The Central Sensitization Inventory and Pain Sensitivity Questionnaire: An exploration of construct validity and associations with widespread pain sensitivity among individuals with shoulder pain

Evaluation of the segmental distribution of pain sensitivity among patients with central sensitization associated with chronic subacromial pain syndrome: A cross-sectional study

INTRODUCTION

Pain sensitivity is the main finding of central sensitization (CS) and can occur in patients with chronic shoulder pain. However, there is limited evidence concerning the distribution of pain sensitivity in shoulders, forearms, and legs in patients with CS associated with chronic shoulder pain. The present study aimed to determine the distribution of pain sensitivity in patients with CS associated with chronic subacromial pain syndrome (SPS).

METHOD

This cross-sectional study included 58 patients with chronic SPS and CS (patient group) and 58 healthy participants (control group). The presence of CS was determined using the Central Sensitization Inventory (CSI). To determine the distribution of pain sensitivity, pressure pain threshold (PPT) measurements were performed from the shoulders, forearms, and legs.

RESULTS

There was no significant difference between the two groups in terms of sociodemographic data (p > 0.05). The patient group had a significantly higher CSI score (p < 0.001) and lower PPTs in all regions (p < 0.05) than the control group. Unlike the control group, the patient group had lower PPTs on the affected side for the shoulder [mean difference (MD) 95% confidence interval (CI): 1.2 (-1.7 to -0.6)], forearm [MD 95% CI: 1.1 (-1.7 to -0.6)], and leg [MD 95% CI: 0.9 (-1.4 to -0.3)] compared with the contralateral side (p < 0.001).

CONCLUSION

Pain sensitivity is more pronounced in the affected shoulder and the forearm and leg located on this side than in those on the contralateral side in patients with CS associated with chronic SPS.

Cross-sectional experimental assessment of pain modulation as part of multidimensional profiling of people with cervicogenic headache: protocol for a feasibility study

BACKGROUND

An endogenous pain modulation profile, reflecting antinociceptive and pronociceptive mechanisms, may help to direct management by targeting the involved pain mechanism. For individuals with cervicogenic headache (CeH), the characteristics of such profiles were never investigated. However, the individual nature of experiencing pain demands profiling within a multidimensional framework including psychosocial lifestyle characteristics. The objective of the current protocol is to assess the pain modulation profile, which includes psychosocial lifestyle characteristics among people with CeH.

METHODS AND ANALYSIS

A protocol is described to map pain modulation profiles in people with CeH. A cross-sectional non-randomised experimental design will be used to assess feasibility of mapping these profiles. The pain modulation profile is composed based on results on the Depression, Anxiety, Stress Scale, Pittsburgh Sleep Quality Index, Headache Impact Test and on responses to temporal summation of pain (pinprick), conditioned pain modulation and widespread hyperalgesia (mechanical pressure pain threshold and cuff algometry). Primary analyses will report results relating to outcomes on feasibility. Secondary analyses will involve an analysis of proportions (%) of the different psychosocial lifestyle profiles and pain profiles.

ETHICS AND DISSEMINATION

Ethical approval was granted by the Ethics Committee Research UZ/KU Leuven (Registration number B3222024001434) on 30 May 2024. Results will be published in peer-reviewed journals, at scientific conferences and, through press releases. Protocol V.3. protocol date: 3 June 2024.

Correlations of The Central Sensitization Inventory, conditioned pain modulation, cognitions and psychological factors in individuals with chronic neck pain: A cross-sectional study

INTRODUCTION

Chronic neck pain (CNP) is a global public health problem, with high prevalence and absenteeism rates. Central sensitization (CS) as a basis for chronic pain may play an essential role in its development and progression. It is often comorbid with low conditioned pain modulation (CPM) effects, cognitions, and psychological problems.

OBJECTIVES

The purposes of this study were to (1) explore the relationship between pain-related cognitions and psychological factors, CPM effects, and the central sensitization inventory (CSI) scores; and (2) determine whether cognitions and psychological factors can predict CSI scores and CPM effects in individuals with CNP.

