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Objectives: This study had two objectives. First, baseline audiometric data was assessed for associations with noise exposure history. Seconds, subjects were followed prospectively to assess potential auditory effects of new loud recreational activities. Material and methods: Testing included tympanometry, pure-tone and speech reception thresholds, word-in-noise tests, and ABR and DPOAE measurements. All tests were completed at baseline, and repeated the day after a "loud" recreational event and one week later. Results: There was no reliable relationship between recreational noise history and auditory test metrics. After acute event exposures, a variety of dose-dependent temporary changes were observed across metrics. Final tests one week later showed recovery. Conclusions: Recreational noise was not correlated with chronic or acute changes in function or evoked potential amplitude. However, two subjects with 16-hr exposures had changes in function, indicating hazardous exposures for which hearing protection was needed. [ABSTRACT FROM AUTHOR]

Objectives: Noise exposures that produce robust temporary threshold shift (TTS) reduce auditory brainstem response (ABR) wave-I amplitude. This study evaluated whether these ABR reductions were associated with functional hearing-in-noise deficits. Material and methods: ABR threshold and amplitude, otoacoustic emissions, and hearing-in-noise were assessed in rats before and after noise exposure (106 or 109 dB SPL octave band noise, 8-16 kHz, 2 h). Hearing-in-noise was assessed at various signal-to-noise ratios (SNR). Results: The 106 dB SPL exposure had no effect on ABR or hearing-in-noise after 2 weeks. In contrast, the 109-dB SPL noise reduced ABR wave-1 amplitude at 16-24 kHz and showed hearing-in-noise deficits in the poorest SNR condition, despite threshold recovery. Conclusions: Reduced wave-I amplitude and poorer hearing- in-noise were observed after noise exposure producing robust (>30 dB) TTS at 24 hrs post exposure. Future studies should assess effects of lower level, repeated, exposures that model occupational noise. [ABSTRACT FROM AUTHOR]

There is an urgent need for otoprotective drug agents. Prevention of noise-induced hearing loss continues to be a major challenge for military personnel and workers in a variety of industries despite the requirements that at-risk individuals use hearing protection devices such as ear plugs or ear muffs. Drug-induced hearing loss is also a major quality-of-life issue with many patients experiencing clinically significant hearing loss as a side effect of treatment with life-saving drug agents such as cisplatin and aminoglycoside antibiotics. There are no pharmaceutical agents approved by the United States Food and Drug Administration for the purpose of protecting the inner ear against damage, and preventing associated hearing loss (otoprotection). However, a variety of preclinical studies have suggested promise, with some supporting data from clinical trials now being available as well. Additional research within this promising area is urgently needed.