But, if you have some form of hearing problem in at least one ear, this ability is disrupted and the brain struggles to tell one sound from another.

The key to understanding this ability lies in the brain. Scientists are currently trying to work out exactly what part of the brain is responsible and how it allows us to distinguish one sound from lots of noise. Early research has had some remarkable results.

Most mammals also have this ability and in 2006, scientists working in the Oxford Auditory Neuroscience Group found that spatial hearing in ferrets has the ability to bounce-back or adapt to a hearing loss over time. Their brains are being "trained" to cope with the hearing loss and distinguish sounds much better.

The Oxford study placed healthy ferrets in a "ring of sound" where a sound is played from one of 12 speakers placed in a circle around the ferret and their response is monitored to see if they can detect which speaker the sound is coming from. Ferrets with normal hearing are very good at this and have excellent spatial hearing.

The team then fitted each of the ferrets with a small earplug in one ear which blocks some of the sound and so mimics a hearing loss. They then got the ferrets to perform the same task twice a day for two weeks and made a startling discovery. At first, the ferrets' ability to identify where the sound was coming from was dramatically reduced (because their spatial hearing had been disrupted by the earplug) but after two weeks they regained their ability and by the end of the period were as good at detecting the location of the sounds as they were before being fitted with an earplug.

Something in their brain was changing or adapting to the new situation and they were l
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Contact: David Reid
david.reid@deafnessresearch.org.uk
44-207-837-8092
Deafness Research UK
6-Oct-2006