Ultrasonic monitoring of skeletal muscle response to electrical stimulation of peripheral nerve

Peripheral nerve stimulation (PNS) is the excitation of motor nerves to invoke involuntary muscle contraction and has applications in regional anesthesia for dosage control. In this study, a wearable ultrasonic sensor is used to measure the muscle activity while minimizing motion artifact and allowing freedom of tissue movement beneath the sensor. Muscle activity from PNS is evaluated based on muscle displacement and peak displacement velocity. The ultrasound method proposed in this study is shown to be sensitive enough to detect muscle motion which is not visually or externally observable. As the PNS current increases the muscle displacement reaches a maximum; however displacement velocity still increases slightly beyond this point.