Does Sensorimotor Incongruence Trigger Pain and Sensory Disturbances in People With Chronic Low Back Pain? A Randomized Cross-Over Experiment.

Chronic low back pain (CLBP) has major public health implications, and underlying mechanisms are still unclear. Sensorimotor incongruence (SMI)-an ongoing mismatch between top-down motor output and predicted sensory feedback-may play a role in the course of chronic nonspecific low back pain. The hypothesis of this study was that the induction of SMI causes sensory disturbances and/or pain in people with CLBP and healthy volunteers. A sample of 66 people (33 people with CLBP and 33 healthy volunteers) participated in a visual feedback experiment involving real-time images of their own lower backs-either during movement or in a static position-provided via a live video feed. Experimental SMI was induced via distorting visual feedback of the lower back during movement. There were no significant differences in sensory disturbances or pain intensity between experimental SMI and the other movement conditions in people with CLBP and healthy volunteers (P > .05). Static visual feedback had a significant effect on the intensity of sensory disturbances in people with CLBP (P = .038) and healthy volunteers (P < .001). In conclusion, experimental SMI did not affect sensory disturbances or pain in either group. Therefore, the research hypothesis was not supported. PERSPECTIVE: The results of this study show that sensorimotor incongruence does not cause additional symptoms and pain in people with chronic low back pain. The conceptual premise that sensorimotor incongruence is an underlying contributor in the course of pain in this population is not supported.

In the spine or in the brain? Recent advances in pain neuroscience applied in the intervention for low back pain.

Conservative, surgical and pharmacological strategies for chronic low back pain (CLBP) management offer at best modest effect sizes in reducing pain and related disability, indicating a need for improvement. Such improvement may be derived from applying contemporary pain neuroscience to the management of CLBP. Current interventions for people with CLBP are often based entirely on a "biomedical" or "psychological" model without consideration of information concerning underlying pain mechanisms and contemporary pain neuroscience. Here we update readers with our current understanding of pain in people with CLBP, showing that CLBP is not limited to spinal impairments, but is also characterised by brain changes, including functional connectivity reorganisation in several brain regions and increased activation in brain regions of the so-called 'pain matrix' (or 'pain connectome'). Indeed, in a subgroup of the CLBP population brain changes associated with the presence of central sensitisation are seen. Understanding the role of these brain changes in CLBP improves our understanding not only of pain symptoms, but also of prevalent CLBP associated comorbidities such as sleep disturbances and fear avoidance behaviour. Applying contemporary pain neuroscience to improve care for people with CLBP includes identifying relevant pain mechanisms to steer intervention, addressing sleep problems and optimising exercise and activity interventions. This approach includes cognitively preparing patients for exercise therapy using (therapeutic) pain neuroscience education, followed by cognition-targeted functional exercise therapy.

The Effect of Visual Feedback of the Neck During Movement in People With Chronic Whiplash-Associated Disorders: An Experimental Study.

Study Design Controlled laboratory study. Background Chronic whiplash-associated disorder (WAD) is an important health issue associated with poor recovery outcomes. Sensorimotor incongruence (SMI), defined as a mismatch between the efference copy in the brain and afferent sensory feedback from the body, is proposed as a possible underlying cause of chronic pain. Objectives To determine whether SMI causes sensory disturbances or pain in people with chronic WAD and healthy controls. Methods Sixty-four participants (30 with chronic WAD and 34 healthy controls) participated in a visual feedback experiment involving the neck and a bimanual coordination experiment involving the arms. In both experimental setups, SMI was induced by modifying the visual feedback during movement. Sensory disturbances and pain were the primary outcomes. Results A statistically significant difference in perceived sensory disturbance between conditions was found in the WAD group (P<.001). Intensity scores were highest for induced SMI, but only for visual feedback of the neck and not for visual feedback of the arms. This effect was not present in the control group (P = .139). Sensorimotor incongruence did not affect pain in either group. Conclusion Persons with chronic WAD are more susceptible to sensory disturbances owing to SMI, and this effect is specific to the region affected by pain. The hypothesis that SMI causes pain was not substantiated by the results of the present study. J Orthop Sports Phys Ther 2017;47(3):190-199. Epub 3 Feb 2017. doi:10.2519/jospt.2017.6891.

Abnormal Pain Response to Visual Feedback During Cervical Movements in Chronic Whiplash: An Experimental Study.

