前田 寛文

Objective: The therapeutic effectiveness of phenol motor point block in patients with spasticity of the lower extremity was assessed by measuring ankle plantar flexion torque. Patient factors influencing therapeutic effectiveness were evaluated. Methods: Twelve patients with spasticity of the lower extremity after cerebrovascular disorders were enrolled in this study. Plantar flexion torques at 5°/s or 90°/s under passive ankle dorsiflexion were measured before and after treatment with phenol motor block in flexor muscles of the lower leg. Patient factors influencing therapeutic effectiveness were evaluated before and after treatment using torque changes as an indicator of therapeutic effectiveness. Results: Therapeutic effectiveness showed a significantly negative correlation with plantar flexion torques at 5°/s before treatment (ρ= -0.741, p = 0.006) and with the time from onset (ρ= -0.680, p = 0.015). A significantly positive correlation between therapeutic effectiveness and presence of self-exercise (ρ= 0.661, p = 0.019) was observed. Conclusion: Patients who were less affected by immobilization including those with small plantar flexion torque at 5°/s or those who engaged in self-exercise are expected to achieve large therapeutic effects with regard to phenol motor point block against spasticity of the lower extremity.

[Purpose] To develop a device for measuring the torque of an ankle joint during walking in order to quantify the characteristics of spasticity of the ankle and to verify the functionality of the device by testing it on the gait of an able-bodied individual and an equinovarus patient. [Subjects and Methods] An adjustable posterior strut (APS) ankle-foot orthosis (AFO) was used in which two torque sensors were mounted on the aluminum strut for measuring the anterior-posterior (AP) and medial-lateral (ML) directions. Two switches were also mounted at the heel and toe in order to detect the gait phase. An able-bodied individual and a left hemiplegic patient with equinovarus participated. They wore the device and walked on a treadmill to investigate the device's functionality. [Results] Linear relationships between the torques and the corresponding output of the torque sensors were observed. Upon the analyses of gait of an able-body subject and a hemiplegic patient, we observed toque matrices in both AP and ML directions during the gait of the both subjects. [Conclusion] We developed a device capable of measuring the torque in the AP and ML directions of ankle joints during gait.

Objective: This research aimed to develop a system to measure the stiffness of the ankle joint for evaluating spasticity or contracture, and for quantifying the characteristics of spasticity. Functionality of the system was verified by testing it on an able-bodied individual and a hemiplegic patient. Additionally, a biomechanical model was developed to estimate the plantar flexion torque caused by viscoelasticity and muscle contraction. Methods: An electromotor, rack and pinion, potentiometer, and torque sensor were installed on a double Klenzak ankle-foot orthosis (AFO). By rotating the electromotor, the ankle joint of the AFO moves dorsally at a fixed speed. The angle and torque of dorsiflexion were measured simultaneously. The subjects sat either in a chair or a wheelchair and wore the abovementioned AFO in the knee-extension and knee-flexion positions, while the AFO moved dorsally. Electromyograms of the tibialis anterior and gastrocnemius muscles were recorded concurrently. The contributions of elastic, viscous, and muscle-contraction components to the plantar flexion torque were calculated using the system identification approach. Results: The system’s ability to measure dynamic characteristics, and also its accuracy, were confirmed. The plantar flexion torque was found to be larger in the knee-extension position than in the knee-flexion position in both the able-bodied person and the patient. Moreover, the patient showed larger plantar flexion torque than the able-bodied subject. Conclusions: A system that measures ankle-joint stiffness for evaluating spasticity was developed, and sufficient functionality was verified by applying it to both an able-bodied individual and a hemiplegic patient. In addition, plantar flexion torque caused by viscoelasticity and muscle contraction was estimated.