University of Nevada - School of Medicine

Hearing loss afflicts more than 25 million Americans. Nearly one-third of those over 60- years-old and about one-half of those over 85-years-old have hearing loss.

People who work in areas with high levels of noise are particularly at risk as are those with a family history of hearing loss. Nevada's Newborn Hearing Screening Program, initiated in 2002, is now allowing for earlier detection and treatment of hearing loss in newborns.

How we hear
The ear consists of three parts: the outer ear, middle ear and inner ear, with sound traveling across all three parts. Sound waves enter the ear canal and vibrate the eardrum. The eardrum vibrations are transmitted across three middle ear bones that are connected to each other. The third middle ear bone, called the stapes, is connected to the inner ear where these vibrations continue.

The inner ear hearing organ is a fluid-filled chamber called the cochlea. The cochlea contains sound receptors, called hair cells, which are specialized nerve endings. As the vibrations continue from the middle ear bones to the inner ear, a fluid wave is created. The hair cells or nerve endings are stimulated by the fluid movement. The brain receives the nerve input and perceives sound.

Causes of hearing loss
Causes of hearing loss can come from the outer, middle or inner ear. There are three types of hearing loss: conductive, sensorineural (nerve), and mixed. In a conductive hearing loss, there is usually a problem with sound conducting to the inner ear. There is difficulty with sound transmission across the ear canal, eardrum and middle ear bones to the inner ear. In sensorineural hearing loss, there is usually a problem with the hair cell receptors in the inner ear or with the hearing nerve leading to the brain. A mixed hearing loss features both a conductive and a sensorineural hearing loss component. An audiogram (hearing test) can distinguish the type of hearing loss.

Treatments for hearing loss Surgery may correct a conductive hearing loss. Eardrums can be surgically repaired and diseased middle ear bones replaced with prosthetic implants. Surgery is not typically performed on patients with a nerve hearing loss. Rather, a hearing aid is usually used to treat nerve loss. The exception is the cochlear implant that treats bilateral complete sensorineural deafness.

If you are struggling to hear or if you avoid situations that challenge your hearing, you should consider a hearing aid. A hearing aid is an amplifier that picks up sounds and makes them louder, much like turning up the volume on a stereo. An audiogram provides information regarding your hearing and whether you might be a good candidate for a hearing aid. A cochlear implant is an electronic device that is surgically implanted into the hearing organ to treat total deafness. It converts sound information into programmed electrical stimulation through a wire electrode. Different parts of the cochlea receive certain frequencies and are stimulated with electrical current allowing the brain to receive frequency-rich stimulation. The hearing from a cochlear implant is not normal or natural in the sense of what you or I are used to, but a person with a cochlear implant can detect environmental sounds and voices.

Several things can make hearing easier and listening more effective. Face the person that is speaking to you. Situate yourself so that your better hearing ear is toward the sound source. Choose a seat that allows you to face a speaker. When in a group, position yourself to see as many faces as possible. Maintain good vision by wearing your corrective lens. Avoid areas with poor lighting and try to reduce or eliminate competing background noise, such as turning down the TV or moving to a quiet room.

For more information, contact your primary care physician or University Health System, the clinical practice of the University of Nevada School of Medicine at www.UHSNevada.org