BACKGROUND: Whiplash-associated disorders (WAD) are a debilitating condition. In chronic WAD, sensorimotor incongruence exacerbates symptoms. Sensorimotor incongruence occurs when somatosensory input and predicted motor output are in conflict, which can trigger pain. On the other hand, there is evidence that visual feedback can decrease pain in certain chronic pain conditions. Therefore, the aim of this study was to examine the effect of visual feedback and sensorimotor incongruence on pain thresholds in chronic WAD. METHODS: Sixty-four participants (healthy controls and patients with chronic WAD) were subjected to six experimental conditions. Participants watched correct real-time or modified visual feedback of the neck or hand (without movement as well as during repetitive neck lateroflexion). Sensorimotor incongruence was induced by manipulating visual feedback. Pressure pain thresholds were measured at baseline and during each condition. RESULTS: Marked between-group differences were observed. Visual feedback of the neck-correct or modified-did not influence pain thresholds in chronic WAD. In contrast, healthy controls had significantly higher pain thresholds when provided with the correct or modified visual feedback. When a movement of the neck was added during visual feedback, patients with chronic WAD showed no significant difference in pain thresholds, while an increase in pain thresholds was found in the healthy control group. CONCLUSION: In contrast to the healthy controls, visual feedback and sensorimotor incongruence did not alter pain thresholds in patients with chronic WAD. These findings suggest an abnormal pain response to visual feedback and somatosensory incongruence as well as failing mechanisms of pain inhibition in chronic WAD.

Sensorimotor Incongruence in People with Musculoskeletal Pain: A Systematic Review.

OBJECTIVES: Musculoskeletal pain has major public health implications, but the theoretical framework remains unclear. It is hypothesized that sensorimotor incongruence (SMI) might be a cause of long-lasting pain sensations in people with chronic musculoskeletal pain. Research data about experimental SMI triggering pain has been equivocal, making the relation between SMI and pain elusive. The aim of this study was to systematically review the studies on experimental SMI in people with musculoskeletal pain and healthy individuals. METHODS: Preferred reporting items for systematic reviews and meta-analyses guidelines were followed. A systematic literature search was conducted using several databases until January 2015. To identify relevant articles, keywords regarding musculoskeletal pain or healthy subjects and the sensory or the motor system were combined. Study characteristics were extracted. Risk of bias was assessed using the Dutch Institute for Healthcare Improvement (CBO) checklist for randomized controlled trials, and level of evidence was judged. RESULTS: Eight cross-over studies met the inclusion criteria. The methodological quality of the studies varied, and populations were heterogeneous. In populations with musculoskeletal pain, outcomes of sensory disturbances and pain were higher during all experimental conditions compared to baseline conditions. In healthy subjects, pain reports during experimental SMI were very low or did not occur at all. DISCUSSION: Based on the current evidence and despite some methodological issues, there is no evidence that experimental SMI triggers pain in healthy individuals and in people with chronic musculoskeletal pain. However, people with chronic musculoskeletal pain report more sensory disturbances and pain during the experimental conditions, indicating that visual manipulation influences pain outcomes in this population.

Psychologically induced cooling of a specific body part caused by the illusory ownership of an artificial counterpart.

The sense of body ownership represents a fundamental aspect of our self-awareness, but is disrupted in many neurological, psychiatric, and psychological conditions that are also characterized by disruption of skin temperature regulation, sometimes in a single limb. We hypothesized that skin temperature in a specific limb could be disrupted by psychologically disrupting the sense of ownership of that limb. In six separate experiments, and by using an established protocol to induce the rubber hand illusion, we demonstrate that skin temperature of the real hand decreases when we take ownership of an artificial counterpart. The decrease in skin temperature is limb-specific: it does not occur in the unstimulated hand, nor in the ipsilateral foot. The effect is not evoked by tactile or visual input per se, nor by simultaneous tactile and visual input per se, nor by a shift in attention toward the experimental side or limb. In fact, taking ownership of an artificial hand slows tactile processing of information from the real hand, which is also observed in patients who demonstrate body disownership after stroke. These findings of psychologically induced limb-specific disruption of temperature regulation provide the first evidence that: taking ownership of an artificial body part has consequences for the real body part; that the awareness of our physical self and the physiological regulation of self are closely linked in a top-down manner; and that cognitive processes that disrupt the sense of body ownership may in turn disrupt temperature regulation in numerous states characterized by both.