Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Better hearing with bone conducted sound

22.06.2009
New technology to hear vibrations through the skull bone has been developed at Chalmers University of Technology.

Besides investigating the function of a new implantable bone conduction hearing aid, Sabine Reinfeldt has studied the sensitivity for bone conducted sound and also examined the possibilities for a two-way communication system that is utilizing bone conduction in noisy environments.

A new Bone Conduction Implant (BCI) hearing system was investigated by Sabine Reinfeldt:

"This hearing aid does not require a permanent skin penetration, in contrast to the Bone-Anchored Hearing Aids (BAHAs) used today."

Measurements showed that the new BCI hearing system can be a realistic alternative to the BAHA.

Sound is normally perceived through Air Conduction (AC), which means that the sound waves in the air enter the ear-canal and are transmitted to the cochlea in the inner ear. However, sound can also be perceived via Bone Conduction (BC). Vibrations are then transmitted to the cochleae through the skull bone from either one's own voice, the surrounding sound field, or a BC transducer.

In two-way communication systems, BC is believed to improve the sound quality when used in extremely noisy environments which require hearing protection devices in the ear-canals.

Several studies were performed to investigate the possibilities for a BC communication system and to increase the general knowledge of BC sound perception.

The low-frequency increase in perceived BC sound when wearing ear-plugs and/or ear-muffs is called the occlusion effect. This effect was studied by different methods and it was found that it is lower for deeper insertion of ear-plugs and for larger ear-muffs, and that it varies for different stimulations.

The difference in sensitivity of the BC and AC parts of one's own voice was estimated, showing that the BC component dominated for most sounds between 1 and 2 kHz. To be able to measure the BC component of a person's own voice, a large ear-muff was developed to attenuate the AC sound and to minimize the occlusion effect.

The study also showed that the sensitivity difference between the BC and AC parts of one's own voice were different for different kinds of sounds, depending on where in the mouth the sound is produced and on the influence from the vocal cords.

Also estimated was the difference in sensitivity between BC and AC sound from a surrounding sound field, demonstrating that the BC part was 40 to 60 dB lower than the AC part. This measure gives the maximum attenuation achievable with ordinary hearing protection devices, like ear-plugs and ear-muffs. It also shows the possible noise reduction from the surrounding noise by using a BC microphone, instead of an ordinary AC microphone in front of the mouth, to record one's own voice in a noisy environment.

Moreover, the amount of BC sound reaching the cochleae from different positions of the skull bone was examined with the conclusion that relative BC hearing can be estimated from ear-canal sound pressure and cochlear vibrations.

The thesis "Bone Conduction Hearing in Human Communication - Sensitivity, Transmission, and Applications" was defended in public on June 5, 2009.

More information:
Sabine Reinfeldt, Biomedical Engineering, Signals and Systems, Chalmers university of Technology, Göteborg
+46(0)31-772 80 63, +46(0)708-14 16 49
sabine.reinfeldt@chalmers.se
Pressofficer: Sofie Hebrand; +46 736-79 35 90; sofie.hebrand@chalmers.se
Tutors:
Bo Håkansson, Chalmers university of Technology, Göteborg
+46(0)31-772 18 07
Stefan Stenfelt, Linköping University
+46(0)13-22 28 56

Sofie Hebrand | idw
Further information:
http://www.chalmers.se
http://www.vr.se

More articles from Communications Media:

nachricht On patrol in social networks
25.01.2017 | Fraunhofer-Institut für Arbeitswirtschaft und Organisation IAO

nachricht Tile Based DASH Streaming for Virtual Reality with HEVC from Fraunhofer HHI
03.01.2017 | Fraunhofer-Institut für Nachrichtentechnik Heinrich-Hertz-Institut

All articles from Communications Media >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>