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01_20_05

New Short Electrode Will Allow Greater Benefit from Cochlear Implants

Background: Cochlear implants are commercially available miniature hearing prostheses capable of assisting those who are profoundly deaf or severely hearing impaired. Approximately 60,000 individuals all over the world have received cochlear implants. The implant bypasses damaged or missing hair cells to send electrical signals through an array of electrodes within the cochlea (inner ear). Current cochlear implants send sound information that covers the entire frequency range. In order to send both high and low frequency information, the electrodes of the cochlear implant are inserted as far into the cochlea as possible. Unfortunately, inserting the electrodes into the cochlea compromises any residual (remaining) hearing the individual may have had prior to implantation.

Illustration of cochlear implant.
Cochlear implant.
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Advance: Consequently, scientists developed a new shorter electrode to help an additional population of individuals with hearing loss. These individuals have a considerable amount of residual hearing and their primary hearing loss is in sounds in the high frequency range. They are also experienced, yet unsuccessful, adult hearing aid users with severe-to-profound hearing impairment who would not have been conventional cochlear implant candidates. The short electrode is inserted into the base (or bottom) of the cochlea to restore hearing at high frequencies, while preserving low frequency hearing, or residual hearing, in the apex (or top) of the implanted ear.

Implications: The preliminary data demonstrates residual hearing can be preserved with this short electrode, and provides evidence that this is most beneficial for understanding speech in a noisy background. Furthermore, the innovative short electrode may be an ideal treatment for those with presbycusis, which is the loss of hearing that gradually occurs in most individuals as they grow older. Therefore, this new electrode design allows many more people with some degree of hearing loss to benefit from cochlear implant technology.

Gantz BJ, Turner CW. Combining Acoustic and Electric Hearing. Laryngoscope 113:
1726–1730,2003.

Turner CW, Gantz BJ, Vidal C, Behrens A. Speech Recognition in Noise for Cochlear Implants
Listeners:Benefits of Residual Acoustic Hearing. In Press.

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