METHODS

Fifty-four individuals with CNP were recruited for this cross-sectional study. The following outcome measures were evaluated: The CSI (screening tool) was compared with the cold pressor test (CPT), which was the psychophysical test used to assess the CPM; neck pain intensity using the visual analogue scale (VAS), as well as pain-related cognitions (including kinesiophobia and pain catastrophization) and psychological states (including anxiety and depression) using self-report questionnaires.

RESULTS

CSI score was not associated with the CPM effect (r = 0.257, p > 0.05), and no cognitions or psychological factors were associated with CPM (p > 0.05), but CSI score was moderately positively correlated with kinesiophobia (r = 0.554, p < 0.01), lowly positively correlated with pain catastrophization (r = 0.332, p = 0.017) and anxiety (r = 0.492, p < 0.01), but not depression (r = 0.207, p = 0.132). Multiple linear regression analysis showed that kinesiophobia (B = 1.308, p < 0.01) and anxiety (B = 1.806, p = 0.02) were significant positive predictors of CSI score.

CONCLUSIONS

The findings confirm some of our hypotheses. Accordingly, the findings inferred that the CSI does not seem to respond to CPM effect in patients with CNP effectively. In addition, CSI score was associated with cognitions and psychological factors, of which kinesiophobia and anxiety were effective predictors. In clinical practice, pain-related cognitions and psychological factors should be fully considered to manage neck pain efficiently.

Sensory profiles and their role in the persistence of central sensitization symptoms in low back pain. A prospective cohort study

INTRODUCTION

Acute lower back pain can lead to neuroplastic changes in the central nervous system, and symptoms of central sensitization after 12 weeks. While sensory sensitivity has been shown to predict symptoms of central sensitization, trait sensory profiles may be prognostic in the persistence of central sensitization symptoms in low back pain over time.

OBJECTIVE

To examine sensory profiles as prognostic symptoms of central sensitization in people with acute low back pain.

METHODS

A longitudinal type 2 prognostic factor research study was performed according to the PROGRESS framework. Baseline and 12-week follow-up measures were taken using the Adolescent/Adult Sensory Profile and the Central Sensitization Inventory measures. Study participants were consecutively included from primary care physiotherapy practices. Univariable, and multivariable regression analyses were performed to adjust sensory profiles based on previous history of low back pain, baseline Central Sensitization Inventory scores, level of pain, disability, age, and duration of low back pain.

RESULTS

After adjustment, the sensory profiles of Low Registration B = 0.44, 95%CI (0.18, 0.70), Sensation Seeking B = 0.38, 95%CI (0.19, 0.57), Sensory Sensitive B = 0.49, 95%CI (0.25, 0.74), Sensation Avoiding B = 0.40, 95% CI (0.15, 0.65) was significantly associated with the persistence of central sensitization symptoms (N = 103).

CONCLUSION

Sensory profiles may predict symptoms of central sensitization after 12 weeks in people with acute low back pain.

Nociceptive, neuropathic, or nociplastic low back pain? The low back pain phenotyping (BACPAP) consortium's international and multidisciplinary consensus recommendations

The potential to classify low back pain as being characterised by dominant nociceptive, neuropathic, or nociplastic mechanisms is a clinically relevant issue. Preliminary evidence suggests that these low back pain phenotypes might respond differently to treatments; however, more research must be done before making specific recommendations. Accordingly, the low back pain phenotyping (BACPAP) consortium was established as a group of 36 clinicians and researchers from 13 countries (five continents) and 29 institutions, to apply a modified Nominal Group Technique methodology to develop international and multidisciplinary consensus recommendations to provide guidance for identifying the dominant pain phenotype in patients with low back pain, and potentially adapt pain management strategies. The BACPAP consortium's recommendations are also intended to provide direction for future clinical research by building on the established clinical criteria for neuropathic and nociplastic pain. The BACPAP consortium's consensus recommendations are a necessary early step in the process to determine if personalised pain medicine based on pain phenotypes is feasible for low back pain management. Therefore, these recommendations are not ready to be implemented in clinical practice until additional evidence is generated that is specific to these low back pain phenotypes.

