Rasool Ghulam, Wang Allison B, Rymer William Z, Lee Sabrina S M
Annu Int Conf IEEE Eng Med Biol Soc. 2016 Aug;2016:2869-2872. doi: 10.1109/EMBC.2016.7591328.
As a result of a brain injury such as stroke, the skeletal muscles may undergo numerous structural and functional alterations. These abnormal changes are linked to muscle weakness, joint contracture, and abnormal muscle tone and eventually, result in motor impairment. A subset of these alterations affects passive muscle stiffness, i.e., viscoelastic properties. However, in vivo estimation of changes in viscoelastic properties is a challenging task. Here, we used the shear wave velocity, estimated through ultrasound SuperSonic imaging (SSI), as a surrogate for viscoelastic properties. We estimated shear wave group and phase velocities (dispersion), and thus, quantified both elasticity and viscosity of the muscle tissue, respectively in muscles of hemiplegic stroke survivors. In these individuals, we found significantly higher group and phase velocities in the stroke-affected muscles (p<; 05) compared to those of the contralateral non-affected side. We hypothesize that in addition to changes in neural and contractile properties, there are also, changes in elastic and tissue dispersive properties through local mechanisms. An enhanced understanding of post-stroke changes in skeletal muscles will lead to better and targeted interventions for rehabilitation.
由于诸如中风等脑损伤，骨骼肌可能会经历众多结构和功能改变。这些异常变化与肌肉无力、关节挛缩和异常肌张力相关，最终导致运动障碍。这些改变的一个子集影响被动肌肉僵硬度，即粘弹性特性。然而，体内粘弹性特性变化的估计是一项具有挑战性的任务。在此，我们使用通过超声超音速成像（SSI）估计的剪切波速度作为粘弹性特性的替代指标。我们估计了剪切波群速度和相速度（频散），从而分别量化了偏瘫中风幸存者肌肉中肌肉组织的弹性和粘性。在这些个体中，我们发现与对侧未受影响侧相比，中风受累肌肉中的群速度和相速度显著更高（p<0.05）。我们推测，除了神经和收缩特性的变化外，还存在通过局部机制导致的弹性和组织频散特性的变化。对中风后骨骼肌变化的深入理解将有助于制定更好的针对性康复干预措施。
