Australasian Science: Australia's authority on science since 1938

Keeping the Noise Down

Credit: psdesign1/Adobe

Credit: psdesign1/Adobe

By Gary Housley

Transgenic mice have revealed how the cochlea protects itself from loud noise and why some people may be more susceptible to hearing loss than others.

The full text of this article can be purchased from Informit.

Hearing loss is the most prevalent sensory disability in our society and the second leading cause of disability after depression, reflecting a larger non-fatal burden than alcohol-related health issues, osteoarthritis and schizophrenia (www.tinyurl.com/ofzpqfu). Hearing loss is getting worse in our society because we are exposing our ears to more noise over our lifetime, and this stress exacerbates hearing loss with ageing.

It’s now possible to examine differences in the vulnerability of hearing to noise stress in the lab by measuring hearing in mice with particular gene mutations. Using this approach, we have identified new aspects of cochlear physiology that explain why some people may be more susceptible to hearing loss than others.

The Amazing Process of Hearing

The middle ear ossicles, which are the smallest bones in our body, transfer the sound vibrations collected by the ear drum to our cochlea, causing tiny bundles of hairs to flex. This flexing causes small ion channels at the tips of the hair bundles to open and let positive ions from the surrounding fluid enter for just long enough to trigger the release of glutamate neurotransmitter. Glutamate receptors on cochlear nerve fibres detect the neurotransmitter and trigger action potentials that travel along the...

The full text of this article can be purchased from Informit.