Parkinsonian Rigidity Shows Variable Properties Depending on the Elbow Joint Angle

Figure 1

Schematic diagram of muscle tone measurement system. This system consists of small 3-axis force sensors, a gyro sensor, and surface electrodes. Two force sensors are placed to sandwich the wrist joint with soft pads to measure the force along the 𝑧-axis during flexion and extension movements of the elbow joint and calculate the torque at the elbow joint. The signals from the gyro sensor attached between the force sensors are used to calculate the angle of the elbow joint. The surface electrodes are applied to the muscle belly of the biceps and triceps brachii to record myoelectric activity.