Hearing Loss in Adults
Hearing loss in adults can occur quickly or slowly over time, and the severity can range from mild to severe. The cause of hearing loss can be biological (i.e., infection, disease, tumors, aging) or environmental (i.e., trauma, exposure to noise or to ototoxic drugs).
There are two categories of hearing loss:
- Conductive hearing loss is due to the inability of the outer and/or middle ear to conduct sound properly. Hearing loss is generally less severe in conductive hearing loss cases because the inner ear still functions correctly.
- Sensorineural hearing loss is caused by insensitivity of the inner ear, cochlea, or by an impairment of the auditory nervous system. The severity of sensorineural hearing loss can range from mild to total deafness.
Primary Causes of Hearing Loss in Adults
Infection- A bacterial infection can damage hearing in a number of ways. The eardrum or middle ear bones can be injured, or a buildup of fluids in the ear can prevent good hearing.
Otosclerosis- This disease involves the middle ear, where one or more of the bones overgrow, preventing them from functioning normally. The onset of the disease is generally middle age, and more women are affected than men. Otosclerosis is treated with hearing aids or with a surgery called stapedectomy.
Meniere’s disease- This disease affects the membranous inner ear. Symptoms include: loss of hearing, dizziness (vertigo), and a “stuffy” feeling and ringing in the ears. A build up of fluid in the ear is believed to be responsible for the hearing loss, but the cause of Meniere’s disease is unknown.
Medication- Some medications are known to damage the auditory system. These drugs are called ototoxic medications. Some examples of ototoxic drugs are: antibiotics (such as streptomycin, neomycin, and kanamycin), aspirin, loop diuretics (such as lasix and ethacrynic acid), antimalaria drugs, and chemotherapy drugs (such as cisplatin, carboplatin, and nitrogen mustard).
Acoustic neuroma- This is caused by a benign (noncancerous) tumor on the cranial nerve, which transmits information from the ear to the brain. Other symptoms of acoustic neuroma include dizziness and balance problems.
Sudden sensorineural hearing loss- This is when a person loses hearing, usually in only one ear, in three days or fewer. The cause is unknown but doctors believe it is caused by a virus.
Noise- There are several ways of acquiring noise-induced hearing loss. Hearing can be damaged by a single, very loud, sound, like an explosion or gunshot. However, most cases of noise-induced hearing loss are caused gradually, by constant loud noises. Certain work environments can be damaging to employees’ hearing. For example, construction workers, miners, factory workers, and people working with explosives tend to experience more hearing loss than the general population. Other activities can damage hearing as well. Riding motorcycles and personal watercrafts, listening to loud music, shooting guns, and mowing can all damage hearing. People who are around loud noises should use ear protection.
Trauma- Physical trauma to the ears or head can cause hearing loss. Foreign objects (such as Q-tips), sudden changes in pressure, and temporal bone fractures are all examples of traumatic causes of hearing loss.
Age- Age related hearing loss, or presbycusis, is the result of the cumulative effects of aging on the ears. Both ears are affected, and high-pitched tones are generally more difficult to hear than lower tones. This type of hearing loss occurs gradually over time, but generally is noticeable after 60 years of age.