Audiology in Brief Research suggests that cochlear hair cells damaged by noise can be regenerated if intervention occurs within 10 days of noise exposure. Scientists at Creighton University (Neb.) and the Chinese PLA General Hospital (Beijing) subjected guinea pigs to an impulse noise simulating gunfire, causing severe hearing loss. Electron microscopy showed ... News in Brief
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News in Brief  |   March 01, 2010
Audiology in Brief
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Hearing Disorders / News in Brief
News in Brief   |   March 01, 2010
Audiology in Brief
The ASHA Leader, March 2010, Vol. 15, 5. doi:10.1044/leader.NIB.15032010.5
The ASHA Leader, March 2010, Vol. 15, 5. doi:10.1044/leader.NIB.15032010.5
Math1 to the Rescue
Research suggests that cochlear hair cells damaged by noise can be regenerated if intervention occurs within 10 days of noise exposure.
Scientists at Creighton University (Neb.) and the Chinese PLA General Hospital (Beijing) subjected guinea pigs to an impulse noise simulating gunfire, causing severe hearing loss. Electron microscopy showed extensive stereocilia damage throughout the inner ear. However, when the researchers injected math1—a key gene for the development of hair cells—into the inner ear within a week after the damage, the stereocilia were able to regenerate. The regenerated stereocilia were able to convert sound vibrations into electrical signals. Tissue culture studies will be conducted to determine whether these findings are supported at the cellular level.
The research was presented at the 2010 Midwinter Meeting of the Association for Research in Otolaryngology on Feb. 6–10. Visit The Association for Research in Otolaryngology’s Web site for more information.
Age and Bilateral Cochlear Implants
The age at which a child receives the first implant is an important factor that determines whether the second implant will be effective. Researchers at the University of Colorado at Boulder, Arizona State University, and the Rocky Mountain Ear Center studied 38 children who received their first cochlear implant by 3.5 years of age and received their second implant between the ages of 1 and 17 years.
Measurements of auditory cortex neural activity showed that children who received their first implant before age 1.5 years responded well to the second implant, even if they received the second implant as late as 9 years of age.
Conversely, all of the children who received their first implant at age 2.5 or later did not respond as well to the second implant, regardless of when they received it.
The research was presented at the 2010 Midwinter Meeting of the Association for Research in Otolaryngology on Feb. 6–10. Visit The Association for Research in Otolaryngology’s Web site for more information.
Seeing How We Hear
A recent study of the auditory cortex using advanced imaging techniques shows a much more complex and chaotic picture of neural activity than the precise neuronal maps previously suggested, according to research published in the Jan. 31 online edition of Nature Neuroscience.
University of Maryland researchers used an “in vivo 2-photon calcium imaging” technique to provide a high-resolution picture of a large portion of the auditory cortex by injecting living mice with a dye that glows brightly when calcium levels rise, a key signal that neurons are firing. Specific regions of the cortex were selectively illuminated with laser to measure the activity of hundreds of neurons in response to simple tones of different frequencies.
By using different dyes, the researchers measured differences in how the neurons receive sound information (the inputs), and how they process that sound (the outputs). Neighboring neurons that received the same inputs were previously assumed to produce the same outputs, but the researchers found greater individuality. Their research suggests that there is very little redundancy in the function of auditory cortex cells, perhaps because our acoustic environment changes much faster than our visual environment and we must constantly adapt to new situations. Visit Newswise for more information.
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March 2010
Volume 15, Issue 3