Audiology: Research and Resources A brain imaging device under development may improve audiologists’ ability to assess accurately the effectiveness of a baby’s cochlear implant and fine-tune the program—even before the child can speak—to give babies the best hearing possible to assist with language development. The system will use magnetoencephalography (MEG) to measure ... Research in Brief
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Research in Brief  |   March 01, 2011
Audiology: Research and Resources
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Hearing Disorders / Research in Brief
Research in Brief   |   March 01, 2011
Audiology: Research and Resources
The ASHA Leader, March 2011, Vol. 16, 21. doi:10.1044/leader.RIB.16032011.21
The ASHA Leader, March 2011, Vol. 16, 21. doi:10.1044/leader.RIB.16032011.21
Audiology: Research
Brain Imaging and CIs in Infants
A brain imaging device under development may improve audiologists’ ability to assess accurately the effectiveness of a baby’s cochlear implant and fine-tune the program—even before the child can speak—to give babies the best hearing possible to assist with language development.
The system will use magnetoencephalography (MEG) to measure the magnetic fields generated by a child’s brain during cognitive processing. However, if used with cochlear implants, the MEG system would be “overwhelmed with the powerful signals emitted by its electronic components,” according to Stephen Crain, from Macquarie University’s Centre for Cognitive Science.
For a MEG system to be used with cochlear implants, researchers will need to develop a way to shield the MEG sensors from the cochlear implant. Such a device is being developed through a collaboration among Macquarie University and other Australia-based organizations, including Cochlear Limited, National Acoustic Laboratories, and the Commonwealth Scientific and Industrial Research Organisation, and the Kanazawa Institute of Technology in Japan. Visit the Macquarie University website for more information.
Function of Molecule That Underlies Deafness Revealed
The discovery that a molecular mechanism underlying some types of congential deafness may be caused by a mutation of a specific microRNA called miR-96 could provide the basis for treating progressive hearing loss and deafness.
United Kingdom researchers found that the mutation in miR-96 prevents development of the auditory sensory hair cells, which are essential for encoding sound as electrical signals that are then sent to the brain.
The research was based on studies of mice, which do not normally hear until about 12 days after birth. Prior to this age their immature hair cells must execute a precise genetic program that regulates the development of inner and outer hair cells. Hair cell development was arrested around birth in a strain of mice that carry a single base mutation in the miR-96 gene.
The study shows that miR-96 normally regulates hair cell development by influencing the expression of many different genes associated with a wide range of developmental processes at a specific stage. The researchers discovered that the mutation hinders the development not only of the mechanically sensitive hair bundle on the cell apex, but also of the synaptic structures at the base that govern transfer of electrical information to sensory nerves. These new findings suggest that miR-96 is a master regulator that coordinates the development of sensory cells that are vital to hearing.
Because the mutation is known to cause human deafness and microRNA molecules can be targeted by drugs, the work raises new opportunities for developing treatments for congenital hearing loss. Search “Marcotti” at the Proceedings of the National Academy of Sciences website.
Tinnitus and Neural Networks
Researchers at Georgetown University Medical Center hypothesize that tinnitus may be produced by an unfortunate confluence of structural and functional changes in the brain. According to the study, the phantom ringing heard by about 40 million people in the United States today are caused by brains that try—but fail—to protect their human hosts against overwhelming auditory stimuli. Researchers add that the same process may be responsible for chronic pain and other perceptual disorders.
The researchers say that the absence of sound from hearing loss in certain frequencies—due to normal aging, loud-noise exposure, or an accident—forces the brain to produce sounds to replace what is missing. Tinnitus results when the brain’s limbic system, which is involved in processing emotions and other functions, fails to stop these sounds from reaching conscious auditory processing.
“We believe that a dysregulation of the limbic and auditory networks may be at the heart of chronic tinnitus,” said neuroscientist Josef P. Rauschecker, the study’s lead investigator. “A complete understanding of and ultimate cure for tinnitus may depend on a detailed understanding of the nature and basis of this dysregulation.”
Using functional magnetic resonance imaging (fMRI), the researchers tested 22 volunteers, half of whom had been diagnosed with chronic tinnitus. They found moderate hyperactivity in the primary and posterior auditory cortices of tinnitus patients; the nucleus accumbens exhibited the greatest degree of hyperactivity, specifically to sounds that were matched to the patient’s lost frequencies. Search “Rauschecker” at Neuron’sonline journal.
Audiology: Resources
ASHA’s audiology webpage offers links to survey reports, patient education materials, discussion forums, practice policies, and links to journal articles.
General Information
  • News and announcements

  • Audiology event calendar

ASHA Practice Policy
  • Code of Ethics

  • Scope of Practice

  • Preferred Practice Patterns

Practice Settings
  • Educational/pediatric

  • Private practice

  • Hearing conservation/occupational

  • Health care

Practice Management
  • Frequently asked questions

  • Survey reports

  • Patient education materials

  • Quality improvement

  • Evidence-based practice guidelines and systematic reviews

  • ProSearch

  • Billing and reimbursement

  • Professional consultation

Connections to Colleagues
  • Special interest groups

  • Audiology e-mail list

  • Audiology discussion forums

  • Member directory

  • ASHA’s Classroom Acoustics Coalition on Facebook

  • ASHA and Council on Education of the Deaf (CED) Joint Committee

Publications
  • American Journal of Audiology

  • Perspectives

  • Audiology Connections

  • Access Audiology

Certification
  • Audiology certification standards

  • Frequently asked questions about audiology certification

  • Clinical specialty recognition

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March 2011
Volume 16, Issue 3