Landau-Kleffner Syndrome (LKS)

Landau-Kleffner syndrome (LKS) is a rare brain condition that causes children to lose their ability to speak and understand language. Children with LKS have abnormal brain activity during sleep, and many also experience seizures. Healthcare providers may treat LKS with medication, speech therapy and behavioral therapy.


What is Landau-Kleffner syndrome (LKS)?

Landau-Kleffner syndrome is a condition that affects your brain by causing seizures and a loss or decline in speech and language skills. Children with LKS have abnormal electrical signals in their brains that affect their ability to understand language and speak.


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Who does Landau-Kleffner syndrome affect?

LKS typically affects children, starting when they’re between 3 and 8 years old. But children as young as 2, as well as adolescents, can have the condition. Boys are more likely to have LKS than girls.

How does LKS affect my child?

If your child has LKS, they may lose their ability to speak and understand language (aphasia). This can happen rapidly all at once, or slowly. Many children with LKS — about 70% — also have seizures, often during sleep.


Is Landau-Kleffner syndrome the same as autism?

Landau-Kleffner syndrome isn’t autism. But diagnosing Landau-Kleffner syndrome vs. autism can be challenging because their symptoms are similar. Often, EEGs taken when your child is awake and when your child is asleep can distinguish between the two conditions.

Does Landau-Kleffner syndrome have any other names?

Healthcare providers sometimes call this condition acquired aphasia with epilepsy.


How common is Landau-Kleffner syndrome?

Landau-Kleffner syndrome is rare, but researchers aren’t sure exactly how many people have it.

Symptoms and Causes

What causes Landau-Kleffner syndrome?

No cause can be found in the majority of children with LKS. About 20% of children with LKS have changes (mutations) in their GRIN2A gene, though. Children inherit this mutation from one of their parents. But not everyone with this genetic change develops LKS. Some children with LKS have mutations in other genes. They might be the first person in their family to have the mutation, known as a de novo mutation.

Researchers think these gene mutations cause electrical signals in their brains to misfire. These abnormal signals can cause LKS symptoms.

Researchers are also studying whether there’s a link between LKS and the immune system. An autoimmune response in which the immune system attacks the body’s cells may contribute to LKS.

What are the symptoms of Landau-Kleffner syndrome?

Not every child with LKS has the same symptoms. If your child has LKS, it may seem like they can’t hear you. They may have a hard time understanding what you and others say to them. They may also have new developmental delays, intellectual differences or learning disabilities. Sometimes, these language difficulties can make your child to feel frustrated and cause behavioral symptoms such as agitation, not paying attention, anger outbursts or acting out.

Children with LKS may be:

Diagnosis and Tests

How do healthcare providers diagnose Landau-Kleffner syndrome?

Children with LKS usually meet typical child development milestones before LKS begins. You may notice your child has trouble speaking. Or your child’s healthcare provider may notice symptoms during a well-child visit.

LKS is challenging to diagnose. Tell your healthcare provider about any behavioral changes you’ve noticed in your child.

What tests do healthcare providers use to diagnose LKS?

Your child’s healthcare provider may recommend an electroencephalogram (EEG) to measure electrical impulses in your child’s brain. This painless test lets their healthcare provider check your child’s brain activity.

Healthcare providers may do this test while your child is sleeping and again when they’re awake. Typically, your child’s brain waves slow down as they enter the early stages of sleep. When they enter the rapid eye movement (REM) sleep phase, their brain waves become more active. But EEGs in children with LKS often show continuous levels of abnormal brain wave activity during all sleep phases.

Your child’s healthcare provider may also recommend:

Management and Treatment

How do healthcare providers treat Landau-Kleffner syndrome?

Healthcare providers use medication, speech therapy and behavioral therapy to treat children with LKS. The earlier speech therapy begins, the better your child’s chance of regaining their language skills. Sometimes, healthcare providers recommend a ketogenic diet for epilepsy.

What medications do healthcare providers use to treat LKS?

Your healthcare provider may prescribe:

  • Anticonvulsant medications to control seizures.
  • Corticosteroids to reduce immune system response.

Do healthcare providers use surgery to treat LKS?

Rarely, surgeons perform multiple subpial transections. It isn’t conclusive whether this brain surgery has proven benefits. Benefits and risks should be carefully considered after a thorough pre-surgical evaluation.

How soon after Landau-Kleffner syndrome treatment will my child improve?

There’s no one right way to treat LKS. Your child may improve with speech therapy and other treatments. But in some cases, they may not respond to treatment. Your healthcare provider will check your child’s progress and adjust their treatment as necessary.


How can I reduce my child’s risk of Landau-Kleffner syndrome?

LKS is a genetic disorder. There isn’t anything you can do to reduce the risk of developing Landau-Kleffner syndrome.

Outlook / Prognosis

Can Landau-Kleffner syndrome be cured?

Some children regain their ability to speak and understand language. Others may partly recover their language skills. Children who start showing symptoms after age 6 and begin speech therapy right away have the best chance of improving. Seizures often stop by adulthood.

What can I expect if my child has LKS?

It can take a long time for your child to recover from LKS. You may see some improvements over time, or your child may lose language skills after making progress (relapse). Your healthcare provider may recommend special education classes or learning sign language to help meet your child’s needs.

Living With

How do I take care of my child with Landau-Kleffner syndrome?

Follow your healthcare provider’s instructions to help keep your child healthy. Let them know about any new symptoms your child has so they can get treatment right away.

A note from Cleveland Clinic

Landau-Kleffner syndrome causes children with typical development to lose their ability to speak and understand language. Children with LKS have abnormal brain activity during sleep and often have seizures. Healthcare providers may treat LKS with medication and speech therapy. With time and treatment, children may regain their language abilities.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 04/06/2022.

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