Coma is the prolonged period of unconsciousness following a severe traumatic brain injury. In this unresponsive state, there is no speech, the eyes are typically closed, there is no response to commands. Yet a brain injured person in coma may have a simple reflex in response to touch or pain. The brain injured person may react to pain by groaning or moving, but will have no memory or recollection of the pain.
It may also appear to those who wait that the brain injured person is showing signs of hearing and comprehending. Yet such signs are often simple reflexes and not actual in response to the external stimuli. It may be some time before a patient shows signs of real emergence or the processing information. Even though it is difficult to do research to prove this, we suggest that people talk about or to the TBI survivor as if they can comprehend what is being said.
There are several stages of coma. Medical professionals measure coma stages by the degree of responsiveness of the brain injured person. In the acute phase of severe brain injury, the Glasgow Coma Scale is used. As the brain injured patient improves or stabilizes, the Rancho Los Amigos Scale is often the better measure, as it has more graduated levels of returning cognitive functioning (understanding and reasoning).