Clonus is a type of neurological condition that creates involuntary muscle contractions. This results in uncontrollable, rhythmic, shaking movements. People who experience clonus report repeated contractions that occur rapidly. It’s not the same as an occasional muscle contraction. Clonus is a long-term condition. Before you can be treated for it, your doctor will need to diagnose the condition. First, your doctor will perform a physical exam. They will look at the areas that have the most contractions and pain. If you have a muscle contraction while at the doctor’s office, your doctor will measure how many “beats” or contractions occur. Your doctor may order certain tests to diagnose clonus, as well. These tests can also help your doctor identify any undiagnosed conditions you might have. Possibilities include: balance and coordination tests blood tests MRI of the brain spinal fluid samples No single test can diagnose the cause of clonus. You might need to take a series of tests before your doctor makes a diagnosis.