Audiology in Brief Modern hearing aids, although quite sophisticated, still do not faithfully reproduce sound as perceived by people with normal hearing. New findings at the Weizmann Institute of Science shed light on a crucial mechanism underlying pitch perception, which may have implications for better hearing aid design. Research by Itay Rousso ... News in Brief
Free
News in Brief  |   May 01, 2007
Audiology in Brief
Author Notes
Article Information
Hearing Disorders / News in Brief
News in Brief   |   May 01, 2007
Audiology in Brief
The ASHA Leader, May 2007, Vol. 12, 5. doi:10.1044/leader.NIB.12072007.5
The ASHA Leader, May 2007, Vol. 12, 5. doi:10.1044/leader.NIB.12072007.5
One Membrane, Many Frequencies
Modern hearing aids, although quite sophisticated, still do not faithfully reproduce sound as perceived by people with normal hearing. New findings at the Weizmann Institute of Science shed light on a crucial mechanism underlying pitch perception, which may have implications for better hearing aid design.
Research by Itay Rousso of the Weizmann Institute’s Structural Biology Department, which recently appeared in the Oct. 3, 2006, Proceedings of the National Academy of Sciences (PNAS), suggests that the tectorial membrane, which communicates between the outer hair cells and the inner hair cells, responds to different frequencies.
Rousso and colleagues, together with researchers at the Ben-Gurion University of the Negev, tested the resistance of the gel-like tectorial membrane at various points to assess rigidity or flexibility. They found that the level of rigidity varies significantly along the length of the membrane, with one end up to 10 times more rigid than the other.
These differences occur in the part of the membrane that is in direct contact with the outer hair cells. Observation revealed that this variation is due to changes in the arrangement of the protein fibers. At one end, they form a flimsy, net-like structure that allows the membrane to be flexible; on the rigid side, the fibers are densely and uniformly packed.
The more rigid a tectorial membrane, the higher the frequency at which it can vibrate. Thus, the rigid end of the membrane is found near hair cells that transmit high frequencies and the flexible end is found near hair cells that respond to low-frequency vibration. This spatial separation, say the scientists, translates into the ability to distinguish between sounds of different frequencies. The new understanding of the mechanics of hearing may assist in the development of better hearing aids. Download the article from PNAS archives.
More Hearing Aid-Compatible Phones Ahead
A consensus between groups representing people with hearing loss and the wireless industry will increase the number of hearing aid-compatible (HAC) telephones over the next few years.
This landmark agreement marks the first time since efforts to achieve HAC telephones began in 1973 that consumers and industry reached consensus without federal oversight.
Consumer organizations sought to find common ground with industry to develop rules that consider the technical challenges facing industry while addressing accessibility needs of hearing aid and cochlear implant users.
The agreement will:
  • Increase the number of telecoil-compatible phones

  • Ensure that consumers will benefit from new technology from the outset

  • Facilitate research to improve audio output and volume control on telephones

  • Ensure a variety of accessible telephones with different prices, features, and styles

  • Provide increased availability of M-rated phones for all people with hearing loss

  • Ensure a new portfolio of accessible phones each year

The proposal was presented to the Federal Communications Commission on April 23, 2007. The FCC has taken the proposal under advisement and is awaiting further input on a few data points. Visit ATIS’ Web site for a copy of the April 23, 2007, Exparte Letter and Executive Summary and Consensus Proposal.
0 Comments
Submit a Comment
Submit A Comment
Name
Comment Title
Comment


This feature is available to Subscribers Only
Sign In or Create an Account ×
FROM THIS ISSUE
May 2007
Volume 12, Issue 7