Segmental and suprasegmental speech processing in a child with Landau-Kleffner Syndrome

In the present study we examined the speech processing skills of a child having Landau-Kleffer syndrome (LKS). We assessed two kind of language processing skills using event related brain potentials (ERPs): the discrimination of segmental and that of suprasegmental cues. Results indicate that the two kind of cues were processed asymmetrically: the mismatch negativity component (MMN) was obtained for the phoneme difference, however no difference in the ERPs was obtained for the stress pattern difference. At the same time, another patient having Benign epilepsy of childhood with centrotemporal spikes (BECT), a childhood epilepsy similar to LKS to some extent, with no language problems showed MMN to both kind of difference. Beside the ERP study several other assessment were carried out so as to obtain a more complex picture on the language deficit, including the examination of the source of epileptic activity using electric source localizations method and PET, and the neuropsychological assessment of cognitive and behavioral skills. As a conclusion we believe that LKS is language disorder that can be used to study what happens to the language system if in the course of development the essential neural circuits are severely disturbed. We believe also that the tools we use, that is the electrophysiological measurement of pre-attentive language processing is a fruitful approach since it makes possible the assessment of subtle processing skills while it does not require the patient / child to be responsive.