PP317 - Electroacoustic Comparison of Over-the-Counter and Proprietary Remote Microphone Systems

Abstract: Can a $25 smartphone-based remote microphone from Amazon compete with a proprietary hearing aid remote microphone with a much higher cost? Our team completed electroacoustic analyses and on-ear measurements on three over-the-counter microphone options and an Oticon ConnectClip to determine if a cost effective, direct-to-consumer (DTC) option exists in the remote microphone space. An ANSI S3.22 electroacoustic battery was run on each DTC microphone system followed by a NAL-NL2 real-ear target match on a Carl simulated ear using standardized audiograms. The results showed promising DTC options for some patients and we discuss future avenues of research in this area.

Summary:

Introduction
While hearing aids alone are sufficient for many patients with hearing loss, for some who have to listen in excessive background noise or hear at a distance, more support is needed. Research shows remote microphones (RMs) have been shown to improve listening for those with hearing loss or other auditory conditions in noisy and reverberant environments and across distances. Such devices are routinely recommended by audiologists and other health care providers to aid listening in these complex settings. However, many hearing aid manufacturer-made RMs are expensive ($250+) and not covered by insurance, even when hearing aids are. This leaves this beneficial technology out of reach for many patients. After noting the availability of much less expensive (~$25) smartphone-based microphones on Amazon, we conducted a study to determine if relatively inexpensive direct-to-consumer (DTC) RMs could be adapted to stream to hearing aids and, if so, could such devices perform comparably to more expensive proprietary devices, becoming a more affordable option for some patients.

Methods
An Oticon MORE 1 miniRITE-R hearing aid with an 85-power receiver programmed to be fit with a power dome was used as the basis for all testing, and was selected as a common prescription hearing aid. The remote microphones used were as follows: 1) Oticon EduMic (proprietary RM), 2) Lewinner lapel Bluetooth microphone (DTC RM), 3) Bietrun lapel Bluetooth microphone (DTC RM), and 4) an iPhone using the built-in Live Listen function (DTC RM). The DTC microphones were selected for having high user ratings on Amazon.com, where they were found.

An Axiom test box and real ear system was used for all testing. An ANSI S3.22 electroacoustic analysis was run on with each of the microphones connected to hearing aid (with the exception of the EduMic, which could not be connected while the aid was in ANSI mode. Real-ear measures were then performed using a Carl simulated head and matching to NAL-NL2 targets for a standardized mild and moderate audiogram. Directionality was also tested in the test box.

Results
Electroacoustic results were reported for hearing aids alone and hearing aids paired with each of the DTC microphones.  A wide variance in DTC microphone performance was seen, with some coming close to ANSI targets while others were quite far off. Real-ear testing results were reported as the difference between the measured output and NAL-NL2 target for tested frequencies.  For the mild audiogram, all tested devices had at least 70% of measured frequencies within 5dB of the NAL-NL2 target. For the moderate audiogram 2 devices had 80% of frequencies within 5dB of the target.

Conclusions
Based on the results, it appears that DTC microphones may be acceptable alternatives for some patients in some situations.  Not all DTC devices are made equal, however, so quality testing is important. Further, the usability of these devices depends on the technological savvy of the user. Future research should be conducted looking at patient performance in quiet and noise with these RMs, and patient perceptions of using the devices.