Original Research, Human Studies, Basic Neurobiology, Method

Psychological flexibility (PF) is a model of well-being and daily functioning that is applied to chronic pain, and is the model behind Acceptance and Commitment Therapy (ACT). However, studies of PF in chronic pain are limited by the lack of a single measure capturing all facets. The Multidimensional Psychological Flexibility Inventory (MPFI) assesses all facets of PF and psychological inflexibility (PI) and could remedy this problem. The current study employs this measure. Adult participants with chronic pain (N = 404) were recruited online and completed the MPFI, other validated measures of PF/PI, and measures of pain, work and social adjustment, and depression, at two time points. The reliability, factor structure, and validity of the MPFI were assessed. Confirmatory factor analysis results demonstrated a good model fit for the proposed factor-and subscale structure. Correlations between MPFI and theoretically similar measures were moderate to strong, and correlations with pain intensity, pain interference, work-and social adjustment, and depression, were small to large. In this first examination of the potential utility of the MPFI within a chronic pain population, we found it to be valid and reliable. It should be noted that the MPFI was less predictive of outcomes compared with more established measures in most cases. Despite this, results from the wide range of variables available from the MPFI highlights the potential importance of aspects of PF and PI not previously emphasized, including the greater predictive utility of the inflexibility facets. Further use and study of the MPFI is recommended. ClinicalTrials.gov ID: NCT05050565 Perspective: This article presents a comprehensive examination of a self-report measure assessing all facets of psychological flexibility and inflexibility, in a chronic pain sample. The results support the role of facets not previously emphasized. Comprehensive assessment of PF and PI appears possible and is recommended depending on research questions being asked.

The thermal grill illusion of pain (TGIP) is a paradoxical burning pain sensation elicited by the simultaneous application of innocuous cutaneous warm and cold stimuli with a thermode ('thermal grill') consisting of interlaced heated and cooled bars. Its neurophysiological mechanisms are unclear, but TGIP may have some mechanisms in common with pathological pain, including central sensitization in particular, through the involvement of N-methyl-D-aspartate (NMDA) receptors. However, few studies have investigated TGIP in chronic pain patients and its clinical relevance is uncertain. We hypothesized that the TGIP would be increased in comparison with controls in patients with fibromyalgia or irritable bowel syndrome (IBS), which are regarded as typical "nociplastic" primary pain syndromes related to changes in central pain processing. We compared the sensations elicited by a large range of combinations of temperature differentials between the warm and cold bars of a thermal grill applied to the hand between patients with fibromyalgia (n = 30) or IBS (n= 30) and controls (n = 30). The percentage of TGIP responses, and the intensity and unpleasantness of TGIP were significantly greater in patients than controls. Furthermore, positive correlations were found between TGIP intensity and clinical pain intensity, and between TGIP intensity and the cold pain threshold measured on the hand. These results are consistent with our working hypothesis of shared mechanisms between TGIP and clinical pain mechanisms in patients with nociplastic chronic pain syndromes and suggest that TGIP might represent a clinical marker of central sensitization in these patients.

At present, there are two techniques which are widely applied clinically; the midline and the paramedian. Both methods are difficult for clinicians when treating the elderly. The aim of this work is to explore the feasibility of an ultrasound-assisted modified paramedian technique for spinal anesthesia in the elderly. This would provide clinicians with a new and easy-to-operate technique.

Treating chronic symptoms for pain and movement disorders with neuromodulation therapies involves fine-tuning of programming parameters over several visits to achieve and maintain symptom relief. This, together with challenges in access to trained specialists, has led to a growing need for an integrated wireless remote care platform for neuromodulation devices. In March of 2021, we launched the first neuromodulation device with an integrated remote programming platform. Here, we summarize the biodesign steps taken to identify the unmet patient need, invent, implement, and test the new technology, and finally gain market approval for the remote care platform. Specifically, we illustrate how agile development aligned with the evolving regulatory requirements can enable patient-centric digital health technology in neuromodulation, such as the remote care platform. The three steps of the biodesign process applied for remote care platform development are: (1) Identify, (2) Invent, and (3) Implement. First, we identified the unmet patient needs through market research and voice-of-customer (VOC) process. Next, during the concept generation phase of the invention step, we integrated the results from the VOC into defining requirements for prototype development. Subsequently, in the concept screening phase, ten subjects with PD participated in a clinical pilot study aimed at characterizing the safety of the remote care prototype. Lastly, during the implementation step, lessons learned from the pilot experience were integrated into final product development as new features. Following final product development, we completed usability testing to validate the full remote care system and collected preliminary data from the limited market release experience. The VOC data, during prototype development, helped us identify thresholds for video quality and needs priorities for clinicians and patients. During the pilot study, one subject reported anticipated remote-care-related adverse events that were resolved without sequelae. For usability analysis following final product development, the failure rates for task completion for both user groups were about 1%. Lastly, during the initial 4 weeks of the limited market release experience, a total of 858 remote care sessions were conducted with a 93% success rate. Overall, we developed a remote care platform by adopting a user-centric approach. Although the system intended to address pre-COVID19 challenges associated with disease management, the unforeseen overlap of the study with the pandemic elevated the importance of such a system and an innovative development process enabled us to advance a patient-centric platform to gain regulatory approval and successfully launch the remote care platform to market.

Lower limb pain, whether induced experimentally or as a result of a musculoskeletal injury, can impair motor control, leading to gait adaptations such as increased muscle stiffness or modified load distribution around joints. These adaptations may initially reduce pain but can also lead to longer-term maladaptive plasticity and to the development of chronic pain. In humans, many current experimental musculoskeletal-like pain models are invasive, and most don't accurately reproduce the movement-related characteristics of musculoskeletal pain. The main objective of this study was to measure pain adaptation strategies during gait of a musculoskeletal-like experimental pain protocol induced by phase-specific, non-invasive electrical stimulation. Sixteen healthy participants walked on a treadmill at 4 km/h for three consecutive periods (BASELINE, PAIN, and POST-PAIN). Painful electrical stimulations were delivered at heel strike for the duration of heel contact (HC) using electrodes placed around the right lateral malleolus to mimic ankle sprains. Gait adaptations were quantified bilaterally using instrumented pressure-sensitive insoles. One-way ANOVAs and group time course analyses were performed to characterize the impact of electrical stimulation on heel and forefoot contact pressure and contact duration. During the first few painful strides, peak HC pressure decreased on the painful side (8.6 ± 1.0%, < 0.0001) and increased on the non-stimulated side (11.9 ± 0.9%, < 0.0001) while HC duration was significantly reduced bilaterally (painful: 12.1 ± 0.9%, < 0.0001; non-stimulated: 4.8 ± 0.8%, < 0.0001). No clinically meaningful modifications were observed for the forefoot. One minute after the onset of painful stimulation, perceived pain levels stabilized and peak HC pressure remained significantly decreased on the painful side, while the other gait adaptations returned to pre-stimulation values. These results demonstrate that a non-invasive, phase-specific pain can produce a stable painful gait pattern. Therefore, this protocol will be useful to study musculoskeletal pain locomotor adaptation strategies under controlled conditions.

Chronic pain conditions affect up to one third of the adult population in the United Kingdom. Sleep problems are prevalent and negatively impact quality of life. Lack of standardised tools for routine screening and assessment of sleep changes have been a barrier for sleep management. Novel sleep wearables offer an exciting and accessible way to measure sleep but have not been tested outside of the consumer-led landscape and are not commonly used in research and clinical settings.