Mechanics of Cochlear Implant
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Cochlear Implant

To understand the mechanics of this device we need to understand the design and action of a healthy normal sound interpretation system in the human body.

Conductive hearing (transmission of sound) involves:

the outer ear consisting of the outer lobe (auricle – pinna) which is shaped like a disc to concentrate auditory waves and the channel (auditory - relating to the process of hearing) leading to the tympanic membrane (eardrum) which separates it from the middle ear,

middle ear forms part of Eustachian tube and consist of three small bones (Malleus – hammer), (Incus – anvil) and (Stapes – stirrup) conducting auditory waves from the eardrum to the cochlea (auditory chamber) and dictating to the cochlea,

inner ear consists of the cochlea, a snail-shaped tube (in the inner ear coiled around the modiolus) where sound vibrations are converted into nerve impulses by the Organ of Corti, with estimated 16,000 follicles each picking up its designated pitch level where over the spectrum of auditory signals, low pitch resonance moves the farther distance and high pitch resonance moves the shorter distance and feeding it to the auditory nerve cell as electrical impulses and via the auditory nerve transporting stimulation to the auditory portion of the brain.

Resonance is a vibration of large amplitude produced by a relatively small vibration near the same frequency of vibration as the natural frequency of the resonating system.

The quality of resonance is imparted to voiced speech sounds by the action of the resonating chambers of the throat and mouth and nasal cavities.

In the cochlea, the resonant vibrations are translated into electrical impulses and pased on via the auditory nerve to the auditory portion of the brain where it is translated into recognizable sound. This latter process is known to be sensorineural hearing.

For the purpose of this article it is not necessary to elaborate about the workings of this complicated organ with all its channels, membranes and nerves, but only to be amazed at the design and complexity of this organ.

Loss of conductive hearing involves:

Outer or middle ear deviation (damage, disease or obstruction) may impair hearing but could be treated relatively easy with medicinal or surgical intervention.

When the follicles in the inner ear are damaged or lost, the vehicle to convey resonant waves to electrical stimulation is absent or do not function. This result in the neural process of sensation loss.
It may be caused:


genetically (hereditary),
  chemically (ototoxic medication or envirnoment),
  mechanically (excessive loud noises or accidents) in factories
  recreation (excessive loud noises or accidents) or
  bacterial infestation (meningitis etc).

Currently there exist no medical cure for the diagnoses and only a cochlear implant may provide some sort of hearing sense. Please note the presence of a viable auditory nerve is of essence to succeed with this procedure.

The cochlear implant circumvents the follicles and energizes the cochlea auditory nerve by using electrical nerve stimulation without any natural intercession. This stimulace with its specific resonance and wave length is conducted to the brain and interpreted as specific sound in the same way that the natural process with healthy follicles on the basilar membrane would have occurred, except for the fact that the quality of stimulace are markedly impov´erished. The brain however has the capacity to improvise and together with visual perception seems to be able to overcome the shortcommings and an acceptable quality of hearing is achievable.