Greater Trauma Associated With Amplification of Pain, Spinal Nociception

A new study assessed temporal summation of the nociceptive flexion reflex (TS-NFR; a physiological marker of spinal nociception) and temporal summation of pain (TS-Pain), as presented at the American Pain Society 36th Annual Scientific Meeting, May 17-20, in Pittsburgh, Pennsylvania.

This study, conducted by Cassandra A. Sturycz, MA, from the University of Oklahoma in Tulsa, and colleagues aimed to further explore the relationship between pain and trauma exposure. “Trauma exposure and posttraumatic stress disorder (PTSD) are related to enhanced pain in response to suprathreshold stimuli and are often associated with the development of chronic pain,” the researchers said.

The researchers focused on the mechanism of central sensitization — the hyperexcitability of spinal neurons to pain signals — which can be assessed by TS-Pain.

They divided 184 healthy men and women into 3 levels of trauma exposure that ranged from low (0-1) to medium (2-3) to high (≥4), according to the Life Events Checklist (LEC-5), before being exposed to repeated painful electronic stimulations over the ankle.

Although all 3 groups demonstrated significant TS-NFR and TS-Pain, the degree of summation was greatest in the high-exposure group (P <.05, according to linear mixed model ANOVAs); TS-NFR and TS-Pain were similar in the other groups (P >.05 for all).

“These findings suggest that greater trauma exposure is associated with greater amplification of pain and spinal nociception,” the researchers concluded.

“Future research should examine potential psychosocial (eg, [posttraumatic stress disorder] symptoms, catastrophizing, emotional regulation) or biological (eg, allostatic load) factors that mediate the relationship between trauma exposure and enhanced TS-NFR and TS-Pain,” they added.

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