The relationship of behavioral and psychological traits with pain sensitivity in females with patellofemoral pain: A cross-sectional study

OBJECTIVE

The purpose of this study was to describe the relationship between behavioral and psychological traits with indicators of central sensitization in female runners with patellofemoral pain (PFP), and to determine if behavioral and psychological traits improve with strength training.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Twenty-eight active females (mean age 32 ± 8.1 years) with PFP completed testing at baseline, 8 weeks (post intervention), and 12 weeks.

MAIN OUTCOME MEASURES

Behavioral and psychological questionnaires included the General Anxiety Disorder-7, Patient Health Questionairre-9, Pain Catastrophizing Scale, Tampa Scale of Kinesiophobia-11, and Central Sensitization Inventory. Quantitative sensory testing (QST) measures were also collected. After baseline testing, subjects were instructed in a hip and knee strengthening intervention to be completed twice daily over 8 weeks.

RESULTS

A statistically significant improvement was found at 12 weeks for anxiety (p = .015; ηp (Boling et al., 2010) = 0.099) and kinesiophobia (p = .041; ηp (Boling et al., 2010) = 0.076). There was no significant improvement for depression, catastrophizing, or subjective central sensitization. No significant correlations were found between any of the behavioral and psychological questionnaires with baseline QST variables.

CONCLUSIONS

No relationship was found for behavioral and psychological characteristics with QST measures in female runners with persistent PFP.

Translation, cross-cultural adaptation, and measurement properties of the Arabic version of the pain sensitivity questionnaire

Background

The Pain Sensitivity Questionnaire (PSQ) is a reliable and valid self-reported tool for the assessment of pain sensitivity in clinical practice. The PSQ has been translated, validated, and cross-culturally adapted into multiple languages. However, a validated Arabic version of the PSQ is not available. Thus, this study aims to translate, validate, and cross-culturally adapt the English version of the PSQ into the Arabic language.

Methods and materials

The English version of the PSQ was translated and culturally adapted into Arabic following international guidelines. The psychometric properties of the final version of the PSQ-Arabic (PSQ-A) were tested among 119 patients with different persistent musculoskeletal (MSK) pain.

Findings

The Cronbach's α for the PSQ-A-total, PSQ-A-moderate, and PSQ-C-minor were 0.81, 0.79, and 0.76, respectively. The means for the PSQ-A-total, PSQ-A-moderate, and PSQ-C-minor scores were 5.07 (±1.28), 5.64 (±2.07), and 4.50 (±0.50). The test-retest reliability measured with the interclass correlation coefficient for 68 subjects was 0.80 for the PSQ-A-total, 0.74 for the PSQ-A-moderate, and 0.77 for the PSQ-A-minor. The PSQ-A-total and the PSQ-A-minor showed positive significant correlations with pain catastrophizing scale (PCS) (r = 0.15, 0.17); P ≤ 0.05), respectively. The PSQ-A-total, PSQ-A-moderate, and PSQ-A-minor showed positive significant correlations with the Brief Pain Inventory (BPI)-pain scores (r = 0.47, 0.43, 0.45; P ≤ 0.01), respectively and with the BPI-pain interference scores (r = 0.37, 0.33, 0.34; P ≤ 0.01), respectively.

Conclusions

This study shows that the PSQ-A is a reliable and valid tool to assess individuals with pain sensitivity in Arabic populations. Further studies are recommended to examine the concurrent validity of the PSQ-A against experimental pain sensitivity measures.

Effectiveness of pain neuroscience education on somatosensory functioning after surgery for breast cancer: A double-blinded randomized controlled trial

Pain is one of the most prevalent and long-term adverse effects described by people who have undergone breast cancer surgery. Non-helpful perceptions and thoughts about pain may contribute to the transition of acute to persistent pain. Adding educational interventions to the current physical therapy program in this population may help to improve or prevent persistent pain. Pain neuroscience education (PNE) is a type of educational intervention that addresses the experience of pain in a broader sense by explaining pain not only from a biomedical perspective, but also from a psychological and social perspective. A double-blinded randomized controlled trial (EduCan trial) investigated whether PNE, in addition to a standard physiotherapy program immediately after surgery for breast cancer, was more effective on somatosensory functioning in the short (4 months postoperatively) and long term (18 months postoperatively), than providing a biomedical explanation for pain. Somatosensory functioning was evaluated using a self-reported questionnaire as well as a comprehensive quantitative sensory testing evaluation. The findings of this study revealed that adding six sessions of PNE to a standard physical therapy program (n = 184) did not result in a significantly different course of somatosensory functioning up to 18 months postoperatively as compared to biomedical pain education. These findings provide an interesting basis for future research into who should receive PNE after surgery for breast cancer (e.g., patient profiling or phenotyping) and how we can tailor it to the individual to increase its effectiveness.

