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

nachricht NASA Goddard network maintains communications from space to ground
02.03.2016 | NASA/Goddard Space Flight Center

All articles from Communications Media >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>