Average optimal DPOAE primary tone levels in normal-hearing adults

Abstract

Objective: Despite great progress towards optimizing DPOAE primary tone characteristics, factors such as stimulus and intra-subject emission variability have not been addressed. The purpose of this study was to identify optimal primary tone level relationships when these sources of variability were acknowledged, and to identify any influences of test frequency. Design: Following coupler-based measurements assessing primary tone level stability, two experiments were conducted. In experiment 1, DPOAE test-retest reliability without probe replacement was measured for f₂ = 1–6 kHz with L₁= L₂= 65 dB SPL. In experiment 2, optimal L₁-L₂ relationships were identified for f₂ = 1–6 kHz. For 20 ≤ L₂ ≤75 dB SPL, L₁ was varied 15 dB SPL above and below the recommendation of L₁ = 0.4 L₂+39 [dB SPL]. Study sample: Eleven normal-hearing adults participated in experiment 1. Thirty normal-hearing adults participated in experiment 2. Results: Stimulus variability did not exceed 0.1 dB SPL. DPOAE reliability testing revealed an across-frequency mean standard error of measurement of 0.52 dB SPL. The average optimal L₁-L₂ relationship was described by L₁ = 0.49 L₂+41 [dB SPL]. A significant effect of frequency was identified for 6 kHz. Conclusion: Including relevant sources of variability improves internal validity of a primary tone level optimization formula.

Key Words:

• Otoacoustic emissions
• anatomy and physiology
• medical audiology
• instrumentation
• pediatrics

Declaration of interests

The authors report no conflicts of interest.