Explain the different methods used for assessing various states of consciousness

Freud divided human consciousness into three levels of awareness: the conscious, preconscious, and unconscious. Each of these levels corresponds and overlaps with Freud's ideas of the id, ego, and superego.

Brain scans, heart rate, breathing rate, and galvanic skin response can be used to indicate a higher or lower level of consciousness.
Brain scans can accurately indicate an individuals level of consciousness as they show what parts of the brain are active. Limited activity in the lobes means a lower level of consciousness, while more activity indicates a higher level of consciousness.

Heart rate, breathing rate and galvanic skin response can also indicate the level of consciousness as they fluctuate depending on activity, mood, stress; the higher they are the higher the level of consciousness.