The present invention relates to systems, devices and methods for acquiring, measuring, monitoring, processing and analyzing physiological signals. More particularly, the present invention relates to using physiological signals to determine a subject's response to various conditions, variables or constraints. Still more particularly, the present invention relates to monitoring the subject's external body motion and/or environmental factors and determining the amount of pain a subject is suffering as a result of the motion and factors. Still more particularly, the present invention relates to a system, device and methods of quantifying a subject's pain to provide an objective measurement of the subject's pain. The present invention further relates to establishing and improving pain management protocols and therapy or treatment for the subject's pain based on the quantified pain measurement.
