Cochlear Implants
Cochlear implants are indicated for people whose hearing levels are too poor for conventional hearing aids to be beneficial. In these patients a cochlear implant would be able to restore hearing to the implanted ear.
How They Work
Normal hearing aids work by amplifying sound and presenting it into the ear canal at a louder level so that the sound can be heard by the hearing-impaired ear. Cochlear implants work differently as the sound signals are converted into electrical signals and sent directly to the auditory (hearing) nerve, which then passes these signals onto the brain, which recognises these signals as sound.
How They Are Inserted
A cochlear implant consists of an internally implanted component and an external component which attaches to the internal component through the skin through magnetic attraction. The internal component is inserted through surgery which takes around 2 hours, under a general anaesthetic. Surgical access to the cochlea (where the electrode is inserted) is through the mastoid and middle ear. A surgical drill is used to take down the mastoid air cells
(see ‘Middle Ear & Mastoid Surgery’)
and an opening into the cochlea is made, through which the electrode is inserted. The receiver stimulator is inserted under the scalp and the wound is closed.
After the wound has healed, the external processor is loaded and the processor can be switched on. This would be when the patient starts to hear sounds through the implant.It usually takes months for the patient to get used to the electrical signals and for their brain to interpret these electrical signals as natural sounds. This requires continued work with the Audiologist to adjust stimulation levels and implant settings according to the patient’s hearing experience.
Please see the links below to read more information about cochlear implants:
https://ais.southampton.ac.uk/cochlear-implant/
https://www.bcig.org.uk/patients.aspx