Psychometric Properties of Patient-reported Outcome Measures to Assess Resilience in Individuals with Musculoskeletal Pain or Rheumatic Conditions: A COSMIN-based Systematic Review

OBJECTIVES

The objective of this systematic review was to provide a comprehensive overview of the measurement properties of patient-reported outcome measures (PROMs) used to assess resilience in individuals with musculoskeletal and rheumatic conditions.

METHODS

Four electronic databases (MEDLINE, CINAHL, PsycINFO, and Web of Science) were searched. Studies assessing any measurement property in the target populations were included. Two reviewers independently screened all studies and assessed the risk of bias using the COSMIN checklist. Thereafter, each measurement property of each PROM was classified as sufficient, insufficient, or inconsistent based on the COSMIN criteria for good measurement properties.

RESULTS

Four families of PROMs [Brief Resilient Coping Scale (BRCS); Resilience Scale (RS-18); Connor-Davidson Resilience Scale (CD-RISC-10 and CD-RISC-2); and Pain Resilience Scale (PRS-14 and PRS-12)] were identified from the 9 included studies. Even if no PROM showed sufficient evidence for all measurement properties, the PRS and CD-RISC had the most properties evaluated and showed the best measurement properties, although responsiveness still needs to be assessed for both PROMs. Both PROMs showed good levels of reliability (intraclass coefficient correlation 0.61 to 0.8) and good internal consistency (Cronbach's alpha ≥0.70). Minimal detectable change values were 24.5% for PRS and between 4.7% and 29.8% for CD-RISC.

DISCUSSION

Although BRCS, RS-18, CD-RISC, and PRS have been used to evaluate resilience in individuals with musculoskeletal and rheumatic conditions, the current evidence only supports the use of PRS and CD-RISC in this population. Further methodological studies are therefore needed and should prioritize the assessment of reliability and responsiveness.

Brain morphology predicts individual sensitivity to pain: a multicenter machine learning approach

ABSTRACT

Sensitivity to pain shows a remarkable interindividual variance that has been reported to both forecast and accompany various clinical pain conditions. Although pain thresholds have been reported to be associated to brain morphology, it is still unclear how well these findings replicate in independent data and whether they are powerful enough to provide reliable pain sensitivity predictions on the individual level. In this study, we constructed a predictive model of pain sensitivity (as measured with pain thresholds) using structural magnetic resonance imaging-based cortical thickness data from a multicentre data set (3 centres and 131 healthy participants). Cross-validated estimates revealed a statistically significant and clinically relevant predictive performance (Pearson r = 0.36, P < 0.0002, R2 = 0.13). The predictions were found to be specific to physical pain thresholds and not biased towards potential confounding effects (eg, anxiety, stress, depression, centre effects, and pain self-evaluation). Analysis of model coefficients suggests that the most robust cortical thickness predictors of pain sensitivity are the right rostral anterior cingulate gyrus, left parahippocampal gyrus, and left temporal pole. Cortical thickness in these regions was negatively correlated to pain sensitivity. Our results can be considered as a proof-of-concept for the capacity of brain morphology to predict pain sensitivity, paving the way towards future multimodal brain-based biomarkers of pain.

Sensitization-associated and neuropathic-associated symptoms in patients with unilateral lateral elbow tendinopathy: an exploratory study

OBJECTIVES

We evaluate the presence of sensitization-associated symptoms and neuropathic pain features and identify if there is an association between these symptoms and pressure pain sensitivity, pain, and related-disability in lateral elbow tendinopathy.

