Does Parkinson's disease lead to alterations in the facial expression of pain?

Not only overall quantitative changes in the degree of facial pain expressiveness occurred in PD patients but also qualitative changes were found. The latter refer to a strongly affected encoding of the sensory dimension of pain (eye-narrowing) while the encoding of the affective dimension of pain (contradiction of the eyebrows) was preserved. This imbalanced pain signal might affect pain communication and pain assessment.