This is a reflex test. With ALS, hyperreflexia (overactive reflexes), is a sign of upper motor neuron damage. The brain loses its ability to regulate reflex signs, so even a light tap can cause a big reaction. It’s one of those things that doctors look for when diagnosing and tracking the progression of ALS and in other cases PLS! #ALS #alsawareness #neurology #medicaltok #chronicillness