MM206 - Improving the Fit of Custom In-Ear Monitors: Applying Custom Hearing Aid Fitting Skills

Abstract: The use of in-ear monitor (IEM) systems has become a popular means to help reduce cartage and storage of loudspeaker systems in the music industry. Audiologists are in an ideal position to address the noise and music-induced risks of IEM use when consulted by music workers. The proposed presentation is designed to help share ways audiologists may be able to improve the fit and isolation of custom-fit IEMs using custom hearing aid modification principles. Examples of custom IEM modifications to improve attenuation and isolation of fit will be presented.

Summary: Relevance
Music industry workers who use custom in-ear monitor (IEM) systems often use these systems to enhance their music performance and reduce their risk of hearing health related injury. If poorly manufactured, custom IEMs may not provide adequate attenuation to prevent hearing related injuries. The purpose of this presentation is to review audiological methods for measuring isolation/attenuation measures of custom IEM devices manufactured by major companies, and demonstrate the use of custom hearing aid modification skills that can be applied to custom IEM devices.

Methods presented
Two pairs of custom IEMs that resulted in poor isolation and fit made and ordered from two companies will be the subject of the instruction of this presentation. Measures of each device were completed using equipment available within a University audiology clinic setting. Attenuation was measured using real-ear attenuation at threshold (REAT) measures in a sound-field audiometric sound booth condition, using frequency specific narrowband noise signals with contralateral masking through an insert earphone in the non-test ear as recommended by Portnuff and Price (2018). Analyses of frequency specific and average attenuation results will be presented to show the difference between pre/post modifications made of the custom IEM .

Takeaways
Data differences across the two pairs of custom IEMs from the two manufacturers will be presented. Variance in characteristics of each manufacturer's device will be demonstrated, including differences in the device sizes, amount of material that was used to modify, canal length, canal tip, and concha/bowl fill. Data collected thus far has revealed average attenuation reduction values (250-8 kHz) for REAT measures ranging between -13 and -24 dB HL across the pairs of IEMs. Additional analyses for post-modification are underway to be completed by the end of December 2023 and will be presented.

Importance of Work
Better understanding of the characteristics and how audiologists may play a role in modifying custom IEM devices for music industry working patients, as measured by equipment available to audiologists, will help in the development of more accurate performance expectations among consumers, and provide clinical support to guide audiological service delivery in improving facilitation practices of custom IEMs.