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By NBF News
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On the day that Mr. Opeoluwa Sotonwa and Olatokunbo Oluwayemisi said 'I do' and were joined in matrimony, (Sunday Sun, July 3, 201), they looked so beautiful many bachelors and spinsters seeing them must have secretly wished their own wedding day would hasten its arrival. Moreover, the bride's bevy of beautiful maids, some of them foreigners who journeyed to Nigeria to share in the joy of the day added colour to the event.

If a passerby was not told, such person would not have sensed that both the newly wedded couple and the bridesmaid were all either hearing impaired or deaf but through advancements in educational, sociology and psychology, people with this physical challenges have learnt how to overcome the hindrance which either hearing impairment or deafness poses to communication. To most laymen, hearing impairment and deafness mean the same thing. But Dr Olawale Olubi, an Ear, Nose and Throat specialist clears that misconception and offers further explanation in this interview. Excerpts..

One often hears of hearing impairment, hearing loss and deafness, are they the same?

First, it is necessary to define each: hearing is a situation where the person's hearing ability is not at the normal level as it is supposed to be considering the factors of sex, age and environment. On the other hand, deafness refers to a situation where the person does not have any residual hearing at all.

When you say 'residual hearing', what exactly do you mean?

It means that if the patient can still hear a little then it can be augmented. It is like someone making use of a pair of glasses, which means that the individual is still seeing a little and that is why glasses are used as visual aid to augment the sight. Likewise, a hearing aid can be used to augment whatever is left of the hearing. But if there is no hearing at all, then there is nothing to augment and that means that person is deaf. Therefore deafness is used to describe people who can't hear at all, which means that the hearing organ has been totally been damaged.

What then are the differences?
Hearing impairment means that hearing is not optimal and could be in varying degree. For instance if a person can't hear a whisper, another can't hear a conversation and yet another can't hear a shout or a plane flying above. These are different levels of sound production and the degree of impairment can be described as mildly impaired, moderately impaired and severely/profoundly impaired. Deafness is the final level of impairment while every other one is described as impairment or hearing loss.

And where does the term partial deafness comes in?
The expression 'partial deafness' is no longer used in medicine. Partial deafness only refers to impairment when we don't want to use the word impairment. The same way you say that somebody is physically challenged instead of disabled, so hearing impairment stands for hearing challenge. These are terminologies that evolve daily but in all deafness is used for those who can't hear at all.

What are the causes of hearing defects?
A wide spectrum of causes has been associated with hearing defects ranging from congenital to acquired. Congenital cases refer to where some people are born with the defect as a result of a deformity in the development of the hearing apparatus in the womb. Probably the hearing apparatus did not develop properly but was destroyed due to certain ways the mother was handled during pregnancy.

It could either be that the mother was sick or that she took some drugs that affected development of the inner ear of the baby in the womb. The other type of hearing defect is said to be acquired if the person developed it while growing up as a teenager or in adulthood and may be due to sources in the environment.

What are the risk factors that affect the hearing of an individual?

There are a lot of risk factors especially in this environment that contribute to it. For instance, trauma, where one can be slapped, injured or forcing an object into the ear so that the tympanic membrane is punctured; different kind of noise- loud or disco noise or even bomb blast, environmental noise pollution like that of a noisy generator, all these destroy the hearing ability over a period of time. In fact it is said that if someone stays in a very noisy environment continuously, mainly those who work in factories or construction sites and expose themselves to loud noise always and for a long time, their hearing decreases gradually until they go deaf. Another factor is disease such as cerebral malaria, malaria/severe malaria, meningitis, mumps and measles all occurring in childhood can actually destroy the hearing and cause deafness.

How does the ear function in hearing and what are the forms of hearing loss?

Things that could occur and is common in children is that there could be impairment that is reversible while others are irreversible and is classified into conductive or obstructive hearing loss before it gets to the sound production. The sound we hear is collected by the outer ear and transferred to the hole/eardrum, which passes through some small bones (middle ear) then to the inner ear. The inner ear in turn converts it into an electrical impulse that sends it to the brain and that is when one starts hearing; the transfer from the external ear, collection through the canal, eardrum and bones is called conductive hearing while the transformation into electrical impulses is called sensory-neural hearing. Where there is a sensory-neural hearing loss, most time it is not likely to be reversible. Conductive hearing loss can either be due to some obstruction, wax inversion, narrowing of the canal, perforated eardrum, fluid inside the middle ear which can cause impairment. All that is needed is to remove whatever that is causing the obstruction and the problem is solved but the ones affecting the nerves depending on the severity of the assault and duration of the affectation faces either irreversible, partial reversal or complete hearing loss.

What signs and symptoms show that one is beginning to lose hearing?

