Landau and Kleffner5 were the first to report an acquired aphasia occurring in childhood that was associated with a convulsive disorder.6–11 Typically, language comprehension in a previously normal child (usually a male) between the ages of 3 and 7 years deteriorates over days to weeks.

Initially, parents often are concerned that their child is becoming deaf. The child is able to hear, however; he or she is alert to environmental sounds and the audiogram or brainstem auditory responses are normal.

The child cannot process meaningful language (verbal auditory agnosia).12–15 The language comprehension deficit generally is followed by the insidious loss of speech. Poorly articulated, dysprosodic speech is the rule. Mutism occurs occasionally. (This is believed to occur because expressive language is not yet automatized in the young child and therefore deteriorates without reinforcement.) Older children with this disorder often have greater expressive language deficits (including writing) than receptive deficits.16–19

Many children with classic Landau-Kleffner syndrome (LKS) can access language in the visual modality. That is, they can gesture, learn sign language, read, and write.

Except for the language impairment, children with LKS are intellectually normal, as measured (for example) by nonverbal reasoning tests. Sometimes they have behavioral difficulties such as hyperactivity or attention deficit, presumably as a secondary response to their communication impairment. Rarely, psychosis has been described.

Adapted from: Nass R and Gross A. Landau-Kleffner syndrome and its variants. In: Devinsky O and Westbrook LE, eds. Epilepsy and Developmental Disabilities. Boston: Butterworth-Heinemann; 2001;79–92.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised May 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.