Department of Communication Sciences and Disorders, James Madison University, Harrisonburg, Virginia, USA.
Ear Hear. 2021 May/Jun;42(3):596-605. doi: 10.1097/AUD.0000000000000978.
A variety of stimulus delivery methods can elicit vestibular evoked myogenic potentials (VEMPs). The current study compared bone conduction (BC) cervical VEMPs (cVEMPs) across two different clinical bone vibrators. It was hypothesized that the B81 transducer would be more effective for producing larger BC-cVEMP peak to peak amplitudes due to its low-frequency advantages in pure-tone audiometry applications.
Twenty young adults under the age of 40 years with no reported history of hearing or balance disorders participated in the study. BC cVEMPs were elicited using two clinical bone transducers: the Radioear B71 bone vibrator and the Radioear B81 bone vibrator. Both transducers were calibrated using the acoustic method of calibration before data collection, and the linear dynamic range of the transducers was determined. Participants were asked to sit and match a fixed electromyography (EMG) target level of 100 µV, while BC cVEMPs were recorded using stimulus frequencies of 250, 500, and 750 Hz.
Statistically significant differences in raw amplitude at 250 and 750 Hz between the B71 and B81 were observed; the B71 produced larger peak to peak amplitudes over the B81. At 500 Hz, larger amplitudes were observed with the B71, but results were not statistically significant. The B71 produced significantly lower cVEMP thresholds at all three frequencies. Across both transducers, 500 Hz produced the largest peak to peak amplitude compared with 250 and 750 Hz. Peak to peak amplitude did not increase above 55 dB nHL for 250 and 500 Hz, but amplitude continued to increase at 750 Hz.
The present study found statistically significant differences in BC-cVEMP amplitude and threshold between the B71 and B81, but results were not what we hypothesized. In general, the B71 elicited larger BC-cVEMP amplitudes and lower thresholds compared with the B81. Additionally, 500 Hz was found to be the best frequency for both BC transducers, contrasting previous studies suggesting lower frequencies yield larger BC-cVEMP amplitudes. It is possible that these average differences could also be clinically significant when looking at individual amplitude differences. Larger peak to peak amplitudes at 500 Hz may be partially due to the underlying physical levels used in the current study, as well as the output spectra of the transducers, and may explain the larger response amplitudes observed at 500 Hz compared with 250 Hz.
各种刺激传递方法均可引出前庭诱发肌源性电位（VEMP）。本研究比较了两种不同临床骨振器的骨导（BC）颈 VEMP（cVEMP）。由于其在纯音测听应用中的低频优势，假设 B81 换能器在产生更大的 BC-cVEMP 峰间幅度方面更有效。
20 名年龄在 40 岁以下、无听力或平衡障碍病史的年轻人参加了这项研究。使用两种临床骨传声器：Radioear B71 骨振器和 Radioear B81 骨振器引出 BC cVEMP。在数据采集之前，使用声学校准方法对两个换能器进行校准，并确定换能器的线性动态范围。要求参与者坐下并匹配 100µV 的固定肌电图（EMG）目标水平，同时使用 250、500 和 750Hz 的刺激频率记录 BC cVEMP。
在 250 和 750Hz 处，B71 和 B81 之间的原始振幅存在统计学上的显著差异；B71 产生的峰间幅度大于 B81。在 500Hz 处，B71 产生的幅度较大，但结果无统计学意义。在所有三个频率下，B71 产生的 cVEMP 阈值均显著较低。在两个换能器中，500Hz 产生的峰间幅度均大于 250Hz 和 750Hz。对于 250 和 500Hz，峰间幅度不会超过 55dB nHL，但幅度会在 750Hz 继续增加。
本研究发现 B71 和 B81 之间的 BC-cVEMP 幅度和阈值存在统计学上的显著差异，但结果并非我们假设的那样。一般来说，B71 引出的 BC-cVEMP 幅度大于 B81，阈值较低。此外，发现 500Hz 是两种 BC 换能器的最佳频率，与先前表明较低频率产生较大 BC-cVEMP 幅度的研究相反。当观察个体幅度差异时，这些平均差异也可能具有临床意义。500Hz 时的峰间幅度较大可能部分归因于当前研究中使用的潜在物理水平，以及换能器的输出频谱，并可能解释与 250Hz 相比在 500Hz 观察到的较大响应幅度。
