A hearing aid is an electronic, battery-operated device that amplifies and changes sound to allow for improved communication. Hearing aids receive sound through a microphone, which then converts the sound waves to electrical signals. The amplifier increases the loudness of the signals and then sends the sound to the ear through a speaker.
How Common Is Hearing Loss and What Causes It?
Approximately 28 million Americans have a hearing impairment. Hearing loss is one of the most prevalent chronic health conditions in the United States, affecting people of all ages, in all segments of the population, and across all socioeconomic levels. Hearing loss affects approximately 17 in 1,000 children under age 18. Incidence increases with age: approximately 314 in 1,000 people over age 65 have hearing loss. Hearing loss can be hereditary, or it can result from disease, trauma, or long-term exposure to damaging noise or medications. Hearing loss can vary from a mild but important loss of sensitivity, to a total loss of hearing.
Hearing depends on the following series of events that change sound waves in the air into electrical impulses that the auditory (hearing) nerve carries to the brain. The ear has three major parts, described as the outer ear, middle ear, and inner ear.
- Sound waves enter the outer ear (pinna) and travel through a narrow tube (ear canal) that leads inside the ear to the eardrum (tympanic membrane). The eardrum vibrates from the incoming sound waves and transmits these vibrations through three tiny bones called the ossicles (the malleus, incus, and stapes) in the middle ear. They amplify the sound and send it through the entrance to the inner ear (oval window) and into the fluid-filled hearing organ (cochlea).
- The vibrations create ripples in the fluid that bend projections from tiny hair cells in the cochlea, causing electrical impulses that the auditory nerve, or eighth cranial nerve, sends to the brain.
- The brain translates these impulses into what we experience as sound.
There are different types of hearing loss. Conductive hearing loss occurs when sound waves are prevented from passing to the inner ear. This can be caused by a variety of problems including buildup of earwax (cerumen), infection, fluid in the middle ear (ear infection or otitis media), or a punctured eardrum. Sensorineural (nerve) hearing loss develops when the auditory nerve or hair cells in the inner ear are damaged by aging, noise, illness, injury, infection, head trauma, toxic medications, or an inherited condition. Mixed hearing loss is a combination of both conductive and sensorineural hearing loss. A conductive hearing loss can often be corrected with medical or surgical treatment, while sensorineural hearing loss usually cannot be reversed.
People with hearing loss may experience some or all of the following problems:
- Difficulty hearing conversations, especially when there is background noise.
- Hissing, roaring, or ringing in the ears (tinnitus).
- Difficulty hearing the television or radio at a normal volume.
- Fatigue and irritation caused by the effort to hear.
- Dizziness or problems with balance.
How Can I Find Out if I Have Hearing Loss?
If you think you might have hearing loss, visit your physician, who may refer you to an otolaryngologist or audiologist. An otolaryngologist is a physician who specializes in ear, nose, and throat disorders, and will investigate the cause of the hearing loss. An audiologist is a hearing health professional who identifies and measures hearing loss and will perform a hearing test to assess the type and degree of loss.
