Efferent auditory system: its effect on auditory processing

Auditory processing depends on afferent and efferent auditory pathways integrity. The efferent auditory system may be assessed in humans by two non-invasive and objective methods: acoustic reflex and otoacoustic emissions suppression. AIM: Analyze the efferent auditory system activity by otoacoustic emission suppression and acoustic reflex sensitization in human subjects with auditory processing disorders. METHOD: Prospective study: fifty children with auditory processing disorders (study group) and thirty-eight children without auditory processing disorders (control group) were evaluated using otoacoustic emission with and without contralateral noise; and acoustic reflex with and without contralateral facilitating stimuli. RESULTS: OAE suppression mean value was equal to or less than 1.50 dB for the control group, and equal to or less than 1.26 dB for the study group. The mean sensitization reflex value was equal to or less than 14.60 dB for the study group and equal to or less than 15.21 dB for the control group. There was no statistically significant difference between the responses from the control group and the study group in both procedures. CONCLUSION: The study group had lower OAE suppression values and higher acoustic reflex sensitization values when compared to the control group.