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.body image ͉ consciousness ͉ crossmodal integration ͉ homeostasis

Background: Stroke is not only an acute disease, but for the majority of patients, it also becomes a chronic condition. There is a major concern about the long-term follow-up with respect to activities of daily living (ADL) in stroke survivors. Some patients seem to be at risk for decline after a first-ever stroke. The purpose of this study was to determine the course of ADL from 3 months after the first-ever stroke and onward and identify factors associated with decline in ADL. Methods: A systematic literature search of 3 electronic databases through June 2015 was conducted. Longitudinal studies evaluating changes in ADL from 3 months post stroke onward were included. Cohorts including recurrent strokes and transient ischemic attacks were excluded. Regarding the course of ADL, a meta-analysis was performed using random-effects model. A best evidence synthesis was performed to identify factors associated with decline in ADL. Results: Out of 10,473 publications, 28 unique studies were included. A small but significant improvement in ADL was found from 3 to 12 months post stroke (standardized mean difference (SMD) 0.17 (0.04-0.30)), which mainly seemed to occur between 3 and 6 months post stroke (SMD 0.15 (0.05-0.26)). From 1 to 3 years post stroke, no significant change was found. Five studies found a decline in ADL status over time in 12-40% of patients. Nine factors were associated with ADL decline. There is moderate evidence for being dependent in ADL and impaired motor function of the leg. Limited evidence was found associated with insurance status, living alone, age ≥80, inactive state and having impaired cognitive function, depression and fatigue with decline in ADL. Conclusion: Although on an average patients do not seem to decline in ADL for up to 3 years, there is considerable variation within the population. Some modifiable factors associated with decline in ADL were identified. However, more research is needed before patients at risk of deterioration in ADL can be identified.

Background Learning to predict threatening events enables an organism to engage in protective behavior and prevent harm. Failure to differentiate between cues that truly predict danger and those that do not, however, may lead to indiscriminate fear and avoidance behaviors, which in turn may contribute to disability in people with persistent pain. We aimed to test whether people with persistent neck pain exhibit contingency learning deficits in predicting pain relative to pain-free, gender-and age-matched controls. Method We developed a differential predictive learning task with a neck pain-relevant scenario. During the acquisition phase, images displaying two distinct neck positions were presented and participants were asked to predict whether these neck positions would lead to pain in a fictive patient with persistent neck pain (see fictive patient scenario details in Appendix A). After participants gave their pain-expectancy judgment in the hypothetical scenario, the verbal outcome (PAIN or NO PAIN) was shown on the screen. One image (CS+) was followed by the outcome “PAIN”, while another image (CS−) was followed by the outcome “NO PAIN”. During the generalization phase, novel but related images depicting neck positions along a continuum between the CS+ and CS− images (generalization stimuli; GSs) were introduced to assess the generalization of acquired predictive learning to the novel images; the GSs were always followed by the verbal outcome “NOTES UNREADABLE” to prevent extinction learning. Finally, an extinction phase was included in which all images were followed by “NO PAIN” assessing the persistence of pain-expectancy judgments following disconfirming information. Results Differential pain-expectancy learning was reduced in people with neck pain relative to controls, resulting from patients giving significantly lower pain-expectancy judgments for the CS+, and significantly higher pain-expectancy judgments for the CS−. People with neck pain also demonstrated flatter generalization gradients relative to controls. No differences in extinction were noted. Discussion The results support the hypothesis that people with persistent neck pain exhibit reduced differential pain-expectancy learning and flatter generalization gradients, reflecting deficits in predictive learning. Contrary to our hypothesis, no differences in extinction were found. These findings may be relevant to understanding behavioral aspects of chronic pain.

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Background: Virtual reality (VR) allows people to embody avatars that are different from themselves in appearance and ability. These experiences provide opportunities to challenge bodily perceptions. We devised a novel VR Body Image Training (VR-BIT) approach to target self-perceptions and pain in people with persistent pain.Methods: A 45-year old male with a 5-year history of disabling chronic low back pain participated in a 4-week VR-BIT intervention. Pain began following a fall from a first-floor deck. Pain was central and on the right side of his lower back, radiating to his right buttock and thigh. Pain was constant and varying at a 5/10 average intensity. The 4-week intervention consistent of three face-to-face sessions 1-week apart, followed by 1-week of in-home VR-BIT. During the first face-to-face session, the participant embodied three athletic avatars: a superhero (Incredible Hulk), a boxer, and a rock climber. Since the participant strongly identified with the boxer, only boxing experiences were subsequently used. Primary outcomes relating to body image (self-perceived strength, vulnerability, agility, and confidence with activity) and pain intensity were assessed using numerical rating scales (0-10 NRS). Disability, kinesiophobia, overall change, and self-efficacy were assessed as secondary outcomes. Outcomes were assessed during each face-to-face session, and at 1-week and 3-month follow-up.Results: The participant reported a high degree of engagement. Positive changes were noted during and after VR for all body image and pain assessments. Improvements were retained at 3-months for body image ratings (mean change: 4.5/10 NRS) and average pain intensity (change: 2/10 NRS). Improvements in disability (45% improvement); self-efficacy (pre: 2/12; post: 10/12); and overall change ("Very much improved") were noted at 3-month follow-up. No change in kinesiophobia was detected. No adverse advents were recorded. Conclusion:The participant engaged strongly with the intervention and showed clinically meaningful changes in body image, pain, disability, and self-efficacy. Despite his long history of pain and rapid improvements, reported changes may be due to non-treatment effects. Nonetheless, VR-BIT clearly warrants further investigation as a potential addition to usual care.

Innocuous cues that become associated with pain can enhance pain. This is termed classically conditioned hyperalgesia. The size of this effect varies under different conditions. We aimed to test whether the sensitising effect of pain-associated cues depends on the intensity of the paired test stimulus. To do this, two virtual reality environments were paired with either painful or non-painful vibrotactile stimuli in a counterbalanced fashion. The differential effect of the two environments was evaluated using pain intensity ratings of paired electrocutaneous test stimuli at three different intensity levels. Forty healthy participants were included in the study; 30 participants experienced sufficient pain during the learning phase and were included in the main analysis. An effect of environment (p = 0.014) and interaction between environment and test stimulus intensity was found (p = 0.046). Only the most intense test stimulus was modulated by environment. While the effect was small, the results are consistent with the proposition that pain-associated cues may induce hyperalgesia to some degree, under certain conditions. In particular, results highlight the potential relevance of stimulus intensity during and after the initial painful experience. Further attention is needed to comprehensively understand the variables that impact classically conditioned hyperalgesia.

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