Do Cochlear Implants Cure Deafness?
Do Cochlear Implants Actually Offer a Cure for Deafness?Unfortunately, there is no way to dress up this simple fact. The truth is that conventional hearing aids do not offer a cure for deafness and neither do cochlear implants. To date, there has been only limited progress in the attempt to find a way to reverse permanent hearing loss. Instead, the main focus of research in the field continues to be on developing improvements to the existing devices with the more modest goal of making auditory impairment more manageable. So why is there a need for two types of assisted hearing devices and how do they differ?
The need is simple to explain, and is related to the severity and the type of hearing impairment. However sophisticated its additional features may be, a hearing aid is basically an amplification device. Providing the wearer has sufficient residual acuity, selective amplification of those frequencies of sound with which he or she has difficulties is normally sufficient to overcome most difficulties. However, while we now know that cochlear implants do not provide a cure for deafness in those patients whose auditory impairment is severe to profound, a hearing aid will normally offer no measurable benefit and an implanted device is more likely to be of help.
The typical candidate for implantation is either a child who was born deaf or lost their hearing while still young, or an adult who has experienced an injury to or severe deterioration of essential structures within the ear. In the case of those children who have hearing parents and who have not yet learnt to speak, implantation can assist them to study more effectively by enabling them to communicate with their teachers, parents, and peers. Although cochlear implants do not actually cure their deafness, they can make it a lot easier for their users to interact with a predominately hearing society.
In addition to differing in their suitability, the two devices also operate in very different ways. As already stated, the hearing aid is simply a sophisticated, miniature unit with the ability to amplify sounds selectively. By contrast, the implanted devices provide no amplification at all. In fact, they are an option for those affected by severe to profound sensorineural hearing loss and who are unable to convert incoming sounds into signals that can be deciphered by the brain. Clearly, increasing the volume of sound can have no effect in such cases.
In answer to the question: “Do cochlear implants cure deafness?” – the answer is still no. However, they do act to bypass the damaged sensory cells in the middle ear and transmit a modulated but alternative type of signal to the auditory cortices in the brain. Because the signal is modulated, its variations reflect those in the incoming sounds, but because the nature of the signal produced differs from that generated by healthy sensory cells, it can take a while before the implanted individual adapts to the difference. Some assistance from a speech therapist will often be needed before these altered signals begin to make sense, while the ability to lip-read can also provide valuable visual cues that can speed up the adaptation process.
However, not only do cochlear implants not cure deafness, but they are also not necessarily suitable for everyone who is unable to benefit from the use of a conventional hearing aid. Even though the basic requirements for candidacy of severe to profound sensorineural hearing loss may have been met, before proceeding with the implantation, the ENT surgeon will require a more in-depth evaluation of each potential candidate.
Much of the evaluation is centred around the possible value of the procedure based on factors such as age and speech ability, and while cochlear implants do not cure deafness, any benefit they can offer might depend on the patient’s suitability for surgery. In addition to a visual examination, X-rays and CT scans may be necessary to ensure a candidate displays no anatomical anomalies that might subsequently interfere with the process of surgical implantation.
Given the green light, a receiver is positioned above the mastoid bone to form a magnetic connection with a combined speech processor and transmitter positioned behind the ear. Digital signals from the receiver are directed to various positions along the cochlear wall by an electrode array and, in turn, are relayed to the brain via the auditory nerves, thus bypassing the need for functional sensory cells.
Do cochlear implants cure deafness? No! However, very often, they provide the only means with which to manage it.