Researchers at the famed Massachusetts Institute of Technology (MIT) may have cracked the code on one of hearing’s most bewildering mysteries, and the insight could result in the modification of the design of future hearing aids.
Results from an MIT study debunked the idea that neural processing is what lets us single out voices. Isolating specific sound levels might actually be handled by a biochemical filter according to this study.
How our ability to hear is affected by background noise
Only a small fraction of the millions of people who suffer from hearing loss actually use hearing aids to deal with it.
Though a hearing aid can provide a significant boost to one’s ability to hear, environments with a lot of background noise have traditionally been a problem for individuals who use a hearing improvement device. For instance, the continuous buzz associated with settings like parties and restaurants can wreak havoc on a person’s ability to discriminate a voice.
If you’re a person who is afflicted with hearing loss, you very likely recognize how annoying and stressful it can be to have a one-on-one conversation with someone in a crowded room.
For decades scientists have been studying hearing loss. The way that sound waves travel through the ear and how those waves are differentiated, due to this body of research, was thought to be well understood.
Scientists discover the tectorial membrane
But the tectorial membrane wasn’t discovered by scientists until 2007. You won’t see this microscopic membrane made of a gel-like substance in any other parts of the body. What really intrigued scientists was how the membrane provides mechanical filtering that can decipher and delineate between sounds.
Minute in size, the tectorial membrane rests on little hairs within the cochlea, with small pores that manage how water moves back and forth in response to vibrations. Researchers observed that different frequencies of sound reacted differently to the amplification made by the membrane.
The middle tones were found to have strong amplification and the frequencies at the lower and higher ends of the spectrum were less impacted.
It’s that development that leads some scientists to believe MIT’s groundbreaking breakthrough could be the conduit to more effective hearing aids that ultimately allow for better single-voice identification.
Hearing aid design of the future
The basic concepts of hearing aid design haven’t changed very much over the years. A microphone to detect sound and a loudspeaker to amplify it are the basic components of hearing aids which, besides a few technology tweaks, have remained the same. This is, regrettably, where the drawback of this design becomes obvious.
All frequencies are boosted with an amplification device and that includes background noise. Tectorial membrane research could, according to another MIT researcher, result in new, state-of-the-art hearing aid designs which would offer better speech recognition.
In theory, these new-and-improved hearing aids could functionally tune in to a distinct frequency range, which would permit the user to hear isolated sounds like a single voice. Only the chosen frequencies would be boosted with these hearing aids and everything else would be left alone.
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References
https://www.machinedesign.com/motion-control/researchers-discover-secret-how-we-can-pick-out-voice-crowd
http://www.xinhuanet.com/english/2019-01/16/c_137749535.htm
https://medicalxpress.com/news/2010-11-tuning-mechanism.html