Landau-Kleffner Syndrome


This is in some areas claimed to be an extension of autism, and in others claimed to possess many of the symptoms of autism but actually to be different.  I present the information and allow the reader to choose.


Basically, Landau-Kleffner Syndrome occurs in children between the ages of 3 and 8 years old (some say 7).  It manifests itself as a drop or deterioration in spoken ability, together with an abnormal EEG pattern and occasional seizures.  The latter can be obvious or so insignificant that even the parents may miss them.


And now to the information base, which I am presenting as a series of extracts from the sources which I link to.


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NINDS Landau-Kleffner Syndrome Information Page

LKS occurs most frequently in normally developing children who are between 3 and 7 years of age. For no apparent reason, these children begin having trouble understanding what is said to them. Doctors often refer to this problem as auditory agnosia or "word deafness." The auditory agnosia may occur slowly or very quickly. Parents often think that the child is developing a hearing problem or has become suddenly deaf. Hearing tests, however, show normal hearing. Children may also appear to be autistic or developmentally delayed.

The inability to understand language eventually affects the child's spoken language which may progress to a complete loss of the ability to speak (mutism). Children who have learned to read and write before the onset of auditory agnosia can often continue communicating through written language. Some children develop a type of gestural communication or sign-like language. The communication problems may lead to behavioral or psychological problems. Intelligence usually appears to be unaffected



Landau Kleffner Syndrome - a description
Also known as Acquired Epileptic Aphasia in Childhood.



Most children first show signs of this syndrome somewhere between the age of three and nine years old. Prior to this they have usually grown and developed normally with no sign of a seizure.



The first sign of difficulty usually appears in the form of difficulty with communicating with speech and language. They show not only difficulty understanding what is said to them (a receptive dysphasia) but also have difficulty in putting their thoughts into words (an expressive dysphasia). Other aspects of learning are probably not affected.

Seizures will appear in the majority of these children certainly within a few weeks of the first signs of the language difficulty. They take the form either of tonic clonic seizures which are probably partial in origin or complex partial seizures.



 The EEG will show signs of a brain malfunction involving both cerebral hemispheres but usually the spike and wave activity seen on the EEG will be more prominent in the dominant cerebral hemisphere which deals with language function. For most people this will be on the left side.

 The cause of the syndrome is not known. Twice as many boys than girls are affected which may mean that for many the problem results from some of the computer networks within the brain falling short of full development. In other children, the problem seems to be precipitated by a viral infection and it may be that information within the computer networks is the cause in those children.

 Special investigations looking at the body’s metabolism and scanning of the brain are usually all quite normal. At times signs of a recent viral infection may be shown.



The long term outlook for most children with this condition is good. In the vast majority, the seizures will disappear by the time they are in their mid-teens. In half the children, the language difficulties will disappear within a few months or certainly the first year or two. In the remaining half, some improvement will occur in time. In perhaps 20 per cent, or one in five, of cases the children will keep their language difficulties.



Most children in the early stages will need treatment with anti-epileptic drugs for the partial seizures. There are reports that steroid treatment may help recovery but as so many children do well anyway, these reports are difficult to judge.

In children where there are persisting seizures associated with persisting language difficulties, surgery has been shown to help but this needs to follow a very careful selection process. The group of nerve cells which are showing most signs of malfunction are isolated from the rest of the brain by a process known as subpial resection.

A careful assessment of a child’s educational strengths and weaknesses is just as important as medical treatment so that appropriate help at school can be found. The doctors involved will probably contact the Education Authority with this in mind. If a child is supported in this way, the chances of them becoming frustrated and confused and showing behavioural difficulty will be reduced.


Society For The Autistically Handicapped


Seizure Disorders and Landau-Kleffner Syndrome in the Autistic Population:


A Review of Seizure Disorders and Landau-Kleffner Syndrome in the Autistic Population: reprinted by kind permission Joanna S. Dalldorf, M.D. Developmental Pediatrician.


Seizure Disorders and Landau-Kleffner Syndrome in the Autistic Population:

1.Definition and Frequency of Epilepsy in Autistic Population
2.Clinical Observations.
3.Diagnostic Studies
4.Seizure Treatment
5.Landau-Kleffner Syndrome


What is LKS?


Landau Kleffner Syndrome is a rare form of childhood epilepsy which results in a severe language disorder. The cause of the condition is unknown.

