Tay Vanis, who was reduced to a mindless shell as a result of torture inflicted by Darth Vader.
A persistent vegetative state describes a condition affecting patients who have experienced significant brain injury, where a coma has evolved into a state where the patient is awake but shows no signs of awareness. The story of Tay Vanis provides a clear illustration; he was a rebel subjected to torture by Darth Vader, which resulted in him existing in a vegetative state.