Pain That Inhibits Other Pain
Conditioned pain modulation (CPM) describes the phenomenon in which one painful stimulus can reduce the perceived intensity of a second, separate painful stimulus elsewhere in the body — commonly summarised as "pain inhibiting pain" (Yarnitsky, 2010).
How Researchers Measure It
In a laboratory setting, CPM is typically tested by having a person rate a standard painful stimulus (such as pressure or heat), then repeating that rating while a separate, strongly stimulating "conditioning" stimulus — often the hand immersed in cold water — is applied elsewhere on the body. A reduction in the pain rating of the first stimulus during the conditioning stimulus indicates a functioning CPM response.
Why an Efficient CPM Response Matters
A robust CPM response is generally considered a marker of a well-regulated, healthy descending pain-modulatory system. Several chronic pain conditions are associated with a measurably blunted or even absent CPM response, suggesting an impaired capacity of the nervous system to naturally dampen its own pain signalling — a finding with implications for how persistent pain is understood and managed.
References & Further Reading
- Yarnitsky D. Conditioned pain modulation (the diffuse noxious inhibitory control-like effect): its relevance for acute and chronic pain states. Curr Opin Anaesthesiol. 2010;23(5):611-615.