METHODS

Thirty-seven (43% women, age: 45.5 ± 9.5 years) patients with lateral elbow tendinopathy completed: demographic (i.e. age, height, and weight); clinical (i.e. pain history, pain intensity, and Disabilities of the Arm, Shoulder and Hand); and psychophysical (i.e. pressure pain thresholds at the elbow, cervical spine, hand, and leg) outcomes, and the Central Sensitization Inventory and Self-administered Leeds Assessment of Neuropathic Symptoms and Signs questionnaires. Step-wise multiple linear regression models were performed to identify predictors of sensitization- or neuropathic-associated symptoms.

RESULTS

Six (16%) patients exhibited sensitization-associated symptoms (mean: 46.5, SD: 6.1), whereas 13 (35%) patients showed neuropathic-associated symptoms (mean: 13.5; SD: 1.4). Sensitization-associated symptoms were positively associated with neuropathic-associated symptoms (r = 0.538, P = .001) and negatively associated with pressure pain thresholds at the leg (r = -0.378, P = .021). Neuropathic-associated symptoms were positively associated with related-disability (r = 0.479, P = .003) and negatively associated with pressure pain threshold at the elbow (r = -0.394, P = .017). Stepwise regression analyses revealed that neuropathic-like symptoms explained 26.8% of the variance of sensitization symptoms (r2: 0.268), whereas pressure pain threshold at the elbow explained an additional 6.6% to neuropathic-like symptoms (r2: 0.334).

CONCLUSION

This explorative study identified sensitization- and neuropathic-associated symptoms in 16% and 35% of the people with lateral elbow tendinopathy. Sensitization- and neuropathic-associated symptoms were associated. Pressure pain sensitivity at the elbow (peripheral sensitization) was associated with neuropathic -associated symptoms.

The Association Between the Patient Self-Report Survey for the Assessment of Fibromyalgia with Pain Sensitivity and Psychological Factors in Individuals with Musculoskeletal Pain

Purpose

The Patient Self-Report Survey for the Assessment of Fibromyalgia may potentially be a method for subgrouping patients with musculoskeletal pain who have a nociplastic pain presentation. Limited research has explored the convergent validity of this questionnaire against psychophysical measures of pain sensitivity and psychological factors in individuals with musculoskeletal pain. Therefore, the purpose of this study is to examine the strength of the association between total scores on the Patient Self-Report Survey for the Assessment of Fibromyalgia with clinical, pain sensitivity, and psychological factors.

Patients and Methods

As a secondary analysis of a cross-sectional study, participants with shoulder (n = 20) or low back pain (n = 20) completed Quantitative Sensory Testing (QST), pain-related psychological questionnaires, and the Patient Self-Report Survey for the Assessment of Fibromyalgia. A Spearman correlation determined the association between total scores on the Patient Self Report Survey for the Assessment of Fibromyalgia with psychological factors and pain sensitivity behaviorally assessed with QST.

Results

Negative psychological factors demonstrate moderate to strong positive associations with the Patient Self-Report Survey for the Assessment of Fibromyalgia (rho range = 0.36-0.80), suggesting greater negative psychological factors were observed in patients with higher severity of fibromyalgia symptoms. Pain sensitivity factors demonstrated weak to moderate negative associations with The Patient Self-Report Survey for the Assessment of Fibromyalgia (PPT rho range=-0.36- -0.41), suggesting that elevated pain sensitivity was observed in individuals with higher severity of nociplastic pain symptoms.

Conclusion

Collectively, this supports the convergent validity of the Patient Self-Report Survey for the Assessment of Fibromyalgia with psychological and pain sensitivity factors in patients with musculoskeletal pain.

Central sensitization syndrome in patients with rotator cuff tear: prevalence and associated factors

INTRODUCTION

A significant number of rotator cuff tear (RCT) patients developed chronic shoulder pain that did not correspond to physiological changes. Central sensitization syndrome (CSS) is a neurophysiological adaptation process that can result in hypersensitivity to peripheral stimuli. Although there is evidence of an association between CSS and musculoskeletal problems, no studies have focused on the association between CSS and RCT. The primary purpose of this study was to examine the prevalence of CSS in patients with RCT. The secondary purpose was to document the associated conditions and comorbidity that were associated with the CSS.

