Quantitative assessment of experimental pain perception: multiple domains of clinical relevance

Inter-individual variation in pain perception is substantial (Gracely, 1999); threshold and tolerance in response to a variety of painful stimuli are approximately normally distributed in the general population. These individual differences are evaluated by administering standardized noxious stimuli and quantifying pain responses under controlled laboratory conditions. However, there is little consensus on whether findings from quantitative sensory testing (QST), or psychophysical studies of pain, are relevant to the clinical experience of pain (Gracely, 1999). Indeed, pain induced by laboratory-administered noxious stimuli can differ substantially from naturally-occurring pain along such dimensions as controllability, duration of stimulation, and range of stimulus intensities, such that the ascribed meaning of noxious stimulation is rarely comparable across laboratory and naturalistic settings (Edwards et at., 2004). Recently, however, studies demonstrating alterations in pain perception among many clinical populations have highlighted the potential value of experimental pain assessment, or QST (terms which we will use interchangeably), in understanding chronic pain. Moreover, scrutiny of this literature reveals multiple domains in which the clinical relevance of