This is a state of minimally decreased wakefulness where the primary deficit is attention. The patient is easily distracted and has faulty memory, but retains the ability to communicate by verbal or nonverbal means. Drowsiness is prominent. Communication is partially preserved. Stupor is clinically equivalent to deep physiologic sleep from which the patient can be partially or only temporarily aroused, and only by vigorous and repeated stimulation.
Communication is minimal or nonexistent.
Coma can be defined as a reduction in neuronal function resulting from disruption of cerebral cortical or brain stem integrity. This is a state of unarouseable unresponsiveness in which the patient lies without spontaneous movement with the eyes closed. There is no intelligent speech. The patient may withdraw from noxious stimuli, but cannot localize pain with discrete, defensive movements. These states are not to be confused with delirium which is an abnormal mental state characterized by disorientation, instability, delusions, or hallucinations.