Why does my nephew have profound hearing loss?
Q: My 18-month-old nephew recently underwent a BERA test. He was diagnosed with profound hearing loss due to damage to celiae in cochlea and was recommended a hearing aid. What are the reasons behind this condition? Nobody in our near and extended family suffers from hearing loss. Is there any surgical procedure to alleviate the condition? Where is a good speech therapy or hearing aid centre in Mumbai?
A:The ear has three parts - the external, the middle and the inner. The inner part can be further subdivided into the cochlea and the labyrinth. The cochlea subserves the hearing function. The labyrinth subserves the function of balance. The ciliae are brush like organs situated within both parts of the inner ear; they play a role in the process of transforming the vibratory form of sound energy into electrical energy. They are very minute and can only be seen under the electron microscope. They are very delicate and can get damaged very easily due to various reasons. Sometimes, they may be absent right from conception due to genetic causes, the mother might have had some fever or other illnesses during pregnancy; during the process of delivery, some delay or trauma might have occurred; in the new born period jaundice or some other illness might have occurred; certain drugs also might cause such damage. The term genetic only means that the cause resides in the genes. The label genetic does not imply that one of the parents or grandparents must have manifested the same illness in them. Certain genetic changes arise unpredictably and suddenly. These sudden changes in the composition of the genes are called mutations. Several tests are now available to find out the cause, to pinpoint the site of damage and to quantify the degree of the hearing loss. However, in the present state of the art, this task is extremely difficult and also, only probabilities can be arrived at. The priorities, as far as this particular child is concerned, are as follows: 1. The first priority is to rehabilitate the child. Do a hearing level test and assess the degree of loss from the functional point of view. Fit a hearing aid. Ideally this should have been done at the age of 3-6 months. Care must be taken to fit an appropriate hearing aid. In essence, the hearing aids are amplifiers of sound energy. If the child does not hear at low volumes, these hearing aids increase the sound volume and render the hearing possible. In the case of hearing aids, expensiveness does not necessarily mean that they are either better or more appropriate. Of course, this is true of every other thing in life! Many times, a less expensive hearing aid may be the most suitable. It is the training that is given to child after fitting that marks the difference between success and failure. Rehabilitation of hearing is not a "fit and forget" proposition. 2. Sometimes, such absence of ciliae may occur in other organs also and result in other defects like defective teeth, malposition of heart and other organ systems, sperm dysmotility, absence of sweating, etc. A systematic search must be made to look for their presence. If such are present, they must be treated. 3. Advanced testing could be done to ascertain the cause, if possible. Such testing may also give an indication whether this loss will be progressive. Another benefit of such testing will be to predict the possibility of similar defect in subsequent pregnancies. 4. Cochlear implants are a recent discovery in hearing aids. Unlike the hearing aids, in this piece of equipment, a microphone collects the sounds, changes them into electrical signals and feeds these electrical signals directly into the cochlea. Thus, any defect in the ability of the cochlea to transform sound energy into electrical energy is bypassed. Cochlear implants can bypass a defective cochlea, which the hearing aids cannot achieve. The disadvantages are - they are expensive; they are still being developed. By the time you find the finance and fit the current cochlear implant, another better model might have arrived. You cannot replace the old with the new one, as it costs even more. Besides, it may be impossible because of the earlier surgery, and would be certainly more risky. The technique of operation is not very difficult. Most of the ENT surgeons in India have the skill to do similar surgery. It is the post operative audiological facilities, which are lacking in several hospitals and this is the main stumbling block. The immediate post operative training of the child takes about one year. During this period, the child and the parents will have to be under the constant supervision and guidance of the speech trainer. Otherwise, the entire exercise comes to naught. This period of support, in most cases, extend to the entire lifetime. The President of India, Shri Abdul Kalam has initiated a project to manufacture cochlear implants at an affordable price and the fruition is expected in a few years. When such implants become available, a cascade effect might occur, resulting in betterment of audiological services and speech training facilities. The child is already receiving competent medical attention. The treating doctor can give you further details. You can request your audiologist to give you the address of a nearby institutional facility e.g. Ali Yavar Jung National Institute of Hearing and Speech.