Unilateral abnormalities on MEG auditory evoked fields in children with Landau-Kleffner Syndrome

Landau-Kleffner Syndrome (LKS) is known to disrupt auditory processing but the exact nature of these disruptions has not been established. We compared the MEG auditory evoked fields (AEF) to monaural tone stimulation in a group of 4 children (aged 7–10 years) with LKS and a group of age-matched clinical controls. In all 4 control children, bilateral AEFs were observable and dipoles localizable to both superior temporal gyri. In the children with LKS, an AEF was observable only over one hemisphere (3 left temporal lobes; 1 right). The AEF generated in the other hemisphere demonstrated non-dipolar topographies that were not localizable. Furthermore, in the group of children with LKS, the hemispheric concordance between EEG and AEF abnormality was 50%. Our evidence concurs with the literature that there are unilateral auditory processing abnormalities in LKS. We add to the existing data by further describing the nature of these abnormalities.