Repeatability of high-frequency distortion-product otoacoustic emissions in normal-hearing adults.

OBJECTIVES: Distortion-product otoacoustic emissions (DPOAEs) are repeatable over time at lower frequencies (8 kHz) for DPOAE level measurements. The average DPOAE level differences-between-trials for the higher and lower frequencies for the four different stimulus level conditions was 5.15 (SD = 4.40 dB) and 2.80 (SD = 2.70 dB) dB, respectively. Individual subject analysis revealed that high-frequency DPOAE levels varied no more than 10 dB for 87.5 and 83.1% of young adult subjects for the 70/55 and 60/50 dB SPL stimulus level conditions, respectively. For low frequencies, repeated DPOAE level variations were within +/-10 dB for 98.4 and 96% of young adult subjects for the 70/55 and 60/50 dB SPL stimulus level conditions, respectively. For DPOAE group delay, greater variability was noted at lower frequencies (