Actually, there are different kinds among these. There are those whose souls are very much intact and even growing through the experiences in the inner being, somewhat like in a dream state. In all likelihood, they do receive the thoughts and the general state of consciousness of those around. Studies do indicate that their brain do respond to external stimuli, so things are getting registered even though not as they would in the waking state. Possibly, touch and smell remain intact for a long time, even when eyes, ears, and taste are not functioning.
However, it does happen sometimes that the soul has departed and the senses leaving only the body as a living shell kept functioning artificially. Sometimes these bodies may be occupied with small little vital entities to have a taste of the human house.
Affectionately,
Alok Da
