Effects of N-Acetylcysteine on Thresholds and Otoacoustic Emissions Following Noise Exposure

摘要

Animal research suggests that antioxidants can protect the cochlea from the damaging effects of intense noise exposure. If similar results were found in humans, antioxidants could serve as non-barrier hearing protection, greatly reducing compliance problems associated with wearing ear plugs, muffs, etc.. The current study evaluated the effectiveness of one antioxidant, Nacetylcysteine (NAC), on temporary cochlear changes in humans by using both behavioral and physiological measures. Two levels of supplement (900 mg of NAC or placebo) and two levels of noise (60 dB and 102 dB) were used in a full- factorial, within-subjects design. Participants ingested the supplement 60 minutes prior to exposure to a ten minute narrow-band noise centered at 2 kHz (60 dB or 102 dB intensity). The 102 dB exposure was designed to induce a 10 15- dB temporary threshold shift (TTS). Pure-tone thresholds and otoacoustic emissions (OAEs) were measured for 62 minutes after the noise exposure. No significant threshold differences between NAC and placebo occurred. Results from the 102 dB noise conditions showed that OAEs were reduced from baseline, and this reduction was greater with NAC treatment compared to a placebo.