Validation,reproducibility and safety of trans dermal electrical stimulation in chronic pain patients and healthy volunteers

Background  

Surrogate pain models have been extensively tested in Normal Human Volunteers (NHV). There are few studies that examined pain models in chronic pain patients. Patients are likely to have altered pain mechanisms. It is of interest to test patient pain responses to selective pain stimuli under controlled laboratory conditions.     

Psychometric evaluation of the Orofacial Pain Scale for Non‐Verbal Individuals as a screening tool for orofacial pain in people with dementia

Objective

The aim of this study was to describe the psychometric evaluation of the Orofacial Pain Scale for Non‐Verbal Individuals (OPS‐NVI) as a screening tool for orofacial pain in people with dementia.

Background

The OPS‐NVI has recently been developed and needs psychometric evaluation for clinical use in people with dementia. The pain self‐report is imperative as a reference standard and can be provided by people with mild‐to‐moderate cognitive impairment.

Methods

The presence of orofacial pain during rest, drinking, chewing and oral hygiene care was observed in people with mild cognitive impairment (MCI) and dementia using the OPS‐NVI. Participants who were considered to present a reliable self‐report were asked about pain presence, and in all participants, the oral health was examined by a dentist for the presence of potential painful conditions. After item‐reduction, inter‐rater reliability and criterion validity were determined.

Results

The presence of orofacial pain in this population was low (0%‐10%), resulting in an average Positive Agreement of 0%‐100%, an average Negative Agreement of 77%‐100%, a sensitivity of 0%‐100% and a specificity of 66%‐100% for the individual items of the OPS‐NVI. At the same time, the presence of oral problems, such as ulcers, tooth root remnants and caries was high (64.5%).

Conclusion

The orofacial pain presence in this MCI and dementia population was low, resulting in low scores for average Positive Agreement and sensitivity and high scores for average Negative Agreement and specificity. Therefore, the OPS‐NVI in its current form cannot be recommended as a screening tool for orofacial pain in people with MCI and dementia. However, the inter‐rater reliability and criterion validity of the individual items in this study provide more insight for the further adjustment of the OPS‐NVI for diagnostic use. Notably, oral health problems were frequently present, although no pain was reported or observed, indicating that oral health problems cannot be used as a new reference standard for orofacial pain, and a regular oral examination by care providers and oral hygiene care professionals remains indispensable.     

Effects of dextromethorphan and oxycodone on treatment of neuropathic pain in mice

Background

Neuropathic pain is a very troublesome and difficult pain to treat. Although opioids are the best analgesics for cancer and surgical pain in clinic, only oxycodone among opioids shows better efficacy to alleviate neuropathic pain. However, many side effects associated with the use of oxycodone render the continued use of it in neuropathic pain treatment undesirable. Hence, we explored whether dextromethorphan (DM, a known N-methyl-D-aspartate receptor antagonist with neuroprotective properties) could potentiate the anti-allodynic effect of oxycodone and underlying mechanisms regarding to glial cells (astrocytes and microglia) activation and proinflammatory cytokines release in a spinal nerve injury (SNL) mice model.

Results

Oxycodone produced a dose-dependent anti-allodynic effect. Co-administration of DM at a dose of 10 mg/kg (i.p.) (DM10) which had no anti-allodynic effect by itself enhanced the acute oxycodone (1 mg/kg, s.c.) effect. When the chronic anti-allodynic effects were examined, co-administration of DM10 also significantly enhanced the oxycodone effect at 3 mg/kg. Furthermore, oxycodone decreased SNL-induced activation of glial cells (astrocytes and microglia) and plasma levels of proinflammatory cytokines (IL-6, IL-1β and TNF-α). Co-administration of DM10 potentiated these effects of oxycodone.

Conclusion

The combined use of DM with oxycodone may have therapeutic potential for decreasing the effective dose of oxycodone on the treatment of neuropathic pain. Attenuation of the glial activation and proinflammatory cytokines in the spinal cord may be important mechanisms for these effects of DM.     

Effect of buspirone on thermal sensory and pain thresholds in human volunteers

Background  

Buspirone is a partial 5-HT_1A receptor agonist. Animal studies have shown that modulation of serotoninergic transmission at the 5-HT_1A receptor can induce analgesia in acute pain models. However, no studies have been published so far on the effects of serotonin receptor agonists on pain perception in humans.     

