@feruze-- My wife has both hyperreflexia and clonus as a result of a spinal cord injury from a car accident.
The two are similar, and the causes can be the same. Hyperreflexia is when the reflex responses are exaggerated and clonus is when there are multiple involuntary muscle contractions.
It's easy to confuse these together but doctors have different physical tests to diagnose them and my wife has been diagnosed with both. Doctors are still trying to figure out the stimulus that's causing these in her. Apparently, the only way to treat these conditions is to find and eliminate the stimulus. It's probably pressure on one of the nerves in her spinal cord. She has to go through a few more MRIs next week.