Epileptic encephalopathy is a group of neurologic conditions that involve severe epilepsy. In epileptic encephalopathy conditions, the seizures cause additional harm to the brain.

Epileptic encephalopathy (EE) is a group of brain disorders that generally start in infancy but can begin during adulthood as well. They are characterized by severe, sometimes continuous, seizure activity that injures the brain and affects development, cognition (thinking ability), and behavior.

These conditions may be difficult to treat with antiepileptic medications and may require several medications and other treatments, including surgery.

The International League Against Epilepsy defines EE conditions as those in which seizure activity itself contributes to severe cognitive and behavioral impairments, greater than would be expected from the underlying condition alone. These impairments may get worse over time.

In infants with EE, seizures may be continuous, and the seizures can injure the brain, affecting cognitive and behavioral functioning. Infants may have developmental delays, regress in development, or stop progressing.

There are several types of EE that have unique causes and symptoms:

  • Ohtahara syndrome
  • West syndrome (infantile spasms)
  • Dravet syndrome
  • myoclonic status in nonprogressive encephalopathies
  • Lennox-Gastaut syndrome
  • Landau-Kleffner syndrome
  • early myoclonic encephalopathy
  • epilepsy with continuous spike waves during slow-wave sleep

Learn more about encephalopathy.

The symptoms of EE will depend on the specific condition an individual has. However, all types involve frequent seizures, and most involve more than one seizure type.

The most common types of seizures seen in EE are:

  • Tonic seizures: These often occur during sleep and involve stiffening of muscles in the limbs or trunk.
  • Atonic seizures: Also called akinetic seizures or drop attacks, atonic seizures involve a sudden loss of muscle strength.
  • Myoclonic seizures: Myoclonic seizures involve short, jerky motions and can affect a single muscle or a group of muscles.

Individuals who have EE can also experience other types of seizures, such as:

Babies and children with EE may experience developmental delays or regression — the loss of skills they had previously gained.

Structural changes in an infant’s brain are the most common cause of EE. The changes may be congenital (present before birth), or they may develop after delivery because of other factors, such as a lack of oxygen to the brain before or during delivery.

EE has several other possible causes:

  • Genetic mutations: Most genetic causes of epilepsy are random gene mutations that do not run in families.
  • Inherited genetic changes: EE may be caused by inherited changes in genes on chromosome 2 or changes in several other single genes.
  • Metabolic disorders: Metabolic disorders cause the body to make too much or too little of a protein or enzyme. They can cause seizures, and several have been linked to EE.
  • Structural changes or atypical development of the brain: A baby’s brain may develop in an atypical way that could increase the risk of seizures.
  • Brain injury: Injury to the brain may occur during development or delivery or after birth and may cause EE.

Electroencephalogram (EEG) is the primary method of diagnosing EE. This test uses small electrodes, which are either in a cap that the baby wears or lightly glued or stuck temporarily to the baby’s head. Healthcare professionals will usually perform this test both when the infant is awake and while they are asleep.

Healthcare professionals may also use the following tests when diagnosing EE:

The main features of EE are severe seizures and worsening neurologic function. In some types of EE, successfully treating the seizures may improve the developmental outlook for a child.

Infants with EE will likely need lifelong care for epilepsy, developmental delays, and cognitive disabilities. Some infants with EE are more likely to die as a result of seizures or other conditions.

Is epileptic encephalopathy fatal?

Infants with some types of EE are at a greater risk of premature death than infants who don’t have EE, but that depends on the type they have and any other underlying conditions.

Is epileptic encephalopathy curable?

Research into the treatment of EE is ongoing, but the condition is not usually curable. Depending on the type, treatment can help reduce symptoms and improve development. However, EE is associated with loss of neurologic function over time.

Is epileptic encephalopathy genetic?

Yes, it can be. Some forms of EE have been linked to inherited genetic changes and random genetic mutations.

EE is a group of conditions characterized by severe seizures that cause brain injury and cognitive and behavioral delays. Treating these seizures may help improve development. However, some types of EE may not respond well to antiepileptic medications.

EE occurs mainly in babies and young children but can also occur in adults. Individuals with EE will likely need lifelong care and treatment.