Pain and the body schema: effects of pain severity on mental representations of movement.

Previous research suggests that response times for imagined movements provide a sensitive measure of the integrity of the motor system. In a group of 12 patients with chronic unilateral arm pain, the authors demonstrate that response times for imagined movements are influenced by the severity of pain. Simulated large-amplitude arm movements were slower for the painful as compared with the unaffected arms before, but not after, effective music therapy entrainment, suggesting that mental representations of movement are influenced by the current state of nociceptive feedback.