Influence of repeated acoustic overstimulation on the development of tinnitus in the Mongolian gerbil

内耳过度刺激和损伤后出现的耳鸣对患者来说是一个巨大的心理负担，往往会因提前退休而导致经济损失。产生幻觉噪音的确切原因在很大程度上是未知的，这是由于内耳和大脑中各个参与中心之间存在大量复杂的关系。过去，由于实验动物耳鸣检测方法有限，耳鸣的基础研究往往耗时且复杂。然而，现在有一种新的方法可以对实验动物的耳鸣进行有效和详细的研究。患有耳鸣的动物现在可以通过一种反射来识别，这种反射使用了声学惊吓反应的修改。基于早期对蒙古沙鼠耳鸣发展的成功研究（Nowotny et al., 2011），我们计划进行新的研究，以获得更多关于重复声过度刺激后耳鸣的起源的见解。初步结果表明，所谓的内耳隐性听力损失，可以通过详细的脑电位分析来识别，可能与耳鸣的出现有关。此外，我们的研究结果表明，隐性听力损失可能是一个总结性的过程。因此，反复的声音过度刺激会增加耳鸣的风险。我们将在沙鼠身上测试我们的假设。为了避免对实验动物进行不必要的治疗，我们将与已经患有耳鸣的动物同时进行内耳声创伤性损伤和脑活动变化的相关研究。

The emergence of tinnitus after acoustic overstimulation and damage to the inner ear is an enormous psychological burden for patients and often leads to economic losses through early retirement from working life. The exact causes of the resulting phantom noise are largely unknown, which is due to the high number of complex relationships in the inner ear and in the various participating centers in the brain. In the past, basic research on tinnitus was often time consuming and complicated because of the available methods to detect tinnitus in laboratory animals. However, a new method now allows the effective and detailed investigation of tinnitus in laboratory animals. Animals with tinnitus can now be identified by a reflex using a modification of the acoustic startle response. Based on earlier successful studies on the development of tinnitus in the Mongolian gerbil (Nowotny et al., 2011), we plan new investigations to obtained more insights into the origin of tinnitus after repeated acoustic overstimulation. Preliminary results suggest that a so called hidden hearing loss in the inner ear, which can be identified with a detailed analysis of brain potentials, is potentially related to the emergence of tinnitus. Furthermore, our results indicate that the hidden hearing loss could be a summative process. Hence, repeated acoustic overstimulation could increase the risk of developing tinnitus. We will test our hypotheses on gerbils. To avoid unnecessary treatment of laboratory animals, we will perform related studies on acoustic trauma-induced damage in the inner ear and changes in brain activity with those animals already suffering from tinnitus in parallel.