Hearing sounds without ears. Strange as it sounds but it is already possible nowadays. The deaf had hold on to sign language long enough and wore hearing aid long enough. Now shines a new light. Cochlear Implant built at 1946 is a new technology efinitely the deaf community should know about this as it may help them brought back the sense that was gone or diminishing in their physicality.
Today I am going to discuss: cochlear implant as a marvel of electronic wizardry, how it works, the difference with hearing aids, the people that can wear them, and its effectiveness and efficiency. Cochlear implants are marvels of electronic wizardry and a masterpiece of miniaturization. The implant has two parts, the external component which placed behind the ear and the internal part which has to be surgically implanted under the skin. The cochlear implant is designed to restore the sense of hearing.
It has a microphone to convert sound into discernable signal. It is a processor which synthesizes signals from the microphone (Parent Resources 2006, What are cochlear implants 2007), It is a transmitter and translator which converts signals from the sound processor into electrical impulses (Parent Resources 2006, What are cochlear implants 2007). It is a series of electrodes that collects the impulses from the translator and distribute them to different nerves in the auditory system (NIDCC, as cited in Parent Resources 2006, What are cochlear implants 2007).
Transition: We have already discussed what a cochlear implant is and its part now lets move on to how it works. How a cochlear implant work is a wonder in itself. By working through the structure of the inner ear specifically the basilar membrane in a process called “frequency-to-place” mapping which enables the brain to disparate sound patterns. In effect, the implant acts as the go between so that sound could reach the basilar membrane as deep vibrations.
As a background information, high frequency or high pitched travel only short distances in the membrane but low frequency sounds travel longer distances (Pantev et al, 1989). How sounds or vibration travel in the membrane is due to the movement of hair cells located all along the basilar membrane. These hair cells once stimulated create a disturbance which is electrical in nature which are picked up other hair cells. The brain then maps from where the vibrations are coming from and hence able to determine what kind of sound frequency is being heard (Accessed at http://147.162.36.50/cochlea/cochleapages/theory/bm/bm.htm).
The cochlear implant substitutes for the hair cells and directly stimulates the nerve centers in the inner ear through electrical impulses allowing the brain to recognize sound frequencies just like what hair cells do to the basilar membrane. There is of course a difference between cochlear implant aided hearing and normal hearing. It takes some time and adjustment but the implants allow hearing impaired people to recognize different sounds such as warning signals and words. (Axistive.com, 2007)
What is the difference between a hearing aid and a cochlear implant? Hearing aid amplifies sound waves. However, the cochlear implants do not. Cochlear implant can replace the function of the inner and outer ear.
Persons with hearing inabilities such as sensorineural hearing loss most likely have fewer and damaged hair cells. Sensorineural hearing loss is a type of hearing loss originating from the inside of the vestibulocochlear nerve, the inner ear, or central processing centers of the brain. There are several reasons for hair cell loss or damage.
It could be due to genetics and hence hereditary or due to certain illnesses such as meningitis. Some medication may also cause damage to hair cells. Loud noises over prolonged period can also cause damage.
Transition: Next, let us focus on the people who can wear this electronic device. Cochlear implant works in a wide array of cases and is recommended for those totally deaf or severely hearing impaired. There are around 100,000 people in the world who according to the Food and Drug Administration’s (FDA’s) 2005 data have benefitted from cochlear implants (What are cochlear implants, 2007). In the United States, there are around 22,000 adults and around 15,000 children who have been fitted with cochlear implants. Just how effective are cochlear implants have been the subject of many studies. An implant is not a cure for deafness or hearing impairment, it is an artificial replacement for hearing and reaction to it is varied.
It is interesting to note that the quality of these implants is such that adults who have lost all or most of their hearing late in life, once fitted could associate the signals they receive through the implants with sounds they remember thereby facilitating speech recognition (NIDCC, 2007). There are some who find the implants very effective and this is true for adults who just lost their hearing for a short time. They can easily adapt and regain functional speech. Implants could pose a problem for adults who are deaf most of their lives as many find them irritating if not outright useless. This is because of the nature of deafness and the prolonged period without the capacity to hear.
For children, the results varied with some cases of failure due to inability of the implant to stimulate the auditory nerve system. Generally, the implant is effective in cases of progressive lost of hearing.
Apparently, the neural patterns or sound characteristics they learned early in life are important in speech recognition using the implant. This is shown in the experiences of people who shifted from hearing aids to cochlear implants as perception of sound continues because of the hearing aid sound amplification (Delost, 200).
Transition: Let me summarize the major points in cochlear implants. Conclusion:
- Cochlear implants are examples of the wonders of science and technology
- It could help totally deaf or severely hearing impaired people.
- Prior speech knowledge is still needed for successful use of the implant.
- Although, sounds filtered by the device are not the same as that of a normal person, it could still be of great help to the deaf when communicating with others.
- If you know someone who has a hearing problem, show them information about the cochlear implant!
References
- Axistive.com, Assistive Technology Web Site, “What Are Cochlear Implants?” 2007. (September 21, 2007). <http://www.axistive.com/what-are-cochlear-implants-.html>.
- Delost, Shelli. “The Cochlear Implant Controversy “. 2000. <http://www.drury.edu/multinl/story.cfm?ID=2442&NLID=166>.
- National Institute and other Communication Disorders (NIDCD), “Cochlear Implants”. 2007 <http://www.nidcd.nih.gov/health/hearing/coch.asp>.
- Pantev, C Hoke, M Lutkenhoner B, and Lehnertz K. “Tonotopic organization of the auditory cortex: pitch versus frequency representation”. Institute of Experimental Audiology, University of Munster, Federal Republic of Germany, 1989, < http://www.sciencemag.org/cgi/content/abstract/246/4929/486>
- “Parent Resources Disorders defined”. Carolina Rehabilitation Specialists, 2006. < http://www.carolinarehab.net/res_disorders.php>
- “What are cochlear implants, how do they work, and who typically gets them?” University of Washington, 2007. < http://www.washington.edu/accesscomputing/dhh/print.html?ID=395>