METHODS

This was a cross-sectional study of patients with RCT who completed the Central Sensitization Inventory (CSI). Patients with score of ≥ 40/100 were considered positive for CSS. Demographic and clinical data and CSI results were collected to analyze the prevalence and associated factors of CSS in RCT patients.

RESULTS

A total of 404 RCT patients were included, and the CSS prevalence was 39.4%. Compared to the non-CSS group, the CSS group had an odds ratio of 4.13 (95% CI, 2.70-6.32; p＜0.001) for ages 51-60, 3.07 (95% CI, 2.00-4.69; p＜0.001) for symptoms lasting more than 6 months, 6.08 (95% CI, 3.90-9.47; p＜0.001) for nonphysical laborers, 3.69 (95%CI, 2.42-5.61; p＜0.001) for long head of biceps (LHB) abnormality, 2.93 (95% CI, 1.93-4.45; p＜0.001) for concurrent shoulder stiffness, 4.82 (95% CI, 2.55-9.10; p＜0.001) for anxiety or panic episodes, and 2.11 (95% CI, 1.12, 4.00; p＜0.001) for depression.

CONCLUSIONS

The prevalence of CSS in patients with RCT was relatively high at 39.4%. The CSS was associated with higher age, female gender, and clinical findings of symptoms lasting over six months, nonphysical laborers, abnormal LHB, concurrent shoulder stiffness, anxiety, and depression.

Evolution of somatosensory processing signs after nociceptive targeted surgery in patients with musculoskeletal disorders: a systematic review

ABSTRACT

Surgery is often advised when conservative treatment fails in musculoskeletal pain conditions, but a substantial proportion still suffers chronic pain after surgery. Somatosensory processing system (SPS) signs were previously studied as potential predictors for chronic postsurgical pain, but results are inconsistent. Therefore, studying the evolution of SPS signs could be of added value. The aim was to summarize all studies that measured how SPS signs evolved after nociceptive targeted surgery in musculoskeletal disorders and to find preoperative, perioperative, and postoperative predictors for the evolution of these SPS signs. Data were summarized, and risk of bias and level of evidence and recommendation were determined. Twenty-one studies were included. Five scored a low, 3 a moderate, and 13 a high risk of bias. In general, no consistent evolution of SPS signs comparing preoperative and postoperative values and predictors for this evolution in musculoskeletal disorders could be found. In most cases, static quantitative sensory testing (QST) did not change or conflicting results were found. On the other hand, dynamic QST mostly improved after surgery. Worthfully mentioning is that worsening of SPS signs was only seen at a follow-up of <3 months after surgery, that conclusions are stronger when evaluating dynamic QST with a follow-up of ≥3 months after surgery, and that pain improvement postsurgery was an important predictor. Future high-quality research should focus on the evolution of SPS signs after nociceptive targeted surgery, accounting for pain improvement groups and focusing on preoperative, perioperative, and postoperative predictors of this evolution.

The effect of central sensitization on disease activity measures, quality of life and clinical parameters in axial spondyloarthritis: a cross-sectional study

Objective

Despite biological drug therapy, pain remains a persistent complaint in patients with axial spondyloarthritis (axSpA). We aimed to investigate the effect of central sensitization (CS) on disease activity measures, quality of life, and clinical parameters in axSpA patients.

Methods

We consecutively recruited axSpA patients who were followed up at our rheumatology outpatient clinic, and age- and sex-matched controls in this cross-sectional study. The central sensitization inventory, douleur neuropathique 4 (DN4) questions, and 2010 American College of Rheumatology fibromyalgia (FM) diagnostic criteria were applied to all individuals. The patients' clinical parameters were recorded. The data of the patient and control groups were compared.

Results

Of the 116 axSpA patients (57 female) and 95 controls (46 female) who participated in this study, CS was determined in 46.6% of axSpA patients and 13.7% of controls (p<0.001). Patients with CS exhibited high disease activity, and poor quality of life and functionality than without it (all p<0.001). The median CS, frequency of FM and frequency of neuropathic pain were higher in patients than in the controls (all p<0.001). CS-related conditions, including anxiety and depression, were higher in axSpA patients than in controls (both p<0.05).

