Department of Neurology, Division of Neuromuscular Diseases, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA.
Physiol Meas. 2010 Nov;31(11):1437-48. doi: 10.1088/0967-3334/31/11/003. Epub 2010 Sep 10.
Previous work has shown that electrical impedance measurements of muscle can assist in quantifying the degree of muscle atrophy resulting from neuronal injury, with impedance values correlating strongly with standard clinical parameters. However, the relationship between such data and neurophysiologic measurements is unexplored. In this study, 24 Wistar rats underwent sciatic crush, with measurement of the 2-1000 kHz impedance spectrum, standard electrophysiological measures, including nerve conduction studies, needle electromyography, and motor unit number estimation (MUNE) before and after sciatic crush, with animals assessed weekly for 4 weeks post-injury. All electrical impedance values, including a group of 'collapsed' variables, in which the spectral characteristics were reduced to single values, showed reductions as high as 47.2% after sciatic crush, paralleling and correlating with changes in compound motor action potential amplitude, conduction velocity and most closely to MUNE, but not to the presence of fibrillation potentials observed on needle electromyography. These results support the concept that localized impedance measurements can serve as surrogate makers of nerve injury; these measurements may be especially useful in assessing nerve injury impacting proximal or axial muscles where standard quantitative neurophysiologic methods such as nerve conduction or MUNE cannot be readily performed.
先前的工作表明，肌肉的阻抗测量可以协助量化神经元损伤导致的肌肉萎缩程度，阻抗值与标准临床参数密切相关。然而，这种数据与神经生理测量之间的关系尚未得到探索。在这项研究中，24 只 Wistar 大鼠接受坐骨神经挤压，在挤压前后测量 2-1000 kHz 的阻抗谱、标准电生理测量，包括神经传导研究、针电极肌电图和运动单位数量估计（MUNE），动物在损伤后每周评估 4 周。所有的电阻抗值，包括一组“塌陷”变量，即其中频谱特征被简化为单个值，在坐骨神经挤压后降低高达 47.2%，与复合运动动作电位幅度、传导速度的变化平行且相关，与 MUNE 最密切相关，但与针电极肌电图上观察到的纤颤电位的存在无关。这些结果支持了局部阻抗测量可以作为神经损伤替代标志物的概念；这些测量方法在评估影响近端或轴向肌肉的神经损伤时可能特别有用，在这些部位，无法轻易进行神经传导或 MUNE 等标准定量神经生理方法。
