Coma Causes, Symptoms, Diagnosis, Assessment, and Treatment

What is a "coma"? Coma is a state of unconsciousness whereby a patient cannot react with the surrounding environment. The patient cannot be wakened with outside physical or auditory stimulation. The inability to waken differentiates coma from sleep. Patients can have different levels of unconsciousness and unresponsiveness depending upon how much or how little of the brain is functioning.