Landau-Kleffner syndrome (LKS) is a rare childhood neurological syndrome. It is characterised by a sudden or gradual loss of ability to understand of express language (aphasia) and usually occurs in children between the ages of 3 and 7 years. Rolandic epilepsy is the most common epilepsy syndrome in childhood with involvement of the oropharyngeal manifestations, hypersalivation and arrest of speech. These two syndromes are considered to be aspects of the ‘epilepsy-aphasia spectrum’ with common rolandic epilepsy being the mildest form and LKS the most severe.

Thierry Deonna, Emeritus Professor of Neurology, the Child Neurology Unit, University of Lausanne Children's Hospital,the University of Lausanne, Switzerland.

Eliane Roulet-Perez, Professor of Paediatric Neurology at the Faculty of Biology and Medicine, University of Lausanne, Switzerland. Head of the Paediatric Neurology and Neurorehabilitation Unit, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.