Follow up on the short discussion of the Jahi case and the longer one on Terri Schiavo.
Guidance for Neurologists on how to determine brain death
http://surgery.med.miami.edu/laora/clinical-operations/brain-death-diagnosis
Discussion from the National Inst of Neurological Disorders on characteristics of Coma and Persistent Vegetative State (PVS).
http://www.ninds.nih.gov/disorders/coma/coma.htm