【Paper】Spatial and force dependency of mechanomyographic signal features
Posted On 2008年12月30日 星期二 at 於 上午11:41 by 阿宏
●這一篇文章主要是在描述MMG信號特徵當中的空間與力量的相關性，以此說明使用單一MMG來評估MUs的技巧中因為在力量與MMG在位置上的影響所造成的限制。
●These results highlight limitations when using single-channel MMG features for the assessment of motor unit control strategies, due to a substantial effect of position on the relation between force and MMG characteristics.
元件：
●accelerometers：ADXL202JE, Analog Devices Inc., Norwood, MA, USA
●motor units (MUs)：motor unit運動單位指的是單一運動神經元 (motor neuron) 以及其所支配的肌肉纖維 (muscle fibers) 所構成；而運動神經元 (大多數為Alpha-運動神經元) 所支配的肌肉纖維數量從5 (存在某些眼睛的肌肉；為了精細的控制眼球)到1000 (存在於大肌肉之中，例如腓腸肌) 都有
參數：
●MVC：maximum voluntary contraction
●RMS：root mean square ,
●ARV：average rectified value ,
●MDF：median power spectral frequency
●MNF：mean power spectral frequency .
衍伸不錯的文獻：
Cescon C, Farina D, Gobbo M, Merletti R, Orizio C. Effect of accelerometer location on mechanomyogram variables during voluntary, constant-force contractions in three human muscles. Med Biol Eng Comput 2004;42: 121–7. |
Cescon C, Madeleine P, Graven-Nielsen T, Merletti R, Farina D, Twodimensional spatial distribution of surface mechanomyography response to single motor unit activity. J Neurosci Meth 2006; submitted for publication. |
Holtermann A, Roeleveld K, Karlsson JS. Inhomogeneities in muscle activation reveal motor unit recruitment. J Electromyogr Kinesiol 2005;15: 131–7. |
Madeleine P, Arendt-Nielsen L. Experimental muscle pain increases mechanomyographic signal activity during sub-maximal isometric contractions. J Electromyogr Kinesiol 2005;15:27–36. |
Madeleine P, Bajaj P, Søgaard K, Arendt-Nielsen L. Mechanomyography and electromyography force relationships during concentric, isometric and eccentric contractions. J Electromyogr Kinesiol 2001;11:113–21. |
Madeleine P, Farina D, Merletti R, Arendt-Nielsen L. Upper trapezius muscle mechanomyographic and electromyographic activity in humans during low force fatiguing and non-fatiguing contractions. Eur J Appl Physiol 2002;87:327–36. |
Madeleine P, Ge HY, Jaskolska A, Farina D, Jaskolski A, Arendt-Nielsen L. Characterization of the mechanomyographic signals recorded with accelerometer and microphone during sustained contraction. Med Biol Eng Comput 2006;44:290–7. |
Orizio C. Surface mechanomyogram. In: Merletti R, Parker P, editors. Electromyography. Physiology, engineering and noninvasive applications. Hoboken : IEEE Press John Wiley & Sons; 2004. p. 305–22. |
Orizio C, Gobbo M, Diemont B, Esposito F, Veicsteinas A. The surface mechanomyogram as a tool to describe the influence of fatigue on biceps brachii motor unit activation strategy. Historical basis and novel evidence. Eur J Appl Physiol 2003;90:326–36. |
Orizio C, Liberati D, Locatelli C, De Grandis D, Veicsteinas A. Surface mechanomyogram reflects muscle fibres twitches summation. J Biomech 1996;29:475–81. |
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Abstract
The aim was to investigate with a novel technique the spatial inhomogeneity in surface mechanomyographic (MMG) response to muscle contraction at varying force levels. MMG signals were detected over the dominant tibialis anterior muscle of 10 volunteers using a 5×3 grid of accelerometers. The subjects performed 3 s long isometric contractions at forces ranging from 0% to 100% of the maximal force (10% increment) in a randomised order. From the two-dimensional MMG recordings, maps of absolute and normalized temporal and spectral MMG descriptors were obtained. The centroid and entropy of these maps were computed to describe the spatial centre of activity and degree of homogeneity, respectively. MMG absolute amplitude did not depend on location over the muscle while normalized amplitude did and the centroid shifted with increasing force. Amplitude increased with force and its entropy decreased. Absolute and normalized spectral variables depended on location over the muscle and their centroid shifted with increasing force. In addition, the dependency of absolute and normalized spectral variables on force was affected by location. These results highlight limitations when using single-channel MMG features for the assessment of motor unit control strategies, due to a substantial effect of position on the relation between force and MMG characteristics.
閱讀時間：20081209-20081229
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