment with antiepileptic medication, overall prognosis is generally very good
• Photosensitivity is found in between 20%-50% of people

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Symptomatic Partial Epilepsies
Symptomatic partial (or focal) epilepsy can begin at any age, but is the most common type of epilepsy that begins in adulthood. This type of epilepsy is caused by an abnormality limited to a small area of the brain. This can be present at birth or result from a number of things including; strokes, tumours, trauma, scarring of brain tissue (common in the temporal lobe), cysts or infections.

Sometimes these brain abnormalities can be seen on brain scans, but often they cannot be identified, despite repeated attempts, because they are so small. These seizures can be difficult to control with medication.

The seizures seen in symptomatic partial epilepsies are commonly referred to as partial or focal seizures. About 60% of people with epilepsy have partial seizures. These seizures start in one area of the brain and may remain confined to that area or can spread to other regions of the brain. They sometimes spread to become a generalised seizure, most commonly a tonic-clonic seizure. These seizures can often be very subtle or unusual, and may go unnoticed or be confused with other events such as drunken behaviour.
Examples include:

1. Temporal lobe epilepsy (TLE)
There are two temporal lobes, one on each side of the brain located about the level of the ears. These lobes allow a person to recognise smells, sounds and language. They also help to sort new information and are intrinsically associated with memory.

The seizures associated with TLE are usually simple partial seizures without loss of awareness (aura) and complex partial seizures, causing loss of awareness.

Seizures can differ vastly, but some typical symptoms of temporal lobe seizures are listed below:

Auras (simple partial seizures) occur in approximately 80% of temporal lobe seizures.
Sensations include:

• Changes of taste and smell.
• Auditory hallucinations – hearing buzzing sound, a voice or voices, or muffling of surrounding sounds.
• Visual hallucinations – seeing formed or unformed figures
• Distortions of shape, size, and distance of objects – things may appear smaller or larger than usual.

Feelings include:

• Feelings of déjà vu or jamais vu, a sense of familiarity or unfamiliarity, respectively.
• Feelings of detachment from oneself or surroundings appear unreal.
• Fear, anxiety, anger, or elation.
• People may describe a sense of dissociation where they report seeing their own body from outside.

Body function changes include:

• Changes in heart rate
• Hair standing on end and goose-bumps
• Sweating
• Blushing or loss of colour
• A "rising" sensation from the stomach, or nausea
• Clonus or spasm to muscle(s)

Complex Partial Seizures can have a vast array of symptoms. Some include:

• Wide-eyed, motionless stare, dilated pupils, and the person stops what they are doing
• Lip smacking, chewing, and swallowing may be seen (automatisms)
• Unusual limb postures or movements also may be observed
• The person may continue their activity or react to their surroundings such as fidgeting with objects around them (automatisms)
• Most seizures last approximately 1-3 minutes
• Afterwards people usually experience a period of confusion for several minutes
• Occasionally longer periods of confusion are encountered that may last several days
• Usually there is little or no memory of the event

A simple or complex partial seizure may evolve to a secondarily generalised seizure, often a tonic-clonic seizure.

2. Frontal lobe epilepsy
The frontal lobe is a very large section of the brain situated at the front of the head. It's functions include allowing us to plan, organise, problem solve, and have selective attention. It also contributes to our personality and a variety of "higher cognitive functions" including behaviour and emotions. It also contains the motor cortex, which is responsible for movement.

Frequently, frontal seizure types are simple partial or complex partial and secondarily generalisation may occur. Symptoms tend to reflect where the seizure begins in the lobe, and ranges from behavioural to motor or postural changes.

Typical clinical features of the seizures include:

• Seizures usually short lived with brief (<30 seconds), with stereotyped, sometimes repetitive features
• Frequent seizures can occur with clustering – a number of seizures in a row
• They often occur during sleep
• They start and end abruptly and usually have rapid recovery
• Awareness is lost at the onset
• Often unusual limb postures and/or stiffening (tonic) spasms are seen during seizures
• Can be bizarre or unusual and sometimes misdiagnosed or misunderstood as other events
• Minimal confusion after the partial seizure
• The seizures often and rapidly evolve to a secondarily generalised tonic-clonic seizure
• Status epilepticus may be associated more often with frontal lobe seizures than with seizures arising from other areas.

