1. A method for acquiring, characterising and classifying biosignals from a living being for determining the state of consciousness of said being comprising: acquiring at least one continuous biosignal; stimulating an evoked potential response signal in said being; deriving at least one evoked potential response signal from said at least continuous biosignal using a processor; deriving a first index of consciousness from said continuous biosignal; deriving a second index of consciousness from said evoked potential response signal; and classifying said indices as being representative of entering or leaving consciousness according to a weighting process.