There are various signs one would notice to show that one is gradually going deaf and sometimes the patient might not know. Signs like when people talk to him and he is not responding back or you probably call the name of the child and don't get a response. In the past, people say the child is stubborn and instead give him an additional slap because he didn't answer when the parent called meanwhile the child wasn't actually hearing. Another sign in adults is that when answering/making phone calls they can't hear with one side of the ear while children who have it from birth prefer to do the hearing from a particular side of the ear but until they grow up to appreciate that it is the two ears that are used and not one. Another sign is when the patient has been exposed to noise and even after he is no longer in that environment or when after being given injection in the hospital, a ringing sensation is observed then it is a warning sign that the ear is beginning to lose hearing. Others could be due to inflammation and you can observe pain or discharge of some sort.

Why is it that a lot of people don't know it is happening?

Yes, that is because it is a gradual thing and sometimes it is an acute thing; for instance a bomb blast, the bang from fireworks or a gunshot very close to the ear. So hearing loss is classified into: sudden hearing loss and gradual hearing loss depending on what caused it.

Why do some people complain they can't hear anything after a flight?

That is quite normal and it is actually due to the Eustachian tube or the tympanic tube which is a tube that connects the back of the nose to the middle ear and functions by equalizing pressure between the external ear and the middle ear so that the pressures will not increase. What usually happens is that when the plane is descending there is an increase in pressure due to an increase in depth and that increase causes the tube to close so it doesn't equalize pressure again. So there is a buildup of pressure in the ear and that is why when you get into the plane you see a lot of children crying especially when the plane is descending because a lot of them have narrow tube and catarrh has probably blocked some of them.

How is hearing impairment/ deafness diagnosed?
A patient comes to the clinic and says he can't hear with the ears. In diagnosing, proper history is taken to find out what went wrong to know if the hearing loss is sudden or gradual, congenital or acquired? Is it is due to trauma or inflammation, infection or degenerative changes like old age, drugs or exposure to noise? Then the patient's ear is examined and facial nerves tested to find out if there is a tumor or growth. Afterwards an audiological test is done to assess the hearing ability of the patient is carried out. Audiological test involves a pure tone auditory, a middle ear analyzer and then you can have auditory brain stem response audiometry, then audio acoustic emission which is a battery of tests done to ascertain if the patient truly has a hearing loss, the degree of hearing loss, the site of hearing loss and if there is a solution or not. Most times, there is solution while other times there is no solution.

What kind of solutions are available?
As earlier stated, if it is wax, mass or foreign body that is blocking the ear, the doctor gets it out. If the canal is narrow, it is expanded for the sound to pass through; if the tympanic membrane is torn you have to repair it by getting a graft to the tympanic membrane; if it is the ossicles that are damaged, it can be replaced with fabricated ones. If it is the fluid in the middle ear, it can be remove through ventilation and for others the patient could either use a hearing aid. There are various types: those behind the ear, in the canal, middle ear implants hearing aid, brain stem implants, bone anchor hearing aid and the ultimate now is the cochlea implant. The success rate is increasing daily though it is expensive. These surgeries are done under anesthesia where the patient is made to sleep but it all depends on the suitability and the candidature of the patient like age, type of hearing loss and desirability of the patient. Like asking if the patient wants the type of implant, if they can afford it and the cause of the hearing loss. If it is a loss resulting from meningitis using a cochlea implant is almost impossible.

What kind of drug can cause hearing impairment?
Quite a lot of drugs such as injectables, tablets, aspirin, gentamicin, streptomycin; most of these drugs are ortotoxic and can actually damage the eardrum or cause a tear in the tympanic membrane if used wrongly; which why it is better to go and see a doctor when there is a problem. Some of them are reversible while others are not and some cases, once withdrawn, hearing comes back to normal.

Can hearing impairment be prevented?
Prevention of intrauterine infection from mother; the mother should avoid inappropriate use of drugs during pregnancy. Proper and timely immunization of the child from meningitis, mumps, measles. Prevent exposure to noise by plugging the ear with a plug or ear muffin especially if you work in industry. Government should legislate against noise and educate people on inappropriate blowing of horn while driving.

What is the prevalence of hearing impairment and deafness in our environment?

It is increasing by the day and if we are not careful, we would have half of the population deaf. There is urgent need to start screening people to see how many people hear very well. In the developed world, they screen people for hearing both for pre-school, pre-employment, in-employment. Those who work in industry are supposed to have yearly screening. For those entering school the screening helps to know where to place the children in class because some of them might not be hearing well but they are thought to be unintelligent. So if you identify those not hearing well, it will be known why the child is not hearing well and quickly treated. So there is need for yearly periodic screening of the ear and involves using the audiometer.

Government's intervention
There are a lot of people out there who are partially deaf or hearing impaired and are not being helped because the cost of procuring the hearing aid is much (on an average for one year, it's between N125, 000 to N500, 000), so I think what they should do in the National Health Insurance Scheme (NHIS), is to have a provision where they can subsidize the cost. Another is to promote cochlea implants in Nigeria and Non-governmental organizations (NGO) and philanthropic individuals really need to help out.