Neural Responses to Injury: Prevention, Protection, and Repair. Volume 6. Protecting the Auditory System and Prevention of Hearing Problems

摘要

ANIMAL PROJECT: The SPECIFIC AIMS of this study are to demonstrate and explore mechanisms for preventing the effects of intense sound. In years 01, 02, 03 we discovered that continuous, ipsilateral sound stimulation (CM-LIPS) will produce complex changes in the mechanics of the cochlea. In year 04 we obtained additional evidence that ATP is involved in generating this mechanics. We completed the noise exposure studies and found that continuous noise is less effective than interrupted noise in inducing toughening. Cellular mechanism studies discovered that ATP is not only a cytotoxin but also a mitogen, indicating that ATP may be a key player in noise-induced deafness, 'toughening' and cell growth. HUMAN PROJECT: We have found that binaural noise suppresses linear click evoked emissions twice as much as ipsilateral noise and 3 times as much as contralateral noise. However, of 39 subjects enrolled and 30 completely tested so far in the multi-day protocol, subjects with noise exposure effects at higher frequencies show LESS suppression to clicks in the left ear than do subjects with no hearing loss. This may support the original hypothesis in this program that 'Noise Tender Ears' will show different emission suppression patterns from ears that are tough and supports the observation that, in general, males tend to show more left ear noise trauma than right ear noise trauma.