For more than 50 years, it has been known that sound waves in the inner ear move up and down. Now, scientists from the Massachusetts Institute of Technology, MIT, have discovered that some inner ear sound waves move from side to side.
The sideways sound waves move along the tectorial membrane in the cochlea of the inner ear. The tectorial membrane is a tiny gelatinous structure. In spite of its small size it plays a big and previously unrecognized part in hearing, as it picks up and transmits energy to different parts of the cochlea via the side-to-side sound waves.
Better understanding of hearing
Scientists have so far been unable to explain in detail how the ear receives and discriminates between sounds. What, for instance, makes us able to hear a soft whisper or a single instrument out of tune in a symphony orchestra? The new knowledge of the movement of sound in the inner ear may bring us one step closer to an explanation.
The researchers at MIT hope that their discovery of the importance of the tectorial membrane and sideways sound waves may lead to improvements in hearing aids and cochlear implants. The new knowledge may also lead to advances in treating people with hearing loss related to the tectorial membrane.
Source: MIT news, 10 October 2007.