title: Efficacy of the antioxidant N-acetylcysteine (NAC) in protecting ears exposed to loud music.
abstract: Antioxidants have been reported to be effective in reducing acoustic trauma in animal models but have not been studied in humans. In this study, the antioxidant N-acetylcysteine (NAC) was evaluated to determine if it would reduce temporary changes in auditory function as a result of exposure to loud music in humans. Pure-tone thresholds and distortion product otoacoustic emissions (DPOAEs) were collected in 31 normal-hearing participants, using a randomized, double-blind, placebo-controlled design, before and after two hours of live music in a nightclub. Using repeated measures analysis of variance, no statistically significant differences were found between participants who received NAC versus a placebo for any of the outcome measures. Across all subjects, the largest pure-tone threshold shift occurred at 4 kHz. DPOAE measures were characterized by reductions in amplitude and a trend for shorter group delay values. When the 3 and 4 kHz data were examined by imposing specific criteria of greater than 2 dB DPOAE amplitude reductions and 10 dB or greater pure-tone threshold shifts, DPOAE reductions occurred more often at 3 kHz, and pure-tone shifts occurred more often at 4 kHz.
authors.affiliation: School of Speech, Language, and Hearing Sciences, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182-1518, USA. skramer@mail.sdsu.edu
authors.forename: Steven
authors.initials: S
authors.lastname: Kramer
authors.forename: Laura
authors.initials: L
authors.lastname: Dreisbach
authors.forename: Jill
authors.initials: J
authors.lastname: Lockwood
authors.forename: Kristy
authors.initials: K
authors.lastname: Baldwin
authors.forename: Richard
authors.initials: R
authors.lastname: Kopke
authors.forename: Shawn
authors.initials: S
authors.lastname: Scranton
authors.forename: Michael
authors.initials: M
authors.lastname: O'Leary
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage / Q000494:pharmacology*; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology*; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000517:prevention & control*; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology
chemical_list: D000975:Antioxidants; D000111:Acetylcysteine