Landau-Kleffner syndrome is a rare neurological condition in which children lose the ability to speak and understand language. This change is associated with seizures that are usually infrequent or easily controlled with medication and with a specific EEG pattern known as spike wave activation in sleep (SWAS). The syndrome usually appears in children who were previously developing typically.
Landau-Kleffner syndrome is a subtype of a condition called epileptic encephalopathy with spike wave activation in sleep (EE-SWAS).
What are other terms for Landau-Kleffner syndrome?
Other terms for Landau-Kleffner syndrome include:
- acquired childhood aphasia with convulsive disorder
- acquired epileptic aphasia
- Landau-Kleffner acquired epileptiform aphasia
What are the features of Landau-Kleffner syndrome?
Landau-Kleffner syndrome usually begins when the child is between three and eight years old. A child who has learned to speak gradually loses the ability to understand language and stops responding to spoken words. The child’s parents and health-care provider may assume at first that they have lost their hearing.
The child may begin to stutter or to make mistakes in their speech, such as mispronouncing words or using the wrong words or the wrong combinations of words. They talk less and less. In severe cases, they may stop talking altogether and may not even respond to non-verbal sounds such as a ringing telephone. These symptoms were originally described as “auditory agnosia”.
In some cases, children with Landau-Kleffner syndrome can still communicate without speech, for instance by writing or using sign language.
It is common for these children to develop behaviour disorders, including hyperactivity, excitability and attention deficit. In some cases, a child’s behaviour is severely affected and interferes with daily activities at school and at home.
Children with Landau-Kleffner syndrome have a characteristic diagnostic EEG pattern known as spike wave activation in sleep (SWAS). During sleep, the EEG pattern is dominated by spike and wave discharges. Whenever there is a suspicion of the syndrome, the EEG must capture the child during sleep. In some patients, the awake part of the EEG can be normal. Children with Landau-Kleffner syndrome also have seizures. These may be focal motor seizures (most common), generalized tonic-clonic seizures, atypical absence seizures or atonic seizures. They usually occur in sleep.
Typically, the seizures are less severe than the child’s language problems. Seizures are usually easily controlled with anti-seizure medications. The seizures and the abnormal EEG patterns usually go away by the time the child reaches age 15, and the language problems may improve somewhat at or after this point.
What causes Landau-Kleffner syndrome?
The cause of Landau-Kleffner syndrome is not known. However, similar symptoms can sometimes be seen in children with a focal brain abnormality. The same abnormal EEG pattern and impaired language are common aspects of Landau-Kleffner syndrome.
A genetic mutation of the GRIN2A gene has been found in a small group of children with Landau-Kleffner syndrome, but this is not common.
How many other children have Landau-Kleffner syndrome?
It is not known how many children have Landau-Kleffner syndrome, but it is quite rare.
How do you know a child has Landau-Kleffner syndrome?
Landau-Kleffner syndrome may be confused with deafness or autism spectrum disorder. Unlike children with autism spectrum disorder, children with Landau Kleffner syndrome have a clear period of typical language development until three to five years of age and then regress. To diagnose Landau-Kleffner syndrome, it is important for the child’s health-care provider to understand their development, particularly in terms of language. Their health-care provider may ask to see school reports and any other reports on the child’s behaviour and development. They may also order or perform a variety of tests, such as:
- neuropsychological testing to evaluate how their brain processes language and performs other functions, and to find out the specific type of language problem that is affecting them
- EEG while the child is awake and asleep
- in rare cases, video-EEG
- neuroimaging (MRI)
How is Landau-Kleffner syndrome treated?
Because Landau-Kleffner syndrome is so rare and its outlook varies, there have been no controlled trials to study its treatment. What is known about the treatment options for this syndrome comes only from case reports.
The seizures caused by Landau-Kleffner syndrome are usually mild and easy to control. Most anti-seizure medications are effective in preventing the seizures but have little effect on behaviour or language problems. For the language difficulties, primary treatments include benzodiazepines such as clobazam or diazepam. If these medications are not effective, high-dose corticosteroids are prescribed. Rarely, intravenous immune globulin (IVIG) may be beneficial.
Most importantly, children with Landau-Kleffner syndrome may need learning strategies that take their language problems into account. Each child has their own particular needs, but some approaches that may be helpful include:
- a helper in the classroom to give the child one-on-one help with understanding and presenting information
- using sign language, pictures, colour coding and other visual cues to help the child understand spoken information
- computer programs with colourful images and very simple verbal information
- speech and language therapy
Teachers need to be educated about the child’s condition so that they can give them the support they need and understand that the child may have problems processing spoken language for some time.
What is the outlook for a child with Landau-Kleffner syndrome?
The outlook for children with Landau-Kleffner syndrome varies. The seizures can usually be controlled with anti-seizure medications, and the seizures and abnormal EEG patterns usually stop by themselves after a few years. Less than 20 per cent of children with Landau-Kleffner syndrome continue to have seizures, and they are usually rare.
Once the EEG abnormalities improve, the child’s language abilities may also improve, and they may be better able to learn. However, they will usually need intensive language therapy and help with school, even after the seizures are under control.
In at least half of cases, children may have permanent problems with language and verbal short-term memory. These may affect a child’s education and their everyday life, even as an adult. The outlook for their language abilities depends on:
- how old the child was when the syndrome began; the younger they were, the more severe the problems, because the syndrome was active while they were developing language skills
- how severe the EEG disturbances were
- the location of the disturbances
- how long the EEG disturbances continued
There is no connection between the number of seizures a child has and the outcome of their language abilities.