Cochlear implant
How it works
In the speech processor, the sound waves received by a microphone are converted into digital signals and transmitted through the skin to the implant via the transmitter coil. In the implant, these signals are converted into electrical impulses and transmitted to an electrode array located in the cochlea. The impulses from the individual activated electrodes directly excite the auditory nerve fibres. From here, signals are transmitted to the brain, where an auditory impression is created.
In some cases, the hearing loss is mainly in the high frequency range, while the low frequencies can still be heard very well. Such people can only understand speech very poorly despite good low-frequency hearing. The high frequencies in particular can only be equalised with difficulty and often insufficiently with conventional hearing aids. Such people can also benefit from a special cochlear implant. In this case, the speech processor is combined with a conventional hearing aid(electrical acoustic stimulation = EAS or hybrid CI). The low-pitched sounds are amplified by the hearing aid function and transmitted to the inner ear via the normal route (auditory canal, middle ear). The high frequencies are encoded in the speech processor and transmitted to the auditory nerves and the brain via the cochlear implant. The acoustic and electrical information is combined in the brain to create an auditory impression.
Indications
Cochlear implants are suitable for people with profound sensorineural hearing loss or deafness.
Adults
For adults, the prerequisite is that the hearing impairment has occurred after language acquisition (around the age of 4-6) (postlingual deafness). People without language acquisition only benefit from implantation in individual cases.
Children
Children born deaf or with early onset deafness should, if possible before the age of 2 be fitted with a cochlear implant. It is known that normal speech development in such children is only possible if they are implanted as early as possible. The later the implantation takes place, the worse the chances of normal hearing and speech development.
- Deafness due to an accident or meningitis
Children or adults with deafness caused by an accident or meningitis should undergo cochlear implantation as soon as possible, as in these cases there is a risk of ossification of the cochlea (cochleasclerosis), so that an electrode can no longer be inserted into the cochlea.
- Single-sided deafness
For some years now, people with unilateral deafness and normal hearing on the opposite side can also be fitted with a cochlear implant.
- EAS, HYBRID-CI
People with good residual hearing in the low frequency range who do not achieve sufficient speech intelligibility with conventional hearing aids benefit from a combined fitting.