Reproducibility of amplitude and latency in short-pulse distortion-product otoacoustic emission recordings

Introduction:

Distortion-product otoacoustic emissions (DPOAEs) provide a non-invasive tool to monitor ototoxic hair cell damage within the cochlea. DPOAEs consist mainly of two components, a nonlinear-distortion component and a coherent reflection component. Wave interference between the DPOAE components limit the accuracy of the nonlinear-distortion component. Short-pulsed primary tones enable the separation of the two components in the time domain by exploiting their different latencies yielding a more accurate evaluation of the inner ear (Zelle et al. 2017). In order to establish short-pulse DPOAEs to diagnose ototoxic hearing impairment, this work analyzes the test-retest reliability in normal-hearing subjects.

Methods:

Short-pulse DPOAEs were recorded in seven normal-hearing ears at eight frequencies in the range of f2 = 1 to 8 kHz for L2 = 55 dB SPL with frequency-specific L1 levels (Zelle et al., 2015). Subjects were tested ten times within one day. Between each series of measurement, ear probes were removed, reinserted and calibrated. Time-domain analysis of the short-pulse DPOAE signals yielded amplitude and latency of the nonlinear-distortion component as a function of f2.

Results:

DPOAE latencies exhibit a higher stability with standard deviations between 0.72 at f2 = 4 kHz and 1.98 dB at 6 kHz in comparison to DPOAE amplitudes with 1.16 dB at 1 kHz and 4.37 dB at 4 kHz. The variability of both parameter correlates significantly with frequency-dependent variations in the transducer transfer functions (r > 0.71; p < 0.05).

Conclusion:

Short-pulse DPOAE amplitude and latency represent two reliable parameters to detect cochlear damage and thereby offer a promising tool to monitor ototoxic hearing loss.

Publication History

Publication Date:
23 April 2019 (online)