I've just come across a condition called Synaesthesia. It is where ones senses get confused, for instance one can see sounds, or hear colour. Apparently 1 in 1000 people suffer from it, according to an article I just read:
The research field has grown from grapheme-colour synaesthesia to include other forms of synaesthesia in which flavours are evoked by music or words (lexical-gustatory synaesthesia), space structures by time units, colours by music, etc. Experts on Experimental Psychology from the University of Granada are studying this phenomenon. The results of this research have been published by the following scientific journals, among others: Cortex, Experimental Brain Research and Consciousness and Cognition.
Surprising as it may seem, there are people who can smell sounds, see smells or hear colours. Actually, all of as, at some point in our lives, have had this skill (some authors affirm that it is common in newborns). This phenomenon, called “synaesthesia” – from the Greek “syn” (with) and “aisthesis” (sensation) – consists of the pairing of two bodily senses by which the perception of a determined stimulus activates a different subjective perception with no external stimulus (in science, the evoker stimulus is called inducer and the additional experience concurrent).
I'm thinking this could perhaps explain some of the supanatural things that people report - auras, ghosts and so on.