Final answer:
An Electromyography (EMG) assesses muscle movement by evaluating the electrical activity of muscles, which helps to diagnose muscle or nerve disorders.
Step-by-step explanation:
The technique that assesses muscle movement is the Electromyography (EMG). Unlike EEG, which measures brain activity, or EKG, which assesses heart activity, an EMG is used to evaluate the electrical activity produced by skeletal muscles during contraction and at rest. This can help to diagnose conditions affecting muscle function or the nerves controlling the muscles. An EMG involves inserting a needle electrode through the skin into the muscle whose activity is being examined. MRI, including functional MRI (fMRI), on the other hand, is a technique that can visualize the muscle structure and is used for a wide variety of diagnostic assessments but does not directly measure muscle movement.