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Effect of Prolonged Non-Traumatic Noise Exposure on Unvoiced Speech Recognition

Zhang, Mengchao (2020) Effect of Prolonged Non-Traumatic Noise Exposure on Unvoiced Speech Recognition. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Animal models in the past decade have shown that noise exposure may affect temporal envelope processing at supra-threshold levels while the absolute hearing threshold remains in the normal range. However, human studies have failed to consistently find such issue due to poor control of the participants’ noise exposure history and the measure sensitivity. The current study operationally defined non-traumatic noise exposure (NTNE) to be noise exposure at dental schools because of its distinctive high-pass spectral feature, non-traumatic nature, and systematic exposure schedule across dental students of different years. Temporal envelope processing was examined through unvoiced speech recognition interrupted by noise or by silence. The results showed that people who had systematic exposure to dental noise performed more poorly on tasks of temporal envelope processing than the exposed people. The effect of high-frequency NTNE on temporal envelope processing was more robust inside than outside the spectral band of dental noise and was more obvious in conditions that required finer temporal resolution (e.g faster noise modulation rate) than in those requiring less fine temporal resolution (e.g. slower noise modulation rate). Furthermore, there was a significant performance difference between the exposed and the unexposed groups on tasks of spectral envelope processing at low frequency. Meanwhile, the two groups performed similarly in tasks near threshold. Additional analyses showed that factors such as age, years of musical training, non-dental noise exposure history and peripheral auditory function were not able to explain the variance of the performance in tasks of temporal or spectral envelope processing. The findings from the current study support the general assumptions from animal models of NTNE that temporal and spectral envelope processing issues related to NTNE likely occur in retro-cochlear sites, at supra-threshold levels, and could be easily overlooked by clinically routine audiologic screening.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Zhang, Mengchaomez52@pitt.edumez52
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairBrown, Christopher
Committee MemberPalmer, Catherine
Committee MemberChandrasekaran, Bharath
Committee MemberStern, Richard
Date: 8 September 2020
Date Type: Publication
Defense Date: 4 June 2020
Approval Date: 8 September 2020
Submission Date: 10 July 2020
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 156
Institution: University of Pittsburgh
Schools and Programs: School of Health and Rehabilitation Sciences > Communication Science and Disorders
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: auditory perception, hidden hearing loss, noise exposure, spectral processing, temporal processing
Date Deposited: 08 Sep 2020 14:26
Last Modified: 08 Sep 2020 14:26


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