Do Airbags Cause Hearing Loss?

Most of you know that this newsletter has a companion website called Hearing Loss Web (http://www.hearinglossweb.com) One of the features of our website is a reader forum (http://www.hearinglossweb.com/discus), where people can exchange ideas about a variety of hearing loss topics. One of the topics that I found especially interesting was an exchange about air bags damaging hearing.

It began with a post from a young person who said (in part):

"Last week I was involved in what should have been a minor car accident. I wasn't paying attention and 'gently' hit the car in front of me, which was stopped for a light.

"What happened next was terrifying. The inside of the car seemed to explode in a deafening roar. I had an unimaginable pain in both ears and considerable bleeding from my ear canals. I also had a very loud ringing and was virtually deaf.

"I was taken to the hospital where it was quickly determined that my eardrums had ruptured. I was referred to an ENT who said they should heal in 2-3 weeks but possibly with some scar tissue that would affect my ability to hear low sounds. As for the ringing, he said that could be permanent. He also said I had suffered inner ear damage that would affect my high frequency hearing although he said it was hard to tell how much. He concluded by saying I would need to face life 'hearing impaired' and may need to look at hearing aids.

"I just can't believe this. What has our government done in requiring air bags that leave passengers deafened from minor accidents. I have always protected my hearing and never would have thought about going to loud concerts or auto races without effective ear protection. I'm only 22 and I can barely hear conversation in a quiet room. With background noise, I am almost deaf."

The next few posts were from people who had similar experiences. Some reported that their hearing had returned to near normal, while others reported that their hearing had not.

Then a practicing ENT replied, stating that he has treated several folks for airbag-related conditions. He posted the following information:

"This is a big problem that needs concerted attention. I'm a practicing ENT who has treated a number of patients with air bag induced ear problems.

"I'd like to outline the facts as I see them. When an airbag is deployed, there is a loud "explosion" caused by the rapid escape of high pressure air. This is what gives the protection the air bag is designed for. Sound levels for this deployment have been extensively studied and generally will not cause permanent hearing damage in most cases. The noise is hazardous, but most of us will not experience more than 1 or 2 air bag deployments in a lifetime. Serious ear injury is likely to only occur if the person's ear is right next to the airbag when it goes off. This is almost impossible for the driver but can occur for the passenger. For most people, the impact of an airbag will be a TSS that may cause several hours of ringing and hearing loss.

"The problem that hasn't really been studied is the associated concussion that will occur in the car. The magnitude of this will be determined by the interior volume of the car, the number of air bags deployed, and whether windows are open or shut.

"Small cars, with closed windows, are clearly the worst. The other factor is the physical size of a person's ear canals. People with small or average ear canals (or the opening to the ear canal) will have the impact of the concussion moderated. For people with large or extra large canals, the full force of the concussion will strike their eardrums, sometimes with catastrophic results. Eardrums can be ruptured, the delicate bones of the middle ear can be dislocated, and major inner ear damage can occur. I have treated over 10 patients that experienced this level of injury. All suffered some degree of permanent hearing loss. For reasons I can't explain, 9 of them were women. I believe women, in general, are more susceptible to ear damage than men."

A second ENT then replied, stating that he believes that the number of people whose hearing is damaged by airbags is in the thousands. He believes that cars need to be designed with built-in concussion relief, so the concussion effects described above do not occur. He also thinks that airbag sensitivities should be adjusted so that they are not deployed in a fender bender. He points out that a bloody nose or chipped tooth is preferable to a lifetime of hearing loss.

He also proposes a (somewhat tedious) partial solution. He suggests that people pack cotton very loosely in the openings of their ear canals, stating that this will not affect hearing, but will effectively moderate airbag concussion.