Evaluating the novel added value of neurophysiological pain sensitivity within the fear-avoidance model of pain

Acceptance of Chronic Pain in Cancer Patients in Iran: the Role of Anxiety Sensitivity, Emotional Suppression, and Learned Helplessness

BACKGROUND

Acceptance of pain is one of the most significant topics in the field of chronic pain due to its influence on the adaptation and response of people. Also, chronic pain and pain caused by the progress of cancer have a high prevalence in all stages and types of cancer.

AIMS

The present study aimed to predict the acceptance of chronic pain in patients with cancer based on anxiety sensitivity and emotional suppression with the mediating role of learned helplessness.

METHODS

The current research method was descriptive-correlation and structural equation modeling. A number of patients with cancer (400), admitted to the oncology department of Imam Khomeini Hospital in Ardabil City of Iran in the second half of 2022, were selected as the convenience sample and responded to McCracker et al.'s chronic pain acceptance scale, Rees et al.'s anxiety sensitivity scale, Roger and Nasho's emotional control questionnaire, and Quinles and Nielson's learned helplessness questionnaire.

RESULTS

Based on the obtained results, the causal relationship between anxiety sensitivity, emotional suppression, learned helplessness, and acceptance of chronic pain in patients with cancer was confirmed based on various fit indices. Anxiety sensitivity, emotional suppression, and learned helplessness had a direct effect on the acceptance of chronic pain in patients with cancer. Moreover, anxiety sensitivity and emotional suppression through learned helplessness had indirect effects on pain acceptance in patients with cancer (p < .05).

CONCLUSIONS

Thus, anxiety sensitivity, emotional suppression, and learned helplessness play an essential role in the level of pain acceptance in patients with cancer, and targeting these three components through psychological treatments can be effective in the level of pain acceptance in these patients.

Validation of a spring loaded probe for single and repeat pressure pain testing, including public domain specifications for design and manufacture

Temporal summation of pressure pain is technically more challenging than simple pressure pain thresholds. The current study describes the design, manufacture and validation of a simple mechanical test apparatus to assess the temporal summation of deep pressure pain. We release design details into the public domain with the intention of providing free access for researchers especially in low income countries. Utility and validity of the probes were assessed by pressure application in three different experimental setups: A. Identifying potential issues which needed to be addressed to ensure a reliable test procedure (189 tests with 24 testers using four different probes). B. Selecting the most reliable target force curve (one tester conducted 20 tests). C. Estimating classic inter and intra-examiner reliability and comparing probe measures to other QST measures (repeated measures study with counterbalancing). We make recommendations on best use of the probes. Pressure pain thresholds assessed using probes were affected by anatomical test site and testing tool, but not by tester, day or session. Temporal summation of pressure pain was significantly greater than that of a single pressure application. We found no correlation between temporal summation using the probes on the Infra-Spinatus muscle and temporal summation using a pneumatic cuff on the lower leg. The probe was a useful tool for assessing pain intensity and temporal summation of pressure pain intensity, but not for pain thresholds. A number of caveats need to be considered when using the probe, including but not limited to audio cues and target ideal wave function.

Impact of central sensitization on pain, disability and psychological distress in patients with knee osteoarthritis and chronic low back pain

BACKGROUND

Central sensitization (CS) is becoming increasingly recognized as a significant factor in many chronic pain conditions, including knee osteoarthritis (KOA) and chronic low back pain (CLBP). Yet it presently remains unclear how strong is the involvement of CS in KOA and CLBP and which factors are involved in CS in these two chronic disabling diseases.

