2 = normal . 3 = increased (hyperactive) . 4 = clonus . Some examiners use a grade of 5 to designate sustained clonus, reserving 4 for unsustained clonus that eventually fades after 2 to 10 beats.

How many beats of clonus is normal?

Diagnosis. Clonus at the ankle is tested by rapidly flexing the foot into dorsiflexion (upward), inducing a stretch to the gastrocnemius muscle. Subsequent beating of the foot will result, however only a sustained clonus (5 beats or more) is considered abnormal.

Is 1 clonus beat normal?

Clonus can be physiologic, for instance, term infants can be hyperreflexic, and a few beats of clonus can be a normal finding in this population; however, most infants will not exhibit this finding, and most infants who will go on to demonstrate cerebral palsy will not exhibit clonus.