THE LANDAU-KLEFFNER SYNDROME - INCREASED UNDERSTANDING

The Landau-Kleffner and the continuous spike and wave discharges durin g slow sleep (CSWS) syndromes are described and possible links between the two are discussed. They certainly overlap, with clinical and elec troencephalographic features in common. Potential causes are discussed . There is seldom a definite reason for the seizures but it way well b e that the spike and wave discharges seen in the EEG, whatever their o rigin, may disrupt the development of language and cognitive function at a critical stage. If neurons and axons are involved in this disorga nized activity they surely cannot perform normally. The evidence that these discharges in the Landau-Kleffner syndrome can have a focal orig in in areas important for language supports this hypothesis. Certain v ariations among studies quoted may be due to factors such as age of on set, the duration of the paroxysmal activity, its intensity and especi ally its localization. Also, if development has been distorted subsequ ent progress is likely to be disturbed after the primary condition has ceased to exist. The diagnosis can sometimes present difficulties, fo r example from deafness, psychiatric condition, post-ical dysphasia an d from progressive degenerative neurological disorders. if the possibl e role of the epileptic activity is accepted, there are strong reasons for advocating anti-epileptic treatment, even if overt seizures are r are. The response to drugs is varied. Fits will usually stop, but not so often the spike and wave discharges, and it is justifiable to try v arious regimes. Subpial resection has been reported to be successful, possibly by preventing the cortex generating seizures, and their sprea d. (C) 1997 Elsevier Science B.V.