METHODS

This is a cross-sectional study in which included a total of 178 patients with KOA and 118 patients with CLBP. Inclusion criteria for eligible participants for the KOA group were a confirmed diagnosis of KOA according to the American College of Rheumatology criteria, and for the CLBP group a chronic low back pain for more than 3 months. Subjects were excluded if they presented with a diagnosed psychiatric disorder or if they lacked the capacity to provide informed consent, understand study questionnaires or perform physical performance tests. In each group, were assessed; CS-related symptoms using the Central Sentization Inventory (CSI); demographic and clinical characteristics such as disease duration, pain intensity on a visual analog scale, self-reported function using the Lequesne index for KOA patients and the Oswestry Disability index for CLBP patients, and physical performance with the 6 minutes' walk test; as well as psychosocial risk factors using the Patient Health Questionnaire for depression (PHQ-9), the Generalized Anxiety Disorder (GAD-7) and the Pain Catastrophizing Scale (PCS).

RESULTS

CSI scores significantly correlated with pain intensity and disability in KOA and CLBP patients, and were highly correlated with self-reported symptoms of depression, anxiety and pain catastrophizing. Depression significantly predicted the CSI score in both groups.

CONCLUSION

These findings provide further evidence for the impact of CS on pain, function and physical performance in KOA and CLBP patients. Psychosocial symptoms such as pain catastrophizing, anxiety and depression should also be considered as they are also associated with CS.

Reductions in kinesiophobia and distress after pain neuroscience education and exercise lead to favourable outcomes: a secondary mediation analysis of a randomized controlled trial in primary care

ABSTRACT

Pain neuroscience education combined with exercise (PNE + exercise) is an effective treatment for patients with chronic spinal pain. Yet, however, little is known about its underlying therapeutic mechanisms. Thus, this study aimed to provide the first insights by performing a novel mediation analysis approach in a published randomized controlled trial in primary care where PNE + exercise was compared with standard physiotherapy. Four mediators (catastrophizing, kinesiophobia, central sensitization-related distress, and pain intensity) measured at postintervention and 3 outcomes (disability, health-related quality of life, and pain medication intake) measured at 6-month follow-up were included into the analysis. The postintervention measure of each outcome was also introduced as a competing candidate mediator in each respective model. In addition, we repeated the analysis by including all pairwise mediator-mediator interactions to allow the effect of each mediator to differ based on the other mediators' values. Postintervention improvements in disability, medication intake, and health-related quality of life strongly mediated PNE + exercise effects on each of these outcomes at 6-month follow-up, respectively. Reductions in disability and medication intake were also mediated by reductions in kinesiophobia and central sensitization-related distress. Reductions in kinesiophobia also mediated gains in the quality of life. Changes in catastrophizing and pain intensity did not mediate improvements in any outcome. The mediation analyses with mediator-mediator interactions suggested a potential effect modification rather than causal independence among the mediators. The current results, therefore, support the PNE framework to some extent as well as highlight the need for implementing the recent approaches for mediation analysis to accommodate dependencies among the mediators.

Pain catastrophising in Chinese patients with breast cancer during postoperative chemotherapy: a qualitative study

OBJECTIVE

To investigate the pain catastrophising in patients with breast cancer during postoperative chemotherapy.

METHODS

Objective sampling method was used to select patients with breast cancer who underwent breast surgery and received chemotherapy in a third-class hospital of Wuhan from October to December 2022 through semi-structured interview. The interview data were sorted out and analysed by content analysis method.

RESULTS

A total of 11 patients were interviewed and five categories were summarised: (1) Physical memory of pain; (2) the special meaning of time; (3) disease treatment and prognosis; (4) interpersonal communication and coping; (5) personal behaviour and growth.

CONCLUSION

Patients with breast cancer have adverse pain experience during postoperative chemotherapy. The evaluation and screening of psychological variables such as pain catastrophising should be strengthened to provide new ideas for pain management.