What are the main symptoms?

All children with LKS have abnormal electrical activity in one, sometimes both temporal lobes, the area of the brain responsible among other functions for processing language. This epileptiform activity shows up in an EEG test particularly when the child is asleep.

About two-thirds of LKS children have seizures. Seizures during the night are common. Many children have very few seizures and these are readily controlled by anti-epileptic drugs. Some children never have obvious seizures: it is not necessary to have a seizure to have LKS. A few children have many seizures which are harder to control.

The language disorder in most children affects comprehension or understanding. Many LKS children become unable to understand their own name. They are also likely to have difficulty recognising environmental sounds such as the telephone ringing. These children may appear to be deaf.

Expressive language - the ability to speak is often seriously affected; some children lose their speech completely. Rarely, a child may be able to understand language, but have difficulty with speaking.


acquired epileptiform aphasia

Landau-Kleffner syndrome (acquired epileptiform aphasia) is a disorder in which young children with previously normal language development undergo a deterioration in language skills in association with epileptiform (seizure-like) abnormalities on EEG. Between 70 - 80% of children with acquired epileptic aphasia have seizures, but these are not mandatory for diagnosis. Some of the children may have associated behavioral abnormalities including hyperactivity, decreased attention, distractibility, temper tantrums, aggressiveness and social withdrawal.



Center for the Study of Autism


Landau-Kleffner Syndrome



Written by Stephen M. Edelson, Ph.D.
Center for the Study of Autism, Salem, Oregon



Landau-Kleffner Syndrome is manifested as a form of aphasia, (loss of language), which usually develops between 3 and 7 years. It is twice as common in males than females. Initially, these individuals have a healthy, problem-free development with normal speech and vocabulary. These individuals first lose their ability to comprehend (i.e., receptive speech) and then their ability to speak (i.e., expressive speech). These changes can occur gradually or suddenly.

People with Landau-Kleffner Syndrome have abnormal EEG patterns (i.e., brain waves) in the temporal lobe (located on the sides of the brain) and in the temporo-parieto-occipital regions during sleep. Diagnosis of this syndrome usually involves examining the person's EEG patterns during sleep. Approximately 70% develop epilepsy; and these seizures are typically infrequent and can be either with or without convulsions.


Speech Evaluation in Landau-KleffnerSyndrome


by Pat Van Slyke, MS

Language deterioration which occurs after a period of normal speech and language acquisition with epileptiform activity in the speech cortex is a primary characteristic of Landau-Kleffner Syndrome (LKS). Initially, children with LKS may appear not to hear or have difficulty understanding even simple directions. Although their hearing sensitivity is within normal limits, their ability to process the verbal language input is seriously impaired (verbal auditory agnosia). Subsequently, expressive language may become telegraphic and contain multiple articulation errors, possibly deteriorating to the point of mutism. Often these children are misdiagnosed as hearing impaired. However, assessment of hearing sensitivity through Auditory Brainstem Response Testing is always within normal limits.


quoted from a Rush Institute Newsletter. 1996


A Review of Seizure Disorders and Landau-Kleffner Syndrome in the Autistic Population

Landau-Kleffner Syndrome

This syndrome was first described in 1957 and is also known as acquired epileptic aphasia. By definition, this condition affects children, usually between the ages of 3 and 7, who previously had no developmental, language, or interactional difficulties. They usually experience a rather abrupt loss of language comprehension and a diminution in their ability to express themselves. They usually have clear-cut seizures- Their EEC, especially their sleep EEG, is abnormal.

Children with Landau-Kleffner syndrome do not necessarily appear autistic, although the quick loss of language comprehension and the resultant communication handicap could certainly cause significant confusion and frustration. Some affected children therefore might appear autistic.

BobJanet, U.K.

with a complete site on LKS



No, they're not saying "Oh, isn't this lovely, let's have some more... ";  they have started a group who are friends to all people who suffer from, directly or indirectly (eg parents and teachers) LKS.   I recommend getting in touch with them;  a great pair of hearts, and a loving cyber-smile for everyone.



Recently, new data arrived here about an email support group called "FOLKS", and I have put the main gist of it below.   

To visit the main FOLKS website go to

To download the FOLKS LKS Information Pack or FOLKS newsletters go to