3. Occipital lobe epilepsy
The occipital lobe is the part of the brain at the back of the skull that processes visual information – it is responsible for sight. It also has areas that help us recognise shapes and colours. Damage to this lobe can cause visual problems.

The symptoms of these seizures are associated with vision and the way we see things. Flashing lights, balls of light or strange colours are typical symptoms, usually affecting half of the vision. This occurs in the opposite side of the body to the lobe where the seizure originates, but can spread to the entire visual field.

Occipital lobe epilepsy syndromes are usually characterised by simple partial and secondarily generalised tonic clonic seizures. Complex partial seizures may occur if the seizure spreads beyond the occipital lobe.

Usually, but not always, visual symptoms are associated with these seizures. Some typical seizure characteristics include:

• Blind spots, loss of half vision, or blindness
• Sparks, flashes, or sensations of light
• Distortion of objects – such as change in size, shape, distance
• Extreme turning of the eyes and head, or sometimes the eyes only.
• Head and eye turning are common
• Rapid eye blinking, closure of eyelids.

Occasionally the seizures become secondarily generalised tonic-clonic seizures.

4. Parietal lobe epilepsy
The parietal lobes are located behind the frontal lobe at the top of the brain. The parietal lobe deals with our bodily sensations (touch, pain, pressure) and judgement of texture, weight, size and shape.

Simple partial seizures beginning in this part of the brain can cause strange physical sensations. A tingling or warmth down one side of the body is typical symptom.

Because the parietal lobe is closely associated with the frontal lobe, people sometimes experience movement changes also. Known as ‘sensory seizures’ the after effect can involve a period of numbness, which wears off after a period of time.

Parietal lobe epilepsy syndromes are usually characterised by simple and secondarily generalised seizures. Most seizures remain as simple partial seizures, but complex partial seizures may occur if the seizures spreads beyond the parietal lobe.

Seizures arising from the parietal lobe may have the following features:

• Tingling and feeling of electricity, which may be confined to one area or spread to other parts of the body
• Numbness, a loss of awareness of a body part or half the body
• There may be a desire to move a body part or feel a sensation as if a part of the body is being moved
• Muscle tone may be lost
• The hands, arm, and face are the parts most frequently involved
• There may be facial or tongue sensations
• Occasionally an intra-abdominal sensation of sinking, choking, or nausea may occur
• Rarely, there may be painful sensations
• Formed visual hallucinations may occur
• Distortion of visual images
• Vertigo or dizziness with sensation of movement (eg. head spins)
• Sexual arousal

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Symptomatic Generalised Epilepsies
These types of epilepsy are usually associated with widespread brain damage. The cause may be known (symptomatic), such as lack of oxygen to the brain at birth, brain infections or a metabolic or chromosomal defect, or it may be unknown (idiopatic=unknown, cryptogenic=suspected but not proven).

Consequently, these people often have diffuse brain dysfunction, such as an intellectual disability (eg, developmental delay) and or a physical disability (eg, hemiplegia or cerebral palsy). Multiple types of seizures are common in this group, making the epilepsy often difficult to control. Some syndromes include:

1. West Syndrome (Infantile Spasms)
Infantile spasms are a specific type of seizure seen in an epilepsy syndrome of infancy and early childhood known as West Syndrome.

West Syndrome is characterised by infantile spasms, hypsarrhythmia (abnormal, chaotic EEG brain wave patterns), and intellectual disability. Other neurological disorders, such as cerebral palsy, may be seen in 30-50% of those with West Syndrome. Characteristics of the syndrome include:

