For a long time I have wondered whether or not patients that have been declared to be in a "vegetative state" are actually conscious mentally. It has been the topic of debate for many years. If there is no way of expressing awareness through direct commands and responses to those commands, how can we actually tell? The following video explains a method of communicating with patients in the vegetative state by scanning their brain activity under certain conditions. This has resulted in them finding that a surprising number of patients are conscious and aware despite having no control over their body.
Human: Can Comatose People Hear? : Discovery News
The video was made nearly 2 years ago now but I still think it's very interesting.

This article shows how this method has been used already.
BBC News - Vegetative patient Scott Routley says 'I'm not in pain'

What are your thoughts on this and how do you think it could be used in the future to gain more of an understanding of patients in the vegetative state?