Disorder of phase-related modulation of soleus H-reflex during hip movement in stroke patients

Purpose: The soleus H-reflex during passive hip movement was measured to clarify the modulation of excitability of the soleus monosynaptic reflex during locomotion-like movement in spastic stroke patients. Method: The experiment was performed in five patients with spastic hemiparesis. The hip joint was moved passively ranging from 0 to 40 degrees. The knee joint was fixed at full extension and the ankle joint was fixed at the mid-position. During the movement, the soleus M-wave and soleus H-reflex were measured. Results: Flexion caused a decrease in the soleus H-reflex, whereas extension caused an increase symmetrically for both the static and dynamic conditions. In addition, the lowest value was observed at the end of the flexion phase during fast movement. Conclusion: These findings indicate that the phase-related modulation of soleus H-reflex during hip movement is partially disordered in stroke patients.