• Onset is predominantly in the first year of life, typically between 3-6 months.
• The typical pattern of a spasm is a sudden bending forward and stiffening of the body, arms, and legs; although there can also be arching of the torso.
• Spasms tend to begin soon after arousal from sleep.
• Individual spasms typically last for 1 to 5 seconds and occur in clusters, ranging from 2 to 100 spasms at a time. Infants may have dozens of clusters and several hundred spasms per day.
• Infantile spasms usually stop by age 5, but more than half of the children develop other seizure types.
• Treatment is usually initiated quickly and aggressively after diagnosis. Unfortunately, no one medical treatment gives satisfactory relief for all infants with West syndrome and steroids (ACTH, prednisone) and different types of antiepileptic medications are commonly used.
• The ketogenic diet has been used successfully to treat a variety of seizure types. However, the role of the ketogenic diet in successfully treating infants with West syndrome has not established.
• Prognosis is dependent on the underlying causes (eg., infections, Down's syndrome or inadequate blood flow to the foetus. This mostly occurs in-utero, but can also occur during or after birth).
• About 30% of children have no identifiable cause, and prognosis of these cases is generally better.
• The intellectual prognosis is generally poor because many babies have neurological impairment prior to the onset of spasms. Intellectual disability is seen in up to 90% of children.
• There appears to be a close relationship between West Syndrome and Lennox-Gastaut Syndrome, an epilepsy syndrome of later childhood.
• Less than 5% of children may die in the acute phase of spasms depending on the underlying causes.

2. Lennox-Gastaut Syndrome (LGS)
This syndrome is a severe form of epilepsy sometimes used to describe intractable or difficult to control epilepsy. Brain injury, severe brain infections, genetic brain diseases, and developmental malformations of the brain or metabolic conditions can cause the disorder. In some cases however, no cause can be found. It is characterised by multiple seizure types that are resistant to treatment, specific EEG abnormalities are seen and intellectual disability. Some features of the syndrome include:

• It usually develops in children between 1 and 14 years old
• There are several different types of seizures, which vary among different people, but include generalised tonic-clonic, partial, tonic, atonic, atypical absence and myoclonic (sudden muscle jerks).
• Most children (>90%) have some degree of intellectual disability.
• Behavioural problems may be seen.
• Mental deterioration may be seen, particularly with those diagnosed before age 2.
• Treatment often involves a combination of medications. Seizure control is very difficult.
• Children who improve initially may later show tolerance to a drug or have difficult to control seizures.
• Surgery can be offered for drop attacks (tonic/atonic seizures).
• Vagus Nerve Stimulation may reduce the frequency of seizures by > 50%
• Ketogenic diet may be considered. It has been tried with varying results.
• Prognosis varies. Complete recovery, including freedom from seizures and normal development, is very unusual.
• The severity of the seizures, frequent injuries, developmental delays, and behaviour problems can take a large toll.
• Approximately 22-30% of people have no known cause (idiopathic), where 70-78% of people have a symptomatic cause.
• Status epilepticus is common, especially non-convulsive forms.

3. Progressive Myoclonic Epilepsy (PME)
This is a rare form of epilepsy with myoclonic and tonic-clonic seizures. Children with this condition may have trouble with unsteadiness, experience rigid muscles and mental deterioration.

This is not a single disorder but includes a group of syndromes with various names including Severe Myoclonic Epilepsy of Infancy (Dravet Syndrome), Lafora Disease and different mitochondrial encephalopathies. Charracteristics include:

• The age of onset can vary from infancy to adulthood, depending upon the specific type of myoclonic epilepsy.
• Both males and females are affected.
• It is often a resulting from hereditary metabolic disorders, but sometimes metabolic test results are normal and the cause remains unknown.
• Treatment is often successful only for a few months or years. These people may require more than one antiepileptic medication.
• As the disorder progresses, the medications become less effective, and side effects may become more severe as higher doses are used. It may be worthwhile to try lower doses.
• Prognosis is generally unfavourable, but varies greatly from person to person. Seizures are difficult to control and people often lose abilities involving thinking and movement.

Special Syndromes

1. Febrile convulsions (Convulsions with fever)
Are one of the most common seizure presentations in children.

In approximately 2-5% of children between 6 months and 6 years, fever can cause seizures, called febrile convulsions. The seizures usually happen during the first few hours of a febrile illness.

Febrile convulsions are not considered epilepsy because they have a clearly known cause and are not characterised by a tendency to re-occur, unless further febrile episodes occur. They do not cause brain damage. Around 30 per cent of babies and children who have had one febrile convulsion will have another with the same illness or following ones, always associated with a rise in body temperature. These seizures often run in families but there is no way to predict who will be affected or when this will happen.

