About three years ago, my wife’s nephew was found to have a benign tumor on the auditory nerve (the cranial nerve connecting the inner ear with the brain). While the tumor was successfully removed, it caused irreparable damage to the nerve. As a result, my wife’s nephew is suffering from hearing impairment, the type known as nerve loss, or otherwise termed in the medical field as sensorineural hearing impairment.
Generally speaking, hearing impairment has two types: conduction loss and that which my wife’s nephew suffers from. Medical records estimate that over ninety percent of people with hearing impairment suffer from sensorineural hearing impairment. This type of hearing impairment usually occurs when the nerves of the inner ear have been damaged, either partially or completely.
The inner ear has about thirty thousand nerve fibers, and these can suffer damage from a number of causes, including excessive exposure to loud music or noise, a blow to the head, deterioration of physical characters in relation to one’s age, and the presence of a tumor on the auditory nerve. Whatever the cause, the auditory nerve can never be restored once it is damaged.
Fortunately, hearing aids can help improve the condition by increasing the intensity of sounds for transmission by nerve fibers that are still working or functioning. As a matter of fact, most of those who wear hearing aids are people who suffer from sensorineural hearing impairment.
In conduction loss, sound waves are prevented from reaching the inner ear as these are blocked in the outer or middle ear. The simplest form of this type of hearing impairment is that which is caused by a foreign body, or the ear’s wax itself, lodged in the outer ear canal. Normal hearing can be restored with the doctor getting rid of the blockade without difficulty. Another possible cause of conduction loss is a perforated eardrum; this problem, however, can be easily solved with the use or application of any of the modern microsurgical methods now available.
Otosclerosis is another common form of conduction loss. This condition involves bone growth in the middle ear, and can be remedied by a surgical method known as stapedectomy. In this delicate operation, which doctors claim has more or less eighty percent success rate, the diseased bone is removed and in its place a prosthetic replacement is fixed. If the operation turns out fine, it may then be performed on the other ear as well.
According to the doctor who attended to the case of my wife’s nephew, it is also possible for a person to suffer from a mixed hearing impairment, that is, both types of hearing impairment are involved. This condition can affect both the middle ear and the inner ear.