کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4356252 | 1615674 | 2007 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effect of infrasound on cochlear damage from exposure to a 4Â kHz octave band of noise
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کلمات کلیدی
infrasoundSPLABRDPOAENIHLnoise-induced hearing loss - افت شنوایی ناشی از سر و صداdistortion product otoacoustic emission - انتشار محصولات octo آکوستیک محصول اعوجاجorgan of Corti - اندام کورتیNoise - سر و صداSound pressure level - سطح فشار صوتtympanic membrane - غشای تمپانHistopathology - هیستوپاتولوژیauditory brainstem response - پاسخ شنوایی مغزChinchilla - چینچیلا
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
سیستم های حسی
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چکیده انگلیسی
Infrasound (i.e., <20Â Hz for humans; <100Â Hz for chinchillas) is not audible, but exposure to high-levels of infrasound will produce large movements of cochlear fluids. We speculated that high-level infrasound might bias the basilar membrane and perhaps be able to minimize noise-induced hearing loss. Chinchillas were simultaneously exposed to a 30Â Hz tone at 100Â dB SPL and a 4Â kHz OBN at either 108Â dB SPL for 1.75Â h or 86Â dB SPL for 24Â h. For each animal, the tympanic membrane (TM) in one ear was perforated (â¼1Â mm2) prior to exposure to attenuate infrasound transmission to that cochlea by about 50Â dB SPL. Controls included animals that were exposed to the infrasound only or the 4Â kHz OBN only. ABR threshold shifts (TSs) and DPOAE level shifts (LSs) were determined pre- and post-TM-perforation and immediately post-exposure, just before cochlear fixation. The cochleae were dehydrated, embedded in plastic, and dissected into flat preparations of the organ of Corti (OC). Each dissected segment was evaluated for losses of inner hair cells (IHCs) and outer hair cells (OHCs). For each chinchilla, the magnitude and pattern of functional and hair cell losses were compared between their right and left cochleae. The TM perforation produced no ABR TS across frequency but did produce a 10-21Â dB DPOAE LS from 0.6 to 2Â kHz. The infrasound exposure alone resulted in a 10-20Â dB ABR TS at and below 2Â kHz, no DPOAE LS and no IHC or OHC losses. Exposure to the 4Â kHz OBN alone at 108Â dB produced a 10-50Â dB ABR TS for 0.5-12Â kHz, a 10-60Â dB DPOAE LS for 0.6-16Â kHz and severe OHC loss in the middle of the first turn. When infrasound was present during exposure to the 4Â kHz OBN at 108Â dB, the functional losses and OHC losses extended much further toward the apical and basal tips of the OC than in cochleae exposed to the 4Â kHz OBN alone. Exposure to only the 4Â kHz OBN at 86Â dB produces a 10-40Â dB ABR TS for 3-12Â kHz and 10-30Â dB DPOAE LS for 3-8Â kHz but little or no OHC loss in the middle of the first turn. No differences were found in the functional and hair-cell losses from exposure to the 4Â kHz OBN at 86Â dB in the presence or absence of infrasound. We hypothesize that exposure to infrasound and an intense 4Â kHz OBN increases cochlear damage because the large fluid movements from infrasound cause more intermixing of cochlear fluids through the damaged reticular lamina. Simultaneous infrasound and a moderate 4Â kHz OBN did not increase cochlear damage because the reticular lamina rarely breaks down during this moderate level exposure.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Hearing Research - Volume 225, Issues 1â2, March 2007, Pages 128-138
Journal: Hearing Research - Volume 225, Issues 1â2, March 2007, Pages 128-138
نویسندگان
Gary W. Harding, Barbara A. Bohne, Steve C. Lee, Alec N. Salt,