What is CPM?

CPM, Conditioned Pain Modulation, is one of our neural system mechanisms to control pain. CPM is an endogenous descending pain inhibition mechanism, located in the brain stem, the most “primitive” part of the brain, which is a critical area for nociception and pain processing.

In essence, pain is the brain’s way of notifying that there is a problem, danger, a threat that has to be escaped from or eliminated, etc. The brain stem is capable of “deciding” that a certain painful stimulus is not essential and does not represent a real threat. This “decision” results with the increased released of certain substances – neurotransmitters – that flow down the neural system and are capable of aborting the pain by blocking the nociceptive messages from propagating up the neural system.

CPM is an endogenous mechanism, but in many people suffering from certain neurological diseases it is deficient and is not “triggered” when it should have.

Triggering the CPM

This deficiency can be compensated by utilizing a strong, yet sub-painful stimulus, located remotely from that of the original pain. This “conditioning” stimulus then has a better chance to trigger the CPM – which has a global impact, over the entire body. The stimulus applies a specific electrical waveform especially engineered to recruit many nociceptive nerve fibers, i.e. nerve fibers, whose purpose is to propagate painful messages. When these messages are received in the brain stem, they have a high probability to trigger the CPM – and abort the original pain.