Levels of Response
"Are they conscious?" is either "Yes" or "No" which is too simplistic. Consciousness is a spectrum so we use the AVPU scale to show the casualty's Level of Response.
If you are reading this you are more than Conscious, you are fully ALERT - as you can answer Who, Where, When and What just happened?
Anyone who is not alert is Unconscious, but they may still be able to respond to stimuli. Firstly shout a strong and simple command like "Open your eyes!" The response you get may be overt, they may actually open their eyes and look at you - or it may be subtle, they may simply groan or flinch. In either case this casualty is unconscious but responsive to VOICE.
If they don't respond to your voice, do they respond to PAIN? Pinch the casualty's ear lobe and if no response then pinch the muscle along the top of the shoulder hard or the tricep, always looking at the casualty's face for a response, be it overt or subtle. .
If they do not respond to pain, they are unconscious and UNRESPONSIVE.
Your casualty can now be categorised using AVPU:
"Unconscious but responding to Voice" or
"Unconscious but responding to Pain" or
"Unconscious and Unresponsive"
It is much more useful to know how RESPONSIVE they are rather than if they are conscious or not, and also how they progress through the spectrum.
(Adapted from an excellent article by Real First Aid.co.uk)