Soleus H-Reflex Change in Poststroke Spasticity: Modulation due to Body Position.

Wenting Qin,Lingjing Jin,Lijun Zhen,Fang Li,Mingzhen Yang,Anjing Zhang,Chan Chen,Hong Yang,Chun Lei Shan

doi:10.1155/2021/9955153

Abstract

Purpose This study is aimed at exploring how soleus H-reflex change in poststroke patients with spasticity influenced by body position. Materials and Methods Twenty-four stroke patients with spastic hemiplegia and twelve age-matched healthy controls were investigated. Maximal Hoffmann-reflex (Hmax) and motor potential (Mmax) were elicited at the popliteal fossa in both prone and standing positions, respectively, and the Hmax/Mmax ratio at each body position was determined. Compare changes in reflex behavior in both spastic and contralateral muscles of stroke survivors in prone and standing positions, and match healthy subjects in the same position. Results In healthy subjects, Hmax and Hmax/Mmax ratios were significantly decreased in the standing position compared to the prone position (Hmax: p = 0.000, Hmax/Mmax: p = 0.016). However, Hmax/Mmax ratios were increased in standing position on both sides in poststroke patients with spasticity (unaffected side: p = 0.006, affected side: p = 0.095). The Hmax and Hmax/Mmax ratios were significantly more increased on the affected side than unaffected side irrespective of the position. Conclusions The motor neuron excitability of both sides was not suppressed but instead upregulated in the standing position in subjects with spasticity, which may suggest that there was abnormal regulation of the Ia pathway on both sides.

Highlights

Spasticity is defined as velocity-dependent increase in the tonic stretch reflexes [1], which is one of the positive signs of upper motor neuron syndrome
A previous study conducted by our research group showed that from the supine position to standing or sitting position, Modified Tardieu Scale (MTS) and Triple Spasticity Scale (TSS) scores significantly increased in the evaluated muscles of the hemiplegic upper limb in all poststroke patients [3]
Significant differences existed between the affected side and the unaffected side (p = 0:0002), but the differences between the affected side and the healthy subjects as well as the unaffected side and the healthy subjects were not statistically significant (Figure 1)

Summary

Introduction

Spasticity is defined as velocity-dependent increase in the tonic stretch reflexes (muscle tone) [1], which is one of the positive signs of upper motor neuron syndrome. It can cause continuous contraction of the affected muscles and difficulty in muscle coordination. A previous study conducted by our research group showed that from the supine position to standing or sitting position, Modified Tardieu Scale (MTS) and Triple Spasticity Scale (TSS) scores significantly increased in the evaluated muscles of the hemiplegic upper limb in all poststroke patients [3]. All above studies indicated that posture plays an important role in the spasticity regulation

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Conclusion