Conclusion

The results showed that CS was common in axSpA patients, and patients with CS had higher disease activity, worse quality of life, and worse functional status than those without CS.

Do "central sensitization" questionnaires reflect measures of nociceptive sensitization or psychological constructs? A systematic review and meta-analyses

ABSTRACT

Central sensitization (CS) is defined as an increased nociceptive responsiveness due to sensitization of neurons in the central nervous system, usually the result of prolonged nociceptive input or a disease state associated with noxious inputs (eg, polyarthritis). The concept of CS has recently been adopted in clinical assessments of chronic pain, but its diagnosis in humans may now include a wide range of hypervigilant responses. The purpose of this review is to ascertain whether self-report questionnaires linked with CS are associated with enhanced nociceptive responses or whether they measure sensitivity in a broader sense (ie, emotional responses). According to our published, PROSPERO-registered review protocol (CRD42021208731), a predefined search of studies that involve the Central Sensitization Inventory (CSI) or Pain Sensitivity Questionnaire (PSQ), correlated with either nociceptive sensory tests or emotional hypervigilance was conducted on MEDLINE, PsycINFO, and Web of Science. Correlations between the CSI or PSQ with our primary outcomes were extracted and meta-analysed. A review of 66 studies totalling 13,284 participants found that the CSI (but not the PSQ) strongly correlated with psychological constructs: depression, anxiety, stress, pain catastrophising, sleep, and kinesiophobia. The CSI and PSQ showed weak or no correlations with experimental measures of nociceptive sensitivity: pain thresholds, temporal summation, or conditioned pain modulation. The PSQ did, however, correlate strongly with phasic heat and tonic cold pain tests. The studies reviewed did not provide sufficient evidence that self-report measures reflect a canonical understanding of CS. The CSI more closely reflects psychological hypervigilance than increased responsiveness of nociceptive neurons.

Exploratory Study on Central Sensitization and Bioelectrical Activity of the Selected Masticatory Muscles in Subjects with Myopia

BACKGROUND

Myopia is one of the most common eye disorders involving abnormal focusing of light rays. The studies recognize the association between the stomatognathic and visual systems. This compound may have a neurological basis associated with disorders such as central sensitization. The main aim of this study was to evaluate the influence of central sensitization on the bioelectrical activity of selected muscles of the masticatory organ in subjects with myopia.

METHODS

Selected masticatory and cervical spine muscles were analyzed using an eight-channel BioEMG III electromyograph. Central sensitization was analyzed using the central sensitization inventory.

RESULTS

Statistical analysis revealed significantly higher scores on the central sensitization inventory in subjects with axial myopia compared to subjects without refractive error. Repeated positive correlations were observed in the sternocleidomastoid muscle activity and negative correlations in the digastric muscle activity during open and closed eyes in myopic subjects.

CONCLUSIONS

Subjects with myopia have an increased score in the central sensitization inventory. The increase in the central sensitization inventory score is connected with the changes within the electromyographic activity of the masticatory and neck muscles. The effect of central sensitization on masticatory muscle activity in myopic subjects requires further study.

Mechanisms of chronic pain in inflammatory rheumatism: the role of descending modulation

ABSTRACT

Persistent pain despite satisfactory disease treatment is frequent in rheumatoid arthritis (RA) and spondyloarthritis (Spa) and may result from specific changes in central pain processing. We assessed these mechanisms further by systematically comparing thermal pain thresholds and conditioned pain modulation (CPM) between patients with active RA or Spa and healthy controls. We included 50 patients with RA and 50 patients with Spa and 100 age-matched and sex-matched controls. Heat and cold pain thresholds (HPT-CPT) were measured on the dominant forearm, and CPM was assessed by applying conditioning stimuli (immersion in a cold-water bath) to one foot and the nondominant hand in 2 successive randomized sequences. Descending pain modulation was assessed as the difference in HPTs (in °C) before and after conditioning. Larger HPT differences (ie, a larger CPM effect) reflected more efficient descending inhibition. Potential associations between changes in CPM and clinical data, including disease activity, pain intensity, and psychological and functional variables, were systematically assessed. Heat pain threshold and cold pain threshold were similar in patients and controls. The mean CPM effect was significantly weaker in patients than that in controls for conditioning applied to either the foot (0.25°C ±2.57 vs 2.79°C ±2.31; P < 0.001) or the nondominant hand (0.57°C ±2.74 vs 2.68°C ±2.12; P < 0.001). The smaller CPM effect in patients was correlated with average pain intensity, but not with disease activity or other clinical characteristics, suggesting a significant pathophysiological role for changes in endogenous pain modulation in the mechanisms of chronic pain associated with inflammatory rheumatism.

