On a 5-point scale:
0/4 is absence of any reflex (areflexia)—despite reinforcement.
1/4 is a reduced or weak reflex—usually requiring reinforcement.
2/4 is a normal reflex.
3/4 is a brisk reflex (hyperreflexia).
4/4 is extremely brisk hyperreflexia, usually accompanied by clonus (from the Greek klonos, tumult). This is a self-sustained and rhythmic muscle movement, marked by a rapid sequence of contractions and relaxations, which occurs (and persists) after the clinician has briskly stretched a hyperreflexic muscle and maintained tension on it. Typical of feet, clonus also can be elicited in the quadriceps, jaw, and other muscles.