Portable Measurement Device to Measure Muscle Force

Project goal: To create a neuro-diagnostic research suite to study nerve recovery and repair in animals. The system has two main functions that allow observation of certain characteristics of a repaired nerve and the corresponding muscle it innervates. First, it allows observation of nerve conduction velocity, the speed at which the action potential propagates down the nerve. To calculate conduction velocity, the system stimulates the nerve at two locations along the nerve pathway.Velocity is calculated from the distance between the two points and the time it takes to stimulate the muscle from each location. Frequency and magnitude of can be controlled to observe different muscle excitation characteristics.Second, muscle contraction characteristics can be observed when the nerve is stimulated in different ways. Characteristics include frequency, duration and amplitude of stimulation, and force generated. A force sensor is attached surgically to the subject’s severed tendon at the insertion end of the muscle. When the muscle contracts, the force generated is amplified and transmitted to a computer where it is interpreted. Electrodes connected to an oscilloscope are placed in the subject’s muscle to study electrical stimulation.A surgical stage was designed to hold three different subject sizes in place while testing. The stage consists of a heating pad and sensor that keeps the subject’s temperature within a desired range. Data collected is processed by an Arduino and displayed on a computer via a graphical user interface that allows the user to control the subject’s temperature and stimulation characteristics. The system was not tested on animals, but on models that replicated what would occur during actual use.