Research Focus: Noise Induced Hearing Loss

Loud concerts. Loud headphones. Loud gunfire. A lifetime of exposure, or even a single incident, can cause noise-induced hearing loss. But other things can cause hearing loss, such as some types of chemotherapy and therapeutic radiation to the head.

More than 36 million people suffer from hearing loss. But the good news is  -- SIU School of Medicine researcher Dr. Kathleen Campbell may have found a way to prevent and treat noise and/or drug-induced hearing loss and tinnitus (ringing in the ears).

For nearly 30 years, Dr. Campbell has studied D-methionine, a component of cheese and yogurt. She found that in large doses, it can prevent several types of hearing loss, including noise induced hearing loss, the most common cause of hearing loss worldwide. Noise-induced costs the U.S. military more than $1.9 billion per year and is the most common reason military personnel cannot be redeployed.

 Kathleen Campbell, PhD 

Noise-induced hearing loss also impacts farmers, police officers, firefighters, hunters, emergency personnel, and people whose car airbags deploy. This oral protective agent that could be given either before or even started a day after noise exposure could be helpful to all these people.

Her research has moved from her lab into Phase 3 clinical trials, where military personnel are volunteering right now to take oral D-Met to prevent noise-induced hearing loss and tinnitus.


D-Met also may protect against:

  • Tinnitus, or “ringing in the ears” that results from noise or age.
  • Radiation-induced oral mucositis, a condition that occurs in 80-100 percent of people being treated with radiation to the head for brain cancers or for head and neck cancers During and after radiation, patients’ mucosa can become so sore they can’t eat or swallow, and they suffer from dry mouth. D-met can protect the mucosa.
  • It may reverse noise-induced hearing loss when treatment begins within 24 hours after noise exposure.

About Dr. Campbell

Kathleen Campbell, Ph.D., is the sole inventor on five issued U.S. patents and a variety of foreign patents. Her group is the only group in the world approved by the FDA and funded by the U.S. Department of Defense to proceed with Phase 3 clinical trials.

She is a Distinguished Scholar and Professor at SIU School of Medicine served on the American Academy (AAA) Board of Directors, received an AAA Presidential Citation, two Medical Innovators Awards and is an American Speech Language Hearing Association (ASHA) fellow. She was the 2012 Inventor of the Year for the Southern Illinois University System. She was named university-wide Distinguished Scholar for 2014.


She authored Essential Audiology for Physicians and edited/authored Pharmacology and Ototoxicity for Audiologists. She has received more than 60 grants from NIH and other agencies for her research in otoprotective agents and is the inventor of the protective agent D-methionine patents. Her employer, SIU School of Medicine, owns her patents.