What Causes a Person to Become Hearing Impaired?
More than 28 million Americans are either deaf or struggle with some degree of hearing loss, according to the Merck Manual Online Medical Library. Anything blocking the ear can cause hearing loss. The main cause is overexposure to loud music. Because it's not noticeable to most people when they're young, they continue to expose their ears to loud music, which can cause premature hearing loss.
Aging
The Merck Manual Online Medical Library notes that seniors 65 and older make up about 30 to 40 percent of hearing-impaired people. Hearing loss due to aging is known as presbycusis. With aging, the structures of some peoples' ears become less elastic, making them less responsive to sound waves. In some people hearing loss linked to aging can begin as early as age 20, although most people don't notice it until after the age of 50.
Noise-Induced Hearing Loss
Overexposure to loud noises can cause what's known as noise-induced hearing loss, or NHL. This can be caused by regular exposure to machinery noise or blaring music. Personal music players are the main reason that young people, especially, suffer hearing loss. Other culprits may include television sets, video games, movie theaters and traffic.
Birth Defect
According to a recent KidsHealth article, hearing impairment is the most common birth defect, with about three out of 1,000 babies born with little or no hearing. Autosomal recessive inheritance accounts for most congenital deafness. This condition is the result of both parents carrying and passing on a copy of a defective gene, although neither parent is affected.
Otosclerosis
This hereditary disorder is caused by excessive growth of the bone that surrounds the middle and inner ear. This bone overgrowth results in the stirrup becoming immobilized. When this occurs, the stirrup, which is the ear bone connected to the inner ear, can't transmit sounds correctly. Besides running in families, otosclerosis can also develop from having measles.
External Ear Canal Blockage
Mechanical problems in the middle ear or external ear canal can cause hearing impairment. Often when wax collects in the middle ear, it causes blockage of sound conduction. On rare occasions a tumor can be the reason for the blockage, resulting in hearing loss. However, the most typical cause for middle ear hearing loss is fluid buildup, which usually affects children. Ear infections, allergies or tumors blocking the tube draining the middle ear (eustachian tube) are some of the reasons for fluid accumulation.
Damage to Sensory Structures
Damage to the sensory structure (hair cells) can cause hearing loss. When the auditory nerve or the cranial auditory nerve pathways are damaged, sensorineural hearing loss can result. Drugs, tumors, infections and skull injuries are some causes of sensory structure damage. On the other hand, hearing loss can be caused by a mixture of both.
Diseases
Diseases such as autoimmune disorders can cause hearing loss. The immune system attacks the cochlea cells, resulting in irregular hearing loss. Occurring in both ears, the hearing impairment may be progressive. Other diseases contributing to hearing impairment include rheumatoid arthritis, polyarteritis, systemic lupus and erythematosus.
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