Hearing - March 9, 2010 Newsletter

Ear and Hearing Health

EHE Newsletter, Volume 10, Number 10
March 9, 2010

Hearing loss is a common problem that is caused by noise, aging, disease and heredity. According to the National Institute on Deafness and Other Communication Disorders (NIDCD):

Approximately 17 percent of American adults report some degree of hearing loss.
There is a strong relationship between age and reported hearing loss. Of American adults aged 45 to 64, 18 percent have hearing impairments. The percentage increases with age as 30 percent of adults aged 65 to 74, and 47 percent of adults aged 75 or older, have hearing impairments.
Men are more likely to experience hearing loss than women.
Approximately 15 percent of Americans between the ages of 20 and 69 have high–frequency hearing loss due to exposure to loud sounds, noise at work or noise during leisure activities.
Out of every five people who could benefit from the use of a hearing aid, only one actually wears one.

Physiology of the Ears and Hearing

The physiology of the ear and hearing system can be divided into four parts: Outer ear, Middle ear, Inner ear and Central auditory pathways.

Outer Ear: The outer ear consists of the pinna (or "auricle", the part of the ear that projects outward from the head) and the ear canal (also referred to as the "external auditory canal"). The pinna collects and funnels sound down the ear canal. The ear canal is a curved structure that contains hairs and glands that produce wax (known as "cerumen") which helps to lubricate the skin and keep it moist.

Middle Ear: The middle ear is an air–filled space located in the temporal bone of the skull. Here, air pressure is equalized via the Eustachian tube which drains into the nasopharynx (the area at the back of the throat and nose). The middle ear begins with the tympanic membrane (more commonly referred to as the "eardrum") at the end of the ear canal. The tympanic membrane is a thin membrane that forms the boundary between the outer and middle ear. The vibrations of the tympanic membrane are transmitted through the malleus, incus and stapes — three tiny bones that are also referred to as "ossicles." The stapes fills the oval window which is the connection to the inner ear.

Inner Ear: The inner ear is comprised of two main sections: the vestibular labyrinth and the cochlea. The vestibular labyrinth helps to regulate balance and is comprised of the utricle, saccule and semi–circular canals. The cochlea is involved in hearing and is comprised of the scala tympani, scala media and scala vestibuli. The organ of Corti is the sensory receptor inside the cochlea that releases chemical messengers when vibrations from the stapes activate its tiny hair cells. Signals from these hair cells are translated into nerve impulses which are transmitted to the brain by the auditory nerve.

Central Auditory Pathways: The central auditory system is a complex network of neural pathways in the brain that is responsible for sound localization and lateralization, auditory discrimination, auditory pattern recognition, the temporal aspects of sounds and the ability to deal with degraded and competing acoustic signals.

Proper Ear Care

The ears are complex and delicate — designed by nature to be both self–cleaning and self–protecting. Under ideal circumstances, the ear canals should never have to be cleaned. Earwax is necessary for the ear’s self–cleaning mechanism to work properly. It serves several important functions including:

Coating the skin of the ear canal, repelling water and helping to protect it against injury and infection.
Helping to keep the skin inside the ears from becoming dry and itchy.
Trapping dust and germs, preventing them from reaching the eardrum.

Earwax blockages commonly occur when people try to clean their ears on their own by placing cotton swabs or other items in their ears. Instead of clearing the earwax from the ear, these objects push the wax in deeper. It cannot be stressed enough that ears are, on the whole, self–cleaning and do not require any assistance in removing wax. The ears only need to be cleaned when enough earwax accumulates in the ear to prevent a needed assessment of the ear by a healthcare professional or when symptoms arise such as an earache, a feeling of fullness in the affected ear, ear noise (tinnitus) or decreased hearing in an affected ear. Having these signs and symptoms does not necessarily indicate wax buildup; it is possible that another medical condition involving the ears may need attention.

The Recommended Method of Ear Cleaning

To clean the ears, wash the external ear with a cloth, but do not insert anything into the ear canal. According to The American Academy of Otolaryngology—Head and Neck Surgery, most cases of ear wax blockage respond to home treatments used to soften wax such as placing a few drops of mineral oil, baby oil, glycerin or commercial drops in the ear. Detergent drops such as hydrogen peroxide or carbamide peroxide may also help. Additionally, irrigation (or "ear syringing") is commonly used for cleaning and can be performed by a physician or performed at home using a commercially–available irrigation kit. Ear syringing is most effective when water, saline or wax–dissolving drops are put in the ear canal 15 to 30 minutes before treatment. Manual removal of earwax by an otolaryngologist using suction, special miniature instruments and a microscope to magnify the ear canal is also effective. This method is preferred if an individual’s ear canal is narrow, if the eardrum has a perforation or tube, if other methods have failed or if the individual has diabetes or a weakened immune system.

