The effect of high frequency, low level conditioning exposures on hearing loss from a high frequency traumatic exposure was studied in chinchillas. Animals were made monaural by surgical intervention; recording and ground electrodes were implanted and animals were allowed to recover for at least 2 weeks prior to testing. Conditioning consisted of exposure to an octave band noise centered at 4 kilohertz at 85 decibels for 6 hours per day for 10 days. One group of animals recovered for 5 days while the other group recovered for 18 hours. Animals were then exposed to a 100 decibel noise for 48 hours. A control group was exposed only to the higher decibel level. Changes in hearing were determined after 4 weeks of recovery; measurements included threshold shifts and hair cell loss. The 5 day recovery group incurred greater threshold shifts than the other two groups and greater hair cell loss than the 18 hour recovery group. The 18 hour recovery group incurred less threshold shift and less hair cell loss than the other two groups. The authors conclude that conditioning type exposures may protect the auditory system from subsequent higher level exposures; the degree of protection varies with the time course of recovery.
Keywords
NIOSH-Publication; NIOSH-Grant; Noise-induced-hearing-loss; Hearing-acuity; Hearing-impairment; Laboratory-animals; Noise-exposure; Auditory-system;
Author Keywords: Hearing loss; Conditioning; High frequency traumatic exposure; Base vs. apex
Links with this icon indicate that you are leaving the CDC website.
The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link.
CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website.
For more information on CDC's web notification policies, see Website Disclaimers.
CDC.gov Privacy Settings
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.
Thank you for taking the time to confirm your preferences. If you need to go back and make any changes, you can always do so by going to our Privacy Policy page.