Donald Henderson1
X.Y. Zheng1
Nancy G. Hight1
Sandra L. McFadden1
and Richard Kopke2
(1) Center for Hearing & Deafness
State University of New York at Buffalo
215 Parker Hall
Buffalo, New York, 14214
(2) Naval Medical Center
Neurotology/Skull Base Surgery
34800 Bob Wilson Drive
San Diego, CA
92134-5000
The military has been very successful in developing hearing conservation programs that are built upon education of personal protection devices. Unfortunately, military personnel can be found in situations where hearing protection devices are impartial; consequently, alternative protection strategies need to be developed. Our approach to this problem begins with an evaluation of the processes of cell death associated with noise exposure and understanding the ear's natural defense system. This presentation will review the effects of noise - especially, impulse noise - on the cochlea. We are now learning that immediately after an exposure cochlear lesions are relatively small and expand, involving additional hair cells over 2 to 15 days after an exposure. The mode of cell death includes both necrosis and apoptosis. The stress of a noise exposure increases the concentration of endogenous antioxidants. The ear can be made more resistant to noise by either prophylactic noise exposures that enhance the natural defense system or by increasing cochlear antioxidants by direct application to the cochlea. Basic science information on the effects of noise will serve as the foundation for the development of clinical procedures to protect and rescue the ear by using drugs that prevent the initial attack on cochlear hair cells or block their death after an exposure.
(Research supported by NIH/NIDCD #DC0360001A1)