Don't forget that comas can be medically induced to allow the body to heal itself.
Also, in my experience, a coma looks different than one would think. Soaps are famous for having a person appear to be sleeping while the heart monitor beeps in the background. When Mom was in a coma she would open her eyes without really looking at anything. Also my step-dad's great-niece has gone for a few months without being conscious (I don't know if they are still calling it a coma); she startles at loud noises, on occasion looks at someone who is speaking and on occasion picks at irritants. Neither fits the stereotype.
Elisabeth
