It is an electronic device placed under the skin by the doctors which carries
sound, bypassing the damaged parts of the ear, to stimulate hearing nerve, which
in turn carry those signals to brain for understanding.
Parts of Cochlear Implants:
A microphone, which picks up sound from the environment.
A speech processor, which selects and arranges sounds picked up by the
A transmitter and receiver/stimulator, which receive signals from the
speech processor and convert them into electric impulses.
An electrode array, which is a group of electrodes that collects the
impulses from the stimulator and sends them to different regions of the
How does a cochlear implant work?
The external components capture environmental sounds as well as speech and
They process these sound so they can be transmitted across the skin to the
implant. The implant then passes the signals along to the electrode array.
The individual electrode then delivery these signals to the hearing nerve
where they travel.
Anyone who are suffering with severe to profound deafness, which means unable to
hear sound stronger than 90 dB HL at a frequency of 2 – 4 kHz (a measuring unit
of Intensity of sound). However, apart from assessing functional hearing ability
a thorough assessment will be done by a multi-disciplinary team before surgery
for the factors such as fitness for surgery and the ability of the person to
derive benefit from cochlear implant system.
Individuals 18 years of age or older.
Moderate to profound hearing loss in both ears.
Limited benefit from amplification defined by preoperative test scores of ≤
50% sentence recognition in the ear to be implanted and ≤60% in the opposite
ear or binaural.
Severe to profound hearing loss.
Limited benefit from binaural amplification.
Multisyllabic Lexical Neighborhood Test (MLNT) or Lexical Neighborhood Test
(LNT) scores ≤ 30%.
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hearing loss in elderly people: a review of the technology and treatment
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3. Bond M, Mealing S, Anderson R, et al. The
effectiveness and cost-effectiveness of cochlear implants for severe to
profound deafness in children and adults: a systematic review and economic
model. Health Technol Assess.2009 September;13(44):1–330. [PubMed].