Individualized Protocol for Test-retest Reliabilty of Thermal Temporal Summation 

Pain is a complex phenomenon that affects various areas of the brain in different ways, depending on whether the pain is acute or chronic. Pain researchers conduct a variety of tests using a repeated painful stimulus such as heat, cold, or pin pricks, to study how the brain responds to these stimuli.

Temporal summation is a term that pain researchers use to refer to how people perceive pain when painful (noxious) stimuli are repeatedly applied. Studies have shown that people suffering from fibromyalgia, chronic pelvic pain, tempormandibular joint disorder, and other conditions that cause chronic pain, often have a greater degree of temporal summation, or heightened sensitivity to pain.

We conducted a test of the reliability of thermal, or heat-generated, temporal summation as a means of characterizing chronic pain. We applied repeated heat pulses in 19 study participants over a period of several days. The participants were asked to rate only the “second pain,” the slow, burning sensation felt after the initial, prickly sensation that occurs when the heat pulse is applied, which is called the “first pain.” Most temporal summation tests use a fixed temperature for all patients. In our study, the applied temperatures varied, and the temporal summation was determined for each participant based on their responses to the applied heat stimuli.

We found that our individualized protocol for determining temporal summation produced consistently reliable results for tests conducted on the same day and over a period of several days. This method holds promise for helping researchers understand individual variations in the mechanisms of chronic pain, which could lead to better treatments in the future.

Kong JT, Johnson KA, Balise RR, Mackey S. Test-retest reliability of thermal temporal summation using an individualized protocol. J Pain 2013:14(1);79–88.