There is much already published on the medical websites about the facial expressions in psp. Some call it a "worried look" others say "astonished, grimmising, angry". Some have commented about the look "of someone who has just tasted something bad" There are articles written about the wrinkling forehead and the procerus muscles. This is very common in psp and is noteworthy. Doctors who have seen many many psp patients have noticed this unusual appearance. I want to give my theory on why it happens.
My theory is twofold.. (I have given this a great deal of thought)
-One reason of this wrinkling forehead/eyes look is to limit the amount of light coming into the eyes/brain
-The second reason is to try and keep the eyes open when they are drooping and wanting to close.
I know this because it happens to me every day.