ABR and DPOAE indices of normal loudness in children and adults

Loudness growth prediction using normal templates of loudness derived with ABR and DPOAE measures was investigated in 20 children 4 to 12 years and 20 adults with normal hearing. An ABR click latency-intensity function (LIF), ABR 2 kHz tone LIF, and DPOAE 2 kHz amplitude-intensity function (AIF) were recorded from each listener. A loudness-intensity function was also measured for each electrophysiologic stimulus. Children and adults exhibited similar intensity functions of ABR latency, DPOAE amplitude, and loudness. A statistically significant relationship was found between loudness and ABR latency and DPOAE amplitude. Loudness estimation equations derived with ABR latency and DPOAE amplitude accurately and reliably predicted the loudness-intensity functions of the listeners. Normative ABR and DPOAE templates of predicted loudness growth may have clinical application in site-of-lesion assessment or hearing aid fitting by distinguishing abnormal rates of loudness growth for individuals who cannot provide reliable behavioral measures.