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.
Executive functions were assessed in pain-free elderly participants using neuropsychological tests. Endogenous inhibition of pain was investigated using the paradigm of conditioned pain modulation. We compared pain thresholds before and after the conditioned pain modulation procedure in older and younger participants and in seniors with poor and good performances on executive tests.
Younger participants showed a significant inhibitory effect of phasic pain during prolonged pain stimulation. Older participants with good performance on executive tests showed an absence of inhibiting effect, whereas older participants with poor performance showed a facilitating effect, indicating a significant link between cognitive functions and mechanisms of endogenous inhibition of pain.
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.
*Laboratory of Cognitive Neuroscience and Adaptation, UMR 7364
†Center of Neurocognitive and Neurophysiological Investigations, UMS 3489, CNRS, Université de Strasbourg, Strasbourg, France
The authors declare no conflict of interest.
Reprints: Andre Dufour, PhD, Center of Neurocognitive and Neurophysiological Investigations, 21 rue Becquerel, 67087 Strasbourg, France (e-mail: firstname.lastname@example.org).
Received March 23, 2018
Received in revised form September 4, 2018
Accepted September 6, 2018