Friday, November 19, 1999 Published at 13:02 GMT
New hearing test unveiled
Standard hearing tests could be replaced by a more accurate method
A new hearing test which monitors reflexes in the ear rather than reaction to sounds has been pioneered by scientists.
Experts in Nebraska, USA, have developed the technique, called wide-band reflectance, and say it could be an improvement on standard tests.
The traditional audiogram method relies on patients giving a response to a series of tones, which may not give an accurate reading in young children.
The new test detects an acoustic reflex in the middle ear at lower sound levels - at least 10 decibels lower than standard testing, according to Ohio University audiologist Patrick Feeney.
It emits a series of eight chirping sounds into the ear canal and a computer analysis then shows how well the middle ear has reacted to the sounds.
It could be used to detect middle ear infections, such as glue ear, and other conditions like hardening of the ear bones and facial nerve paralysis.
The traditional examination, using a low frequency 226 hertz tone does not always give the full story, argues Mr Feeney. The wide-band reflectance technique uses a range of 250 to 8,000 hertz allowing a disorder, present at higher frequencies to be measured.
Mr Feeney, who presented his findings on Friday at the American Speech-Language-Hearing Association's annual convention in San Francisco, said: "If we can indicate that a person's reflex is present, it indicates that the middle ear is working well.
"The reflectance technique allows the audiologist to measure the function of the middle ear over the frequency range important for hearing speech."
Professor Mark Haggard at the Medical Research Council's Institute of Hearing Research in Nottingham questioned whether the new technique would necessarily improve diagnoses for patients.
"I have not seen any real evidence that the extra information you receive makes a material impact on the decision you make about the patient," he said.
Current tests were effective and substantial evidence of an improvement would be needed to justify change, he added.
A spokesman for the Royal National Institute for the Deaf said: "There are systems in pace at the moment for testing hearing. We are happy to look at new ideas that come up but we need to wait for further research to be carried out."