Normal Infant and Adult Auditory Brainstem Responses to Bone-Conducted Tones

Abstract

Auditory brainstem responses (ABRs) were recorded to 500- and 2000-Hz bone-conducted (BC) tones from normal infants and adults. Infant ABR thresholds for the 500-Hz BC tones are significantly lower than their thresholds to 2000-Hz BC tones. Infant wave V latencies to 500-Hz BC tones are significantly shorter than those of adults, whereas infant and adult responses to 2000-Hz BC tones are similar in latency, suggesting that the effective intensity of the BC tones may be 9-17 dB greater for infants than for adults. A marked asymmetry between the ipsilaterally and contralaterally recorded wave V is seen for infant responses to 500- and 2000-Hz tones at all intensities; this asymmetry is not as evident in adults, except near threshold.