History of Cochlear Implant - Essay Example

Cochlear Implant Introduction The ear is divided into 3 parts (anatomically) as the Outer, Middle and Inner parts. And Cochlea forms the inner part of the year. “The cochlea is the auditory portion of the inner ear. Its core component is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea. The cochlea is divided into three different chambers, each of which is receptive to different frequencies of sound “(Jarvis 2004). Cochlear damage means complete loss of hearing and it can be caused by various factors like exposure to loud noise, meningitis, acoustic tumors or even intake of certain strong antibiotics. Damages to Cochlea can be surgically repaired using Cochlear implants. “A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. The cochlear implant is often referred to as a bionic ear”. (Bio-Medicine.com, 2009) The rest of the essay deals with the history of Cochlear implants with an explanation of the factors that determine the success of its implantations. History of Cochlear Implant History of Cochlear implant dates back to the late 18th century, with the first ever implant done by Dr. William House in 1961(Berke 2011). It was only in 1984 that the Food and Drug Administration (FDA) approved implantation for adults. A Cochlear implant has four basic parts: a microphone, a speech processor, a transmitter and receiver/stimulator, and electrodes, which collect the impulses from the stimulator and send them to the brain. Constant endeavours towards improvement is made and implemented. It has to be stated clearly that the implant is only a prosthetic substitute for hearing. Success rate of Cochlear implants Studies show that as of April 2009, around 188,000 people including children across the world have received the implant (NIDCD 2010).That gives a very optimistic picture that the implants have been accepted and people have benefitted from it. The success rate of these implant strategy is because of a proper management of psychological problems, apt education on its advantages and disadvantages and timely intervention of audiologic measures. Advancements in technology have also played a major role. An example of it could be the improvements shown in the circuit development reduction of noise factors and adaptable fitting hearings. (Niparko 2009) There are numerous factors that affect the success of any implant. Improved circuits have played their part in advancing the signal processing methods but the continuous increment in the levels of hearing impairment and recruitment for loudness disrupting features of safe listening, the target of achieving 100% success has a long way to go. In addition to this, people who go for hearing aids cannot be said to be completely clear of any hearing loss. It is because there are chances for pathology influences to affect the transduction processes through which these hearing aids transmit sound in the ear. Hearing does not start immediately after the implant. It takes about 1-4 weeks for the brain to register new sounds and generally turn the implant into an active mode. Primary factors that accentuate the success of an implant are the recipient’s immediate reaction and the period since when loss of hearing was detected. In some cases, depending on the pre implant levels of hearing and speech abilities, lip reading and communication modes have shown tremendous improvement. For a successful implantation and working of Cochlear implants, there are three prime characteristics that need to be addressed in human hearing. Audibility loudness and intelligibility. Audibility The success of Cochlear implants depends on how much the ability to hear sounds can be amplified in human hearing. Residual hearing, failure of proper feedback and limitations in the power of the aid used for hearing are some of the problems that may be faced by the cochlear implant patients due to the failure of this characteristic. The success of these implants is by improving this audibility factor through methods which lack the lack the need of hair follicles and rather depend on the electrical signals that are generated and passed in the auditory nerves through a part called as the ‘spiral ganglia’. So, when placed in the ear, the immediately come into effect increasing the audibility levels of hearing. ( Niparko 2009) Loudness The ability of the human ear to detect soft sounds as well as those ranging in 100 dB is an integral characteristic to boast. ‘Recruitment’ is a state of hearing that deals with the inability of the hearing organs to accept higher levels of loudness that are actually capable in a normal hearing process. The reduction in the tolerant levels reduces the dynamic range of sound hearing by some huge amounts. The success of removing this problem depends on how the fibres related to nerves respond to the auditory organs. The hair cells play a vital part through outer level contractions in tuning the basilar membranes – necessary for amplification of sounds that are soft in nature as well as improving the accuracy of the sounds that is heard. Hence, the function of the implants is to suitably activate those nerve fibres of the auditory organs such that the perception of the sound levels is equal to that of a normal hearing process. So, the effect of loudness recruitment plays an important role in the success of Cochlear implants. ( Niparko 2009) Intelligibility Amplification of hearing in case of audibility and suppression of noises in case of recruitment characteristic of loudness play very important roles in the success of implants. Another factor that could easily equal its importance with the other two is the intelligibility characteristic of the auditory organs – the ability to recognise speech. There have been innumerable efforts in research labs all over the world to create implants that match natural hearing pattern in all possible ways. But, all of those research activities found this factor to be a hindrance in achieving that. Apart from the hair cells – the primary factor for hearing capabilities, any damage to the neural sensors and nerve fibres could also affect the hearing capabilities. Such problems bring rise to dead regions in the hearing organs which are not sensitive to any amplification or noise reduction strategies and hence causing the failure of implants. Speech recognition and thereby the intelligibility of the humans are those areas which fail to get activated with an implant because of these issues. There are research activities going on in these troublesome areas which when turning fruitful could do wonders in increasing the success rate of the implants. (Niparko 2009) The aforementioned are factors that influence the success of cochlear implants. However, there are some disadvantages as well like undergoing surgery, which could result in various other infections and health hazards. The FDA has data that shows most children who underwent surgery suffered from acute meningitis post-surgery. They concluded that these recipients have 30 times more probability of acquiring meningitis as compared to normal children. The cost involved for an implant is on the higher side which again not all can afford. Physically adorning the device could be very fastidious and extra precautions are required for it to function properly. If in case the device malfunctions, then the only way to correct it would be to undergo another surgery, which is a high risk factor. The device needs to be maintained well and updated frequently to ensure smooth functioning. Conclusion The debate continues about the use of hearing aids being a better option than cochlear implants. Major cochlear implant companies in the world are Cochlear Corporation, Advanced Bionics, US and MED EL, Austria. To give a panoramic view Cochlear implants are one possible solution for hearing impaired people. The implant has benefitted millions of people across the world and will continue to do so. Works Cited Jarvis, C.. Ears. In Physical Examination & Health Assessment. St. Louis, Missouri:Saunders. 2004. Print. Berke, Jamie. How a Powerful Tool for Hearing Developed. http://deafness.about.com/. Jan. 9, 2011. Web. Jan 10, 2011 National Institute on Deafness and Other Communication Disorders NIDCD. nidcd.nih.gov. 2010. Web.. Jan 10, 2011 “Cochlear Implant Definition “. Bio-medicine.org. Bio-Medicine, 2009. Web. Jan 10, 2011 Niparko John. Cochlear Implants: Principles and Practices. London: Lippincott Williams & Wilkins. 2009. Pp. 85-86. Print Read More