Landau Kleffner Syndrome

Landau Kleffner syndrome is characterized by subacute onset of progressive aphasia in a child with previous age-appropriate language development and cognition. LKS is considered an 'epileptic encephalopathy'. The onset is between 2 and 8 years old (peak 5 to 7 years). The initial presentation may be with progressive aphasia (40%), seizures or both. Both sexes are affected. The aphasia occurs because of an acquired verbal auditory agnosia. Children become progressively unable to comprehend spoken word, cease to understand when spoken to and to respond verbally. The diagnosis is typically delayed as children are thought to have acquired deafness, autistic regression, or mutism. Behavioral (e.g. attention deficit hyperactivity disorder, aggression), psychiatric and cognitive disturbances are commonly observed in addition to language impairment. Language impairment typically fluctuates. Seizures and EEG abnormality resolve with age in most cases, however residual language impairment is seen in the majority (>80%) and may be severe (especially if onset is earlier).

Seizures may not occur in all cases, and when present are infrequent and self-limiting. However, there is a high risk of significant residual language impairment.