Language lateralization development in children with autism: insights from the late field magnetoencephalogram.

Left hemisphere dominance represents the typical language lateralization profile for the majority of neurologically healthy, right-handed individuals. We investigated hemispheric dominance for language in language-impaired children with autism and typically developing controls to investigate the hypothesis that atypical functional specialization for language represents one component of developmental language impairment in autism. Late field magnetoencephalography (MEG) recordings were used to calculate a hemispheric Lateralization Index from the neuromagnetic activity evoked by passive auditory presentation of vowel stimuli. Results indicate that children with autism and typically developing children follow opposite maturational trajectories in language lateralization; while leftward lateralization (i.e. left hemisphere dominance) emerged from bilaterally symmetric neuronal activation as age increased in our sample of typically developing children, rightward lateralization emerged from bilaterally symmetric activity as age increased in our sample of children with autism.