It’s hard to imagine that scientists and researchers don’t already know everything about the human body, but it’s true. In fact, researchers at Massachusetts Institute of Technology just discovered something that completely changes what experts thought they knew about the inner ear’s role in hearing.
The recent MIT research is centered around the tiny tectorial membrane, which is a gelatin-like structure inside the cochlea. They found that it’s function is more important than previously thought: It is able to selectively pick up and send energy to various parts of the cochlea using a certain type of wave.
Researchers have known for more than 50 years that sound waves are converted into up and down waves in the cochlea, which then travel along the basilar membrane as part of the complex function of hearing. But the MIT researchers discovered a side-to-side wave – previously unknown – that travels along the tectorial membrane, which plays a role in stimulating the hair cells that send sounds to the brain.
It seems complicated, but the MIT researchers believe that these waves are stimulated at the same time to excite the hair cells around them, making them very sensitive to sound. They think this dual-wave process is what makes the ear capable of hearing whispers and to picking out and understanding a single voice, even in very noisy environments, or pinpointing a single instrument that is out of tune in a large band.
Roozbeh Ghaffari, the lead author of the paper and graduate student in the Harvard-MIT Division of Health Sciences and Technology, said that the research is important for both medical experts and people with hearing loss in the future:
“It really changes the way we think about this structure,” Ghaffari said of the previously overlooked tectorial membrane. The research found that the pore size and fluid viscosity of the membrane is essential to how it works, which could lead to future alterations of the nanopores using biochemical manipulations to make them more sensitive at discriminating frequencies..
Ghaffari alleged that this discovery could change the way hearing loss solutions are designed in the future:
“In the long run, this could affect the design of hearing aids and cochlear implants,” he said.
Though those solutions are likely far off, this research represents another exciting step in research on the ear and hearing loss.