What are the 4 levels of unconsciousness?

Question

Im studying radiology and working on my homework, the questions is what are the 4 levels of unconsciousness and why is it important to interact effectively with patients that may be in an altered state of consciousness, well i know the answer to the second part but i still cant seem to find the 4 levels of unconsciousness and i have read the whole chapter

Answer 1

I'm guessing it can be defined in different ways.  Here is one:

Level Of Consciousness

The level of consciousness is determined by the activity of the brain. It can be categorized as follows:

   (1) Alert (A) : Sound and clear mind, responding normally and answering questions swiftly..

   (2) Response to voice (V) : Feels tired and sleepy. Wakes up easily and able to do as told or answers simple questions. The patient is in a state of confusion nevertheless and is easily agitated.

   (3) Response to pain (P) : Difficult to wake up but will respond to pain. The patient cannot answer questions properly.

   (4) Unresponsive (U) : Impossible to be woken up with no response to external stimulation.