Coma

In medicine, coma (from the Greek κῶμα koma, meaning "deep sleep") is a state of unconsciousness in which a person: cannot be awakened; fails to respond normally to painful stimuli, light, or sound; lacks a normal wake-sleep cycle; and does not initiate voluntary actions. A person in a state of coma is described as being comatose. Typically, a distinction is made in the medical community between a coma and a medically induced coma, the former is generally understood to be a result of circumstances beyond the control of the medical community, while the latter is generally understood to be a means by which medical professionals may allow a patient's injuries to heal in a controlled environment.