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At a glance

It is a rare medical condition with an onset during childhood characterized by aphasic epilepsy of unknown origin resulting in severe language dysfunction (eg, loss of previously acquired speech and language skills [aphasia] and auditory agnosia). The symptoms typically begin between the ages of 3 and 7 years although the condition may rarely occur in children as young as 18 months of age. Approximately 70% of patients present simple or complex partial seizures as a form of atypical absence. The syndrome can be difficult to diagnose and is often misdiagnosed as autism.

Synonyms

Acquired Epileptiform Aphasia; Aphasia Convulsive Disorder; Acquired Epileptic Aphasia; Infantile Acquired Aphasia.

History

This is a neurologic disorder that was first described in 1957 under the name of Acquired Epileptic Aphasia. It is named after Drs William Landau, Professor of Neurology at the Washington University School of Medicine in St. Louis, and Frank Kleffner, a speech pathologist at St Louis Central Institute for the Deaf, who made the diagnosis on six children.

Incidence

The exact incidence remains unknown. This rare form of epilepsy is mostly seen in males with a predominance of 2:1. The disorder usually occurs in children between the ages of 3 and 7 years.

Genetic inheritance

There is no evidence of a genetic occurrence. However, in a single patient a mutation in the GRIN2A gene was reported. Also, an association with possible autoimmune or inflammatory mechanisms has been suggested.

Pathophysiology

The cause of LKS is not known. Possible suggested mechanisms include a dysfunctional immune system, exposure to a virus, and brain trauma. It affects the Broca and Wernicke’s areas.

Diagnosis

Electroencephalography (EEG) tracings are typical (present even in children with no clinical seizures); there is an epileptiform electrical activity in one but sometimes in both temporal lobes particularly when the child is asleep (“continuous spike waves of sleep” or “electrical status epilepticus of sleep”).

Clinical aspects

LKS usually starts between the ages of 3 and 8 years and may develop either slowly over months or rapidly overnight. Most children have seizures that are readily controlled by antiepileptic drugs, but some children never have obvious seizures. Children with LKS have a language disorder that affects comprehension and/or understanding. They become unable to understand their own name, to identify environmental sounds such as telephone ringing, and to recognize family and friends or common objects, such as food and clothes. They may appear to be deaf. Some patients lose their speech completely and have behavioral problems (hyperactivity, poor attention, depression, and irritability). Occasionally, they have other neurologic problems, such as loss of bladder and bowel control, and visual disturbances (they can see but are unable to understand ...

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