Abstracts

Rationale: The Landau Kleffner syndrome (LKS) is characterized by paroxysmal, sleep potentiated EEG alterations associated with acquired aphasia and epilepsy. LKS often presents with subacute isolated language disturbance associated with an epileptiform EEG in the presence or absence of seizures. Children with LKS have normal language and other developmental milestones before the onset of the convulsive episode. Although epileptic abnormalities appear to be responsible for the manifestations, not all patients respond to antiepileptic medications. Periodic spontaneous recovery, permanent speech abnormalities/aphasia may be encountered. LKS may overlap clinically with Rolandic epilepsy, continuous spike wave discharges in slow wave sleep, acquired epileptiform opercular syndrome, and autism when they are associated with epileptiform EEG, and abnormalities in electrophysiological markers of auditory processing such as 4 Hertz steady state frequency modulated auditory evoked responses (FMAER), and click auditory evoked responses (click AER). These patients may be classified as LKS variants. Methods: We retrospectively identified 4 patients with LKS variant based on presentation with language regression/acquired aphasia, cognitive delay, autistic features with paroxysmal EEG abnormalities and absent FMAER. Results: Patients presented between 18 months and 3 years with regression in verbal output and personal social skills, presence of pervasive features reminiscent of autism spectrum with seizures, epileptiform abnormalities in EEG, and unequivocally absent FMAER with or without AER abnormalities. 1 patient was treated with VPA, LTG, and prednisone, the second was treated with VPA and LEV, and the third was treated with VPA and steroids. The parents of one patient declined treatment. All treated patients responded to treatment. The first had improvement of pervasive features, developed better personal social skills, started vocalizing, babbling and using limited verbal output and sign language. The other two, however, showed improvement of personal social, interactive/communicative skills, and gradually developed speech with full sentences, documented with formal neuropsychological assessment. In addition, patients’ epileptiform EEG as well as FMAER/AER abnormalities ameliorated. The untreated patient, however, still has major communication impairment, and progressive pervasive features, such as absent eye contact, repetitive movements, ritualistic behavior, and parallel play. Conclusions: Patients identified with LKS or LKS variants using EEG assessment for epileptiform abnormalities leading to auditory processing and/or speech impairment, and evaluation of electrophysiological elements for auditory processing, such as FMAER and/or AER analysis may respond to treatment with appropriate antiepileptic medications, particularly the broad spectrum spike suppressors, such as VPA, LEV, or LTG, alone or in combination, or in combination with steroids.