Is GDV a Reliable Instrument for Measuring Stress?
The question may arise if it is really justified to use GDV for stress measurements. In addition to the promising data presented in numerous publications before, including our own, we are presently in the middle of an evaluation targeting a validation of GDV mean area-of-glow as a reliable measure of certain aspects of stress. Although not yet completed, our tests appear to show that this is indeed the case: Parallel measurements of the diurnal time courses of GDV mean area of glow and of biochemical parameters collected from saliva (50-53) indicate that the diurnal curve progressions of GDV image areas and the levels of immunoglobulin A (IgA) go parallel, whilst another accepted parameter of stress, saliva alpha-amylase, progresses just the opposite to IgA and GDV. In other words, a higher GDV mean area of glow value corresponds to a higher IgA level (to be understood as an sign for lower stress or relaxation), and a lower GDV mean area of glow value can be understood as an indication
