Brain death differs from a coma. A person who is brain-dead is considered dead, while a person in a coma is not. Although a comatose person is unconscious, the brain is still working and they are therefore not considered dead (per Better Health Channel). Oppositely, an individual who is brain dead may still be breathing, have a heartbeat, and even feel physically warm to the touch, but this is only because life support is maintaining these functions, not the brain. While recovery is possible for patients in a coma, this is not the case for brain-dead patients who are permanently deceased.
Tell-tale signs of brain death include no response to pain, the absence of a gag reflex when stimulated, and no patient respiratory function once the ventilator is turned off. The eyes also reveal a lot when it comes to brain death. Pupils that do not constrict in response to light, the absence of a blink response when the eyeball is touched, and a lack of eye movement when the head is shifted are all signs of brain death. The absence of a vestibulo-ocular reflex, in which the eyes fail to respond to ice water being dispensed into the ear, is also a sign of brain death. Finally, EEG neuroimaging technology will reveal no brain activity in patients who are brain dead.