Examination of evaluation indicators for spasticity in stroke patients using ultrasound imaging equipment

[Purpose] To compare the muscle evaluation indices obtained by scanning the spastic muscles of stroke patients between the paretic and non-paretic sides using ultrasound imaging equipment, determine whether any features can be detected, and verify whether the evaluation indices that detect differences are valid for measuring the degree of spasticity. [Participants and Methods] The participants were 23 first-ever stroke patients with motor paralysis in one upper or lower limb, admitted to our hospital between 1 and 6 months after onset. The biceps brachii muscle and medial head of the gastrocnemius muscle were evaluated on both sides using ultrasound imaging equipment. The muscle evaluation indices were muscle thickness, muscle echo intensity, muscle stiffness, and muscle-tendon junction displacement. Pennation angles were also measured at the medial head of the gastrocnemius muscle. [Results] Significant differences were found between the paretic and nonparetic sides in the muscle-tendon junction displacement of the biceps brachii muscle and edial head of the gastrocnemius muscle. No significant differences were found in the other muscle evaluation indices. [Conclusion] Muscle-tendon junction displacement was the only index that showed significant differences between the non-paretic and paretic sides. It showed a moderate-to-strong correlation with the Modified Ashworth Scale, suggesting its potential as an alternative evaluation index for muscle strain.