Abstract
Objective
To validate measurement of predicted earmold wideband real-ear-to-coupler difference (wRECD) using an integrated pressure level (IPL) calibrated transducer and the incorporation of an acoustically measured tubing length correction.
Design
Unilateral earmold SPL wRECD using varied hearing aid tubing length and the proposed predicted earmold IPL wRECD measurement procedure were completed on all participants and compared.
Study Sample
22 normal hearing adults with normal middle ear status were recruited.
Results
There were no clinically significant differences between probe-microphone and predicted earmold IPL wRECD measurements between 500 and 2500 Hz. Above 5000 Hz, the predicted earmold IPL wRECD exceeded earmold SPL wRECDs due to lack of standing wave interference. Test-retest reliability of IPL wRECD measurement exceeded the reliability of earmold SPL wRECD measurement across all assessed frequencies, with the greatest improvements in the high frequencies. The acoustically measured tubing length correction largely accounted for acoustic effects of the participant’s earmold.
Conclusions
IPL-based measurements provide a promising alternative to probe-microphone earmold wRECD procedures. Predicted earmold IPL wRECD is measured without probe-microphone placement, agrees well with earmold SPL wRECDs and is expected to extend the valid bandwidth of wRECD measurement.
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Acknowlegements
The authors are grateful to Bernafon Canada for providing all earmolds used in the current study and to Jonathan Vaisberg for sharing raw data from previous studies. The authors are also grateful to Audioscan, a Division of Etymotic Design Incorporated, and Interacoustics A/S for their technical support throughout the study.
Disclosure statement
No potential conflict of interest was reported by the author(s).