Remote microphone technology is a proven and effective method of maximizing the help hearing aids can provide in the most demanding scenarios. Users can reconnect to their favorite activities even in the face of background noise, limited visual cues, speech at a distance, and in multiple talker activities. Here are a few tips for applying the technology.
A hearing aid user can give a remote microphone to a conversational partner, or place it near people he or she wants to hear. The microphone picks up the sound of interest close to the source and transmits it directly to the user’s hearing aids. This increases the signal-to-noise ratio (SNR) dramatically, in a wide variety of listening environments.
Remote microphone technology provides not only the proven performance required to reconnect hearing aid users to the conversation in these difficult listening environments, it also has the versatility to provide benefit in a variety of difficult listening scenarios where remote microphone technology can help. Hearing care professionals can assist patients in getting the best out of the remote microphone technology—giving patients a personalized and optimal experience.
Noisy restaurants are one of the most commonly reported areas of listening difficulty—and why wouldn’t they be? Restaurants frequently have high levels of unpredictable impact and speech background noise, which often overlaps in frequency composition with the target speaker, yielding a low SNR. Combined with limited predictability of noise location, low lighting, and acoustically detrimental architecture, low SNR can negatively contribute to this listening environment. Hearing aid user survey data over the past 25 years has consistently rated noisy situations highest in user dissatisfaction,1,2 and satisfaction ratings for following a conversation in noise in restaurants were the lowest compared to other situations. Utilization of visual cues can aid in speech understanding in noise, but restaurants often do not provide adequate lighting for patients who rely on visual cues for speech reading and seating arrangements can be problematic. It is commonly suggested to those who wear hearing aids that they use a strategy of “sitting with the noise behind you.” While this is moderately effective as shown in testing of directional microphone benefits,3 it is not always feasible due to limited seating options, the presence of multiple noise sources, and the inherent reverberant nature of restaurants.
Another situation where external factors are beyond the control of the hearing aid wearer is in the car. External noise is again a factor, but what distinguishes the car environment from a noisy restaurant is the near-complete absence of visual cues. Regardless of seating arrangement, visual cues are lacking, and speech can often be directed away from the hearing aid user. Without visual cues, hearing aid users cannot use speechreading, which has been shown to provide an additional 4-6 dB SNR improvement in noisy environments. Without visual cues, the patient is already at a disadvantage. The hearing aid user may be at additional disadvantage as the seating arrangement may result in a severely reduced speech signal, either because the hearing aid user is seated behind the target speaker or due to physical obstructions between the speaker and the hearing aid user.
Beyond the lack of visual cues and reduced amplitude of the desired speech, road noise presents another issue. Not only does driving introduce added noise, but the added noise may trigger a directional microphone setting in the user’s hearing aids, making it more difficult to understand the speaker or forcing the hearing aid user to turn his or her head towards the target speaker—which is especially not desirable if the hearing aid user is the one driving!
Remote microphone technology can offset the loss of visual cues by bringing the target speech in clearer and directly to the hearing aids. As noted before, the performance of remote microphone technology is a significant improvement in noisy environments over hearing aids alone, providing more SNR benefit than visual cues alone or directional microphones can. As an improvement over ReSound’s Mini Mic, ReSound’s Multi Mic provides additional noise reduction by entering a “Directional Mode” when worn vertically in the presence of noise. The directional response is directed towards the speaker’s mouth to preferentially amplify their voice, while not impacting other aspects of the hearing aid sound processing. The microphone can be clipped on the target talker (see image) or passed among multiple talkers, keeping the hearing aid user connected to the conversation even if someone is speaking from the back or a side seat of the car. It can also dramatically reduce the hearing aid wearer’s need to turn towards the talker—which means one less distraction for the driving hearing aid user.
Listening from a distance presents its own challenges for hearing aid users. Typically, listening at a distance introduces some degree of reverberation, due to the size of the room, lecture hall, or place of worship. Similar to the car environment, listening at a distance effectively negates the benefits of visual cues, as the hearing aid user likely is not sitting close enough to take cues from the speaker’s face.
The final challenge is the most obvious: the speaker will sound softer to the listener than a typical face-to-face conversation. As the Inverse Square Law dictates, the SPL of any sound will decrease 6 dB with the doubling of the distance from the sound source. Given the size of many places of worship and lecture halls and the possibility of sitting in a new spot each week, the hearing aid user may be receiving a severely lower input compared to the initial signal. Most places of worship have sound systems, but can result in additional issues for the hearing aid user. Many lecture halls or classrooms do not utilize a sound system.
Remote microphone technology can alleviate the strains associated with listening at a distance, because the sound is brought directly into the hearing aids from near the speaker’s mouth—negating the reduction in volume and the addition of reverberation. Multiple studies have shown that the benefits of remote microphone technology do not dissipate when the distance between the remote microphone and the hearing aid user is increased, as long as it is within the working range of the remote microphone transmission protocol. The aforementioned research by Rodemerk and Galster shows that remote microphone technology provides significant improvement in speech perception in noise compared with hearing aids alone, even at a distance of 12 feet.
Research by Jespersen took that one step farther—well, actually several steps farther —by testing the ReSound Mini Mic, which utilizes 2.4 GHz wireless technology, testing the technology at 6 meters (almost 20 feet). They found no significant drop-off in performance in speech perception in noise when compared to shorter distances using the remote microphone technology. This research also found that the remote microphone significantly outperformed hearing aids alone —even in a directional microphone setting at these distances. With the ReSound Multi and Micro microphones, the range is increased so the target speaker can be up to 30 meters (>90 feet) away from the hearing aid user and within a clear line of sight, and the patient can still receive the benefits of the remote microphone technology.
Remote microphone technology is a proven effective method of maximizing the help hearing aids can provide in the most demanding scenarios. Users can reconnect to their favorite activities even in the face of background noise, limited visual cues, speech at a distance, and in multiple talker activities. In real world terms, that means going back to restaurants they stopped going to, trying new places that were once too noisy, reconnecting on road trips and at family reunions, hearing a lecture, chatting on the golf course, and everything else life brings.
Image credit: Hearing Review
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Kochkin S. MarkeTrak VIII: Consumer satisfaction with hearing aids is slowly increasing. Hear Jour. 2010:63(1):19-27.
Bentler R. Effectiveness of directional microphones and noise reduction schemes in hearing aids: A systematic review of the evidence. J Am Acad Audiol. 2005:16(7):473-484.
Abrams H, Kihm J. An Introduction to MarkeTrak IX: A new baseline for the hearing aid market. Hearing Review. 2015:22(6):16-21.
Summerfield Q. Lipreading and audio-visual speech perception. Transactions Royal Soc London B: Biolog Sci. 1992: 335(1273):71-78.
Boothroyd A. Hearing aid accessories for adults: The remote FM microphone. Ear Hear. 2004:25:22-33.
Rodemerk K, Galster J. The benefit of remote microphones using wireless protocols. J Acad Audiol. 2015:26:724-731.
Jespersen CT. A review of wireless hearing aid advantages. Hearing Review. 2012:19(2):48-55.
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