They're all the rage. Loud "boom cars" - cars with powerful sound systems that seem to pulse in rhythm to the music within. You can hear them coming down the street in your neighborhood, in front of you at the stoplight, or passing you on a highway. So, are they really dangerous to hearing? The answer may surprise you.

The car that won the Mankato decibel drag race in July roared in at 132.2 dB - similar to a jet engine at take-off. At this level, hearing loss for the driver may be instantaneous. On the flip side, a study compiled in 1992 (Ramsey and Simmons) concluded the average car owner with a stereo cranked at 108 dB may be safe from any risk of noise-induced hearing loss because the amount of time they listen is short. It is both these factors - decibels and duration - that cause noise-induced hearing loss, perhaps the most common recreational hazard. Yet, this hazard is completely preventable.

"Unfortunately, noise-induced hearing loss is painless, so most people don't realize they're doing any damage," said Ann Napp, audiologist and adviser for SHA. "The feeling that sound is muffled and that ears are ringing are signs of noise damage."

With noise-induced hearing loss, a person loses the ability to hear various sounds that form words - such as f, sh, th, t, and k. For instance, the word "thumb" could sound like the word "dumb." This results in miscommunication, frustration and eventual isolation.

Noise can cause permanent hearing loss at continual exposures of 85 dB or higher for an eight-hour period. Every five-decibel increase represents a doubling of the sound intensity. So, for example, four hours of noise exposure at 90 dB is considered to provide the same noise "dose" as eight hours at 85 dB; and a single gunshot, which is approximately 140 to 170 dB, has the same sound energy as 40 hours of 90 dB noise.
In the City Pages article, Jeff Sweere, owner of a Mankato stereo store called Sweet Sounds Inc., said that people may spend anywhere from $500 to $100,000 to outfit their vehicles with ear-blasting sound systems.

So, without taking a noise-level meter with you on the road, how can you protect yourself?

International Noise Awareness Day, a worldwide effort sponsored by hearing-related organizations, is SHA's largest educational campaign of the year. In Minnesota, SHA partnered with audiologists to offer free hearing screenings and information statewide on April 12.

In response to newspaper and TV coverage, SHA received 534 calls on its toll-free line regarding the free hearing screenings. More than 300 people took advantage of the hearing screenings - and 200 of those were found to have some type of hearing loss.

A special thank you to the following sites that offered free hearing screenings:

Southdale Otolaryngology, Burnsville Allied Hearing Services, Crystal Hearing Associates, Duluth Allied Hearing Services, Edina Audiologists Hearing Center, Edina East Central Audiology, Forest Lake Otolaryngology, Head & Neck Surgery, Maplewood Allied Hearing Services, Minneapolis Minneapolis Neuroscience Institute, Minneapolis University of Minnesota Physicians, Minneapolis University of Minnesota Department of Communication Disorders, Minneapolis Allied Hearing Services, Minnetonka Willmar Hearing Aid Center - Monte Branch, Montevideo

Oakdale ENT, Plymouth Oakdale ENT, Robbinsdale Olmsted Medical Center, Rochester Audiology Associates Hearing Care, Roseville Professional Hearing Services, St. Cloud St. Cloud State University Department of Communication Disorders Allied Hearing Services, St. Louis Park Audiology and Balance Center, St. Louis Park Associated Hearing of St. Paul, St. Paul Otolaryngology, Head & Neck Surgery, St. Paul Stillwater Medical Group, Stillwater Northwest Medical Center, Thief River Falls Fairview Lakes Regional Medical Center, Wyoming

Background
I was born in Pittsburgh, went to engineering school at Northwestern University in Evanston, Ill., and met my wife. Became an M.D. in Philadelphia and did training in ENT (otolaryngology ) in Cleveland. I did special training in neurotology in Nashville and arrived in Minnesota in 1986.

How long have you been involved with SHA?
About 3-4 years.

Why did you become involved?
I joined because I thought that the organization did some really good things. Screening for hearing loss is something that I think is 1) hard to do, 2) needs to be done, and 3) requires real effort. I felt that I had some obligation to support it and advance the organization. My background at the university helps me to learn about cutting-edge technology and this is one area where application of that technology will make a big difference. I personally know that hearing is really critical to people. I lost a close friend to a brain tumor that could have been diagnosed earlier if he had gotten his hearing tested. My uncle was deafened during the second world war. Hearing loss stops people from talking and limits their ability to communicate. It's a real shame that hearing problems are not attended to better by the society as whole. The only way to change that is to work through organizations like SHA. The bottom line is that if someone has strong feelings, talk is cheap, action is not.

When screening children for hearing, the majority of our referrals are because of ear infections (or otitis media). What do parents need to know about this condition and its ability to affect hearing?
Ear infections are very common. Perhaps 90% of children will have one before they reach first grade. Three things have been shown to reduce the frequency of ear infections: 1) No smoking around the kids; 2) No huge day care facilities; and 3) Breast-feeding for the first six months.
Permanent hearing loss is uncommon but lack of adequate early care can lead to complications later. If a parent thinks that a child might have a hearing loss, insist upon testing and referral to specialists in the area.