Healthy Hearing Monday

According to a study by researchers at the Johns Hopkins Center on Aging and Health, nearly two-thirds of American adults over the age 70 have some degree of hearing loss. A 2010 study in the Journal of the American Medical Association showed that the prevalence of hearing loss in 12-19 year olds increased from 14.9 percent in 1988 to 1994 to 19.9 percent in 2005 to 2006.

Hearing loss is not just a minor nuisance; it can lead to many other problems. For older people, hearing loss is linked with cognitive and functional decline, as well as the risk of developing dementia. For younger people, it can cause serious social, developmental and educational challenges.

The exact causes of the most common form of hearing loss, age-related hearing loss or presbycusis, vary greatly. However, the second most common form, noise-induced hearing loss (NIHL), is preventable. NIHL can affect people of all ages, genders and races. It may result from long-term exposure to excessive sound levels or one-time exposure to an extremely loud sound, blast, or impulse.

The louder and closer the sound, the less time it takes to cause hearing loss. According to the National Institute of Deafness and Other Communication Disorders, sounds below 75 decibels are not likely to lead to hearing loss, but sounds at or above 85 decibels begin to damage the structure of tiny hair cells in your ears. You should avoid listening to noises above 100 decibels for longer than 15 minutes unprotected, and less than 1 minute unprotected for those above 110 decibels.

Here are examples of the sound levels of some common noises:

• 30 dB: whispered voice
• 60 dB: normal conversation
• 70 dB: washing machine
• 85 dB: heavy city traffic, hair dryer, power lawn mower, cafeteria
• 95 dB: motorcycle
• 100 dB: snowmobile, power tools
• 110 dB: rock concert, chain saw
• 120 dB: ambulance siren, mp3 devices at maximum level
• 150 dB: firecracker

Workers in industries with higher exposures to dangerous levels of noise (agriculture; mining; construction; manufacturing and utilities; transportation; and military) are at a higher risk for permanent hearing loss. These individuals should take extra precautions to avoid hazardous noise exposure by wearing ear plugs or ear muffs.

If you have difficulty hearing, speak with an otolaryngologist (an ear, nose, and throat physician) or have a hearing evaluation conducted by an audiologist. Depending on your degree of hearing loss, hearing aids, cochlear implants, and/or other hearing rehabilitative devices and strategies may be right for you.

As Frank R. Lin, MD, PhD, from the Johns Hopkins Center on Aging and Health says,“Many adults tend to ignore hearing loss as an inconsequential part of the aging process, but increasingly, research is demonstrating that hearing loss is independently associated with cognitive decline, social isolation, and a person’s risk of developing dementia. We’re currently carrying out clinical studies to figure out if hearing interventions could potentially impact these important outcomes, but in the meantime, there’s no reason not to take a potential hearing loss seriously and get evaluated.”

For more information on presbycusis, visit http://nihseniorhealth.gov/hearingloss.

To learn more about preventing NIHL, go to http://www.nidcd.nih.gov/health/hearing/noise.html, http://www.cdc.gov/healthyyouth/noise, or http://www.aafp.org/afp/20000501/2749.html.

For more on work-related hearing loss, visit http://www.cdc.gov/niosh/docs/2001-103/.

To view the cited studies in depth, go to http://biomedgerontology.oxfordjournals.org/content/66A/5/582.short and http://jama.ama-assn.org/content/304/7/772.abstract.