Authors: Mekka Garcia, MD, NYU Grossman School of Medicine   

Alison L. Christy, MD, PhD, Providence Pediatric Neurology at St. Vincent Medical Center—Portland, Oregon  

 Reviewed: September 2022 

SUMMARY

Landau-Kleffner syndrome (LKS) is a rare childhood epilepsy disorder. It is characterized by loss of previously learned language skills. Abnormal brain waves occur during sleep.

Signs and symptoms usually present when the child is between three and eight years old. There is no cure for LKS. However, supportive care is available.

Disorder Overview

DESCRIPTION

Children with LKS develop normally. It begins to affect them around three to eight years old. At that point, they lose their abilities to:  

• Speak  
• Understand speech  

These children usually have a very abnormal electroencephalogram (EEG). It is particularly abnormal during sleep. It is thought that abnormal electrical brain activity causes an inability to speak.  

The exact number of people affected is unknown. Recent studies have shown that it is more common in boys. 

SIGNS AND SYMPTOMS

Signs and symptoms usually present between three and eight years old. Children with LKS have normal development until this time. They then suddenly lose their previously learned language skills.  

Signs and symptoms may include:

CAUSES

The exact cause of LKS is unknown. It is not usually inherited from a parent. However, LKS has been linked to changes in the GRIN2A gene. This gene is involved in speech and language.

LABORATORY INVESTIGATIONS

The following are key to diagnosis: 

• A thorough history  
• A clinical examination 

Sometimes, more tests are necessary to confirm the diagnosis. These may include:

TREATMENT AND THERAPIES

Currently, there is no cure for LKS. However, supportive care is available. It may include:

OUTLOOK

The severity of language problems can vary for people with LKS. Some children may regain full function of their language skills with treatment (over months to years). Others may not.  

Children generally have more language recovery when they are older at the time that they develop symptoms. People with LKS usually live to adulthood.

RELATED DISORDERS

Some disorders with similar symptoms include: 

• Continuous spike-wave during slow sleep syndrome (CSWS). CSWS is another disorder with abnormal electrical activity during sleep. 
• Lennox-Gastaut syndrome (LGS). LGS is an epilepsy syndrome. It has multiple types of seizures. It also has abnormalities seen on an EEG. 
• Autism spectrum disorder. ASD is characterized by: 
  • Difficulty with communication 
  • Challenges in social interaction 
  • Repetitive behaviors  

Some children with ASD also experience a loss of language skills. This regression usually occurs earlier than three to eight years of age. A child with LKS may also have ASD.  

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Research 

ClinicalTrials.gov for Landau-Kleffner Syndrome (birth to 17).

These are all clinical trials that are terminated, completed, or active. Updates are made daily, so you are encouraged to check back frequently. 

ClinicalTrials.gov is a database of privately and publicly funded clinical studies conducted around the world. This is a resource provided by the U.S. National Library of Medicine (NLM), which is an institute within the National Institutes of Health (NIH). Listing a study does not mean it has been evaluated by the U.S. Federal Government. Please read the NLM disclaimer for details.    

Before participating in a study, you are encouraged to talk to your health care provider and learn about the risks and potential benefits. 

The information in the CNF Child Neurology Disorder Directory is not intended to provide diagnosis, treatment, or medical advice and should not be considered a substitute for advice from a healthcare professional. Content provided is for informational purposes only.  CNF is not responsible for actions taken based on the information included on this webpage. Please consult with a physician or other healthcare professional regarding any medical or health related diagnosis or treatment options. 

Deonna T, Roulet-Perez E. Early-onset acquired epileptic aphasia (Landau-Kleffner syndrome, LKS) and regressive autistic disorders with epileptic EEG abnormalities: the continuing debate. Brain Dev. 2010 Oct;32(9):746-52. https://doi.org/10.1016/j.braindev.2010.06.011. Epub 2010 Jul 15. PMID: 20637551. 

McVicar KA, Shinnar S. Landau-Kleffner syndrome, electrical status epilepticus in slow wave sleep, and language regression in children. Ment Retard Dev Disabil Res Rev. 2004;10(2):144-9. https://doi.org/10.1002/mrdd.20028. PMID: 15362173. 

Muzio MR, Cascella M, Al Khalili Y. Landau Kleffner Syndrome. 2022 Feb 5. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 31613525. 

Stafstrom CE, Carmant L. Seizures and epilepsy: an overview for neuroscientists. Cold Spring Harb Perspect Med. 2015 Jun 1;5(6):a022426. https://doi.org/10.1101/cshperspect.a022426. PMID: 26033084; PMCID: PMC4448698.