Association of preexisting psychiatric disorders with post-COVID-19 prevalence: a cross-sectional study

Evidence demonstrating the association of preexisting psychiatric disorders with post-COVID-19 is limited. We aim to investigate the association using larger sample sizes and more extended postinfection periods than previous studies. A total of 6015 (response rate = 77.5%) COVID-19 survivors were surveyed using a self-administered questionnaire from July to September 2021. Poisson regression analysis with robust error variance was performed to estimate post-COVID-19 prevalence ratios (PRs) with or without preexisting psychiatric disorders. Participants with preexisting psychiatric disorders numbered 1067 (17.7%), and with post-COVID-19 were 2149 (35.7%). Post-COVID-19 PR with preexisting psychiatric disorders was 1.09 (95% CI 1.02-1.18, p = 0.013). The interaction between preexisting psychiatric disorders and postinfection periods was significant (p for interaction < 0.001). The subgroup analysis showed that those with preexisting psychiatric disorders might be at greater prolonged risk of post-COVID-19 than those without the disorders. These findings suggested that preexisting psychiatric disorders were associated with an increased post-COVID-19 risk, and post-COVID-19 with preexisting psychiatric disorders might prolong even if time passes.

Central sensitization and functioning in patients with chronic low back pain: A cross-sectional and longitudinal study

BACKGROUND

Central sensitization (CS) is present in a subgroup of patients with chronic low back pain (CLBP). Studies on the relationship between CS and functioning have limited operationalizations of CS and functioning.

OBJECTIVE

To determine whether CS was related to functioning in patients with CLBP (cross-sectional); and to determine whether changes in CS were related to changes in functioning (longitudinal).

METHODS

An observational prospective cohort study with data collected at baseline and discharge of an interdisciplinary pain rehabilitation program was executed. CS indicators: CS Inventory part A (CSI-A), quantitative sensory testing (QST), root mean square of successive differences of heart-rate variability (RMSSD). Functioning measures: lifting capacity, physical functioning subscale of Rand36 (Rand36-PF), Work Ability Score (WAS), Pain Disability Index (PDI). Main analyses included correlation and multiple regression controlling for confounders; cross-sectional with baseline data and longitudinal with deltas (Δ).

RESULTS

76 patients with primary CLBP participated at baseline and 56 at discharge. Most associations were weak (cross-sectional r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.30-0.24; longitudinal r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.37-0.44). Cross-sectional multiple regression significant associations: mechanical pain threshold-QST and lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙=-0.39), parasympathetic/vagal tone-RMSSD and physical functioning-Rand36-PF (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.26). Longitudinal multiple regression significant associations: Δ parasympathetic/vagal tone-RMSSD and Δ lifting capacity (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.48), ΔCSI-A and Δdisability-PDI (r𝑝𝑎𝑟𝑡𝑖𝑎𝑙= 0.36). Cross-sectional and longitudinal final regression models explained 24.0%-58.3% and 13.3%-38.0% of total variance.

CONCLUSION

CS was weakly related to functioning, and decreases in CS were weakly-moderately related to increases in functioning.

Combined Effect of Vitamin D Supplementation and Physiotherapy on Reducing Pain Among Adult Patients With Musculoskeletal Disorders: A Quasi-Experimental Clinical Trial

Background: The prevalence of musculoskeletal disorders (MSD) and vitamin D insufficiency is high. Past research indicating vitamin D supplementation and physiotherapy are useful for the treatment of MSDs. However, to the best of our knowledge, the combined benefits of vitamin D and physiotherapy are not yet evaluated in MSD. We hypothesized that combined intervention of vitamin D supplementation and physiotherapy would be more effective in relieving the pain of MSD compared to only physiotherapy intervention.

Objective: This study aimed to examine whether combined effect of vitamin D supplementation and physiotherapy was better than physiotherapy alone in reducing pain-related outcomes (e.g., pain severity, affective interference, and physical interference) in patients with MSD.

Methods: A quasi-clinical experiment was conducted between May 2020 and April 2021. Vitamin D level in the blood was measured at the start of the study. Patients with vitamin D levels <20 ng/mL were assigned to the combined physiotherapy and vitamin D group. The physiotherapy group consisted of the patients with vitamin D levels more than 20 ng/mL. The Brief Pain Inventory scale was utilized to measure pain at baseline and after 12 weeks of interventions. We used the paired t-tests for unadjusted analysis. Further, a linear regression model was used to identify the combined effect of physiotherapy and vitamin D on reducing pain scores after adjusting potential confounders.

