The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
An Analysis of the Role of Mental Health in a Randomized Trial of a Walking Intervention for Black Veterans with Chronic Pain.
Black patients and those with co-occurring mental health disorders are disproportionately affected by chronic pain, but few interventions target these populations. This is a secondary analysis of a randomized trial of a walking-focused proactive counseling intervention for Black Veterans with chronic musculoskeletal pain (ACTION). The primary aim was to examine intervention effectiveness among Veterans with an electronic health record-documented mental health diagnosis [depressive disorder, anxiety disorder, substance use disorder, post-traumatic stress disorder or serious mental illness (n = 205)] and those without a diagnosis (n = 175). ⋯ PERSPECTIVE: This study examines the effectiveness of a walking intervention for chronic pain among Black Veterans with a mental health disorder. These patients were more engaged with the intervention than those without a mental health disorder. However, they did not experience reductions in pain-related disability, suggesting more intensive treatment is needed.
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Randomized Controlled Trial
High blood glucose and excess body fat enhance pain sensitivity and weaken pain inhibition in healthy adults: a single-blind cross-over randomised controlled trial.
To investigate links between blood glucose, body fat mass and pain, the effects of acute hyperglycaemia on pain sensitivity and pain inhibition were examined in healthy adults with normal (n = 24) or excess body fat (n = 20) determined by dual-energy X-ray absorptiometry. Effects of hyperglycaemia on heart rate variability and reactive hyperaemia were also explored. For the overall sample, ingesting 75-g glucose enhanced pain sensitivity during 1-minute cold-water immersion of both feet (conditioning stimulus) and weakened the pain inhibitory effect of cold water on pressure pain thresholds (test stimulus). ⋯ Together, these findings suggest that hyperglycaemia and excess fat mass interfere with pain processing and autonomic function. PERSPECTIVE: Ingesting 75-g glucose (equivalent to approximately 2 standard cans of soft drink) interfered with pain-processing and autonomic function, particularly in people with excess body fat mass. As both hyperglycaemia and overweight are risk factors for diabetes, whether these are sources of pain in people with diabetes should be further explored.
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Randomized Controlled Trial Observational Study
The effect of observing high or low pain on the development of central sensitization.
It is unknown whether watching other people in high pain increases mechanical hypersensitivity induced by pain. We applied high-frequency electrical stimulation (HFS) on the skin of healthy volunteers to induce pinprick mechanical hypersensitivity. Before HFS participants were randomly allocated to 2 groups: in the low pain group, which was the control condition, they watched a model expressing and reporting lower pain scores, in the high pain group the model expressed and reported higher scores. ⋯ Our results suggest that watching a person expressing more pain during HFS increases one's own pain ratings during HFS and may weakly facilitate the development of secondary mechanical hypersensitivity, although this latter result needs replication. PERSPECTIVE: Observing a person in high pain can influence the perceived pain intensity of a procedure leading to secondary mechanical hypersensitivity, and has a weak effect on hypersensitivity itself. The role of fear remains to be elucidated.
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Randomized Controlled Trial
Neurofeedback training without explicit phantom hand movements and hand-like visual feedback to modulate pain: A randomized crossover feasibility trial.
Phantom limb pain is attributed to abnormal sensorimotor cortical representations, although the causal relationship between phantom limb pain and sensorimotor cortical representations suffers from the potentially confounding effects of phantom hand movements. We developed neurofeedback training to change sensorimotor cortical representations without explicit phantom hand movements or hand-like visual feedback. We tested the feasibility of neurofeedback training in fourteen patients with phantom limb pain. ⋯ These results suggested that the proposed neurofeedback training changed phantom hand representation and modulated pain without explicit phantom hand movements or hand-like visual feedback, thus showing the relation between the phantom hand representations and pain. PERSPECTIVE: Our work demonstrates the feasibility of using neurofeedback training to change phantom hand representation and modulate pain perception without explicit phantom hand movements and hand-like visual feedback. The results enhance the mechanistic understanding of certain treatments, such as mirror therapy, that change the sensorimotor cortical representation.
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Randomized Controlled Trial Observational Study
Applying the Rapid OPPERA Algorithm to Predict Persistent Pain Outcomes among a Cohort of Women Undergoing Breast Cancer Surgery.
Persistent postmastectomy pain after breast surgery is variable in duration and severity across patients, due in part to interindividual variability in pain processing. The Rapid OPPERA Algorithm (ROPA) empirically identified 3 clusters of patients with different risk of chronic pain based on 4 key psychophysical and psychosocial characteristics. We aimed to test this type of group-based clustering within in a perioperative cohort undergoing breast surgery to investigate differences in postsurgical pain outcomes. ⋯ Findings suggest that patient characteristic-based clustering algorithms, like ROPA, may generalize across diverse diagnoses and clinical settings, indicating the importance of "person type" in understanding pain variability. PERSPECTIVE: This article presents the practical translation of a previously developed patient clustering solution, based within a chronic pain cohort, to a perioperative cohort of women undergoing breast cancer surgery. Such preoperative characterization could potentially help clinicians apply personalized interventions based on predictions concerning postsurgical pain.