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Professor Alan R. Palmer
The sounds around us vary a lot in loudness and in frequency (also known as pitch), but the human ear is a remarkable device that is highly sensitive to a wide range of sounds. A key part of the ear is an organ called the cochlea, which divides up the very complicated waveform of sounds that we hear into a series of overlapping frequency channels. Each fibre in the auditory nerve has to provide information to the brain about how loud an incoming sound is, when it was heard, and its frequency content. When the ear's hair cells or nerves do not function correctly, a type of hearing loss called 'sensorineural' hearing loss results. This makes it harder to hear quiet sounds because hearing thresholds are elevated, and it is also harder to hear pitch due to a broadening of the frequency filtering. When this happens hearing aids can improve our ability to detect quieter sounds, but they donâ€™t do a good job of enabling us to understand what frequency of sound we heard, because they do not restore the sharp frequency filtering. However, in profound deafness a cochlear implant can be used to by-pass the complex frequency analysis that happens in the human cochlear by stimulating nerve fibres directly, yet still provide some frequency information. This device has been dramatically successful and over 100,000 are in use worldwide. Several other prosthetic devices have been developed to stimulate other parts of the auditory nervous system, but to-date none of these work as well as the cochlear implant.
NO TICKETS REQUIRED!
When? 6-7 pm
Where? Maths & Physics Building (B1)
University Park Campus
For more information, contact (e.g.) Dr. Boris Haeussler
The University of NottinghamUniversity Park
Nottingham NG7 2RD
telephone: +44 115 951 5183
fax: +44 115 951 5180