Ailments Affecting the Ears

Many medical conditions can affect hearing health. If left undiagnosed and untreated, some of these conditions can lead to irreversible hearing impairment or deafness. Treatment, on the other hand, can often lead to improved or restored hearing. Some medical conditions that can affect the ears include:

Tinnitus: Tinnitus is often referred to as "ringing in the ears," and can include high–pitched ringing, whining or hissing sounds, or low, roaring noises. Tinnitus ranges from mild to severe and can be persistent, intermittent or throbbing, depending on the cause. It is estimated that approximately 50 million adults suffer from tinnitus. Most tinnitus is a result of damage to the microscopic endings of the hearing nerve in the inner ear. Exposure to loud noise is the leading cause of tinnitus damage in younger people. Tinnitus can also occur naturally due to advancing age. Medical treatments and assistive hearing devices are often helpful to those with this condition.

Otitis media: Otitis media is a bacterial or viral infection of the middle ear and is one of the most common illnesses of early childhood. According to the NIDCD, three out of four children have had at least one ear infection by age three. Although otitis media is primarily a disease of young children, it can also affect adults. Middle ear infections are usually treatable and permanent damage to the ear or hearing is very rare. Otitis media is treated with observation, antibiotics or, in some cases, ear tubes. Acetaminophen or ibuprofen can help relieve earaches and fever until the antibiotic takes effect.

Hearing Loss: According to the Journal of the American Medical Association, there are two major forms of hearing loss: conductive and sensorineural. Conductive hearing loss occurs due to abnormalities in the middle or external ear such as a punctured eardrum, the presence of fluid in the middle ear or accumulation of ear wax in the external ear canal. This type of hearing loss can often be medically or surgically corrected.

Sensorineural hearing loss occurs when there is damage to the cochlea or the nerve pathways between the inner ear and the brain. This type of hearing loss most commonly occurs as a result of excessive noise exposure or aging, but may also occur as a result of exposure to certain diseases, the use of certain drugs, viruses, head trauma or tumors. Individuals with sensorineural hearing loss often have a difficult time filtering out background noise, making it difficult to follow conversations. Sensorineural hearing loss cannot be medically or surgically corrected — it is a permanent loss. Treatment involves the use of sound amplification devices such as hearing aids and/or assistive listening devices such as telephone amplifiers and alerting devices. In cases of severe sensorineural hearing loss, a surgical procedure called "cochlear implantation" may be suggested. Unlike a hearing aid that amplifies sound and directs it into the ear canal, a cochlear implant allows sound vibrations to bypass the hair cells and directly stimulate the nerve that transports sound signals to the brain.

Ménière’s disease: Ménière’s disease is a disorder of the inner ear characterized by vertigo, pressure or fullness in the ear, hearing loss and tinnitus. The symptoms of Ménière’s disease occur suddenly and can arise daily or as infrequently as once a year. According to NIDCD, there is no cure for Ménière’s disease. However, the symptoms of the disease can often be controlled successfully through dietary changes or medication. Eliminating tobacco use and reducing stress levels are additional steps that individuals can take to lessen the severity of their symptoms.

Protecting the Ears and Hearing

Hard and fast rules do not exist for determining how often an individual should receive a hearing exam. Individuals who work in noisy environments, however, should have their ears examined at least annually. Children should also have their ears checked regularly — particularly young children who may not be able to verbalize any discomfort that they may feel.

Many cases of hearing impairment or discomfort can be avoided by employing a few basic hygiene guidelines and some common sense. All individuals should take the following steps to help reduce the chances of developing a hearing disorder:

Avoid loud noise and prolonged exposure to noise. Sounds at or above 85 decibels (dB) can damage the ears (normal conversation is about 60 dB; chainsaws, hammers, drills and bulldozers are over 100 dB).
When noise cannot be avoided, wear ear protection such as ear plugs or other ear protection to prevent hearing loss.
If excessive earwax is a problem, your ears should be cleaned periodically by a healthcare professional. Never stick a cotton swab or other object in your ear to try to remove earwax or to scratch your ear.
Avoid ototoxic drugs. Ototoxic drugs are medications that are toxic to the ear and have the potential to cause permanent or temporary hearing loss. Approximately 200 prescription and over–the–counter drugs are recognized as ototoxic.
Always blow your nose gently and through both nostrils.
During air travel, swallow and yawn frequently when the plane is landing. If you have an upper respiratory problem, take a decongestant a few hours before landing or use a decongestant spray just before landing.
Learn and practice proper underwater descent techniques if you scuba dive.
Always wear your seat belt in the car, and helmet when you bike, ski or skate. These habits can lower your risk of head and ear injury.
Stop smoking. You are more likely to have hearing loss if you smoke.

The ability to hear is critical to the attachment of meaning to the world around us. Our ears not only let us hear, but they also play a role in maintaining our balance, which is vital to our ability to function in daily life. Take the proper steps now to ensure your ear and hearing health.

MEDICAL DISCLAIMER: The information is not intended to constitute medical advice and is not a substitute for consultation with a physician or other health care provider. Individuals with specific complaints should seek immediate consultation from their personal physicians.