What Is Landau-Kleffner Syndrome?

Landau-Kleffner syndrome (LKS) is a rare condition that affects young children, typically starting between ages 2 and 8. It is characterized by a decline in speech and language abilities, learning problems, seizures, and behavior changes—symptoms that make it easily misdiagnosed as other conditions such as autism or deafness. Abnormal findings on an electroencephalogram (EEG), particularly during sleep, are key for a diagnosis of LKS.

If your child is diagnosed with LKS, it is important to maintain close medical follow-up and therapy. Over time, many children experience some improvement in their language abilities, and most do not continue to have seizures as they reach their adolescent years.

Landau-Kleffner Syndrome Symptoms

LKS affects children who were otherwise developing typically before showing signs of the condition. The symptoms can begin gradually over the course of a few weeks or months. Some children also exhibit behavioral changes.

Typically Landau-Kleffner syndrome presents with:

• Loss of language skills: Children who have already developed the ability to speak, understand language—even read and write—may experience regression (backsliding) of their language skills. They're unable to communicate with others, even their parents. The clinical term for difficulty speaking is aphasia. Difficulty understanding language is called speech agnosia.
• Seizures: Most children with this condition have seizures, especially during sleep. The seizures are characterized as focal seizures or generalized tonic-clonic seizures. They cause shaking and jerking of one side of the body, or the whole body. Most seizures last for a few minutes, but some children have episodes of status epilepticus, which is a seizure that does not stop on its own, requiring anti-epileptic drugs (AEDs) to stop it. (Absence seizures and atonic seizures are less common, but may also occur in some cases.)
• Behavior changes: Some children with LKS act out. Attention deficit hyperactivity disorder (ADHD) and learning difficulties are sometimes associated with the condition.

Causes

It is not clear why children develop LKS, although there is evidence that at least some cases arise from a genetic mutation. It also appears the temporal lobe of the brain is involved. Some parents note that their children had a viral infection prior to the initial onset of LKS, but infections have not been verified as a cause of the condition. Inflammation may play a role, as some children improve with anti-inflammatory treatment. LKS affects males and females equally.

Gene Mutation 

Studies have found that around 20% of children with LSK have a mutation in the GRIN2A gene, which is located on chromosome 16. This gene directs production of GluN2A, a glutamate receptor, which normally helps prevent excess nerve activity in the brain. In LKS, the GRIN2A mutation is considered a de novo mutation, which means that a child can develop it without inheriting it from their parents.

Brain Changes

Because language problems and seizures are hallmarks of Landau-Kleffner epilepsy, it is thought the temporal lobe of the brain is affected. The left and right temporal lobes are located at the sides of the brain, near the ears. A person's dominant temporal lobe (the left one in right-handed people, the right one in left-handed people) is involved with speech and language comprehension. Seizures that originate in the temporal lobe can be focal seizures, meaning they involve one side of the body, or may generalize and affect the whole body. 

Diagnosis

Landau-Kleffner syndrome may take weeks or even months to diagnose. Because there are more common causes of seizures and communication problems in young children, it's unlikely to be among the first problems suspected.

Ultimately, a diagnosis of LSK will be made based on a child's history of seizures, loss of language skills, and diagnostic tests to rule out other problems.These include:

Neuropsychological tests to evaluate learning abilities, attention, and comprehension.

Hearing tests to rule out hearing loss as a cause of language regression. Hearing deficits are not typical in LSK.

Brain imaging such as computerized tomography (CT) or magnetic resonance imaging (MRI) to identify structural abnormalities, such as tumors, strokes, or infections. These tests usually are normal in children who have LKS.

Lumbar puncture to look for the presence of infection or inflammation that would rule out encephalitis.

Electroencephalogram (EEG), a non-invasive test performed to assess seizures that is key to diagnosing Landau-Kleffner syndrome. An electroencephalogram involves placing small metal coin-shaped electrodes on the scalp to detect and assess electrical brain activity. The electrodes are connected to wires that send a signal to a computer that “reads” the brain’s rhythm. An EEG can show abnormal electrical brain rhythms during a seizure, and sometimes even when a person is not having a seizure.

The EEG pattern characteristic of LKS shows slow wave spikes of the temporal lobes that are frequently present during sleep. Some children with LKS have continuous evidence of seizures during sleep described as a spike and wave pattern.

Treatment

The goals of treating Landau-Kleffner syndrome focus on reducing brain inflammation, controlling seizures, and helping to restore speech.

Immune Therapy

High-dose intravenous (IV) or oral corticosteroids are recommended for some children who have LKS and are most effective if begun as soon as possible after symptoms begin. The exception are children whose doctors are concerned about the presence of infectious encephalitis (brain infection) or meningitis (infection of the protective lining of the brain), in which case steroids are avoided as they can make an infection worse. Another immunosuppressant, intravenous immunoglobulin (IVIG), may be an option as well.

Antiepilectic Drugs (AEDs) 

Also known as anticonvulsants, AEDs are a first-line treatment for LSk. There are any number of such medications to choose from, including:

• Valproic acid
• Onfi (clobazam)
• Keppra (levetiracetam)
• Zarontin (ethosuximide) 

Speech Therapy 

Although it's difficult to regain lost speech and language skills when the temporal lobe has been been affected, speech therapy is recommended for children with LKS to help optimize their ability to communicate.

Therapy is likely to require patience on the part of parents, as children with LKS aren't always able to participate in every session and likely will experience the most improvement after the acute phase of the condition begins to resolve. Some people who have had LKS continue to benefit from speech therapy during adolescence and adulthood.

Surgery 

Children who have persistent seizures in spite of taking an AED may benefit from epilepsy surgyer. This is a procedure that involves making multiple small incisions in the brain called subpial transections.

Prognosis

LKS often improves over time. Most children do not continue to have seizures after adolescence and do not need long-term treatment with AEDs. However, there is a variable degree of recovery, and speech deficits can affect children throughout their lives, particularly when LKS starts early in life or treatment isn't successful. Children who are treated with corticosteroids or immunoglobulin tend to have the best long-term outcomes.

A Word From Verywell

If you're the parent of a child who's been diagnosed with Landau-Kleffner syndrome, you are no doubt concerned about their future ability to learn, to function socially, and to eventually be independent. Because LKS is such a rare condition with a range of possible outcomes, an LKS diagnosis often means living with uncertainty. It may help to join an online support group for parents of children with epilepsy or speech problems, as other parents can often help you share your feelings and can direct you to useful resources in your community.