A prominent theory of dyslexia states that it is caused, at least in part, by neural deficits in processing auditory information. We examined children with dyslexia for their brain responses to sounds which were designed to challenge the temporal processing capabilities of the auditory system. The sounds were 500-ms broadband noises containing a binaurally embedded pitch. Event-related brain responses were measured with simultaneous 64-channel electroencephalography (EEG) and 160-channel magnetoencephalography (MEG). Nine children with dyslexia and 9 age-matched controls were tested (2 females in each group, Mean age 9.5). During the brain measurements children viewed a video and ignored the acoustic stimuli. Children tolerated the experimental environment well and we were able to collect data from all subjects for 800 trials over a 40-minute experimental session. This resulted in auditory responses with a high signal-to-noise ratio, important because children's auditory responses tend to be considerably noisier and more variable than those of adults. Results showed a delayed neural response to binaural pitches in children with dyslexia compared to control children.
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