An Overview of Landau Kleffner syndrome (LKS)

A Rare Childhood Speech and Seizure Disorder

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Child who is sick

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Ray Kachatorian

 

Landau Kleffner syndrome (LKS) is a rare condition that affects young children, with initial symptoms typically starting between ages 3 and 8 years. The most prominent features of this condition are a decline in speech and language abilities and seizures.

The cause of LKS is not clear. It is not usually an obvious diagnosis, and it can be misdiagnosed as another condition, such as autism or deafness.

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.

Symptoms

LKS affects children who were otherwise normal prior to developing the condition. The symptoms can begin gradually over the course of a few weeks or months. Some children also develop behavioral changes.

Language

Children who have already developed the ability to speak, understand language— and even to read and write—may experience regression (backsliding) of their language skills. Children who have LKS lose their ability to communicate with parents and with other people. The difficulty with speaking is described as aphasia, while the difficulty understanding language is typically described as speech agnosia.

Seizures

Most children with this condition have seizures, especially during sleep. The seizures are characterized as partial seizures or generalized tonic clonic seizures. They manifest with 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.

Behavioral Effects

Some children with LKS have behavioral changes, including anger, frustration, attention deficit hyperactivity disorder (ADHD), and learning difficulties.

Keep in mind that your child is likely feeling helpless due to his or her inability to communicate and that this helplessness can contribute to the behavioral changes.

Causes

It is not clear why children develop LKS. The illness is sporadic, and is not inherited or caused by any known risk factors or triggers. 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.

Temporal Lobe Effects

The language problems and the epilepsy pattern of this condition suggest that 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. The dominant temporal lobe (the left side in right-handed people) is one of the areas in the brain that is involved with speech and language comprehension.

Seizures that originate in the temporal lobe can be focal seizures, involving one side of the body, and may generalize, involving the whole body. 

Experts suggest that encephalitis, which is a brain infection or brain inflammation, could be the root cause of the LKS. 

Gene Mutation 

A mutation in the GRIN2A gene, found on chromosome 16, has been identified in about 15 percent of children who develop LKS. A mutation is an abnormal code in a gene, and a person with a mutation may produce a defective protein. The GRIN2A gene codes for the production of GluN2A, a glutamate receptor, which normally helps prevent excess nerve activity in the brain.

In GRIN2A mutation-associated LKS, the GluN2A protein is defective. In LKS, the GRIN2A mutation is considered a de novo mutation, which means that a child can develop it without inheriting it from his or her parents.

Diagnosis

LKS may take weeks or even months to diagnose. It is a rare disease and there are more common causes of seizures and communication problems in young children. Your child may have several diagnostic tests if he or she exhibits symptoms of LKS. 

Tests used for evaluation of speech regression and seizures include:

Neuropsychological Testing

Your child’s medical team may also perform psychological and cognitive testing to help distinguish the cause of your child’s symptoms. These tests can involve evaluation of learning abilities, attention, and comprehension to help sort out your child’s speech regression.

Hearing Test

Children who have language deficits often have auditory (hearing) tests because hearing loss is a common cause of communication problems. Children who have LKS usually do not have hearing deficits, and auditory tests are often needed to verify that. 

Electroencephalogram (EEG)

An EEG is a non-invasive brain wave test used to assess seizures. This test involves placement of small metal electrodes (shaped like flat coins) on the scalp. The electrodes can detect electrical brain activity. The electrodes are connected to wires, which 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 EEG evidence of seizures during sleep, which is described as a spike and wave pattern.

Brain Imaging

Most children who develop speech problems and seizures will have brain-imaging tests. A brain computerized tomography (CT) or magnetic resonance imaging (MRI) is used to identify structural abnormalities, such as tumors, strokes, or infections. These tests are usually normal in children who have LKS.

Metabolic brain imaging tests, such as positron emission testing (PET) are not customary in the clinical setting, but they are often used in research. Children who have LKS may have abnormal metabolism in the temporal lobe on one of both sides of the brain.

Lumbar Puncture (LP)

A lumbar puncture, also called a spinal tap, is an invasive diagnostic test. This test samples cerebrospinal fluid (CSF), which is the fluid that surrounds the brain and spinal cord. An LP can identify evidence of infections, inflammation, and cancer that could affect the brain.

If your child has an LP, you should be reassured that it is a safe test. Before this test, the doctor will clean your child’s lower back and then carefully insert a thin needle to collect a small amount of CSF. This fluid is analyzed in a lab. In LKS, the CSF fluid may be normal or can show elevated immunoglobulin, which are proteins that can develop when there is inflammation of the brain. 

Differential Diagnosis

LKS can begin with symptoms that are similar to those of autism, Asperger’s syndrome, deafness, and encephalitis.

Autism and Asperger’s syndrome are not usually associated with the seizures and EEG abnormalities of LKS. Deafness is typically detected with a hearing test. Encephalitis is usually associated with significant evidence of inflammation or an infection that can be detected with an LP.

Treatment

LKS can be treated with several approaches. Usually, a high dose of steroids is used to reduce any brain inflammation. For children who have epilepsy, AEDs often help control seizures. And speech therapy is an important part of recovery. 

Immune Therapy

High dose intravenous (IV) or oral corticosteroids are recommended for some children who have LKS. This treatment is considered more effective if it is started shortly after symptoms begin. But if there is concern about infectious encephalitis (brain infection) or meningitis (infection of the protective lining of the brain) then your child’s doctor may opt to avoid steroids, as they can worsen an infection.

Another immunosuppressant, intravenous immunoglobulin (IVIG), may be an option as well.

Anticonvulsants 

AEDs are often needed to control seizures. Some AEDs used for seizure control in LKS include valproate, clobazam, levetiracetam, and ethosuximide

Speech Therapy 

If your child has a speech and language deficit, speech therapy is recommended. It is not easy for a child (or adult) to learn how to communicate when the temporal lobe has been affected by LKS, but therapy can help optimize your child’s communication to the best of his or her ability. 

Keep in mind that it is important to be patient when it comes to speech therapy. Your child may be able to participate during some sessions but not during others, and may be more able to work on improving speech and language skills as 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 

Most of the time, in LKS seizures are well controlled with AEDs. However, if your child has persistent seizures, epilepsy surgery may be considered.

A procedure involving multiple subpial transections, which are small incisions in the brain, may help prevent seizures when medications cannot control them.

As with most types of epilepsy surgery, the procedure could cause neurological deficits, so the decision has to be made very carefully with extensive pre-surgical testing.

Prognosis

LKS is a condition that often improves over time. Most children do not continue to have seizures after adolescence and do not need long-term treatment with AEDs. 

While most children with LKS experience improvements in their speech and communication abilities during adolescence, there is a variable degree of recovery, and speech deficits continue to affect about 80 percent of children throughout their lives.

Children who are treated with corticosteroids or immunoglobulin tend to have better long-term outcomes.

A Word From Verywell

If your child has been diagnosed with LKS, you are understandably going through a lot of stress. It can be exhausting taking care of a child who cannot communicate. Of course, as a parent, you are also concerned about your child’s future and ability to get along with others, to learn, to be happy, and eventually to be able to be independent.

Because this is such a rare condition with a range of possible outcomes, it can be hard to predict your child’s outcome. Uncertainty is difficult for parents and children to deal with.

It may help to find a 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.

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