Background: Accurate data on the sound emitted by transcranial magnetic stimulation (TMS) coils is lacking. Methods: We recorded the sound waveforms of seven coils with high bandwidth. We estimated the neural stimulation strength by measuring the induced electric field and applying a strengtheduration model to account for different waveforms. Results: Across coils, at maximum stimulator output and 25 cm distance, the sound pressure level (SPL) was 98–125 dB(Z) per pulse and 76–98 dB(A) for a 20 Hz pulse train. At 5 cm distance, these values were estimated to increase to 112–139 dB(Z) and 90–112 dB(A), respectively. Conclusions: The coils’ airborne sound can exceed some exposure limits for TMS subjects and, in some cases, for operators. These findings are consistent with the current TMS safety guidelines that recommend the use of hearing protection.

中文翻译：

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七个 TMS 线圈在匹配刺激强度下的声音比较

背景：缺乏关于经颅磁刺激 (TMS) 线圈发出的声音的准确数据。方法：我们记录了七个高带宽线圈的声音波形。我们通过测量感应电场并应用强度模型来解释不同的波形来估计神经刺激强度。结果：跨线圈、最大刺激器输出和 25 厘米距离时，声压级 (SPL) 为每个脉冲 98-125 dB(Z)，20 Hz 脉冲序列为 76-98 dB(A)。在 5 cm 距离处，这些值估计分别增加到 112–139 dB(Z) 和 90–112 dB(A)。结论：线圈的空气传播声音可能会超过 TMS 对象的某些暴露限制，在某些情况下，操作员也会这样做。这些发现与目前推荐使用听力保护装置的 TMS 安全指南一致。