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Research from State University of New York yields new findings on hearing loss
2009 JUL 20 - (NewsRx.com) -- "Previous studies reported that exposure to non-traumatic level sounds after traumatic noise exposure reduced the degree of noise-induced hearing loss and hair cell stereocilia damage. The current study investigated the effects of a 3-day post-noise acoustic environment on the degree of noise-induced hearing loss and cochlear damage," investigators in the United States report. "Female chinchillas were exposed to traumatic continuous noise (4 kHz octave-band noise) at 107 dB SPL for 1 h and then placed in either an augmented acoustic environment (AAE) or deprived acoustic environment (DAE) for 3 days. The AAE group was exposed to a broad-band noise (4-20 kHz) at 80 dB SPL and the DAE animals were fit with conventional earplugs to minimize the level of acoustic stimulation. Auditory brainstem responses (ABRs) were recorded before and 3 days after the traumatic noise exposure. The AAE group showed a significantly lower average threshold shift at the frequencies of 4 and 8 kHz (p < 0.01). Correspondingly, significantly fewer missing and dying outer hair cells (OHCs) were observed in the AAE group than in the DAE group. Although the cochlear reduced and oxidized glutathione levels (GSH and GSSG, respectively) were essentially the same in two groups at day 3, significant correlations were found between GSSG levels and mean ABR threshold shift (1-16 kHz) in the AAE group; as well as GSSG and percentage of total OHC loss in the DAE group," wrote C. Tanaka and colleagues, State University of New York. The researchers concluded: "The results suggest that post-noise acoustic environment influenced the degree of hearing loss and OHC deterioration after traumatic noise exposure." Tanaka and colleagues published their study in Hearing Research (The effects of acoustic environment after traumatic noise exposure on hearing and outer hair cells. Hearing Research, 2009;250(1-2):10-18). For additional information, contact C. Tanaka, SUNY Buffalo, Dept. of Communicat Disorders & Science, Center Hearing & Deafness, 137 Cary Hall, 3435 Main St., Buffalo, NY 14214, USA. The publisher of the journal Hearing Research can be contacted at: Elsevier Science BV, PO Box 211, 1000 AE Amsterdam, Netherlands. Keywords: United States, Buffalo, Audiology, Dietary Supplement, Glutathione, Hearing Loss, Hearing Research, Micronutrient, Otolaryngology, State University of New York. This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2009, Biotech Business Week via NewsRx.com.
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