Evidence based guidelines for complex regional pain syndrome type 1

Background  

Treatment of complex regional pain syndrome type I (CRPS-I) is subject to discussion. The purpose of this study was to develop multidisciplinary guidelines for treatment of CRPS-I.     

The relationship between disease activity, sleep, psychiatric distress and pain sensitivity in rheumatoid arthritis: a cross-sectional study

Introduction  

Despite recent advances in anti-inflammatory therapy, rheumatoid arthritis (RA) patients continue to rate pain as a priority. The etiology of RA pain is likely multifactorial, including both inflammatory and non-inflammatory components. In this study, we examine the association between disease activity, sleep, psychiatric distress and pain sensitivity in RA.     

Intrathecal lidocaine pretreatment attenuates immediate neuropathic pain by modulating Nav1.3 expression and decreasing spinal microglial activation

Background  

Intrathecal lidocaine reverses tactile allodynia after nerve injury, but whether neuropathic pain is attenuated by intrathecal lidocaine pretreatment is uncertain.     

Leg-length inequality is not associated with greater trochanteric pain syndrome

Introduction  

Greater trochanteric pain syndrome (GTPS) is a common condition, the pathogenesis of which is incompletely understood. Although leg-length inequality has been suggested as a potential risk factor for GTPS, this widely held assumption has not been tested.     

Neuromuscular adaptations predict functional disability independently of clinical pain and psychological factors in patients with chronic non-specific low back pain

Patients with chronic low back pain exhibit characteristics such as clinical pain, psychological symptoms and neuromuscular adaptations. The purpose of this study was to determine the independent contribution of clinical pain, psychological factors and neuromuscular adaptations to disability in patients with chronic low back pain. Clinical pain intensity, pain catastrophizing, fear-avoidance beliefs, anxiety, neuromuscular adaptations to chronic pain and neuromuscular responses to experimental pain were assessed in 52 patients with chronic low back pain. Lumbar muscle electromyographic activity was assessed during a flexion–extension task (flexion relaxation phenomenon) to assess both chronic neuromuscular adaptations and neuromuscular responses to experimental pain during the task. Multiple regressions showed that independent predictors of disability included neuromuscular adaptations to chronic pain (β = 0.25, p = 0.006, sr² = 0.06), neuromuscular responses to experimental pain (β = −0.24, p = 0.011, sr² = 0.05), clinical pain intensity (β = 0.28, p = 0.002, sr² = 0.08) and psychological factors (β = 0.58, p < 0.001, sr² = 0.32). Together, these predictors accounted for 65% of variance in disability (R² = 0.65 p < 0.001). The current investigation revealed that neuromuscular adaptations are independent from clinical pain intensity and psychological factors, and contribute to inter-individual differences in patients’ disability. This suggests that disability, in chronic low back pain patients, is determined by a combination of factors, including clinical pain, psychological factors and neuromuscular adaptations.     

Pregabalin,the lidocaine plaster and duloxetine in patients with refractory neuropathic pain: a systematic review

Background  

Patients frequently fail to receive adequate pain relief from, or are intolerant of, first-line therapies prescribed for neuropathic pain (NeP). This refractory chronic pain causes psychological distress and impacts patient quality of life. Published literature for treatment in refractory patients is sparse and often published as conference abstracts only. The aim of this study was to identify published data for three pharmacological treatments: pregabalin, lidocaine plaster, and duloxetine, which are typically used at 2^nd line or later in UK patients with neuropathic pain.     

Relationship between patient-reported disease severity in osteoarthritis and self-reported pain, function and work productivity

Introduction  

Understanding the relationship between patient-reported osteoarthritis (OA) severity and other patient-reported outcomes in the real-world clinical setting can provide a basis for appropriate patient management. The objective of this study was to determine how patient-reported OA severity correlates with patient-reported outcomes including pain, function and productivity.     

Psychological characteristics of Japanese patients with chronic pain assessed by the Rorschach test

Background  

The increasing number of patients with chronic pain in Japan has become a major issue in terms of the patient's quality of life, medical costs, and related social problems. Pain is a multi-dimensional experience with physiological, affective, cognitive, behavioral and social components, and recommended to be managed via a combination of bio-psycho-social aspects. However, a biomedical approach is still the dominant method of pain treatment in Japan. The current study aimed to evaluate comprehensive psychological functions and processes in Japanese chronic pain patients.     

