Changing perspectives on Landau-Kleffner syndrome.

Landau-Kleffner syndrome (LKS) is a childhood disorder characterized by an acquired aphasia that emerges in association with epileptiform electroencephalographic abnormalities. The language loss is often characterized by a severe disturbance of auditory language comprehension (verbal auditory agnosia) combined with a substantial disruption of expressive language. Comorbid behavioral disturbances commonly involve hyperactivity and attentional problems but sometimes encompass a more pervasive pattern of difficulties resembling an autism spectrum disorder. Now one the most frequently described forms of acquired aphasia in children, LKS has had a profound influence on both neurological practice and cognitive neuroscience. Here, we review current conceptualizations of LKS, consider its pleomorphic manifestations and discuss existing and future diagnostic issues and dilemmas. The potential relevance of LKS to understanding other disorders, including autistic regression, is considered.