Until a decade ago, it was thought that noise damaged hearing by intense mechanical vibrations that destroyed the delicate structures of the inner ear. There was no intervention to protect the inner ear other than reducing the intensity of sound reaching it, such as ear plugs, which are not always effective. It was then discovered that noise caused intense metabolic activity in the inner ear and the production of molecules that damage the inner ear cells; and that allowed the discovery of an intervention to prevent these effects.
The laboratory research that led to a new understanding of the mechanisms underlying noise induce hearing loss was funded by the NIH; the preclinical translational research that led to the formulation of AuraQuell as an effective preventative was funded by General Motors and the United Auto Workers.
Miller notes that the military tests in the new study could be of particular importance because of the high number of soldiers who develop hearing loss in the line of duty, due to improvised explosive devices (IEDs) and other noises.
Last year, he says, the Department of Defense spent approximately $1.5 billion in compensation for hearing impairment, and Veterans Affairs hospitals spent close to $1 billion for clinical care and treatment of hearing impairment. The most recent figures in a report by the Institute of Medicine indicated that one-third of returning soldiers fighting in Afghanistan and Iraq cannot be redeployed specifically because of hearing impairment.
"Not only is it an enormous factor in quality of life for the individual affected, in cost to society for health care and compensation," Miller says, "but it fundamentally compromises the effectiveness of our military at this time." Miller has launched a U-M startup company called OtoMedicine, which holds the license to developed the vitamin-and-magnesium pill for human application.
Hearing loss commonly occurs, Green says, when loud noises trigger the formation of molecules inside the ear and these molecules cause damage to the hair cells of the inner ear. The cells then shut down and scar, and they cannot grow back.
The U-M researchers discovered that this new combination of vitamins, when mixed with magnesium, can prevent noise-induced damage to the ears by blocking some of these complex cellular reactions. Read more about the science of hearing loss, free radicals in hearing loss, and the science behind the effectiveness of these nutrients, in this press release.