[Specific language disorders: their diagnosis, classification and study using magnetoencephalography].

Abstract

INTRODUCTION: Specific language disorder (SLD) is defined as a disorder in which language is slow and retarded with respect to the patient's chronological age, and which is not related to a sensory-auditory or motor deficit or to a pervasive development disorder; in other words, structural and functional neurological developmental disorders must be excluded. After many studies and attempts to reach an agreement, specific language disorders have been broadly classified into two groups: specific expressive language disorder and specific receptive-expressive language disorder. AIMS: Our objective was to study SLD using magnetoencephalography (MEG) in order to look for epileptiform manifestations in precise language areas. PATIENTS AND METHODS: We studied a sample made up of 11 patients with SLD, one of whom had Landau-Kleffner syndrome and one with cryptogenic-type SLD. The criteria used were age-dependent autism exclusion tests and specific language tests for SLD. The MSI technique was carried out on all the patients, by magnetic resonance and MEG. RESULTS: A characteristic pattern is obtained for SLD in the form of irregular spike and polyspike-wave discharges in bilateral frontal channels. The dipoles were situated mainly in the left perisylvian areas. CONCLUSIONS: The study of specific language disorders using MEG enables us to identify the SLD included in a proposed classification as primary-type specific language disorder, cryptogenic-type specific language disorder and secondary-type type specific language disorder, like Landau-Kleffner syndrome.