New Research Indicates That Hearing Loss May Not Be an Inevitable Part of Aging

Noel Peterson, ND

Research teams from the University of Buffalo, led by S. L. McFadden and R. J. Salvi of the Hearing Research Lab, studied the relationship between the antioxidant enzyme superoxide dismutase (SOD) and age-related hearing loss. They found that hearing loss was more severe and progressed much faster when deficiencies of SOD were present. The researchers examined mice that had been manipulated to display genetic SOD deficiencies. Mice provide good models for hearing loss because, like humans, they lose hearing at high frequencies first--unlike most other animals.

Compared with the control group, SOD-deficient mice in both experiments lost hearing much faster and much more severely. The investigators postulated that deficiencies in SOD cause free radical excess that severely damages the sensory hair cells in the inner ear. They propose that humans with SOD deficiencies may be at greater risk for losing hearing, both as they age and as they are exposed to environmental noise. Reducing free radical accumulations may be a key strategy in preventing or lessening such losses, they reported.

The results of this study on SOD and hearing loss were presented at a recent meeting of the Association for Research in Otolaryngology in St. Petersburg. In addition to this study, there were ten other presentations by leading experts linking oxidative stress with degenerative hearing loss.

(For abstracts #519 and #520 by the Buffalo teams and related abstracts see: http://www.aro.org/abstracts/1998/A98.html and http://www.aro.org/abstracts/1998/R398.html)