[Landau-Kleffner and autistic regression: the importance of differential diagnosis]

Some neurological disorders may present psychiatric signs and symptoms, therefore the search for an etiological diagnosis is crucial. The aim of this study is to report the case of a patient with a neurological disorder, diagnosed during a psychiatric admission. A boy with normal neuropsychomotor development until the age of 3 years, started presenting epileptic seizures, followed by behavioral disorder and language deterioration. During neurologic follow-up, the patient was referred to the Psychiatry Department with a diagnosis of autism, in this case an autistic regression (AR). During his admission, diagnosis of Landau-Kleffner syndrome (LKS) was established on clinical and EEG grounds. LKS is characterized by acquired aphasia, epilepsy, EEG abnormalities and behavioral changes, including autistic traits. Language regression is observed LKS and AR. We stress the main differences between these two entities because misdiagnosis may postpone early intervention and consequent benefits, as observed in our case.