Baier Lukas, Brümmer Tim, Senay Burak, Siegel Markus, Keleş Ahmet Doğukan, Röhrle Oliver, Klotz Thomas, Noury Nima, Marquetand Justus
Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.
J Neural Eng. 2025 Apr 16;22(2). doi: 10.1088/1741-2552/adc83b.
. Muscle fiber conduction velocity (MFCV) describes the speed at which electrical activity propagates along muscle fibers and is typically assessed using invasive or surface electromyography. Because electrical currents generate magnetic fields, propagation velocity can potentially also be measured magnetically using magnetomyography (MMG), offering the advantage of a contactless approach.. To test this hypothesis, we recorded MMG signals from the right biceps brachii muscle of 24 healthy subjects (12 male, 12 female) using a linear array of seven optically pumped magnetometers (OPMs). Subjects maintained muscle force for 30 s at 20%, 40%, and 60% of their maximum voluntary contraction.. In 20 subjects, propagation of MMG signals was observable. Change in polarity and signal cancellation enabled localization of the innervation zone. We estimated the MFCV for each condition by cross-correlating double-differentiated MMG signals. To validate our results, we examined whether MFCV estimations increased with higher force levels, a well-documented characteristic of the neuromuscular system. The median MFCV significantly increased with force (= 0.007), with median values of 3.2 m sat 20%, 3.8 m sat 40%, and 4.4 m sat 60% across all 20 subjects.. Our results establish the first measurements of magnetic MFCV in MMG using OPMs. These findings pave the way for further developments and application of quantum sensors for contactless clinical neurophysiology.
肌肉纤维传导速度（MFCV）描述了电活动沿肌肉纤维传播的速度，通常使用侵入性或表面肌电图进行评估。由于电流会产生磁场，传播速度也可以通过磁肌电图（MMG）进行磁性测量，这具有非接触式测量的优势。为了验证这一假设，我们使用由七个光泵磁力计（OPM）组成的线性阵列，记录了24名健康受试者（12名男性，12名女性）右侧肱二头肌的MMG信号。受试者在其最大自主收缩的20%、40%和60%水平下保持肌肉力量30秒。在20名受试者中，可以观察到MMG信号的传播。极性变化和信号抵消使得能够定位神经支配区。我们通过对双微分MMG信号进行互相关分析，估计了每种情况下的MFCV。为了验证我们的结果，我们检查了MFCV估计值是否随着更高的力水平而增加，这是神经肌肉系统的一个有充分记录的特征。在所有20名受试者中，MFCV的中位数随力量显著增加（=0.007），在20%、40%和60%水平下的中位数分别为3.2米/秒、3.8米/秒和4.4米/秒。我们的结果首次建立了使用OPM在MMG中对磁性MFCV的测量。这些发现为量子传感器在非接触式临床神经生理学中的进一步发展和应用铺平了道路。
