Defense Dept. awards $1.2 million for research on NIHL treatment/ prevention

Kathleen Campbell

SPRINGFIELD IL—Kathleen C.M. Campbell, PhD, one of America’s leading researchers on the causes of hearing loss and ways to address  it, has been awarded a $1.2 million grant from the U.S. Department of Defense for a study to determine optimal dosages and timing of dosages of D-methionine (D-met) for protection and rescue from noise-induced hearing loss (NIHL).

Campbell, a professor of otolaryngology head and neck surgery at Southern Illinois University (SIU) School of Medicine and director of audiology research there, is the principal investigator for the three-year federally funded project.

D-met, a component of fermented protein, is a potent antioxidant that is present in many foods. However, only in concentrated doses is it effective in preventing or treating NIHL. Campbell’s laboratory has discovered and patented D-met to address hearing loss.

In the first year of the study, Campbell and colleagues will examine the effects of various dosing levels of D-met in preventing NIHL for different types of noise exposures on animal models. D-met can also be first administered after noise exposure ends, but before the hearing loss becomes permanent.

In the second year, researchers hope to determine the maximum time delay for effective D-met protection. In the final year, they will further define maximum time delay for D-met post-noise protection from permanent NIHL and also determine if additional dosing further improves protection and rescue. The data will ultimately support future clinical trials of D-met for hearing protection in military populations.

Interviewed for an August 9 news release from the SIU School of Medicine Office of Public Affairs, Campbell stated, “We have previously proven that D-met pre-and post-administration provides virtually complete protection from permanent noise-induced hearing loss secondary to a high-intensity six-hour exposure in preclinical studies. We now want to determine the lowest D-met dose that is maximally effective for different types of noise exposures and how long we can wait to start treatment to intervene once hearing loss has occurred.”



The U.S. military receives more than 22,000 new claims a year for noise-induced hearing loss, and NIHL is the most common reason that U.S. soldiers cannot be redeployed. The condition is estimated to cost the Department of Veterans Affairs (VA) more than $1 billion annually.

To date, Campbell’s research has received more than $8.2 million in national and international funding and patent income. She has served as principal investigator on more than 20 research grants and contracts funded by agencies such as the VA, the Illinois Department of Public Health, the National Institute of Aging, and the National Institute of Deafness and Communication Disorders. She also has been issued six U.S. patents for her work.

Before coming to SIU in 1989, Campbell was in charge of electrophysiologic measures for the Department of Otolaryngology at the University of Iowa. Earlier, as a clinician in British Columbia, she started the first audiology clinic in the Canadian Rockies for the province’s department of public health.