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

nachricht Product placement: Only brands placed very prominently benefit from 3D technology
07.07.2016 | Alpen-Adria-Universität Klagenfurt

All articles from Communications Media >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>