Neuroengineering

Audition, Speech and Bionic Ear Design

Audition (hearing) is the primary sense required for speech, and also plays a major role in language. Audition involves the transduction of sound waves from the ear drum in the outer ear to the cochlear in the inner ear. Within the cochlear vibrations associated with the sound waves are transformed into electrical signals which are relayed to the brain via neurons in the auditory nerve. The brain analyses these signals, giving rise to our perception of sounds and speech.

There are two common causes of hearing impairment. The first is a reduction in the ability to transduce vibrations from the outer to the inner ear. This requires a hearing aid to increase the amplitude of the sound waves entering the ear in order to compensate for the weak transduction of sound vibrations. The second is the inability of the inner ear to stimulate auditory nerve neurons to transmit sound information in the brain. This may arise either from a severe reduction in the ability to transduce vibrations from the outer to the inner ear, or from the inability to transform the sound vibrations into electrical signals at the inner ear/auditory nerve interface. The solution to the second problem has been the cochlear implant, which detects sound waves using a microphone, transforms these sound waves into electrical signals, and stimulates the auditory nerve so sound information can be transmitted to the brain.

The EEE department is involved in a collaboration with The Bionic Ear Institute to study a variety of problems associated with hearing. Research projects include: cochlear implant design, hearing-aid design, neural modeling of the auditory system, sound localization, speech processing, and speech recognition.

Research Projects

Speech Processing for Cochlear Implants

The cochlear implant has been implanted in thousands of people throughout the world. However, the benefit received from the implant varies considerably. Some people can obtain near perfect perception of speech while others struggle. This project will develop specialised signal processing techniques that will help to better distinguish the different speech sounds.

This research involves careful examination of speech perception by people using the implant. The results of these studies are used to design strategies which will provide the features to the cochlear more adequately and in a way that will improve their perception by the users.

This work is supported in part by the Australian Research Council and the National Health and Medical Research Council

Publications on Audition, Speech and Bionic Ear Design

Student projects in Audition, Speech and Bionic Ear Design

If you are interested in the neural modeling aspects of this research, please contact:
Anthony Burkitt
aburkitt@bionicear.org
+613 9667 7529

Or, if you are interested in the speech processing and bionic ear aspects of this research, please contact:
David Grayden
grayden@ee.unimelb.edu.au
+613 8344 5234