The Landau-Kleffner syndrome consists in the association of an aphasia acquired during childhood or adolescence after a period of normal development, accompanied by epileptic fits and, sometimes, psychological simultaneous. The appearance of the symptoms may, not be simultaneous. The nature of this syndrome has been widely discussed and even the possibility of being a non-unitary syndrome has been considered. It may be possibly due to diverse etiologies, genetic or acquired (infeccious), The relation between the aphasic, the psychologic and the convulsive symptoms has also raised controversies. A case of a female is described in which the psychological symptomatology was so severe, she had to be admitted in a psychiatric unit. The symptoms consisted in agitation during the night and severe persistent insomnia so ns difficulties for relationship during day. No abnormalities were detected in a TAC nor in a RM but electroencephalographic and neuropsychological abnormalities were detected The epileptic fits disappeared with a carbamacepine treatment but the rest of symptoms remained even more accentuated. After her admission, a treatment with valproate achieved to control her fits and the aphasic symptoms and neuropsychological deficits were compensated in the course of several months. After a year of treatment the patient's life was normalized, she resumed her studies the EEG abnormalities disappeared so as the psychological disturbances and the behavior problems with the exception of phobic symptoms, simmilar to the ones of other family members. The patient has a history of epilepsy on its mother's side. The evolution and treatment response suggests that at least in some cases of the Landau-Kleffner syndrome, the etiology of the aplasia and other neuropsychological deficits and of the behavior disorders are related with some subclinical epileptic discharges and with wa "functional inhibition" of some areas of the nervous system.