Results: Combined intervention of vitamin D and physiotherapy showed significantly better results than only physiotherapy intervention in the reduction of three pain-related outcomes (p < 0.001). The multivariable analysis indicated that the combination of physiotherapy and vitamin D treatment reduced pain score by 1.126 (slope = −1.126, p = 0.035) compared to physiotherapy alone.

Conclusion: Combined intervention (vitamin D with physiotherapy) had a better pain-relieving effect than physiotherapy alone. To confirm these findings, more research is needed with randomized control trials.

Clinical Trial Registration: [http://ctri.nic.in/Clinicaltrials/advancesearchmain.php], identifier [CTRI/2020/04/024845].

Static and Dynamic Pain Sensitivity in Adults With Persistent Low Back Pain: Comparison to Healthy Controls and Associations With Movement-evoked Pain Versus Traditional Clinical Pain Measures

OBJECTIVES

Despite its impact, individual factors associated with persistent low back pain (LBP) remain poorly understood. This study investigated static and dynamic pain sensitivity in adults with persistent LBP versus pain-free controls; and investigated associations between pain sensitivity and 3 clinical pain measures: recalled, resting, and movement-evoked pain (MEP).

MATERIALS AND METHODS

A lifespan sample of 60 adults with persistent LBP and 30 age-matched/sex-matched controls completed 4 laboratory sessions. Static pain sensitivity (pressure pain threshold [PPT], heat pain threshold) and dynamic pain sensitivity (heat pain aftersensations [AS], temporal summation [TS] of second heat pain) were measured. Demographic and clinical factors collected were education, global cognition, and perceived health. Resting and recalled pain were measured via questionnaire, and MEP via the Back Performance Scale.

RESULTS

LBP participants demonstrated lower PPT remotely (hand; F1,84=5.34, P=0.024) and locally (low back; F1,84=9.55, P=0.003) and also had higher AS (F1,84=6.01, P=0.016). Neither static nor dynamic pain sensitivity were associated with recalled pain (P>0.05). However, static pain sensitivity (local PPT) explained an additional 9% variance in resting pain, while dynamic pain sensitivity (AS, TS) explained an additional 10% to 12% variance in MEP.

DISCUSSION

This study characterized pain sensitivity measures among individuals with persistent LBP and suggests static pain sensitivity plays a larger role in resting pain while dynamic pain sensitivity plays a larger role in MEP. Future studies will confirm these relationships and elucidate the extent to which changes in static or dynamic pain sensitivity predict or mediate clinical pain among adults with persistent LBP.

Pain and Function in Chronic Musculoskeletal Pain-Treating the Whole Person

Chronic pain is often associated with functional limitations that have a huge impact on patients' lives. However, despite being relatively common, chronic musculoskeletal pain is still viewed by some as a symptom of another disease rather than its own condition, and is therefore poorly addressed. This is compounded by other challenges in the field, including education gaps for both healthcare professionals and patients, a lack of universal and comprehensive assessment tools, poor societal perceptions of chronic pain, and the current stigma around the use of opioids. Here, we review the current chronic musculoskeletal pain management landscape in the United States and offer professional insight into emerging methods that can be used to improve patient outcomes, in particular, the achievement of meaningful functional goals. This perspective incorporates our combined multidisciplinary (psychiatry, psychology, nursing, physical therapy, and general medicine) experience and insights. We believe that chronic pain is a multifactorial experience and treatment requires an integrated, multidisciplinary approach from a range of healthcare providers. For the best patient outcomes, this team should work together to assess and treat the patient as a whole, addressing their pain and also providing education, empowerment, and support to enable patients to set and achieve meaningful functional goals that will provide real improvement in their quality of life. We believe that the healthcare community should elevate the conversation around chronic musculoskeletal pain management beyond that of just pain, to encompass the meaningful benefits that improvement in functional outcomes brings to patients.

