Most audiologists realize that noise-induced hearing loss (NIHL) refers to a gradual, cumulative and preventable decline in auditory function that follows repeated exposure to loud noise. It is, of course, the leading cause of preventable hearing loss. It is also estimated that 10% (30 million) of Americans are encountering hazardous levels of noise, that 25% of those working in the construction, mining, agriculture, manufacturing, transportation, and military industries routinely encounter noise levels above 90 dB (A), and that such noise exposure has already generated a sizeable population of workers who meet the Occupational Safety and Health Administration’s (OSHA) definition for “material impairment of hearing” (over 25 dB threshold at 1000, 2000, and 3000 Hz). This number is probably much greater among workers and participants in high noise activities in countries where regulations are not as stringent as those in developed countries. Since workers and those with recreational hearing losses can have significant effects on their employment, social interactions, family interactions, protecting hearing health in the workplace and while having fun has become very important. Programs and regulations for occupational exposure (e.g. maximum allowed daily noise doses) have been designed, but no matter where you live there are virtually no standards for recreational noise, an emerging contributor to noise-induced hearing loss. There are numerous sources of non-occupational noise exposure. Clark and Bohne have compiled a partial list of significant sources of leisure noise, and music figures prominently in their construct.
Music, in addition, transcends the recreational setting to pose an occupational risk of NIHL for groups such as music venue workers and music performers, even the audiences……
Think back ……
Most of us (yes, even audiologists) have “been there” at one time or another………You are a fan! A BIG FAN (LL Cool J, Beyonce, Madonna, maybe even the Stones)…..and your favorite musical artist is in town for a greatest hits concert! You have a baby sitter, a designated driver….. Look out you are out on the town! As Rick Nelson said, “Sang them all the old songs, thought that is why they came” (click for great old song)…… and that IS why they came…and a super time was had by all ! The Next Day: You wake up with horrible tinnitus, probably a hangover (this is a fun link) as well and wonder why it was so important to get close to the speakers during the rock concert the night before…….As the day goes on you begin to feel better, but the tinnitus lingers on reminding you of a major noise exposure the night before. Over the next day or so, the tinnitus will usually subside and we end up OK, but as audiologists we know that there has been some hair cell destruction. Typically, the noise exposure causes levels of toxic chemicals called “free radicals” inside the hair cell to rise beyond manageable levels, and the cell dies. We also know that if we continue to attend too many of these concerts the exposure to the intense sound levels will ultimately lead to a number of hair cell deaths and, subsequently, a permanent hearing impairment. BUT….What if we could reverse the process, make it like we had never been exposed at all….a Morning After Pill…..Now it probably will not do too much for the hangover, but there may be a method to minimized or eliminate the effects of the noise exposure due to taking a pill that actually works.
The Morning After
Studies in this area have been ongoing for a number of years. Based upon their studies, researchers at the University of Michigan, Kresge Hearing Research Institute have developed AuraQuell (pill) which is a combination of Vitamins A, C and E, plus magnesium, taken before a person is exposed to loud noises. The funding for the Michigan project was provided by General Motors and the United Auto Workers that led to the 2007 study of the mechanism attributed to induce hearing loss and the pre-clinical research that contributed to the development of AuraQuell. During clinical studies, guinea pigs who had been administered AuraQuell experienced about eighty percent preventative blockage of noise-induced hearing impairment (“The treatment one hour before a five hour exposure to 120 decibel (dB) sound pressure level noise, and continued once daily for five days.” Josef M. Lynn, Ph. D., the Lynn and Ruth Townsend Professor of Communication Disorders, Director of the Center for Hearing Disorders at the University of Michigan Department of Otolaryngology’s Kresge Hearing Research Institute and co-leader of the research expects AuraQuell could effectively block fifty percent of noise induced hearing loss in humans. A trademark for AuraQuell was granted in June 2009. Clinical human testing of AuraQuell is being evaluated in four multinational trials: “Military trials in Sweden and Spain, an industrial trial in Spain, and trial involving students at the University of Florida who listen to music at high volumes on their iPods and other PDAs.” The human clinical trials for AuraQuell maybe in the form of a tablet or snack bar. These trials studies are funded by National Institute of Health (NIH).”This is the first NIH – funded clinical trial involving the prevention of noise-induced hearing loss.” AuraQuell may prove to limit induced hearing loss of military personal exposed to improvised explosive devices (IEDs) and other noises. It appears that AuraQuell is still in clinical field trials, but if these trials are successful, Dr. Joseph Miller, the noise-induced hearing loss prevention concoction could be available within two years.
In another study funded by the Oklahoma Medical Research Foundation, researchers Dr. Robert Floyd and retired Army surgeon, Dr. Richard Kopke, M.D., discovered a combination of two compounds stopped damage to the inner ear caused by acute acoustic trauma – something like an IED exploding. Although they did not indicate what the compounds were they felt that,“This is a very exciting finding,” said Dr. Floyd, who holds the Merrick Foundation Chair in Aging Research at OMRF. “The research is still at a pre-clinical stage, but we’re hopeful that we soon can begin testing in humans.
More recently, Dr. Kathryn Campbell’s work at Southern Illinois University involves the use of an antioxidant called D-methionine, a component of fermented protein that is found in yogurt and cheese. The antioxidant, in concentrated doses, has been found to improve some forms of hearing loss and even prevent hearing loss before the exposure to noise. “We’ve been able to show in animal studies that if we give it before and after noise exposure, that we can get pretty full protection from noise-induced hearing loss,” Campbell said. According to Campbell and her colleagues will continue their studies by looking at the effects of varying dosages of D-methionine on animal subjects exposed to different noises. They have already found that the drug can be given up to seven hours after the noise is experienced and still be effective.”It doesn’t mean it’s going to work for long-standing hearing loss, but it does mean that in the early stages, you could intervene and keep it from becoming permanent,” she said. The research will then move into determining if even more time can elapse before the drug is given and the hearing loss becomes permanent. Human clinical trials with the U.S. Army are in the early planning stages, Campbell said.
So, with AuraQuell in field tests to defend against noise-induced hearing loss, the D-methionine possibilities also in clinical trial, and the on going stem cell research reported by Hearing International last fall, a “morning after” (and one last song), pill for that tinnitus and noise induced hearing loss created the night before may soon be a simple swallow away. The hangover (Click here for an interesting video), however, may have to linger.