Causes of Deafness (Hearing Impairment)

The term “deafness” refers to a loss of (sound) hearing sensitivity that renders a person hearing non-functional for day to day purposes, including the reception of speech and language, with or without a hearing aid. The term hard of hearing refers to loss of sensitivity that leaves a person’s hearing functional, through defection. Hearing impairment refers to any degree of hearing loss, which may range from minimal hearing loss to profound deafness NERDC (1981).
Some traditional beliefs in Nigeria hold that certain gods are responsible for the birth of children. If therefore, parents offend these gods, either by not sacrificing animal to them or by worshiping the Christian God, the gods would punish them through the birth of Handicapped Children. This is why the birth of a deaf child like that of the blind was regarded as a curse or punishment from the gods. Children born deaf are allowed to grow up without the benefit of early educational intervention, will normally develop no spoken language. But then traditional beliefs can only hold that such children are abnormal. They were sometimes taunted in some part of the country by other children who would put leaves between their lips to approximate the deaf to lower animals. This belief is still persistent today among traditional minded people. Parents usually try all kinds of native and unconventional treatment – going from one native doctor to another to effect a cure.

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Some believe that deafness is as a result of the use of strong herbal medicine taken by the children’s forefathers as protection during the war. As a result of the powerful protective powers attributed to such herbal applications, the gods could not punish the forefathers so they passed the punishment on to their children and grand children. The persistent nature of this superstitious belief has made it difficult to identify children with hearing impairment at an early age since deafness is an invisible handicap. Some parents hide such children so that outsiders may not know that they have deaf children. In other cases some parents have disowned their child, driven them away or even abandon them in the forest.

Causes of Deafness (Hearing Impairment)
This can be broadly divided into three major causes of deafness (hearing impairment):

1. Before Birth
2. During Birth, &
3. After Birth

A. CAUSES BEFORE BIRTH
Under ‘Before Birth’ we will be looking into the following:
I. Hereditary
II. Prenatal Infections
III. Toxic Condition
IV. Malformation
V. Blood Incompatibility, &
VI. Smoking

B. CAUSES DURING BIRTH
Under ‘During Birth’ we will be looking into the following:
i. Age of Parents
ii. Prolonged Labour
iii. Use of Forceps
iv. Intercranial Hemorrhage
v. Use of Sedatives, &
vi. Blockage of Respiratory Passages

C. CAUSES AFTER BIRTH
Under ‘After Birth’ we will be looking into the following:
i. Disease and Infections
ii. Accidents
iii. Drug
iv. Noise
v. Insect, &
vi. Old age

EXPLANATION TO THE THREE MAJOR CAUSES OF DEAFNESS AS LISTED ABOVE

1. CAUSES BEFORE BIRTH

HEREDITARY
The problem of hearing impairment may run in some families. Certain genetic defects like otosclerosis (a defect of the middle ear) and degeneration of the auditory nerve may affect hearing at any stage of life. Kirk (1972) says that Kloepter discovered that in America 46 to 60 percent of all causes of severe hearing loss as well as adventitious hearing loss may be inheried.

PRENATAL INFECTIONS
Infections like mumps, German measles and influenza causes a variety of disability if the pregnant mother is exposed to these viruses during the first trimester. It may cause degeneration of important nerve cells that result in deafness.

TOXIC CONDITION
Some drugs are believed to be toxic and destructive to the auditory organ, which is one of the most developed. Un-prescribed drugs and some drugs taken during pregnancy may cause hearing loss, e.g. thalidomide cocaine, heroine or marijuana lead to poisoning from numerous sources may also damage the auditory channel.

MALFORMATIONS
The architectural defect in creation can lead to blockage of the auditory canal. A spongy bone may be formed in the middle or inner ear. This may prevent sound from entering into the mechanism of the ear. There are also cases of the absence of the eardrum.

BLOOD INCOMPATIBILITY
Cells and nerve tissues may be damaged if a pregnant woman with Rh negative blood carries a foetus with Rh positive blood. Hearing impairment and other disabilities may be caused if antibodies in the mother’s system destroy cells in the foetus.

SMOKING
This action by the mother during pregnancy affected the eardrum of the child and may lead to hearing loss.

1. CAUSES DURING BIRTH

AGE OF PARENTS
Parents allow their daughter go into early marriage when they have not developed the necessary structures for childbirth. Pelvic pressure in such women produces devastating effects on the auditory passage. This results in hearing impairment.

PROLONGED LABOUR
Difficult delivery leads to prolonged labour. Inadequate supply of oxygen to the child causes anoxia and vital organs including auditory organs are affected.

USE OF FORCEPS
In an attempts to help a pregnant woman under labour with forceps, head injury may occur. The pressure of the forceps on the tender head of the baby may destroy some vital cells, which may impair hearing.

INTERCRANIAL HEMORRHAGE
Severe bleeding in the cranial due to trauma such as forceps, accidents and other external aggression on the child’s head may produce hearing defects. Such an occurrence may cause damage to the nervous system resulting in auditory defect.

USE FO SEDATIVES
The use of sedatives or anesthetic during difficult labour may damage auditory passage. This usually occurs when it is excessively used.

BLOCKAGE OF RESPIRATORY PASSAGES
There are a number of biological factors such as venereal disease web, e.g. syphilis, umblical cord that could block the child’s respiratory passages. If the respiratory passages are blocked, it could produce rapid destruction of important auditory organs.

1. CAUSES AFTER BIRTH

DISEASES AND INFECTIONS
Childhood diseases caused by viruses are associated with the occurrence of hearing impairment. Examples of the viral diseases include scarlet fever, mumps, diphtheria, whooping cough, measles, typhoid fever, pneumonia, influenza, small pox, cerebrospinal menegitis.

ACCIDENTS
This could occur in form of blow or slap causing pus to develop in the middle ear.

DRUG
Some drug like streptomycin and veromycin have been known to produce side effects that may negatively affect hearing effectively. Strong drugs taken to counteract the effects of the diseases could cause deafness.

NOISE
Repeated exposure to loud noises could cause hearing loss such high frequency sounds like in industry or military experiences or disco or juju music could be of much harm.

INSECT
Insects and small objects can accidentally cause damage to the ears to a degree that hearing may be impaired. There may be the blocking of the ear canal by insects and small objects.

OLD AGE
As a man grows older in age. The senses are also growing old. This is a common cause of hearing loss.

CONCLUSION
The deaf does not have any physical deformity, lack of ability to communicate with the larger hearing society through speech has caused many misunderstandings about the handicapped. Specialist are uniquely challenged by the loss of sound or hearing sensitivity that renders a person non functional for day- to-day purpose.