A Cumulative Impact of Psychological and Sensitization Risk Factors on Pain-Related Outcomes

OBJECTIVE

Risk constructs based on psychological risk factors (eg, pain catastrophizing, PC) and sensitization risk factors (eg, pressure pain threshold, PPT) are important in research and clinical practice. Most research looks at individual constructs but does not consider how different constructs might interact within the same individual. An evaluation of the cumulative impact of psychological and sensitization risk factors on pain-related outcomes may help guide us in the risk assessment of patients with pain conditions. The aim of this study is to evaluate the cumulative impact of these psychological (PC) and sensitization (PPT) risk factors on pain-related outcomes (activity avoidance, pain severity, and disability) considering covariates.

METHODS

We included 109 participants (70.60% women; mean ± SD age 53.6 ± 12.3 years) with chronic musculoskeletal pain for data analysis, who completed all measures of this study. Participants completed a single testing session that included measures of risk factors (PC and PPT) and pain-related outcomes (self-reported avoidance, functional avoidance, disability, and pain severity). Subgroups were constructed by dichotomizing of PC and PPT scores, resulting in four groups: (1) low catastrophizing and low sensitivity (N = 26), (2) high catastrophizing and low sensitivity (N = 27), (3) low catastrophizing and high sensitivity (N = 25), and (4) high catastrophizing and high sensitivity (N = 31).

RESULTS

One-way analysis of variance (ANOVA) revealed significant group differences (P < 0.05, η²  = 0.08 to 0.14) in all outcomes of this study (except functional avoidance), and post hoc analysis indicated the significant differences are between group 1 and 4. A cumulative impact is reflected by large effect sizes between group 1 and 4 (d = 0.8 to 1). The group 2 and 3 (one risk dimension groups: either high-PC or high-PPT) represent 47% of the total participants.

CONCLUSIONS

The study suggests both higher level of PC and pressure sensitivity have a cumulative impact on risk screening for pain-related outcomes, considering gender in functional avoidance (task-related outcome). A clinical presentation with high-PC (one dimension of risk) is not associated with high-PPT (another dimension of risk). This finding has important clinical and theoretical implications.

Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals

PURPOSE

Some individuals with chronic pain find daily life sensations (eg, noise, light, or touch) aversive. This amplification of multisensory sensations has been associated with centrally mediated plasticity; for example, greater multisensory sensitivity (MSS) occurs in patients with fibromyalgia than rheumatoid arthritis. However, whether MSS preferentially relates to pain measures which reflect central influences (eg, dynamic quantitative sensory testing (QST) or referred pain), or whether the MSS-pain relationship requires priming from chronic pain, is unknown. Thus, this cross-sectional study investigated the relationships between MSS assessed in a pain-free state and evoked pain sensitivity.

METHODS

Experimental intramuscular infusion pain and multiple static and dynamic QST were assessed in 465 healthy, pain-free adults: pain thresholds using pressure (PPTs) and heat (HPTs), temporal summation of pain (TSP) using pressure, heat or punctate stimuli, and conditioned pain modulation (CPM) using pressure or heat test stimuli. MSS was assessed using 7 items from Barsky's Somatosensory Amplification Scale. Differences in pain and QST between sex-specific MSS quartiles were assessed, adjusting for multiple comparisons. All participants completed at least one intramuscular infusion condition, but not all were asked to complete each QST (n=166-465).

RESULTS

Both static and dynamic QST differed between highest and lowest MSS quartiles using pressure stimuli: lower PPTs (adjusted-p<0.01); increased pressure TSP (adjusted-p=0.02); lower pressure CPM (adjusted-p=0.01). However, none of the heat or punctate QST measures (HPTs, TSP, or CPM) differed between MSS quartiles (adjusted-p>0.05). Odds of experiencing TSP or referred pain was not greater, whereas CPM was 8-fold less likely, in those with highest MSS.

