Electrical status epilepticus during slow-wave sleep (ESES) is a rare and severe form of epilepsy that primarily affects children. It usually resolves by puberty but may cause lasting cognitive difficulties.

ESES is a rare subtype of epilepsy, with one study finding the prevalence to be just 0.2% among 440 epileptic participants. It typically occurs in children between 2 and 12 years of age, with a peak between 3 and 5 years.

ESES is also known as continuous spikes and waves during slow-wave sleep (CSWS). This article looks at ESES epilepsy, its causes, diagnosis, and treatment.

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Scientists first described ESES in 1971. The condition creates a distinctive pattern on an electroencephalogram (EEG), where there is an increase in epileptiform activity (spike and wave discharges) during slow-wave sleep. Slow-wave sleep is a deep sleep that happens during non-rapid eye movement (NREM) sleep.

Read more about deep sleep.

The key symptoms of ESES include:

  • Seizures: While seizures are a common symptom, they may not be as prominent in ESES compared with other forms of epilepsy. Types of seizures include focal (partial) seizures, nocturnal seizures, and generalized seizures. Neurodevelopmental conditions or epilepsy may cause these seizures, which can lead to cognitive impairment and behavioral changes.
  • Cognitive impairment: A notable decline in cognitive functions can occur, especially in areas such as attention, memory, and learning. Children may also have difficulty at school, including problems acquiring new knowledge and skills.
  • Behavioral changes: Children may exhibit changes in behavior, such as increased irritability, hyperactivity, or aggression. They may have social interaction difficulties and possibly symptoms resembling autism spectrum disorders.

Often, the exact cause of ESES is unclear. Doctors think it may involve a combination of genetic and environmental factors.

  • Genetic predisposition: There may be a genetic component, as ESES can occur in families, although research has not linked specific genes to the syndrome.
  • Immune system dysregulation: Some evidence suggests that immune system dysregulation may play a role in ESES, although this is an area of ongoing research.
  • Brain structure abnormalities: Structural abnormalities in the brain, such as lesions or malformations, can be associated with ESES. These include conditions like cortical dysplasia, tumors, or scars from previous brain injury.
  • Neurotransmitter imbalances: Imbalances in neurotransmitters, which are chemicals that facilitate communication between nerve cells in the brain, might contribute to ESES.

Learn more about epilepsy in children.

Although experts do not yet fully understand the cause of ESES, some risk factors may increase a child’s chance of developing it.

These include:

  • A seizure disorder or previous seizures: Children who have had seizures, particularly those with an early onset of epilepsy, may have an increased risk for ESES.
  • Genetic factors: A family history of ESES may increase a child’s risk.
  • Age: ESES typically manifests in early to mid-childhood, so children of 2–12 years may be at increased risk of developing ESES.

The diagnostic process for ESES usually follows the same steps:

  • Electroencephalogram (EEG): The primary diagnostic tool is EEG, which shows continuous spike-wave activity during slow-wave sleep.
  • Medical history and symptom assessment: Doctors will take a detailed medical history and assess symptoms such as learning difficulties, behavioral changes, or seizures.
  • Neuroimaging: MRI or CT scans can identify any structural brain abnormalities.
  • Neuropsychological testing: This can assess cognitive functions and developmental levels.

The response to treatment varies. Some children may experience a significant reduction in EEG abnormalities and improvement in cognitive and behavioral symptoms, while others may have persistent challenges.

Common approaches for treating ESES include:

  • First-line medications: Certain anti-epileptic drugs (AEDs) such as valproic acid, levetiracetam, and ethosuximide may help.
  • Benzodiazepines: Clonazepam or clobazam are often effective in reducing the spike-wave activity during sleep.
  • Combination therapy: Sometimes, a combination of different AEDs is necessary to control seizures and reduce EEG abnormalities.
  • Corticosteroids: Prednisone or methylprednisolone can be effective, particularly in cases resistant to standard AEDs.
  • Intravenous immunoglobulins (IVIG): Doctors may use these in some cases as an alternative to steroids, especially if there is an underlying immune component.
  • Ketogenic diet: A high fat, low carbohydrate diet has shown effectiveness in reducing seizures and improving EEG findings in some cases of ESES.

Read more about epilepsy and the keto diet.

ESES can lead to several complications, primarily related to neurological and cognitive functions. These complications can have a significant impact on the child’s quality of life and include:

  • Cognitive impairment: Children with ESES often experience difficulties in learning, memory, and attention. A regression or stagnation in cognitive development can affect school performance.
  • Behavioral and psychological issues: Behavioral problems such as hyperactivity, aggression, or autism-like behaviors are possible. Emotional difficulties, including anxiety or depression, are also common.
  • Language and communication challenges: Language regression or delays are common in children with ESES. Some children may develop aphasia, a condition that affects their ability to communicate.
  • Motor skill impairment: Difficulties with coordination and fine motor skills may occur. In severe cases, there may be a regression in previously acquired motor abilities.

Clinical seizures and unusual brain wave patterns on EEG tests often get better on their own after a person with ESES goes through puberty.

However, a child’s thinking and learning abilities may not recover completely. The longer a child has ESES, the more likely they are to experience serious cognitive difficulties.

Children with neurodevelopmental disorders or an epilepsy syndrome, such as Landau Kleffner syndrome, often have lifelong neurological problems, learning disability, and seizures, even if the ESES seizures resolve.

ESES is a rare pediatric epilepsy syndrome characterized by distinctive EEG patterns that show continuous spike-wave activity during slow-wave sleep.

ESES can be difficult to treat, as it is often resistant to traditional anti-seizure medications. It typically resolves after puberty, but children may experience impaired thinking and learning abilities.