Development and Preliminary Validation of a Pneumatic Focal Vibration System to the Mitigation of Post-Stroke Spasticity.

Wei Li,Linhong Ji,Yun Xiang,Tianyu Jia,Pan Liu,Yinbo Li,Chong Li,Quan Xu

doi:10.1109/tnsre.2021.3052187

Abstract

Some evidence has demonstrated that focal vibration (FV) plays an important role in the mitigation of spasticity. However, the research on developing the FV system to mitigate the spasticity effectively has been seldom reported. To relieve post-stroke spasticity, a new pneumatic FV system has been proposed in this paper. An image processing approach, in which the edge of vibration actuator was identified by the Canny edge detector, was utilized to quantify this system's parameters: the frequency ranging from 44 Hz to 128 Hz and the corresponding amplitude. Taking one FV protocol with the frequency of 87 Hz and the amplitude 0.28 mm of this system as an example, a clinical experiment was carried out. In the clinical experiment, FV was applied over the muscle belly of the antagonist of spastic muscle for twelve chronic spastic stroke patients. Spasticity was quantified by the muscle compliance and area under the curve for muscle (AUC_muscle). The result has demonstrated that, in the state of flexion of spastic muscle, the AUC_muscle and muscle compliance of the spastic muscle significantly increased immediately after FV compared with before-FV, illustrating the mitigation of the spasticity. This study will not only provide a potential tool to relieve post-stroke spasticity, but also contribute to improving the sensory and motor function of patients with other neurological diseases, e.g. spinal cord injury, multiple sclerosis, Parkinson and dystonia, etc.

Highlights

S TROKE, as the leading cause of the adult disability, impairs patients’ motor abilities and contributes to the long-term neurologic disability [1]
Post-stroke spasticity (PSS) is a common complication associated with the positive features of the upper motor neuron syndrome, which is characterized by a velocity-dependent increase in resistance to passive movements [2]
It has been initially shown that the alleviating effect of Focal vibration (FV) on spasticity could be associated with the spinal mechanism of presynaptic inhibition, which originates from vibration-induced activation of the primary ending of the muscle spindle

Summary

Introduction

S TROKE, as the leading cause of the adult disability, impairs patients’ motor abilities and contributes to the long-term neurologic disability [1]. It has been initially shown that the alleviating effect of FV on spasticity could be associated with the spinal mechanism of presynaptic inhibition, which originates from vibration-induced activation of the primary ending of the muscle spindle. In the past twenty years, more and more attention has been paid to investigate the potential mechanism of FV on the reduction of spasticity at the cortical level. Some studies have indicated that FV activates primary ending of the muscle spindle, causing alteration of corticospinal pathway to reduce spasticity at the cortical level [10]–[12]. The mitigation of spasticity induced by FV is associated with the activation of primary ending of the muscle spindle, whether at the spinal level or at the cortical level

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Discussion

Conclusion