Most of the times, we simply assume that what we feel is an accurate representation of the current state of our tissues. Even more so, when the sensation (e.g., pain or stiffness) is felt in a distinct physical location. However, this “bottom up” idea of somatic input that elicits physiological reactions which are in turn influencing cognitive functioning has become more and more offset: awareness may be able to manipulate physiological control of specific body tissues.
Fifteen people with chronic low back pain (CLBP) and feelings of stiffness, and 15 healthy controls were included. For all 3 experiments, a custom device that is able to administer a standardised force while measuring displacement of its probe – and thus measure objective stiffness – was used.
In experiment 1a, objective stiffness was compared with perceived stiffness as measured on a numeric rating scale (NRS) and between those with and without feelings of stiffness. Experiment 1b consisted of a force magnitude estimation and a force difference detection task – again, the results of both groups were compared. In experiment 2, participants completed a force estimation task, while auditory input was given simultaneously to try to modulate the perception of stiffness.