A cochlear implant is composed of two parts, an internal part that must be implanted by means of a surgical procedure and an external part that is put in or removed by the patient with the ease of a hearing aid. The external part is composed of a microphone that captures the sound, a processor that “orders-processes” it and a transducer that transmits it to the internal component through the skin. The internal part has a receiver-stimulator that converts this acoustic signal into electrical and stimulates through the electrode array implanted in the cochlea (organ of hearing) appropriate neurons and these transmit the sound through the auditory nerve to the cerebral cortex.
What is the difference between conventional hearing aids and cochlear implants?
The fundamental difference is the indication, i.e. cochlear implants are usually placed in patients who do not benefit from a hearing aid. This is because their hearing loss is very severe or sometimes because their hearing loss is very asymmetrical between the bass and the treble. In these cases, a so-called hybrid implant can be fitted: it functions half as an implant and half as a hearing aid. Another important difference is that hearing aids do not require an implantable part, i.e. they do not require surgery, while cochlear implants do. Another difference is that the implant stimulus is electrical, directly in the cochlea and auditory nerve.
When is a cochlear implant recommended?
It is recommended in all those patients with severe or profound hearing loss in whom a hearing aid does not provide sufficient improvement and who are candidates for an implant. This is mainly true in bilateral cases, that is, when the problem affects both ears, but it can also be done in unilateral cases, where the diseased ear is only one.
Can a cochlear implant be used in children or infants?
Undoubtedly, it is in the pediatric population where the benefit of cochlear implantation is most dramatic. Hearing loss can be diagnosed at birth or in the first months of life and even before the age of one year, babies with severe or profound hearing loss can be implanted with a cochlear implant.
On the other hand, it is important to point out that there is no age limit when it comes to implant placement, and due to the current population characteristics, we are implanting more and more elderly patients.
New advances and what to expect in the future
This is an exciting field with many advances and changes in recent years, I would dare say in recent months. Nowadays, we have new processors, new electrode arrays, more atraumatic with the cochlea, more “intelligent” and smaller processors, more water resistant, etc…
At the same time, the range of candidates is expanding to what today we call “non-traditional” candidates, there is a tendency towards bilaterality, there are implants known as hybrids or electro-acoustic stimulation, it can be an effective treatment for tinnitus as well as for unilateral deafness, etc… At this point we are in continuous contact with the Authorities to increase the indications covered by the public health system.
The future will bring implants with atraumatic electrodes, processors with better musical discrimination, processors that are increasingly smaller and even totally integrated inside the patient. And even the possibility of instilling drugs through these electrodes in the cochlea itself.
For more information, consult an ENT specialist.