Facility hones in hearing

A new research and training facility within the School of Audiology and Speech Sciences will help clinicians assess and rehabilitate children and adults with hearing loss more effectively.

Research projects at the Human Auditory Physiology Laboratory will fall into three major areas, says Prof. David Stapells who heads up the facility: developing techniques for measuring hearing thresholds in infants; understanding how hearing loss affects brain activity, processing and perception; and investigating the brain's normal and impaired coding of sound changes in pitch, loudness or duration and locating where in the brain those changes are registered and perceived.

The lab will also train students in the latest techniques in hearing measurement.

Threshold levels of hearing are usually measured behaviourally, however, in young children and infants, such measures are difficult or impossible to obtain.

By focusing on electro-physiological measurement, which tracks electrical brain waves recorded from the top of the head in response to sound, the lab will improve audiologist's ability to diagnose and fit hearing aids in children.

In the lab, research participants are connected to an amplifier by an `electrocap,' a cloth cap studded with electrodes. The electrodes measure how, when, and where in the brain sounds are being received painlessly.

But measuring hearing thresholds is only the beginning.

A recent study at the lab measured how people using hearing aids discriminate word sounds. Even though behavioural responses were nearly perfect, many individuals actually required more brain time to process speech. Brain wave measures showed that processing slows down as sound moves up the brain's auditory pathways. Understanding how hearing affects perception may help audiologists develop more refined treatment.