The cochlear implant (CI) is developed for individuals with severe to profound hearing sensory nerve hearing loss. The Cochlear Implant is surgically implanted electronic device that provides a sense of sound to a person who has lost the hearing ability, profoundly deaf or and with a severe hard of hearing. According to the Centre de Research Cerveau et Cognitive (CERCO/ CNRS-2013), the hearing recovery differs from individual to individual. Most people with severe to profound hearing loss can understand speech in a person or over the phone better they did with the hearing aid. The CI helps one to recognize sounds around, including those of telephone and alarms (Isaac, 2015).
How Cochlear (CI) work
CI differs from the hearing aids in that they consist of a microphone and some electronics that are surgically implanted outside the skin, generally behind the ear while the hearing aids only magnify the sound. The microscope transmits a signal to an array of electrodes placed in the cochlear which stimulates the cochlear nerve. Cochlear Implants use Neuroprosthetics technology – Auditory prosthetics, auditory brainstem implants (ABIs), and auditory midbrain implants (AMIs). ABI electrode arrays stimulate the cochlear nucleus complex in the lower brain stem, and aims stimulates auditory neurons in the inferior colliculus CNRS (2015).
The device consists of two parts: The receiver-stimulator is placed under the skin through a surgical process, and the speech processor is worn behind the ear just like one would wear a hearing aid. First, the receiver is placed under the skin through a small cut and then connected to electrodes which are also surgically put into cochlear in the inner ear. The processor is then connected to the microphone that is worn at the ear or somewhere else in the body depending on individual’s activeness, age or lifestyle. The processors offer different programs and telephone options. They are also connected to assist in listening devices and other technologies one may use including iPods. Some of the processors have rechargeable batteries which lower cost over time.
The microphone and the processor pick sound waves from the surrounding and convert them into electrical impulses. The receiver transmits signals to the electrodes inside the cochlear. Inside the inner ear in the cochlear there is a coil that is connected to the audio processor is fitted with the implant is held in place by magnetic attraction. The entire frequency range of the cochlear is stimulated by the electrode array in the cochlear. The non-functioning part of the cochlear is bypassed, and the sound signal is directly passed onto the hearing nerve.
The audio signals are digitally analyzed by the audio processor which codes sounds into a special pattern of coded electrical signals. These coded signals are sent to the coils and then transmitted through the skin to the implant. The implant generates electrical pulses from the coded signals. These impulses are relayed into the core electrode contact along the electrode array depending on the frequency. The hearing nerve receives these pulses and transfers then into the auditory cortex of the brain where they are perceived as sound. The audio processor and the implant look like and extremely fast minute computer. They are constantly processing an immense amount of acoustic data allowing sounds o be perceived naturally and in real time.
In this way, and for the first time, it is possible to us a medical device to replace the human sense. CIs come in different types and different product combinations to meet individual’s needs and preferences.
Who can use Cochlear Implant?
According to the American Speech-Language-Hearing Association, the devices are best suitable for adults who have severe to profound hearing loss in both ears, hearing loss after they have already learned speech and language and limited help from hearing aids. Also, they are useful for those persons with no medical problems that would make surgery risky and those who have a strong desire to be part of the hearing world. It is also necessary for users to have a good understanding of what the device will and would not –do to them. The cochlear implants also work better for those people who have lost their hearing recently and those who have already used hearing aids successfully (Isaac, 2015). According to National Institute on Deafness and other Communication Disorders ((NIDCD), 2016) the CI is fit for use for both children and the adults with a hearing threshold greater than 90 decibels.
Neuroprosthetics discipline has successfully led to a development of a medical device to replace the human sense. This milestone, therefore, has helped hundreds of thousands of people with severe hearing problems. Although Cochlear implants can be life changing, the results are different among the users. Some people benefits more than others. The CIs help the individuals to hear speeches at nearly normal levels, and one can understand speech without lip reading. They also are significance in sound detection and differentiation between soft, medium and loud sounds. However, if the surgery is not very safe, the operation may cause risks of infections and bleeding. But the study has shown major operations successful with minimal risks.
CNRS. (2013, November 7). Hearing through sight: Brain plasticity and why cochlear implants work better for some people than others. Sciencedaily. Retrieved June 13, 2016 from www.sciencedaily.com/releases/2013/11/131107103534.htm
Isaac, B. (2015, october 7). Understanding Cochlear Implants:. Retrieved from http://www.webmd.com/healthy-aging/cochlear-implants
K. Strelnikov, J. Rouger, J.-F. Demonet, S. Lagleyre, B. Fraysse, O. Deguine, P. Barone. Visual activity predicts auditory recovery from deafness after adult cochlear implantation. Brain, 2013; DOI: 10.1093/brain/awt274
M. (2012). The MAESTRO Cochlear Implant Video for Different types of Hearing loss | MED-EL. Retrieved June 13, 2016, from http://www.youtube.com/watch?v=Zm8w88kzZ1I