The Clinical journal of pain
-
Numbness associated with neuropathic pain suggests the loss of function in myelinated, large diameter sensory neurons. The purpose of this study was to examine the relationships between pain severity and subjective (ie, severity of numbness) and objective (ie, loss of light touch sensations, vibration thresholds) measures of loss of large fiber function in adult survivors with chemotherapy-induced peripheral neuropathy (CIPN, n=426) and breast cancer patients with persistent postsurgical pain (n=80). ⋯ Our findings, in 2 independent samples of oncology patients, suggest that loss of function of myelinated, large diameter fibers contributes to the severity of neuropathic pain.
-
Aging has been associated with increases in pain threshold and reductions in tolerance threshold, as well as a deficiency in endogenous pain inhibition. Top-down pain modulation mainly involves the frontal cortex network, which is also one of the most vulnerable brain regions in aging. As the frontal cortex also sustains executive functions, we aimed to determine whether reductions in executive functions subtended by the frontal network are associated with the lack of descending inhibitor control in pain-free elderly participants. ⋯ These results highlight a significant link between cognitive functions and mechanisms of endogenous inhibition of pain and open new perspectives in investigations of chronic pain in aging.