Language impairments and neuroimaging findings of Landau-Kleffner syndrome, continuous spike-waves during sleep and benign epilepsy with centrotemporal spikes

Epilepsy is a frequent neurological disease in childhood, characterized by the occurrence of two or more seizures at least 24 hours apart. Child epilepsies are mostly age related, and linguistic, cognitive and behavioural symptoms depend on brain development, the maturation process, genetic factors as well as the focal site of seizures. This article specifies the speech and language deficits discovered so far in Landau-Kleffner syndrome (LKS), continuous spike-waves during sleep (CSWS) and benign epilepsy with centrotemporal spikes (BECTS). Landau-Kleffner syndrome and CSWS are currently considered as synonyms, with the core symptom of acquired aphasia. Regression in CSWS is of global type, whereas in LKS it is of linguistic nature. Benign epilepsy with centrotemporal spikes is mostly accompanied by interictal epileptic discharges resulting in reading disability, such as dyslexia, and speech disorder of phonological nature and oromotor deficits. Continuous spike-waves during sleep, LKS and BECTS are age related, sharing common EEG features, results from PET studies, long-term prognosis and therapeutic approaches. There is a need for a new group of syndromes or one syndrome with an epileptic encephalopathy mechanism with regression which is common to all three syndromes or a syndrome of interictal spike and wave discharges. Further research is also needed confirming the type of language disorders in CSWS and BECTS and the severity of language disability in LKS.