• The seizures are usually tonic-clonic seizures.
• Most are brief and last less than 2 minutes.
• On rare occasions the seizures may be prolonged (>15 minutes). This is considered a medical emergency.
• A febrile convulsion is not epilepsy. No regular medication is usually indicated.
• A short-lived seizure will usually not cause brain damage.

The risk for developing epilepsy is no different than other children except if the child has:

• A prolonged seizure lasting longer than 15 minutes
• More than one seizure within 24 hours
• Focal features during or following a seizure

These features increase the risk of developing epilepsy to approximately 6%.

2. Epilepsy with continuous spike and wave in slow wave sleep (CSWS)
This syndrome occurs only in children. It is short-lived but may last for at least several months. Epilepsy with CSWS is associated with various seizure types, and the person may develop one seizure type or several. The characteristics include:

• Age of onset is from 1-10 years – peak at approximately 4-5 years.
• First seizure frequently occurs in sleep
• Seizure types include; partial or generalised, occurring during sleep, and atypical absences when awake. Tonic seizures do not occur.
• Most children have numerous seizures during the day.
• The EEG pattern is grossly abnormal during deep sleep.
• EEG during wakefulness may show a combination of abnormalities
• The duration of the syndrome varies from months to years.
• Prognosis is treated with caution because of the appearance of neuropsychological (cognitive and behavioural) disorders.

Cognitive and Behavioural changes include;

• A severe decrease in IQ, a very marked reduction of language
• Memory problems
• Disturbances of behaviour with reduced attention span
• Excessive movement
• Aggressiveness
• Social difficulties
• In some cases, a psychotic state may develop.

Prognosis: The seizures eventually stop in all cases. The disappearance of seizures and EEG abnormalities is sometimes simultaneous, however the seizures can disappear before, or after the EEG abnormalities.
The neuropsychological and social prognosis is not positive in approximately 50% of children. This does not depend on the age of onset, on the severity of epilepsy or on the severity of the disturbances during CSWS. It may however be related to the duration of CSWS.

3. Landau Kleffner syndrome
Landau Kleffner Syndrome is a rare childhood neurological disorder that is associated with EEG abnormalities, seizures and affects the part of the brain involved with comprehension and speech. This results in a severe language disorder. The cause of the condition is unknown. It is characterised by:

• The onset is most commonly between 3 and 8 years. It may develop slowly over many months or suddenly overnight
• It is seen in predominantly males
• Specific EEG changes in the temporal lobes - particularly when the child is asleep
• About two-thirds of children have seizures. These are infrequent, commonly occur at night and are easily controlled on medication
• A major symptom is failure to understand or express language - some children lose their speech completely. These children may appear to be deaf
• Behavioural problems are common, especially hyper-activity, poor attention, depression and irritability
• Treatment with antiepileptic medication is followed by the addition of steroids if AEDs alone fail to control symptoms
• No abnormalities are seen on brain scans
• Seizures decrease with time but the outcome for speech is less predictable. Seizures generally disappear by adulthood
• Some children may recover their language fully, but many are left with a language disability
• Appropriate speech and language therapy and special education are essential
• Early diagnosis and treatment may improve the child's chance of a good recovery.
• In some cases, remission and relapse may occu
• Prognosis is improved when the onset is after age 6 and when speech therapy is started early

4. Rasmussen's Encephalitis
This is a rare neurological disorder usually affecting one hemisphere (side) of the brain. It causes progressive brain deterioration and uncontrollable seizures. It is characterised by:

• The onset generally occurring in children under the age of 10 years
• Unknown cause
• Frequent and sometimes severe seizures (focal motor or generalised tonic clonic seizures)
• Loss of some movements and speech
• Hemiparesis (paralysis/weakness on one side of the body)
• Encephalitis (inflammation of the brain tissuess)
• The progressive loss of cognitive and intellectual functions, mental deterioration
• Treatment involves antiepileptic drugs and steroids initially
• Other treatments may be used such as; recurrent immune globulin (IVIG) infusion, plasmapheresis (removal and reinfusion of the blood plasma), ketogenic diet and steroids
• Surgery to remove the affected part of the brain (hemispherectomy) may be considered
• If untreated, the condition may lead to severe neurological deficits including intellectual disability and paralysis

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