Sensing the body in chronic pain: a review of psychophysical studies implicating altered body representation.

There is growing evidence that chronic pain conditions can have an associated central pathology, involving both cortical reorganisation and an incongruence between expected and actual sensory-motor feedback. While such findings are primarily driven by the recent proliferation of neuroimaging studies, the psychophysical tasks that complement those investigations have received little attention. In this review, we discuss the literature that involves the subjective appraisal of body representation in patients with chronic pain. We do so by examining three broad sensory systems that form the foundations of the sense of physical self in patients with common chronic pain disorders: (i) reweighting of proprioceptive information; (ii) altered sensitivity to exteroceptive stimuli; and, (iii) disturbed interoceptive awareness of the state of the body. Such findings present compelling evidence for a multisensory and multimodal approach to therapies for chronic pain disorders.