Define Pain Pain is an unpleasant sensory and emotional experience associated with actual or threatened tissue damage. Describe the theories of pain Theoretical frameworks of pain explain the physiological basis of pain. A number of theories have been postulated to describe mechanisms underlying pain perception. 1.Intensive Theory (Erb, 1874) This theory defines pain, not asContinue reading "Define pain, Describe the theories of pain, Explain the applications of Transcutaneous Electrical Nerve Stimulation, Note on mechanism of pain relief."