Featured Research

from universities, journals, and other organizations

Music from the ear: Researchers show how an objective audiometric test can become even more reliable

Date:
January 10, 2013
Source:
Physikalisch-Technische Bundesanstalt (PTB)
Summary:
Not only can the human ear detect sounds, it can also generate them. If the ear hears the two upper tones of a major triad, it produces the fundamental of the chord which can then be measured. This phenomenon, called "otoacoustic emission" (OAE), is used by otologists for objective audiometric tests, e.g. in newborns. Researchers have shown that an OAE audiometric test becomes even more reliable if the two sounds are transmitted to the ear not via a loudspeaker, but by bone conduction.

Combined stimulation of otoacoustic emissions: the first tone is transmitted via air conduction (probe speaker in the ear), the second tone is conveyed via bone conduction (bone vibrator behind the ear).
Credit: PTB

Not only can the human ear detect sounds, it can also generate them. If the ear hears the two upper tones of a major triad, it produces the fundamental of the chord which can then be measured. This phenomenon, called "otoacoustic emission" (OAE), is used by otologists for objective audiometric tests, e.g. in newborns. Investigations at the Physikalisch-Technische Bundesanstalt (PTB) have shown that an OAE audiometric test becomes even more reliable if the two sounds are transmitted to the ear not via a loudspeaker, but by bone conduction.

Related Articles


Regardless of where people come from, whether they are Europeans or Asians, the human ear is always tuned to a major scale. If the ear hears the two upper tones of a major triad, the ear itself produces the third, lowest, tone of the chord. This tone is called "distortion product otoacoustic emission (OAE)" and is generated due to anatomic and physical laws: if the hair cells in the inner ear are healthy and sound, they are stimulated by the two matching tones to vibrate at a third frequency. This lower tone comes out of the ear again and can be measured by means of a highly sensitive microphone. With the aid of this phenomenon, it is possible to check objectively whether the hearing of newborns or infants is intact.

Such a test used to be performed using two tiny loudspeakers, each of which emitted a tone into the ear, as well as a miniaturized microphone, which recorded the third tone (if it came out at all). If this tone is not generated, physicians have a first inkling that the baby might need therapy or a hearing aid. However, it may be that the ear is healthy but does not "hum." This can be caused by a badly calibrated loudspeaker, or due to the fact that the loudspeakers which are placed close to each other emit standing waves into the auditory canal which weaken one of the two tones.

To preclude such malfunctions, alternative tone generation methods have been investigated at PTB within the scope of a DFG project: so-called "bone vibrators" which, in analogy to a tuning fork set onto the bone, convey the tone directly to the bone located behind the ear. The results have shown that both with two bone vibrators and in combination with a loudspeaker, correct otoacoustic emissions are generated. This not only allowed calibration errors to be reduced, but also provided physicians with improved differential diagnosis possibilities, since with the new procedure, they can test the function of the inner ear without a doubt and, potential damage of the middle ear, thus, has less influence. Clinical studies should follow.


Story Source:

The above story is based on materials provided by Physikalisch-Technische Bundesanstalt (PTB). Note: Materials may be edited for content and length.


Cite This Page:

Physikalisch-Technische Bundesanstalt (PTB). "Music from the ear: Researchers show how an objective audiometric test can become even more reliable." ScienceDaily. ScienceDaily, 10 January 2013. <www.sciencedaily.com/releases/2013/01/130110075408.htm>.
Physikalisch-Technische Bundesanstalt (PTB). (2013, January 10). Music from the ear: Researchers show how an objective audiometric test can become even more reliable. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2013/01/130110075408.htm
Physikalisch-Technische Bundesanstalt (PTB). "Music from the ear: Researchers show how an objective audiometric test can become even more reliable." ScienceDaily. www.sciencedaily.com/releases/2013/01/130110075408.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins