von Fraunberg Johannes, Lu Hongyu, Yang Haodi, Marquetand Nura, Braun Christoph, Rüttiger Lukas, Wolpert Stephan, Knipper Marlies, Siegel Markus, Löwenheim Hubert, Marquetand Justus
Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany.
Department of Neural Dynamics and Magnetoencephalography, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
Clin Neurophysiol Pract. 2025 Mar 17;10:134-140. doi: 10.1016/j.cnp.2025.03.003. eCollection 2025.
Measuring facial muscle activity is crucial in the diagnosis of facial palsy. This study investigated whether contactless Magnetomyography (MMG) using optically pumped magnetometers (OPM) is feasible for visualizing facial muscle activity.
An anatomically shaped mask featuring eleven OPM was arranged on one side of the face of five healthy subjects. MMG was recorded while they performed different facial expressions. The root mean square of each OPM signal was calculated for each expression and subject and allocated to the individual face. Moreover, the maximum average muscle activity and the signal-to-noise ratio (SNR) were determined.
The subjects' facial muscle activity could be measured individually per facial expression. Mean RMS was 0.6pT (SD 0.4pT), resulting in a mean SNR of 2.2 (SD 1.2).
Imaging facial activity via MMG using OPM is possible, although the sensor positioning (sensor geometry and distance to the muscle) is decisive. However, the signal amplitude of the facial muscles is low and the interindividual anatomical variability renders the measurement setup challenging.
As the imaging of facial MMG is feasible, this study paves the way for future studies using OPM for the diagnosis, monitoring, and rehabilitation of facial muscle and facial nerve disorders.
测量面部肌肉活动对面部麻痹的诊断至关重要。本研究调查了使用光泵磁力计（OPM）的非接触式磁肌图（MMG）是否可用于可视化面部肌肉活动。
在五名健康受试者的一侧面部布置一个带有11个OPM的解剖形状面罩。在他们进行不同面部表情时记录MMG。计算每个表情和受试者的每个OPM信号的均方根，并分配到个体面部。此外，确定最大平均肌肉活动和信噪比（SNR）。
可以针对每个面部表情单独测量受试者的面部肌肉活动。平均均方根为0.6pT（标准差0.4pT），平均信噪比为2.2（标准差1.2）。
尽管传感器定位（传感器几何形状和与肌肉的距离）起决定性作用，但通过使用OPM的MMG对面部活动进行成像仍是可能的。然而，面部肌肉的信号幅度较低，个体间的解剖变异使得测量设置具有挑战性。
由于面部MMG成像可行，本研究为未来使用OPM诊断、监测和康复面部肌肉及面神经疾病的研究铺平了道路。
