Northeast Florida Medicine
Vol. 66, No. 1 2015
57
Otolaryngology
chain to amplify the sound.
18
Unfortunately, the cost for this
device is significant and beyond the means of most patients.
Some of these patients will have a progressive hearing loss,
whichmay limit the effectiveness of this device as the hearing
loss progresses further. Another implantable hearing device
approved by the FDA is the Vibrant Soundbridge, which
is produced by MED-EL.
18
This device couples to the long
process of the incus and has a floating mass transducer that
moves the incus in response to the sound. This implantable
device consists of the battery and microphone located back
behind the ear. Another device approved by the FDA utilizes
a rare earth magnet attached to the long process of the incus.
This device was originally the Soundtech device, and the
rights to this device have been purchased by Ototronics. It
is currently called the Maxum device. A limited number of
patients have taken advantage of these implantable treatment
options to this point.
18
An exciting option that has been around for several years
and has undergone additional refinement is bone-anchored
amplification. These devices couple with the bone directly
transmitting the sound to the cochlea completely bypassing
the ear canal and ossicular chain. These devices are extreme-
ly helpful for patients with a conductive hearing loss or a
mixed hearing loss. The most common devices in use today
are the Cochlear Corporation Bone Anchored Hearing Aid
(BAHA) or the Bone Anchored Hearing device produced
by Oticon Medical, the Oticon Ponto. Traditionally, these
devices have had an abutment that comes out through the
skinwith a vibrating processor that attaches to the abutment.
Recently, Sophono, a Swiss company, and the Cochlear
Corporation have introduced bone-conducting devices
without an abutment coming through the skin. Both the
Cochlear Corporation device, called the BAHA Attract and
the Sophono device have a magnet implanted under the skin
in the postauricular region. These devices are only useful for
patients who have a conductive hearing loss with essentially
normal cochlear function.
Cochlear Implants
Cochlear implants have undergone significant and pro-
gressive improvement during the past 40 years.These devices
allow transduction of the acoustic signal to an electrical
signal, which is delivered directly to the remaining auditory
elements in the cochlea. There are currently three cochlear
implant companies with FDA approval in the US: MED-
EL, Cochlear and Advanced Bionics. As of December 2012,
324,200 people worldwide have received cochlear implants
with approximately a third of those being in the US.
19
There
are 58,000 adults with cochlear implants and 38,000 children
with cochlear implants in the US.
19
While cochlear implants were initially developed for pa-
tients with a complete loss of hearing, progressive improve-
ment in the function of the cochlear implants has allowed
patients with residual hearing to improve their hearing with
the implants. Hearing preservation with cochlear implant
surgery has been refined significantly in the past few years.
Remarkably, 90 percent of patients with residual hearing
can have some or all of their hearing preserved when they
receive their cochlear implant.
20
Recent approval of the Hy-
brid cochlear implant by the Cochlear Corporation greatly
expands on this group of patients with residual hearing who
are potential cochlear implant candidates.The hybrid device
combines a hearing aid for the low frequency hearing and
electrical stimulation for the middle and high frequency
hearing. The hearing results for these patients are amazing
with patients reporting a tenfold increase in satisfaction over
hearing aids alone, and a two fold increase in hearing overall
in both quiet and noise.
20
Most cochlear implant patients
(both hybrid and standard cochlear implants) are able to
make use of the telephone with more than 80 percent of
patients queried on recent studies using the telephone on a
regular basis.Wireless connectivity for cochlear implants has
provided additional hearing improvement for patients with
hearing loss improving understanding on the telephone and
when watching television. Collaboration between cochlear
implant companies and hearing aid companies has allowed
patients with a hearing aid in one ear and a cochlear implant
in the other ear to have stereo hearing with the wireless,
Bluetooth connectivity allowing an extremely pure auditory
signal with background noise.
Cochlear implant processors are rapidly becoming wa-
terproof as several different manufacturers have developed
waterproof coverings for the processors. Advanced Bionics
has developed a waterproof processor, the Neptune. The
MED-EL implant has recently been granted approval for
MRI compatibility with a 1.5 tesla scanner using approved
scanning techniques.
21
Additional applications for cochlear
implants are also on the horizon. Cochlear implants inEurope
and Canada have received the CE, the European equivalent
of FDA approval, mark for use in patients with unilateral
severe to profound sensorineural hearing loss.
22
These pa-
tients have found improvement in hearing, particularly in
noise, along with tinnitus reduction.
23
It is anticipated that
in the next several years, cochlear implantation for unilateral
sensorineural hearing loss will be possible in the US, as well.
Developments for molecular,
gene, and stem cell therapies for deafness
Unlike lower vertebrates, humans do not have the capacity
to regenerate hair cells within the cochlea. With the large
number of affected patients and improved understanding
