Articles: function.
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Review
Brain changes associated with cognitive and emotional factors in chronic pain: A systematic review.
An emerging technique in chronic pain research is MRI, which has led to the understanding that chronic pain patients display brain structure and function alterations. Many of these altered brain regions and networks are not just involved in pain processing, but also in other sensory and particularly cognitive tasks. Therefore, the next step is to investigate the relation between brain alterations and pain related cognitive and emotional factors. ⋯ In contrast to pain catastrophizing, evidence on anxiety and depressive symptoms shows no clear association with brain characteristics. However, all included cognitive or emotional factors showed significant associations with resting state fMRI data, providing that even at rest the brain reserves a certain activity for these pain-related factors. Brain changes associated with illness perceptions, pain attention, attitudes and beliefs seem to receive less attention in literature.
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Generalization of fear of movement-related pain across novel but similar movements can lead to fear responses to movements that are actually not associated with pain. The peak-shift effect describes a phenomenon whereby particular novel movements elicit even greater fear responses than the original pain-provoking movement (CS+), because they represent a more extreme version of the CS+. There is great variance in the propensity to generalize as well as the speed of extinction learning when these novel movements are not followed by pain. It can be argued that this variance may be associated with executive function capacity, as individuals may be unable to intentionally inhibit fear responses. This study examined whether executive function capacity contributes to generalization and extinction of generalization as well as peak-shift of conditioned fear of movement-related pain and expectancy. ⋯ Low inhibitory capacity is not associated with slower generalization, but extinction of fear generalization. Fear elicited by a novel safe movement, situated outside the CS+/- continuum on the CS+ side, can be as strong as to the original stimulus predicting the pain-onset.
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Randomized Controlled Trial Multicenter Study
A tailored guided internet-based cognitive-behavioral intervention for patients with rheumatoid arthritis as an adjunct to standard rheumatological care: Results of a randomized controlled trial.
For patients with chronic pain conditions such as rheumatoid arthritis (RA), who experience elevated levels of distress, tailored-guided internet-based cognitive-behavioral treatment may be effective in improving psychological and physical functioning, and reducing the impact of RA on daily life. A multicenter, randomized controlled trial was conducted for RA patients with elevated levels of distress as assessed by a disease-specific measure. The control group (n = 71) received standard care and the intervention group (n = 62) additionally received an internet-based tailored cognitive-behavioral intervention. ⋯ No effects were found for the impact of RA on daily life, except for the intervention group experiencing fewer role limitations due to emotional problems (P < 0.001, d = 0.53). Offering guided internet-based cognitive-behavioral therapy is a promising development to aid patients with psychological distress particularly in improving psychological functioning. Further research on adherence and specific intervention ingredients is warranted.
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Protocols of temporal summation (TS) of pain typically involve the delivery of brief repetitive noxious pulses of a constant intensity while measuring the perceived intensity of pain after each pulse. The size percept of noxious repetitive stimulation has been poorly characterized. Furthermore, no studies have investigated age differences in TS of cold pain. ⋯ Additionally, older women experienced greater TS of the size percept of heat stimuli compared with older men and all younger participants. No overall age or sex differences were found in the TS of pain intensity for cold or heat trials. These results suggest dysfunctional modulation of the spatial percept of the painful stimuli by older adults, and in particular older women, during repetitive noxious thermal pulses.
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Despite considerable advances in understanding mechanisms involved in chronic pain, effective treatment remains elusive. Comorbid conditions including anxiety, depression, and cognitive impairment further impact quality of life. Chronic pain is associated with reversible changes in brain anatomy and function and with long-term changes in gene expression. ⋯ S-adenosylmethionine completely blocked nerve injury-induced cognitive impairment and attenuated SNI-induced decreases in global DNA methylation in the frontal cortex. In summary, chronic oral administration of the methyl donor, SAM, attenuated sensory and cognitive symptoms associated with nerve injury in mice. These effects may be mediated, in part, through modulation of DNA methylation in the central nervous system by systemic administration of the methyl donor SAM.