Deafness: Types, Causes, and Treatments

Deafness is the inability to hear. It can affect one or both ears, either totally or partially. Deafness may be present at birth (congenital deafness), or it may occur later, suddenly or gradually.

Q: Are there any obvious signs that a person may be deaf?

A: Yes. Deafness may be suspected if a person fails to react to sounds at various levels or speaks more loudly than is necessary. A child who is partially deaf may give the impression of being bored or uninterested and will have difficulty in learning to speak. Such a child may not progress well at school, and it is often a teacher's report that first leads a parent to suspect that the child may have impaired hearing. Deafness in an older person can lead to a sense of isolation, which can make the person bad-tempered. The degree of hearing loss, however, depends on the kind of deafness involved.

Q: What different kinds of deafness are there?

A: It is usual to categorize deafness as being either conductive deafness or sensorineural deafness. Some persons, however, suffer from a combination of the two.

Q: What is conductive deafness?

A: Conductive deafness is hearing loss resulting from interference with the transmission of sound waves through either the outer or the middle ear. Conductive deafness can be either a temporary or a permanent condition.

Q: What causes conductive deafness?

A: Conductive deafness can have many causes, perhaps the most common of which is earwax (cerumen) that obstructs the ear canal and prevents sound waves from reaching the inner ear. Another common cause of conductive deafness is infection of the middle ear (otitis media), which often arises from various childhood diseases, particularly those involving the upper respiratory tract. To prevent hearing loss, children under the age of six who are subject to recurrent otitis media may need to take daily prophylactic antibiotics. Infections of the upper respiratory tract often cause swelling in or around a Eustachian tube. This tube connects the middle ear with the nasopharynx and helps equalize air pressure on both sides of the eardrum. When the pressures are unequal, as often happens during upper respiratory tract infections, deafness can result. Flying in aircraft, or deep-sea diving, can also change pressure within the ear and cause conductive deafness.

Q: How is conductive deafness diagnosed?

A: In addition to direct observation of the signs, otologists and audiologists (specialists in problems of the ears and of hearing) use various tests to diagnose this kind of hearing impairment. One such test involves the use of a tuning fork. If the sound of a vibrating tuning fork is heard more clearly when the fork is placed close to the ear, the deafness is likely to be conductive. Specialists may then use an audiometer to determine the degree of deafness and X-ray photographs of the skull to pinpoint obstructions that may be causing the deafness.

Q: How is conductive deafness treated?

A: Treatment depends on the cause. For example, if earwax is the cause, removal of the wax often restores hearing. This removal should, however, be done only by a trained person; an untrained person may force the wax deeper into the ear or puncture the eardrum.

Other forms of treatment for conductive deafness may also include antibiotics, as in the case of otitis media; draining the fluid build-up fro m the middle ear; and surgery, in the case of a punctured eardrum or an immobile stapes. Surgery in cases of otosclerosis, called stapediolysis and stapedioplasty, are common and highly successful procedures.

Q: What is sensorineural deafness?

A: Sensorineural, or nerve, deafness arises from the inability of nerve impulses to reach the auditory center of the brain because of nerve damage either to the inner ear or to the brain. For example, nerve damage to the cochlea, which contains the sense organ for hearing (the organ of Corti), damage to the ear's auditory nerve, and nerve damage to the cerebral cortex of the brain can all result in sensorineural deafness.

Q: What causes sensorineural deafness?

A: Diseases are a common cause of sensorineural deafness. The diseases include arteriosclerosis, chicken pox, influenza, Meniere's disease, meningitis, mononucleosis, mumps, Rh disease, and syphilis.

Many children born with sensorineural deafness have mothers who contracted rubella (German measles) during the first three months of pregnancy.

Other causes of sensorineural deafness include tumors of the brain or the middle ear, concussion, blows to the ear, and repeated loud sounds. The toxic effects of certain drugs can also cause sensorineural deafness in some persons.

Q: How is sensorineural deafness diagnosed and treated?

A: Together with observation of the obvious signs of deafness, audiologists and otologists use electronic equipment to detect and diagnose sensorineural deafness. Such equipment, which includes various types of audiometers, can also help specialists to determine if tumors or other problems are involved in causing the deafness. Most cases of sensorineural deafness cannot be treated. [Editor: Note that he is talking about MEDICAL treatment, e.g. surgery. Hearing aids are VERY effective in most cases of sensorineural hearing loss.] However, an operation called a cochlear implant, in which a tiny electronic device is surgically implanted, can be helpful.

Q: Can hearing aids help all hearing-impaired persons?

A: No. Hearing aids amplify sound, but such devices are helpful only to persons who retain some hearing.