Consciousness is a state of awareness of self and the environment and is determined by the level and content of this awareness, also referred to as arousal and awareness respectively (1). Consciousness itself takes many forms, as can be seen in the many combinations of level and content of awareness. When describing comas and vegetative states, people often use the terms interchangeably and freely without regard for the differences in consciousness of patients in these states. This however does not account for the differences in consciousness of patients in these states. In a coma, a patient is described as having “disordered arousal,” as opposed to an impairment of the content of consciousness (as is found in patients in minimally conscious states).