Barry D T, Geiringer S R, Ball R D
Muscle Nerve. 1985 Mar-Apr;8(3):189-94. doi: 10.1002/mus.880080303.
Acoustic myography is the recording of sounds produced by contracting muscle. These sounds become louder with increasing force of contraction. We have compared muscle sounds with surface EMG to monitor the dissociation of electrical from mechanical events (presumably, the loss of excitation-contraction coupling) which occur with motor unit fatigue. Acoustic signals were amplified using a standard phonocardiograph, recorded on FM magnetic tape, and digitally analyzed. Muscles were examined at rest, with intermittent contractions, and with sustained contractions. We found that with fatigue, the acoustic amplitude decayed, but the surface EMG amplitude did not. With decreased effort, however, the acoustic and the surface EMG amplitudes declined simultaneously. By simultaneously recording acoustic signals and needle EMG, individual motor units were resolved acoustically in two muscles with decreased numbers of motor units and increased motor unit size. Fasciculations also produced acoustic signals, although no acoustic signal has yet been found that correlates with fibrillations. Analysis of acoustic signals from muscle provides a noninvasive method for monitoring motor unit fatigue in vivo. It may also be useful in distinguishing muscle fatigue from decreased volition.
肌声描记法是记录肌肉收缩时产生的声音。随着收缩力的增加，这些声音会变得更大。我们将肌肉声音与表面肌电图进行了比较，以监测与运动单位疲劳相关的电活动与机械活动的分离（推测为兴奋 - 收缩偶联的丧失）。声学信号使用标准的心音图仪进行放大，记录在调频磁带上，并进行数字分析。在肌肉休息、间歇性收缩和持续性收缩时对其进行检查。我们发现，随着疲劳的出现，声学振幅衰减，但表面肌电图振幅并未衰减。然而，随着用力程度的降低，声学和表面肌电图振幅同时下降。通过同时记录声学信号和针电极肌电图，在运动单位数量减少且运动单位大小增加的两块肌肉中，通过声学方法分辨出了单个运动单位。肌束震颤也会产生声学信号，尽管尚未发现与纤颤相关的声学信号。对肌肉声学信号的分析提供了一种在体内监测运动单位疲劳的非侵入性方法。它在区分肌肉疲劳和意志减弱方面也可能有用。
