This is an ancient thread, but still great conversation. :)
I have a hunch that the docs are charting triple flexion because they're not convinced the movement is anything more than a spinal reflex that can be stimulated in even brain dead patients. I see charting like that in my Neuro ICU as well. I'm in a Critical Care Consortium right now, and in the neuro lecture, the educator told us to not use the lower extremities when using painful stimuli to determine the motor score. He referenced the American College of Surgeons' Trauma Quality Improvement Program (TQUIP). So I looked it up.... https://www.facs.org/quality-programs/trauma/tqp/center-programs/tqip/best-practice
In the section entitled Management of Traumatic Brain Injury, it mentions:
"The location of the stimulus (central or peripheral) should be standardized and used consistently. To describe the motor response, only the reaction of the arms should be observed, not the legs."
I think if you actually scored true triple flexion, it would get a +1, because it does not reflect any cerebral function at all. I see nurses pretty routinely crank on a toenail bed, and when the patient moves the extremity, they say, "She's withdrawing from pain" and score it a +4.
Unfortunately, in my neuro training (which was pretty recent), the pain reflex, spinal reflex, withdrawal reflex or whatever you want to call it, is something that was never discussed. But it seems pretty important to know.
I'm attaching an interesting conversation on Reddit about the topic. The highlights are mine.