Stewart Courtney E, Kanicki Ariane C, Bauer David S, Altschuler Richard A, King W Michael
Kresge Hearing Research Institute, University of Michigan, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5616.
Mil Med. 2020 Jan 7;185(Suppl 1):454-461. doi: 10.1093/milmed/usz206.
The vestibular system is essential for normal postural control and balance. Because of their proximity to the cochlea, the otolith organs are vulnerable to noise. We previously showed that head jerks that evoke vestibular nerve activity were no longer capable of inducing a response after noise overstimulation. The present study adds a greater range of jerk intensities to determine if the response was abolished or required more intense stimulation (threshold shift).
Vestibular short-latency evoked potential (VsEP) measurements were taken before noise exposure and compared to repeated measurements taken at specific time points for 28 days after noise exposure. Calretinin was used to identify changes in calyx-only afferents in the sacculus.
Results showed that more intense jerk stimuli could generate a VsEP, although it was severely attenuated relative to prenoise values. When the VsEP was evaluated 4 weeks after noise exposure, partial recovery was observed.
These data suggest that noise overstimulation, such as can occur in the military, could introduce an increased risk of imbalance that should be evaluated before returning a subject to situations that require normal agility and motion. Moreover, although there is recovery with time, some dysfunction persists for extended periods.
前庭系统对于正常的姿势控制和平衡至关重要。由于耳石器官靠近耳蜗，它们易受噪声影响。我们之前表明，在噪声过度刺激后，诱发前庭神经活动的头部急动不再能够引发反应。本研究增加了更大范围的急动强度，以确定反应是被消除还是需要更强烈的刺激（阈值变化）。
在噪声暴露前进行前庭短潜伏期诱发电位（VsEP）测量，并与噪声暴露后28天特定时间点的重复测量结果进行比较。使用钙视网膜蛋白来识别球囊中单花萼传入神经的变化。
结果表明，更强烈的急动刺激可以产生VsEP，尽管相对于噪声暴露前的值它严重衰减。在噪声暴露4周后评估VsEP时，观察到部分恢复。
这些数据表明，军事环境中可能发生的噪声过度刺激可能会增加失衡风险，在让受试者恢复到需要正常敏捷性和运动的情况之前应进行评估。此外，虽然随着时间会有恢复，但一些功能障碍会持续很长时间。
