One of the maxims of pain physiology is that "Peripheral damage induces central change." Few researchers would question the correctness of this principle. The induction of central change, however, is not the same thing as Central Pain.

Except for dorsal root avulsions and similar injuries, it is generally not a problem to determine where the primary injury occurred. The problem arises when there is quadriplegia which is not sensorily complete. In this circumstance, there is sometimes a tendency to call all pain symptoms "Central Pain", forgetting to consider contributions from injury to peripheral structures, if any sensation remains.

Failure to remember that damaged peripheral injuries may influence the sensory symptomatology even with profound central motor loss causes frequent misunderstanding about what Central Pain is like. This is even more true when motor loss is minor and the main alteration is in sensation.

The various elements of injury, peripheral and central, complete and incomplete, must be painstakingly sorted out to understand what the patient is saying about pain. It is not enough to say that the patient has burning or neuropathic pain.

It is also important to note gradients in the pains; whether they increase or decrease over the affected area. Gradients in pain will not necessarily follow those of sensation loss. Do not confuse diminished sensation and pain in the patients' description. The broadest display of the various Central Pain sensations appears to occur in those with incomplete damage to the greatest variety and number of sensory tracts. The number of type of pain present does not determine the severity of any one pain type, but the multiplicity of pains does have an impact on the patient's ability to deal. The percentage of the total body area in which the pain is present influences the patient's capacity to cope with the pain.. A patient may have unbearable pain in just one modality of sensation, or they may have pain from many modalities. In general, the more complete the damage, the fewer the varieties of Central Pain types.

The hallmark of Central Pain is a bizarre, indescribable burn which accompanies paradoxical components, such as a sensation of cold. The name for this pain is burning dysesthesia, sometimes just dysesthesia.

This pain is bizarre and is only found with nerve injury. A subcutaneous injection of the active ingredient in pepper spray, capsaicin, may create a similar sensation. Burning pain can also result from injury to peripheral nerves and may be severe, but it is unusual for a component of cold to accompany it.

Injury to the sympathetic pain nerves can also cause burning pain, sometimes called causalgic pain, but it is unusual for a cold component to accompany it. Although some authors speak of sympathetically maintained pain and sympathetically independent pain as separate conditions, they appear to overlap in some Central Pain patients. These authors admit that only the disappearance of the pain after removal of a main sympathetic ganglion can differentiate these conditions, but there is a circularity in such a definition. It says, in effect, "I can determine where all sympathetic pain originates, because if I remove the peripheral ganglion, it stops the pain in some patients out of a group who are otherwise clinically indistinguishable". This approach ignores the possibility that there is both central and peripheral sympathetic pain.

Similarly, although anatomists state that burning pain may be carried in both the reticulospinal tract and the spinothalamic tract, clinical signs to differentiate which type of burning each carries have never been developed. Nor is there the ability to exclude a contribution of sympathetic activity from either. With time, Central Pain will likely be differentiated further according to the anatomic substrate. Currently, a division is beginning to be made of graded and nongraded pain, meaning with or without a gradient in magnitude. This may have a counterpart at the fundamental pain level, which tends to be either marked by action potentials or by graded potentials which are highly summed at the dendrite level.

Many other pain components may be present in Central Pain, including:

needles cold tissue destruction

shooting pain gas pains movement pain

Any or all of these symptoms can be quite severe.

The capacity of Central Pain to devastate it's victims is confirmed by descriptions such as "a pain beyond pain", or like "being napalmed". Recent brain scans reveal the pain signal is so severe that the thalamus shuts down to avoid cell death, allowing the pain signal to go on unchecked into the conscious brain. What results is torture, plain and simple. It merits the same response by professionals and the public as any torture. Torture which is hidden is still torture.