| Researchers at the Center
for Wireless Integrated MicroSystems (WIMS), an NSF-funded Engineering
Research Center (ERC), have been working with academic and private-sector
partners over the past year to join thin-film electrode arrays with backing
structures that permit their deep insertion into the scala tympani and
position the electrodes close to auditory neurons along the length of the
cochlea. WIMS has developed an advanced 32-site cochlear implant
with sites on 250µm centers as a prototype for a 128-site human array.
This is eight times the number of sites currently available in the marketplace.
However, backing the arrays to provide the stiffness and curl needed for
deep insertion has represented a barrier to the development of thin-film
arrays capable of restoring hearing to the deaf in the past. This
problem must be solved to successfully test thin-film electrode arrays
and realistically assess the improvements in pitch perception made possible
using them.
WIMS core partners the University
of Michigan (UM), where the ERC is headquartered, Michigan State University,
and Michigan Technological University (MTU) have been collaborating with
the University of California at San Francisco, the University of California
at Irvine, and Cochlear Corporation on attaching molded backing structures
to the Center-developed parylene arrays to try to achieve this advance.
MTU researchers have attached
articulated polyethylene therephthalate (PET) tubes to electrode arrays
in the past, but this is the first time molded backing has been successfully
applied to make the thin-film arrays similar to commercial wire bundles
in terms of their insertion characteristics. The UM is also working
on backing structures, focusing on a monolithic process that would realize
the needed compliance with just enough built-in stress to allow the array,
at rest, to hug the modiolar wall of the cochlea.
The work done by the ERC
in conjunction with other academic and private sector partners will eventually
improve the cochlear implants by providing more stimulating sites to improve
the quality of sound delivered through cochlear implants, so that the hearing
impaired can hear pitch more realistically and enjoy music more fully. |
