الفهرس 
Active Middle Ear Implants overviewOnly 14 pages are availabe for public view
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Abstract
Summary
AMEIs are indicated for patients with moderate-to-severe
sensorineural hearing loss (SNHL), who have not undergone
middle ear surgery before and have been unsuccessfully with
conventional hearing aids. These indications have recently been
extended to include patients with conductive and mixed hearing
loss. Patients with previously operated middle ears and mixed
hearing loss may particularly benefit. More recently, AMEIs have
been used in patients with otosclerosis . In these cases, the
transducer is coupled directly to the inner ear fluid through a
stapedotomy or coupled to the round window membrane (RWM).
State-of-the-art acoustic devices are competitive, but they are not
suitable for patients with chronic external otitis and might be less
effective for patients with a predominantly high frequency hearing
loss.
AMEIs are contraindicated for patients with retro cochlear,
or central auditory disorders, the patients with nonresponsive
active ear infection, the patients whose hearing loss has
demonstrated an improving and decreasing fluctuation over a two
year period of 15 db in either direction or the patients with any
physical, psychological or emotional disorder that would interfere
with surgery. fully implantable MEIs may not be implanted into
Summary
91
children,deafness in one ear, disorders or malformations of the
auditory canal, middle ear, petrous part of the temporal bone, or
the cerebellopontine angle that might stand in the way of an
implantation or irregular course of the facial nerve
AMEI provide vibrational energy to reach the inner ear by
having the energy raised by electromagnetic or piezoelectric
energy transfer following the placement of the vibratory element
on the middle ear structures .A distinction is made between
partially implantable (only the transducer is im-planted) and fully
implantable devices, where a microphone and power supply are
implanted.
The basic principle of an electromagnetic transducer is the
generation of vibrations through a regulated variable force between
an electric coil through which a current flows, and a magnet. Here
the magnet can be located either inside or outside the coil.
Piezoelectric crystals are able to carry out a relative change
in length with an applied voltage. This characteristic is reversible,
in other words a mechanical conformational change (movement),
and conversely mechanical movement results in an electrical
voltage .
Summary
92
Most adverse events were relatively rare and of low severity.
Serious adverse events such as facial nerve damage were reported
to have occurred rarely .Damage to the chorda tympani nerve was
reported more commonly , however, some instances of taste
disturbance were reported to have been transient and to have
resolved over time. Technical complications related to the device,
including device malfunction, migration, or insufficient gain wer
relatively rare .
AMEI seemed to be cost-effective in patients with
sensorineural hearing loss and with co morbid chronic external
otitis but not apply to patients with pure sensorineural hearing loss
who dislike conventional air-conduction devices for whatever
reason and are searching for an alternative.
For the patients who predominantly had high frequency
hearing loss, the Vibrant Soundbridge is the better option than
acoustic devices. Not only were its aided thresholds comparable or
better than the control acoustic device, but its speech recognition in
noise was also significantly better.