Passive movement of hip and knee joints decreases the amplitude of soleus H-reflex in stroke patients

Objectives: The study aims to investigate the changes of the H-reflex in soleus (Sol-H-reflex) during hip and knee joint movements in stroke patients. Methods: The experiments were carried out on five stroke patients with spastic hemiplegia (2 males and 3 females, 48 to 71 years old). Sol-H-reflexes were measured 200 times for each joint movement speed. Stimulus was given at random intervals (4 to 5 seconds) during the joint movement. Two movement speeds were used to investigate the effects of movement speed. Results: For both fast and slow movements, the amplitude of the Sol-H-reflex decreased in the middle flexion phase. In contrast, the amplitude of the Sol-H-reflex increased in the middle extension phase. For the fast movement, the Sol-H-reflex was smaller in only a small angle range during the flexion and extension phase in comparison to the slow movement. The Sol-H-reflex during the flexion phase was significantly smaller than during the extension phase at almost all angles for both speeds. The Sol-H-reflex for both speeds was smaller than the Sol-H-reflex at rest for the whole angle range. Conclusion: These results demonstrate the differential effects of Sol-H-reflex modulation in stroke patients when compared with normal subjects.