School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, United States; Department of Otolaryngology-Head & Neck Surgery, University of Oklahoma Medical Center, Oklahoma City, OK, United States.
School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, United States.
Hear Res. 2023 Mar 1;429:108702. doi: 10.1016/j.heares.2023.108702. Epub 2023 Jan 13.
Blast-induced auditory injury is primarily caused by exposure to an overwhelming amount of energy transmitted into the external auditory canal, the middle ear, and then the cochlea. Quantification of this energy requires real-time measurement of stapes footplate (SFP) motion and intracochlear pressure in the scala vestibuli (Psv). To date, SFP and Psv have not been measured simultaneously during blast exposure, but a dual-laser experimental approach for detecting the movement of the SFP was reported by Jiang et al. (2021). In this study, we have incorporated the measurement of Psv with SFP motion and developed a novel approach to quantitatively measure the energy flux entering the cochlea during blast exposure. Five fresh human cadaveric temporal bones (TBs) were used in this study. A mastoidectomy and facial recess approach were performed to identify the SFP, followed by a cochleostomy into the scala vestibuli (SV). The TB was mounted to the "head block", a fixture to simulate a real human skull, with two pressure sensors - one inserted into the SV (Psv) and another in the ear canal near the tympanic membrane (P1). The TB was exposed to the blast overpressure (P0) around 4 psi or 28 kPa. Two laser Doppler vibrometers (LDVs) were used to measure the movements of the SFP and TB (as a reference). The LDVs, P1, and Psv signals were triggered by P0 and recorded simultaneously. The results include peak values for Psv of 100.8 ± 51.6 kPa (mean ± SD) and for SFP displacement of 72.6 ± 56.4 μm, which are consistent with published experimental results and finite element modeling data. Most of the P0 input energy flux into the cochlea occurred within 2 ms and resulted in 10-70 μJ total energy entering the cochlea. Although the middle ear pressure gain was close to that measured under acoustic stimulus conditions, the nonlinear behavior of the middle ear was observed from the elevated cochlear input impedance. For the first time, SFP movement and intracochlear pressure Psv have been successfully measured simultaneously during blast exposure. This study provides a new methodology and experimental data for determining the energy flux entering the cochlea during a blast, which serves as an injury index for quantifying blast-induced auditory damage.
爆炸引起的听觉损伤主要是由于暴露于传入外耳道、中耳和耳蜗的大量能量引起的。这种能量的量化需要实时测量镫骨底板（SFP）运动和前庭阶内压（Psv）。迄今为止，在爆炸暴露期间尚未同时测量 SFP 和 Psv，但 Jiang 等人报道了一种用于检测 SFP 运动的双激光实验方法。在这项研究中，我们结合了 SFP 运动和 Psv 的测量，并开发了一种新方法来定量测量爆炸暴露期间进入耳蜗的能量通量。本研究使用了 5 个人体颞骨（TB）标本。进行乳突切除术和面神经管显露术以识别 SFP，然后进行前庭阶 Cochleostomy。将 TB 安装到“头部块”上，这是一个模拟真实人头骨的固定装置，有两个压力传感器-一个插入前庭阶（Psv），另一个插入鼓膜附近的外耳道（P1）。TB 暴露于约 4 磅/平方英寸或 28 kPa 的爆炸超压（P0）下。使用两个激光多普勒测振仪（LDV）测量 SFP 和 TB 的运动（作为参考）。LDV、P1 和 Psv 信号由 P0 触发并同时记录。结果包括 Psv 的峰值为 100.8 ± 51.6 kPa（平均值 ± 标准差）和 SFP 位移为 72.6 ± 56.4 μm，与已发表的实验结果和有限元建模数据一致。大部分 P0 输入能量通量在 2 毫秒内进入耳蜗，导致总共 10-70 μJ 的能量进入耳蜗。尽管中耳压力增益接近在声刺激条件下测量的值，但从中耳输入阻抗的升高观察到中耳的非线性行为。首次成功地在爆炸暴露期间同时测量 SFP 运动和内压 Psv。本研究为确定爆炸期间进入耳蜗的能量通量提供了一种新的方法和实验数据，该方法可作为量化爆炸引起的听觉损伤的损伤指数。
