Like CCRNJEN stated, the term "triple reflex" is often used in place of terms such as "triple flexion response," and "trigroup contraction" (and isn't related to Cushing's Triad, i.e. (1) bradycardia + (2) systolic HTN (i.e. pulse widening caused by elevated SBP with small or no changes to DBP) + (3) respiratory pattern changes or bradypnea), though the triple reflex is usualy a grim prognostic sign. It's sometimes similar in appearance to the evoked clonus (e.g. as we see in SCI pts after a quick manual dorsiflexion of the ankle causes clonus for several seconds following the stimulus). Like clonus that is evoked by the clinician, the triple reflex is a motor response that outlasts the duration of the stimulus. It *can* look like a spontaneous "twitching" but it is not caused by seizure activity. Often it is unilateral, but sometimes both legs are involved. The triple reflex is most noticeable in the ankle, but if you look closely, a true triple reflex also involves the knee and hip. Before calling the movement described a "triple reflex," have a neurologist (or experienced neuro resident) check, because it's quite rare (I've seen it in maybe 10 different patients) and it's often something else. A true triple reflex is a very ominous sign.
Neurosurgical ICU nurse
BSc. in neuroscience
P.S. You'll have more luck looking up the term "triple flexion response."
P.P.S. It's almost 5am so please forgive me in advance for any spelling/grammatical errors (thanks)