Single-dose rofecoxib for acute postoperative pain in adults: a quantitative systematic review

Background  

Rofecoxib is a cyclo-oxygenase 2 selective inhibitor. This systematic review of rofecoxib in acute pain examined studies in adults of analgesic efficacy over six hours, the amount and quality of the evidence on extended duration of analgesia, and the quality and quantity of evidence on adverse events.     

Reproduction of overall spontaneous pain pattern by manual stimulation of active myofascial trigger points in fibromyalgia patients

Introduction  

It has previously been reported that local and referred pain from active myofascial trigger points (MTPs) in the neck and shoulder region contribute to fibromyalgia (FM) pain and that the pain pattern induced from active MTPs can reproduce parts of the spontaneous clinical FM pain pattern. The current study investigated whether the overall spontaneous FM pain pattern can be reproduced by local and referred pain from active MTPs located in different muscles.     

Subgroups of older adults with osteoarthritis based upon differing comorbid symptom presentations and potential underlying pain mechanisms

Introduction  

Although people with knee and hip osteoarthritis (OA) seek treatment because of pain, many of these individuals have commonly co-occurring symptoms (for example, fatigue, sleep problems, mood disorders). The purpose of this study was to characterize adults with OA by identifying subgroups with the above comorbid symptoms along with illness burden (a composite measure of somatic symptoms) to begin to examine whether subsets may have differing underlying pain mechanisms.     

A validity-driven approach to the understanding of the personal and societal burden of low back pain: development of a conceptual and measurement model

Introduction  

While the importance and magnitude of the burden of low back pain upon the individual is well recognized, a systematic understanding of the impact of the condition on individuals is currently hampered by the lack of an organized understanding of what aspects of a person's life are affected and the lack of comprehensive measures for these effects. The aim of the present study was to develop a conceptual and measurement model of the overall burden of low back pain from the individual's perspective using a validity-driven approach.     

Does suprascapular nerve block reduce shoulder pain following stroke: a double-blind randomised controlled trial with masked outcome assessment

Background  

Shoulder pain is a common complication of a stroke which can impede participation in rehabilitation programs and has been associated with poorer outcomes. The evidence base for current medical and therapeutic management options of hemiplegic shoulder pain is limited. This study will evaluate the use of suprascapular nerve block injection as part of an interdisciplinary approach to the treatment of shoulder pain following stroke. The technique has previously been proven safe and effective in the treatment of shoulder pain associated with rheumatoid arthritis and degenerative shoulder conditions but its usefulness in a stroke population is unclear.     

Enhanced reactivity to pain in patients with rheumatoid arthritis

Introduction  

Maladaptive physiological responses to stress appear to play a role in chronic inflammatory diseases such as rheumatoid arthritis (RA). However, relatively little stress research in RA patients has involved the study of pain, the most commonly reported and most impairing stressor in RA. In the present study, we compared psychophysical and physiological responses to standardized noxious stimulation in 19 RA patients and 21 healthy controls.     

The genetic influence on the cortical processing of experimental pain and the moderating effect of pain status

Background

Research suggests that the COMT Val¹⁵⁸Met, BDNF Val⁶⁶Met and OPRM1 A¹¹⁸G polymorphisms moderate the experience of pain. In order to obtain experimental confirmation and extension of findings, cortical processing of experimentally-induced pain was used.

Method

A sample of 78 individuals with chronic low back pain complaints and 37 healthy controls underwent EEG registration. Event-Related Potentials were measured in response to electrical nociceptive stimuli and moderation by COMT Val¹⁵⁸Met, BDNF Val⁶⁶Met and OPRM1 A¹¹⁸G polymorphisms was assessed.

Results

Genetic variation did not have a direct effect on cortical processing of experimental pain. However, genetic effects (COMT Val¹⁵⁸Met and BDNF Val⁶⁶Met) on experimental pain were moderated by the presence of chronic pain. In the presence of chronic pain, the COMT Met allele and the BDNF Met allele augmented cortical pain processing, whilst reducing pain processing in pain-free controls. No significant effects were found concerning the OPRM1 A¹¹⁸G polymorphism.

Conclusions

The current study suggests that chronic experience of pain enhances genetic sensitivity to experimentally induced mildly painful stimuli, possibly through a process of epigenetic modification.