Similarities and differences in distortion-product otoacoustic emissions among four FDA-approved devices

Similarities and differences in distortion-product otoacoustic emissions (DPOAEs) among four Food and Drug Administration (FDA) approved devices were assessed quantitatively. DPOAEs were recorded from 42 adult subjects (84 ears) ranging in age from 19 to 40 years. All subjects had hearing thresholds of 20 dB HL or better for the test frequencies from 0.25 to 8.0 kHz and normal acoustic immittance findings. DPOAEs were collected in a quiet non-sound-treated room. DPOAE measurement parameters included an f2/f1 ratio of approximately 1.2, with f1 at 65 dB SPL (L1) and f2 at 55 dB SPL (L2). There were no significant differences in the mean emissions levels among the four devices. This investigation showed that validity criteria, pass criteria, and strategies for DPOAE measurements interact to produce varying pass and refer results. However, when DPOAEs are obtained with consistent validity criteria, pass criteria, and strategies for measurement, the results are remarkably consistent.