Dr Darren Green recently interviewed Dr Louis Hofmeyr on the program “Medies” on kykNET & kie, channel 145. They discussed contemporary issues on hearing and hearing health.
What is a cochlear implant
The first part of the interview focused on cochlear implantation. It is often said that vision connects people with things, but that
hearing connects people with people. Not being able to hear isolates people and has even been linked to the early development of dementia. Dr Hofmeyr mentioned that a cochlear implant (CI) is an electronic device which consists of an implantable part which stimulates the cochlea via electrodes and an externally worn processor. The processor picks up sound via microphones and transfers the signals to the implanted component. A cochlear implant is specifically designed to bypass a damaged cochlea. It converts mechanical sound energy into electrical nerve currents thatstimulate the auditory centres in the brain.
How does the process work?
A CI is indicated for certain patients with poor hearing who do not benefit from conventional hearing
aids. All prospective candidates must be seen and evaluated by a CI team, such as Cape Hearing implants (CHi). Part of the evaluation includes magnetic resonance imaging (MRI) and computed tomography (CT) to confirm the structural integrity and patency of the cochlea and to exclude nerve and brain pathology that may negatively impact the outcome of cochlear implantation. The surgical procedure takes about 2 hours. It is not regarded as a painful operation, and in many cases, the patients can leave the hospital on the same day. After a healing period of six weeks, the external processor is attached, and the system is activated. It will take a few sessions to adjust and tune (map) the system. The more often it is worn, the quicker the brain can adapt and get used to the sound. Many patients report that after some time of getting used to the implant, the sound from the implant and that of the other ear, whether normal or aided by a hearing aid, sounds the same. Some important cues to hearing loss include social isolation and withdrawal in adults and family
members’ complaints that the television is often too set too loud by the person. In children, speech delay may be indicative of hearing loss.
At what age should a cochlear implant be performed?
Mothers are encouraged to have their newborns screened for hearing loss. Hearing loss must be identified as early as possible so a diagnosis can be confirmed and an intervention instituted. There is a window period when a child’s brain can develop speech and acquire language skills. This occurs in the first few years of life. When a child gets older and significantly beyond five years, it becomes impossible for the brain to develop speech and language, and even a cochlear implant at this point will not benefit a child. Therefore, the earlier the recognition of hearing loss and the intervention, the better the outcome for the child.
Other options for hearing loss
Not everyone with hearing loss is a candidate for cochlear implantation. Some forms of hearing loss, such as in otosclerosis or after trauma, may also benefit from surgery. Prosthesis implanted in the middle ear may improve sound conduction. Closure of a perforation in the eardrum can likewise improve sound transmission. For milder hearing loss, using conventional hearing aids is always an option, and it is encouraging to note that technology constantly improves.
Implantable hearing devices
Other implantable hearing devices, such as the VIBRANT SOUNDBRIDGE and the BONEBRIDGE available. All of these are offered by the CHi. In rare cases where the cochlea is damaged, or the nerve is absent, an auditory brainstem implant (ABI) may be an option. This highlights that a lot can be done for hearing loss in the modern era.
