How our ears determine sound location finally solved

12 May 2015

For decades, how our ears were able to detect where sound was coming from was a total mystery, but now a new study has found an answer in the ear’s array of minute hairs.

The team from the University of New South Wales (UNSW) had set out to discover what allows us to recognise when a sound moves from one ear to the other and that’s important not just for how we are able to locate where the sound is coming from, but also offers protection against loud sounds in one ear.

Known as the olivocochlear reflex, the biological process and what drives the neural reflex linking the cochlea of each ear to the brain’s controls was the missing link but, according to Medical Xpress, the cochlear’s outer hair cells are the key to its ability.

Aside from allowing sound to be amplified, allowing us to hear sound, the cells also provide sensory information, controlling this sound amplification with the help of auditory nerve fibres, the previous missing link.

Leading the way for better future hearing aids

A process of elimination in determining what was the key factor was found following replications of the test on mice, which found that their lack of this nerve fibre connection meant they could not switch the auditory sensor to the other ear.

Given these findings, the researchers believe it could be related to our gradual loss of hearing with age as the fibre connections gradually break down over time.

“With this new information, it could pave the way for much more accurate hearing aids, making them capable of working together,” said senior researcher in the group, Prof Gary Housley.

“The ultimate goal is for cochlear implants in both ears to communicate with each other so that the brain can receive the most accurate soundscape possible.

“This research will help us move closer to that goal.”

Loud noise sign image via C.C. Chapman/Flickr

Colm Gorey was a senior journalist with Silicon Republic