Landau-Kleffner Syndrome

Reviewed by: HU Medical Review Board | Last reviewed: July 2022 | Last updated: October 2023

Landau-Kleffner syndrome (LKS) is a rare form of epilepsy that begins in childhood. It is also known as progressive epileptic aphasia and aphasia with convulsive disorder.1

LKS can be diagnosed anywhere between 2 and 8 years old. It is most commonly diagnosed in children between 5 and 7 years old. Boys are more likely to develop LKS than girls. LKS is rare, only affecting around 300 to 3,000 children in the United States.2

Symptoms ok LKS

Aphasia is a unique symptom of LKS. Aphasia is difficulty creating or understanding language. There are multiple forms of aphasia, including:1

  • Having difficulty saying words
  • Saying sentences that do not make sense
  • Having difficulty understanding what others are saying to you

Children with LKS who have already learned how to talk may quickly or slowly lose that ability. LKS most often affects how children understand what people are saying to them. They also may not recognize familiar sounds. It can appear like children living with LKS are deaf, but the results of their hearing tests will be normal.1

There are other disorders that can cause children to lose their speech, such as autism. However, children with LKS lose their speech at an older age than children with autism.1

LKS often causes attention problems like attention-deficit/hyperactivity disorder (ADHD, formerly called attention deficit disorder), as well as anxiety or aggression.1

LKS seizures are most often focal motor seizures, meaning that they only affect one area of the brain and involve muscle jerking. However, focal seizures can develop into tonic-clonic seizures. This is where the entire body becomes stiff, often falling to the ground, and then jerking movements begin. LKS seizures usually start during sleep and are rare.1

What causes Landau-Kleffner syndrome?

Experts are not sure what causes LKS, but they know that it is a genetic disease. A mutation in the gene GRIN2A has been found in some children with LKS. However, this mutation is not seen in every child living with LKS so experts believe there may be other genes involved. LKS may be passed down through families.2


It is important to give your child’s doctor a detailed history of the child's symptoms and how the child has developed over time. The doctor may first use tests to try to rule out other possible causes. To do this, they will look for your child to have normal results from tests such as:1

  • Hearing tests
  • Blood work
  • Magnetic resonance imaging

You then will likely be referred to a neurologist who can perform an electroencephalogram (EEG). EEG abnormalities are common during sleep in children with LKS. So it is likely that your child will have EEGs done both while they are sleeping and while they are awake. This information is enough to diagnose LKS. Genetic testing is not usually performed.1

Because LKS involves aphasia and difficulties with attention, it can be difficult to diagnose. It may be confused for:3

  • Autism
  • Hearing impairment
  • Learning disability
  • ADHD
  • Treatment

LKS can be treated with steroids or with diazepam, a tranquilizer, at night to prevent seizures. Doctors may also prescribe anti-seizure drugs like:1

  • Ethosuximide (Zarontin®)
  • Valproic acid (Depakote®)
  • Levetiracetam (Keppra®)

There also may be the option of a rare and somewhat controversial surgery for children in whom drugs are not effective. This surgery is called multiple subpial transections and involves cutting through the brain pathways that may be causing the seizures.1

It is important to start speech therapy as soon as possible. This may help children keep their speech longer. It may also be helpful to speak to a child psychologist or psychiatrist to treat symptoms of ADHD, anxiety, or aggression.1

What is the outlook for my child with LKS?

Outcomes for children living with LKS can vary. Some children may experience aphasia permanently. Others may regain their speech, though this can take months to years. A child whose LKS begins after age 6 is likely to have a better outcome. Also, starting speech therapy early is associated with a better outcome.3

If you believe that your child may have LKS, speak to their doctor.

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