Pain is a protective perceptual response shaped by contextual, psychological, and sensory inputs that suggest danger to the body. Sensory cues suggesting that a body part is moving toward a painful position may credibly signal the threat and thereby modulate pain. In this experiment, we used virtual reality to investigate whether manipulating visual proprioceptive cues could alter movement-evoked pain in 24 people with neck pain. We hypothesized that pain would occur at a lesser degree of head rotation when visual feedback overstated true rotation and at a greater degree of rotation when visual feedback understated true rotation. Our hypothesis was clearly supported: When vision overstated the amount of rotation, pain occurred at 7% less rotation than under conditions of accurate visual feedback, and when vision understated rotation, pain occurred at 6% greater rotation than under conditions of accurate visual feedback. We concluded that visual-proprioceptive information modulated the threshold for movement-evoked pain, which suggests that stimuli that become associated with pain can themselves trigger pain.

Objective To investigate whether graded motor imagery (GMI) is effective for reducing phantom limb pain (PLP) in people who have undergone limb amputations. Design A single-blinded randomised, controlled trial. Setting Physiotherapy out-patient departments in three secondary level hospitals in Cape Town, South Africa. Participants Twenty-one adults (≥18 years) who had undergone unilateral upper or lower limb amputations and had self-reported PLP persisting beyond three months. Interventions A 6-week GMI programme was compared to routine physiotherapy. The study outcomes were evaluated at baseline, 6 weeks, 3 months and 6 months. Outcome measures The pain severity scale of the Brief Pain Inventory (BPI) was used to assess the primary outcome -PLP. The pain interference scale of the BPI and the EuroQol EQ-5D-5L were used to assess the secondary outcomes -pain interference with function and health-related quality of life (HRQoL) respectively. Results The participants in the experimental group had significantly greater improvements in pain than the control group at 6 weeks and 6 months. Further, the participants in the experimental group had significantly greater improvements than the control group in pain interference at all follow-up points. There was no between-group difference in HRQoL. ConclusionThe results of the current study suggest that GMI is better than routine physiotherapy for reducing PLP. Based on the significant reduction in PLP and pain interference within the participants who received GMI, and the ease of application, GMI may be a viable treatment for treating PLP in people who have undergone limb amputations. Clinical trial registration number (PACTR201701001979279).

Background: Pain is recognised to have both a sensory dimension (intensity) and an affective dimension (unpleasantness). Pain feels like a single unpleasant bodily experience, but investigations of human pain have long considered these two dimensions of pain to be separable and differentially modifiable. The evidence underpinning this separability and differential modifiability is seldom presented. We aimed to fill this gap by evaluating the current evidence base for whether or not the sensory and affective dimensions of pain can be selectively modulated using cognitive manipulations. Methods: A rigorous systematic search, based on a priori search terms and consultation with field experts, yielded 4270 articles. A detailed screening process was based on the following recommendations: (i) evaluation of effectiveness; (ii) examination of methodological rigour, including each study having an a priori intention to cognitively modulate one of the two dimensions of pain; and (iii) sound theoretical reasoning. These were used to ensure that included studies definitively answered the research question. Results: After in-depth critique of all 12 articles that met the inclusion criteria, we found that there is no compelling evidence that the sensory and affective dimensions of pain can be selectively and intentionally modulated using cognitive manipulations in humans. Conclusions: We offer potential explanations for this discrepancy between assumptions and evidence and contend that this finding highlights several important questions for the field, from both the research and clinical perspectives.