Phantom noises that mimic ringing in the ears, associated with tinnitus, can be experienced by people with normal hearing in quiet situations, according to new research published in the January 2008 edition of Otolaryngology – Head and Neck Surgery.

The Brazilian study, which consisted of 66 people with normal hearing and no tinnitus, found that among subjects placed in a quiet environment where they were asked to focus on their hearing senses, 68 percent experienced phantom ringing noises similar to that of tinnitus. This is compared to only 45.5 percent of participants who heard phantom ringing when asked to focus on visual stimuli and not on their hearing, and 19.7 percent of those asked to focus on a task in a quiet environment.

The authors believe that these findings show that with regards to tinnitus, the role of attention to symptoms, as well as silence, plays a large role in experience and severity.

Tinnitus, an auditory perception that cannot be attributed to an external source, affects at least 36 million Americans on some level, with at least seven million experiencing it so severely that it interferes with daily activities. The disorder is most often caused by damage to the microscopic endings of the hearing nerve in the inner ear, although it can also be attributed to allergies, high or low blood pressure (blood circulation problems), a tumor, diabetes, thyroid problems, injury to the head or neck, and use of medications such as anti-inflammatories, antibiotics, sedatives, antidepressants, and aspirin.

Levels of cholesterol in the membranes of hair cells in the inner ear can affect your hearing, said a consortium of researchers from Baylor College of Medicine, Rice University and Purdue University in a report in the print edition of The Journal of Biological Chemistry.

Dr. William Brownell, professor of otolaryngology at BCM and his colleagues, said that the amount of cholesterol in the outer hair cell membrane found in the inner ear can affect hearing.

“We’ve known for a long time that cholesterol is lower in the outer hair cell membranes than in the other cells of the body,” said Brownell, senior author of the report “What we didn’t know was the relationship it had to hearing.”

Dr. Lavanya Rajagopalan, postdoctoral fellow in otolaryngology at BCM, led the research team that manipulated the cholesterol levels in outer hair cells of mice. She and her colleagues measured the mice’s hearing ability by a technique that uses inaudible sound waves emitted from the ear as it reacts to external sound. There are two types of sensory hair cells in the inner ear called the inner and outer hair cells. It is the outer hair cells that are affected by cholesterol levels and produce the inaudible sounds in the ear canal.

“Depleting the cholesterol resulted in a hearing loss. Adding cholesterol initially increased hearing but later resulted in a hearing loss,” Brownell said. “So you can change an animals hearing just by adding or subtracting cholesterol.”

The fine tuning of the cholesterol happens naturally in development and does not change significantly after birth. In contrast, cholesterol in the bloodstream can vary with eating habits. That is why avoiding fatty foods can promote a healthy heart.

“Will our hearing be affected if we continually eat greasy meals? Right now, we don’t see a connection between the two,” Brownell said. “The results of the study help us understand the cellular mechanisms for regulating hearing and give us another way to potentially help those with hearing loss.”

As consumers snap up electronic toys as gifts for all ages, another, very real danger is being overlooked, according to the American Speech Language Hearing Association (ASHA).

To date, this health threat has been largely overlooked as news reports have focused on the lead content of toys, and other serious concerns.

In its November 20, 2007 news release “CPSC Delivers the ABC’s of Toy Safety”, hearing damage from noisy toys or electronic devices is completely absent from the list of dangers to children, according to the U.S. Consumer Product Safety Commission. Yet electronics are among the fastest-growing segment of the toy market, and are being marketed to younger and younger children.

“It is up to adults to safeguard our children and protect them from dangers that we can easily avoid, including lead, choke hazards and hearing damage from loud toys or playing videogames and music too loud, too long,” said Noma Anderson, Ph.D. president of ASHA.

Loud toys and personal listening technologies that aren’t used safely pose a threat to ears of all ages. Once damaged, ears do not heal. For children, hearing loss can also lead to other problems, including difficulties in academic and social development.

As younger and younger children are asking for and receiving electronic toys and music devices like MP3s and iPods, it is critical that parents learn how to protect their children’s hearing and teach them safe listening habits.

Here are some simple guidelines:

How to Maintain Healthy Hearing

– If you must raise your voice to be heard, it is loud enough to damage hearing.

– When evaluating toys for small children, bear in mind that their arms are short and they tend to hold toys close to their face, making noises even louder.

– If you can hear music from someone else’s earphones three feet away, it’s too loud.

– Give your ears a break from continuous listening.

– Upgrade headphones so that they isolate music from background noise. Lower volumes can then be used.

– Set volume limiters before allowing children to use electronic items.

