Outcome at adulthood of the continuous spike-waves during slow sleep and Landau-Kleffner syndromes

Purpose: The aim of this study was to determine the clinical, social, and/or professional and cognitive outcomes in adulthood of the continuous spike-waves during slow sleep (CSWS) and Landau-Kleffner syndromes, which are two rare epileptic syndromes occurring in children. Methods: We enrolled seven young adults, five who had a CSWS syndrome, and two, a Landau-Kleffner syndrome in childhood. We evaluated their intellectual level as well as their oral and written language and executive functions. Results: This study confirmed that the epilepsy associated with these syndromes has a good prognosis. Only one patient still had active epilepsy. However, the neuropsychological disorders particular to each syndrome persisted. Only two patients had followed a normal pathway in school. Three of the five patients with a CSWS syndrome during childhood remained globally and nonselectively mentally deficient. We found no evidence of the persistence of a dysexecutive syndrome in this study group. The intellectual functions of the two patients with Landau-Kleffner syndrome were normal; however, their everyday lives were disrupted by severe, disabling language disturbances. We discuss the role of some prognostic factors such as the location of the interictal electric focus and the age at onset of CSWS. Conclusions: These two epileptic syndromes of childhood are very similar in many respects, but their clinical outcomes in adulthood are different.