Researchers at the famed Massachusetts Institute of Technology (MIT) may have cracked the code on one of hearing’s most bewildering mysteries, and the revelation could result in the modification of the design of future hearing aids.
Results from an MIT study debunked the belief that neural processing is what allows us to pick out voices. Isolating specific levels of sound may 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 individuals who suffer from hearing loss actually use hearing aids to deal with it.
Though a major boost in one’s ability to hear can be the result of using a hearing aid, people who use a hearing-improvement device have traditionally still struggled in settings with copious amounts of background noise. For instance, the steady buzz surrounding settings like restaurants and parties can wreak havoc on a person’s ability to single out a voice.
If you’re a person who is experiencing hearing loss, you very likely understand how frustrating and stressful it can be to have a personal conversation with someone in a crowded room.
Scientists have been closely studying hearing loss for decades. The way that sound waves travel through the ear and how those waves are distinguished, due to this body of research, was thought to be well understood.
The Tectorial Membrane is Identified
But the tectorial membrane wasn’t identified by scientists until 2007. You won’t see this microscopic membrane composed of a gel-like substance in any other parts of the body. The deciphering and delineation of sound is achieved by a mechanical filtering carried out by this membrane and that might be the most fascinating thing.
Minute in size, the tectorial membrane rests on tiny hairs within the cochlea, with small pores that control how water moves back and forth in response to vibrations. It was observed that the amplification created by the membrane caused a different reaction to different tones.
The tones at the highest and lowest end of the spectrum seemed to be less affected by the amplification, but the study found strong amplification in the middle frequencies.
Some scientists believe that more effective hearing aids that can better identify individual voices will be the outcome of this groundbreaking MIT study.
Hearing Aid Design of The Future
The basic principles of hearing aid design haven’t changed very much over the years. Adjustments and fine-tuning have helped with some enhancements, but most hearing aids are basically comprised of microphones which receive sounds and a loudspeaker that amplifies them. Unfortunately, that’s where one of the design’s drawbacks becomes clear.
Amplifiers, normally, are not able to discern between different frequencies of sounds, because of this, the ear receives increased levels of all sounds, including background noise. Another MIT scientist has long believed tectorial membrane exploration could result in new hearing aid designs that provide better speech recognition for users.
In theory, these new-and-improved hearing aids could functionally tune in to a distinct frequency range, which would enable the user to hear isolated sounds like a single voice. Only the desired 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
