Test Retest Reliability Of Distortion Product Otoacoustic Emissions In The High Frequency Range

This dissertation, "Test-retest Reliability of Distortion Product Otoacoustic Emissions in the High Frequency Range" by Hoi-yee, Iris, Ng, 伍凱怡, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of dissertation entitled Test-retest Reliability of Distortion Product Otoacoustic Emissions in the High Frequency Range submitted by NG, Hoi-Yee Iris for the degree of Master of Science in Audiology at the University of Hong Kong in May 2002 In the current research study, distortion product otoacoustic emissions (DPOAEs) were measured in 35 young Chinese adults (61 ears) with normal audiometric thresholds using an ILO96 OAE system with the default DP-gram protocols as well as user-defined DP spectrum protocols in the high frequency range. Two series of retest were conducted 20 minutes and an average of 15 days later, and the resolution setting for the DP-gram measurements was varied between 1 to 8 points per octave in each test series. Transient evoked otoacoustic emissions (TEOAEs) were also recorded in each test series for comparison purposes. Test-retest partial correlation and standard error of measurement (SEM) were computed to reflect the test-retest reliability of the OAE amplitudes, noise floor and signal-to-noise ratio. Results suggested that OAE amplitudes in the default frequency range (1 to 6 kHz) between test and retest were highly correlated with an average correlation coefficient of 0.85 and SEM was found to be an average of 2.4 dB, while signal-to-noise ratio and noise floor yielded lower correlation coefficients and higher SEMs. OAE amplitudes in the higher frequency range of 6.5 to 7 kHz were also significantly correlated between test and retest (correlation coefficient ranged from 0.74 to 0.80) with SEM from 2.7 to 3.5 dB. Yet DPOAEs at 8 kHz were present with a positive signal-to-noise ratio in only one-third of ears, were less test-retest correlated, and the amplitude revealed a high SEM of 5 dB. No apparent difference was demonstrated among various resolution settings and between short- and long- term retest. This implies that DPOAEs in the high frequency range (6.5 to 7 kHz) could be a potential clinical tool for monitoring cochlear functioning in cases such as exposure to ototoxic medication or noise. vii DOI: 10.5353/th_b2701474 Subjects: Otoacoustic emissions Hearing - Measurement