Innovation: Robotic faces … for humans
February 17, 2009 | Source: New Scientist Tech
University of California, Davis scientists are using artificial polymer muscles to reanimate the facial features of people suffering from severe paralysis.

(WIPO)
Example: If a patient tries to close their eyes, the effort triggers electrical activity in the muscles that would normally close the eyelids. The polymer muscle detects this activity and contracts, pulling on its cords to fully close the eyelids.