levels of consciousness

conscious

awake, alert, aware, responding appropriately

unconscious

unaware and unable to respond to stimuli

lethargy

lowered level of consciousness marked by listlessness, drowsiness, and apathy

stupor

unresponsive, arouses only briefly despite repeated attempts

syncope

• brief loss of consciousness due to decreased blood flow to the brain

• fainting

coma

• a deep state of unconsciousness

• no spontaneous eye movements or response to painful stimuli or speech

persistent vegetative state

• alternating sleep-wake cycles

• person remains unconscious

delirium

acute confusion, disorientation, disordered thinking or memory, agitation, and hallucinations