CONCLUSION

Normal variation in non-noxious MSS is related to both static and dynamic pain sensitivity, without sensitization associated with chronic pain, but is dependent on the QST stimulus. Thus, common influences on MSS and pain sensitivity may involve central mechanisms but are likely more complex than previously recognized.

Coordinated Human Brainstem and Spinal Cord Networks during the Expectation of Pain Have Elements Unique from Resting-State Effects

Functional magnetic resonance imaging (fMRI) research on the human brainstem (BS) and spinal cord (SC) has identified extensive BS/SC resting-state networks (RSNs) by showing spontaneous coordinated blood oxygenation-level dependent (BOLD) signal fluctuations in the absence of a stimulus. Studies have shown that these networks can be influenced by participants’ level of arousal or attention (e.g., watching a video), and linked network function to autonomic homeostatic regulation. Here we explore how the cognitive state of expecting pain can influence connectivity in these networks. Data from two studies (a predictable pain stimulus study, and a resting-state study) were compared to show the effects of expecting pain on BS/SC networks, and how networks differed from networks associated with the resting-state. In each study, BOLD fMRI data were obtained from the cervical SC and brainstem in healthy participants at 3 tesla using a T₂-weighted single-shot fast spin-echo imaging method. Functional connectivity was investigated within the entire 3D volume by means of structural equation modeling (SEM) and analyses of covariance (ANCOVA). Results showed extensive connectivity within/across BS and SC regions during the expectation of pain, and ANCOVA analyses showed that connectivity in specific components of these networks varied with individual pain sensitivity. Comparing these results to RSN fluctuations revealed commonalities in coordination between BS and SC regions, and specific BS–BS connectivity fluctuations unique to the expectation of pain. Based on the regions involved, these results provide evidence of brainstem regulation specific to the expectation of pain.

Quantitative sensory testing to evaluate and compare the results after epidural injection and simple discectomy, in patients with radiculopathy secondary to lumbar disc herniation

The objective assessment of the radiculopathy secondary to lumbar disc herniation is essential to optimize treatment. The quantitative sensory test (QST) is a useful tool to evaluate somatosensory nerves. The aim of our study is quantifying by QST the alterations of patients treated by epidural injections (EI) or surgical lumbar decompression (LD). A prospective, cohort study has done in Hospital Universitario Rio Hortega, Valladolid, Spain, between January 2014 and December 2016.The study includes 74 patients (40 men) who underwent EI (50) or LD (24) with lumbar disc herniation and treated by EI or LD. Participants underwent a brief battery of QST at baseline and after 1, 3 and 6 months of follow-up. QST threshold were measured in three series of five warm and cold stimuli (cold detection threshold, warm detection threshold, cold pain threshold, heat pain threshold) bilateral. Additionally, pain assessment (Visual Analogue Scale) and neurological examination was performed. Thermal thresholds were analysed and compared. In the EI group, warm detection threshold (WDT) measurements were significantly lower after 3 and 6 months of follow-up (40.44 ± 3.42°C vs. 38.30 ± 3.73°C and 37.48 ± 4.58°C respectively, p = 0.031 and p = 0.043). LD group showed lower WDT measurements at 1, 3 and 6 months of follow up (40.20 ± 2.97°C vs., 37.98 ± 2.04°C, 37.43 ± 3.80°C and 36.55 ± 2.77°C respectively, p = 0.049, p = 0.032 and p = 0.024) and lower heat pain threshold (HPT) levels after 3 and 6 months of follow-up (48.75 ± 1.37°C vs. 43.26 ± 0.60°C and 42.06 ± 1.37°C respectively, p = 0.037 and p = 0.021). QST explorations were compared between both groups. At 1-month follow-up only the WDT parameter was different, higher in EI group (40.98 ± 4.04°C vs. 37.98 ± 2.04°C, p = 0.043). There were no differences in any parameter measured by QST after 3 and 6-months follow-up between both groups. Epidural injection should be considered the first-step of treatment.