In 1957, Landau and Kleffner1 described six children with acquired aphasia and continuous temporal interictal discharges in sleep. This condition has since been known variously as epileptic encephalopathy with continuous spike-wave in sleep or as atypical benign partial epilepsy (pseudo-Lennox syndrome). Now, the International League Against Epilepsy’s Task Force on Nosology and Definitions has included this syndrome within the definitions for developmental and epileptic encephalopathy with spike-wave activation in sleep (DEE-SWAS) and epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS).