VARIATION IN ACOUSTIC OVERSTIMULATION CHANGES TINNITUS CHARACTERISTICS
VARIATION IN ACOUSTIC OVERSTIMULATION CHANGES TINNITUS CHARACTERISTICS
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DOI：
10.1016/j.neuroscience.2015.09.023
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发表时间：
2015-12-03
期刊：
影响因子：
3.3
通讯作者：
Nowotny, M.
中科院分区：
文献类型：
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作者：
Kiefer, L.;Schauen, A.;Nowotny, M.
耳鸣常发生在暴露于巨大噪音之后。这就提出了一个问题，反复暴露于噪音是否会增加患耳鸣的风险。因此，我们研究了耳鸣的发展后，反复声过度刺激惊吓和听觉脑干反应技术应用于蒙古沙鼠。带宽范围从0.25到0.5 oct的噪声用于重复的声学过度刺激。听觉脑干反应的测量结果显示，在两组的阈值变化高达约30分贝后，直接声学过度刺激。我们确定了阈值的上限，这是独立的噪声暴露前的基线值。声过度刺激后数周，噪声带宽为0.25 oct的动物表现出永久性阈值偏移，而噪声带宽为0.5 oct的动物仅表现出暂时性阈值偏移。因此，我们得出结论，噪声暴露后的阈值偏移不能直接用作几周后即将到来的阈值水平的指标。通过使用行为测量，我们研究了两组和一组1-oct噪声带宽的耳鸣相关变化的频率依赖性发展。显示耳鸣相关变化的动物的数量是最高的动物，收到噪音的带宽0.5 Oct.这个数字是，在0.25 Oct.带宽的动物的数量相比，没有显着增加后，反复过度刺激。耳鸣相关变化的频率分布范围为4 - 20 kHz。在具有窄带噪声（0.25 oct）的组中，中心在10至12 kHz的一个频率范围内变化。然而，在具有较宽噪声频带（0.5oct）的组中，在8-10 kHz和16-18 kHz处发现两个峰值，这表明耳鸣发展的不同机制。(C)2015作者由Elsevier Ltd.代表IBRO出版。这是一个CC BY-NC-ND许可下的开放获取文章。
Tinnitus often occurs after exposure to loud noise. This raises the question of whether repeated exposure to noise increases the risk of developing tinnitus. We thus studied tinnitus development after repeated acoustic overstimulation using startle and auditory brainstem-response techniques applied to Mongolian gerbils. Noise with bandwidths ranging from 0.25 up to 0.5 oct were used for repeated acoustic overstimulation. Auditory brainstem response measurements revealed similar threshold shifts in both groups of up to about 30 dB directly after the acoustic overstimulation. We identified an upper limit in threshold values, which was independent of the baseline values before the noise exposure. Several weeks after the acoustic overstimulation, animals with the noise bandwidth of 0.25 oct showed a permanent threshold shift, while animals of the group with the 0.5-oct noise band featured only a temporary threshold shift. We thus conclude that the threshold shift directly after noise exposure cannot be used as an indicator for the upcoming threshold level several weeks later. By using behavioral measurements, we investigated the frequency-dependent development of tinnitus-related changes in both groups and one group with 1-oct noise bandwidth. The number of animals that show tinnitus-related changes was highest in animals that received noise with the bandwidth 0.5 oct. This number was, in contrast to the number of animals in the 0.25-oct bandwidth, not significantly increased after repeated overstimulation. The frequency distribution of tinnitus-related changes ranged from 4 to 20 kHz. In the group with the narrow-band noise (0.25 oct) changes center at one frequency range from 10 to 12 kHz. In the group with the broader noise band (0.5 oct), however, two peaks at 8-10 kHz and at 16-18 kHz were found, which suggests that different mechanisms underlie the tinnitus development. (C) 2015 The Authors. Published by Elsevier Ltd. on behalf of IBRO. This is an open access article under the CC BY-NC-ND license.