How to Recognize Hearing Loss in Children

– Frequently misunderstands what is said and want things repeated

– Difficulty following verbal instructions

– Turns up the volume of the television, radio, or stereo

– Difficulty listening or paying attention when there is noise in the background

– Trouble identifying and/or localizing sounds

– Reading, spelling, and other academic problems

– Feelings of isolation, exclusion, annoyance, embarrassment, confusion, and helplessness

– Behavior problems

– Pulling or scratching at ears

– A history of three or more ear infections

– If you suspect hearing loss, seek the care and advice of a certified audiologist.

http://www.asha.org offers referrals and additional materials on hearing loss, including animated video of how sound damages the ear’s hair cells at http://asha.org/about/news/convention06/1106animationEar.htm

ASHA is the first and only healthcare advocacy organization focusing on teaching young children safe listening habits.

About ASHA

ASHA, located in Rockville, Maryland, is the professional, scientific, and credentialing association for more than 127,000 audiologists, speech-language pathologists, and speech, language, and hearing scientists in the United States and internationally.

About the Listen To Your Buds Campaign

ASHA’s Listen to Your Buds campaign is supported by the Consumer Electronics Association, Arlington, Virginia; Califone International, Inc., San Fernando, California; Pause Parent Play, Washington, D.C.; Unwired Technologies of New York, and the rock group, O.A.R.

American Speech Language-Hearing Association (ASHA)
10801 Rockville Pike
Rockville, MD 20852
United States

http://www.asha.org

Research funding into deafness in the UK is around only one thousandth of the estimated lost productivity from hearing impairment. This and other deafness related issues are highlighted in an Editorial in this week’s edition of The Lancet.

At a recent conference organised by The Royal National Institute for the Deaf and Hard of Hearing People (RNID), productivity losses related to hearing impairment were estimated to cost the UK £13•5 billion, whereas just £16•5 million is invested annually.

The Editorial says: “Because hearing loss is commonly of gradual onset, more prevalent with age, often results in stigma, and makes people prone to isolation, estimates of burden are difficult to obtain and usually conservative. Results from a recently published UK study showed that 12% of adults aged 55-74 years had substantially impaired hearing, which on average had been present for a decade. Yet only 3% used a hearing aid, suggesting widespread unmet need.” The 278 million people worldwide (WHO estimate) that have a disabling hearing impairment could increase in parallel with aging populations to 700 million by 2015 and 900 million by 2025. Two thirds of those affected live in developing countries.

The most prevalent form of hearing-loss, presbycusis, is age-related, but influenced by genetic predisposition, cumulative acoustic trauma, and metabolic factors. However, hearing impairment is not confined to old age. A quarter of the UK’s 9 million hearing-impaired people are aged 16-60 years, for whom poor hearing limits their quality of life, as well as educational, social, and employment opportunities.

The Editorial concludes: “Hearing aids can help relieve symptoms, but further interventions are needed to prevent, delay, or reverse hearing damage…Although the many determinants of hearing make research complex, successful strategies would have not only a large and lucrative market, but also great social value.”

Call it acoustic trauma or noise-induced hearing loss. By any name, it’s the most important preventable cause of permanent hearing loss. Up to 28 million Americans have impaired hearing; for as many as a third, acoustic trauma is a significant contributor, reports the December 2007 issue of Harvard Men’s Health Watch.

Acoustic trauma is a product of modern life. On-the-job noise exposure is the most common cause, but recreational noise — such as loud music — is catching up. If present trends continue, the condition may someday be known as “iPod ear.”

A sound’s potential to damage the ear depends on the duration as well as the intensity of the sound. How much sound is dangerous? The Occupational Safety and Health Administration offers guidelines: Sounds below 75 decibels (dB) are safe, but eight hours at 85 dB can be harmful. (The sound of a lawnmower or heavy traffic is approximately 90 dB.)

Most often, noise-induced hearing loss begins with a subtle difficulty hearing high-frequency tones, then slowly begins to encompass lower tones. Usually, both ears are equally involved. Once your hearing is lost, it can’t be restored; your only recourse is to wear a hearing aid. That’s why it is important to recognize the warning signs. If your ears ring or buzz after being exposed to noise, it’s loud enough to cause damage. And if noise exposure makes hearing painful, muffled, blurry, or distant for hours or days, you are already in trouble.

Harvard Men’s Health Watch provides some sound advice: First and foremost, turn down the volume. For occasional exposures, use disposable ear plugs. If you’re frequently at risk, invest in custom-fitted ear plugs. And for maximum protection, add acoustic earmuffs.