Auditory event-related potentials in the assessment of auditory processing disorders: a pilot study

The aim of this pilot study was to investigate whether children with a suspected auditory processing disorder (sAPD) in the presence of normal hearing, differ significantly from normal age-matched controls on particular parameters of auditory event-related potentials. We assessed nine children (mean age 9.5 years) in whom the clinical profile and the results in a screening test for auditory processing disorder (SCAN/SCAN-A) suggested the presence of an auditory processing disorder, and nine age-matched normal control subjects, using auditory event-related potentials (ERP) to phonemes/ba/(standard) and/da/(deviant). Analysis of the auditory ERP recordings revealed an enlarged P85 - 120 and attenuated N1 and P2 in all sAPD children compared to controls. We also found significantly increased N1 peak latency, and a larger peak to peak amplitude of the P85 - 120-N1 and P2-N2 and smaller peak to peak amplitude of the N1-P2 in the sAPD children. Subtraction of the standard auditory ERP from the deviant revealed a mismatch negativity with no significant differences in duration, peak or onset latency between the control subjects and sAPD. Our results indicate that neurophysiological measures may identify a group of children with specific problems suggestive of an auditory processing disorder in the absence of an obvious structural or functional lesion who warrant further study in order to assess whether these findings reflect delayed CNS myelination.