Age-Related Hearing Loss
Age-related hearing loss (ARHL), also called presbycusis, describes the gradual progressive loss of hearing that people experience as they age. Twenty-five percent of people aged 65—74 and 50 percent of people 75 and older have disabling hearing loss (NIDCD, 2010). However, the majority of older adults suffer from a lesser, nondisabling degree of hearing loss. ARHL often affects hearing in both ears and leads to difficulty hearing and understanding speech in noisy environments. Current treatments focus on restoring hearing through the use of hearing aids.
Hearing loss from various causes has been described throughout history, with several attempted techniques to improve hearing. In the 1600s, hollow cones called ear trumpets were placed in the ear to help amplify sound waves and improve hearing. Electronic hearing aids became available in the late 1800s, with constant improvement in the technology throughout the 20th century.
Tuning Fork Test
Health care providers may use a tuning fork to test a patient’s hearing ability; that is, to determine if a patient has a specific type of deafness or difficulty in hearing certain tones. There are two specific tests that use a tuning fork: the Rinne test and the Weber test. These examinations are named after the otologist or physician that created the assay: Drs. Heinrich Adolf Rinne (1819—1868) and Ernst Heinrich Weber (1795—1878), respectively. Using a tuning fork gives a physician a quick and easy tool to determine the patient’s general level of hearing or deafness.
The tuning fork contains two prongs of equal length and a handle. It is usually made of different metals such as aluminum, magnesium alloy, or steel. The health care provider will strike the prongs against their hand or a table. This will cause the prongs to vibrate at a certain frequency—preferably 512 Hertz (Hz)—based on the properties of the metal, and the tuning fork will produce a specific tone.
If the vibrating tuning fork is placed on the skull behind an ear, the physician is testing the conduction of sound through bones. If the vibrating fork is placed near an ear, the physician is testing the conduction of sound through air. This is called the Rinne test, which determines if the patient has deafness due to bone or air conduction. To test if a patient has a hearing loss in only one ear—termed asymmetrical hearing loss—the doctor will use the Weber test.
512 Hz tuning fork (can be purchased on Amazon.com) or other metallic instrument
Rinne test: Gently hit the tuning fork on a table or the palm of your hand. This will make the tuning fork vibrate. Place the end of the handle of the vibrating fork on any bony prominence near and behind the ear. Ask the person to tell you when they no longer hear the tone. Note the duration of time from the start of the test to when the person cannot hear the tone. Next, move the vibrating tuning fork tines perpendicular to the front of the ear canal, about 1 centimeter away. Ask the person to tell you when they no longer hear the tone and note the time. Compare the time differences between each location. Repeat this same test with the other ear.
Weber test: Place the vibrating tuning fork handle on the skull in the middle of the forehead, the middle of the top of the head, or along the midline of the face. Ask the person if the sound is louder in the left ear, right ear, or if both ears hear the tone at the same volume.
Jennifer L. Hellier
Types and Symptoms
ARHL describes the process where people gradually lose hearing as they age. ARHL is often experienced first in the higher pitches. There are several changes in the inner ear related to aging that can explain the decreased sensitivity to sound and decreased ability to understand speech.
In a normal ear, sound waves enter the external ear canal and reach the eardrum, which will then vibrate. These vibrations are transferred through the small bones in the middle ear to the cochlea. The cochlea is fluid filled; the vibrations reaching the cochlea are detected by specialized hair cells as a wave. The hair cells in the cochlea transmit information as a nerve signal to the brain.
Several types of structural changes can cause age-related hearing loss. Hair cells in the cochlea can be damaged, so that they can no longer receive information to transmit to the brain. Damage to the hair cells results in hearing loss for pitches in the higher frequencies. Alternatively, changes in the blood supply to the cochlea can decrease hearing. Hearing loss from cochlear wall damage results in loss of hearing across a range of tones from low to high. Lastly, ARHL can result from changes in the nerve link from the cochlea to the brain. Often this type of hearing loss causes problems understanding speech.
Symptoms of ARHL are a gradual decrease in the ability to hear. This hearing loss is often first noticed in high-pitched sounds, but can include a variety of pitches. Patients may report difficulty in hearing conversations in noisy environments, understanding speech, or confusing words or sounds. Partners may report communication frustrations.
A medical professional will determine the cause of hearing loss. This investigation will include taking a history of symptoms and considering current and past medication use. The health care professional will also examine the ear for mechanical problems such as wax buildup. Once all causes have been investigated, a patient may be diagnosed with ARHL.
Treatment for ARHL involves providing the patient with the best amplification possible. In order to determine which type of hearing aid is appropriate, audiologists perform detailed testing to identify the range of hearing affected and the degree of loss. Current digital hearing aids are programmable to accommodate hearing loss in various ranges and are able to automatically adjust to various sound environments.
ARHL is degenerative. Hearing loss will continue to worsen over time, often at a slow and steady rate. Currently there are no known ways to slow or stop these age-related changes. Hearing aids are available, however, that can restore hearing in the ranges that have been lost, allowing patients to communicate more easily and engage in most activities.
Among patients who seek treatment, most have a positive outcome in terms of restoring hearing and the ability to engage in activities involving hearing. It should be noted, however, that many patients who could benefit from assistive technologies to improve their hearing do not seek help.
As our population ages, more patients will be managing ARHL. Public education could raise awareness of ARHL and the availability of hearing aids to improve hearing.
In addition to developing better assistive devices for communication, research may reveal other therapies that could delay or reverse ARHL. Current areas of research relevant to ARHL include use of antioxidants to reverse or delay hearing loss, stem cell therapy in the cochlea, and cochlear implants. Research preventing or reversing ARHL will improve quality of life and decrease social isolation for those impacted.
Lisa A. Rabe
See also: Auditory Hallucinations; Auditory System; Cochlea; Cochlear Implants; Deafness; Ear Protection
Huang, Tina. (2007). Age-related hearing loss. Minnesota Medicine, 90(10), 48—50.
NIDCD: National Institute on Deafness and Other Communication Disorders. (2014). Quick statistics. Retrieved from http://www.nidcd.nih.gov/health/statistics/Pages/quick.aspx