Association of Central Sensitization Inventory Scores With Pain Outcomes After Endometriosis Surgery

IMPORTANCE

A subset of people who undergo surgery for endometriosis have persistent pain, suggesting that other factors besides the endometriosis, such as central sensitization, may play a role in this pain. The Central Sensitization Inventory, a validated self-reported questionnaire of central sensitization symptoms, may identify individuals with endometriosis who have more pain after surgery due to pain sensitization.

OBJECTIVE

To examine whether greater baseline Central Sensitization Inventory scores are associated with postsurgical pain outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, longitudinal cohort study performed at a tertiary center for endometriosis and pelvic pain in British Columbia, Canada, included all patients aged 18 to 50 years with diagnosed or suspected endometriosis and a baseline visit between January 1, 2018, and December 31, 2019, who underwent surgery after the baseline visit. Individuals who were menopausal, had a prior hysterectomy, or were missing data for outcomes or measures were excluded. Data analysis was performed from July 2021 to June 2022.

MAIN OUTCOMES AND MEASURES

The primary outcome was chronic pelvic pain at follow-up measured on a scale of 0 to 10, with 0 to 3 indicating no pain or mild pain, 4 to 6 indicating moderate pain, and 7 to 10 indicating severe pain. Secondary outcomes were deep dyspareunia, dysmenorrhea, dyschezia, and back pain at follow-up. The main variable of interest was baseline Central Sensitization Inventory score (measured from 0 to 100, consisting of 25 self-reported questions rated from 0 to 4 [never, rarely, sometimes, often, and always, respectively]).

RESULTS

A total of 239 patients (mean [SD] age, 34 [7] years; 189 [79.1%] White [11 (5.8%) identified as White mixed with another ethnicity], 1 [0.4%] Black or African American, 29 [12.1%] Asian, 2 [0.8%] Native Hawaiian or Pacific Islander, 16 [6.7%] other, and 2 [0.8%] mixed race or ethnicity) with follow-up data at more than 4 months after surgery were included in this study (71.0% follow-up rate). The mean (SD) baseline Central Sensitization Inventory score was 43.8 (18.2), and the mean (SD) follow-up was 16.1 (6.1) months. Higher baseline Central Sensitization Inventory scores were significantly associated with higher chronic pelvic pain (odds ratio [OR], 1.02; 95% CI, 1.00-1.03; P = .02), deep dyspareunia (OR, 1.03; 95% CI, 1.01-1.04; P = .004), dyschezia (OR, 1.03; 95% CI, 1.01-1.04; P < .001), and back pain (OR, 1.02; 95% CI, 1.00-1.03; P = .02) at follow-up, when controlling for baseline pain scores. The Central Sensitization Inventory scores themselves decreased slightly from baseline to follow-up (mean [SD] score, 43.8 [18.2] vs 41.7 [18.9]; P = .05); however, individuals with high baseline Central Sensitization Inventory scores still had high scores at follow-up.

CONCLUSIONS AND RELEVANCE

In this cohort study of 239 patients with endometriosis, higher Central Sensitization Inventory scores at baseline were associated with worse pain outcomes after endometriosis surgery, when controlling for baseline pain scores. The Central Sensitization Inventory could be used to counsel patients with endometriosis on their expected outcomes after surgery.

The Effect of Spinal Muscle Fatigue and Psychosocial Factors on Pressure-Pain Threshold in Healthy Adults

Objective

Pain sensitivity decreases following isometric exercise. It is not clear whether this exercise-induced hypoalgesia (EIH) occurs to the same extent in men and women. It is also unclear if the effect is systemic or local to the exercised musculature. The aim of our study was to investigate whether fatiguing isometric exercise of the spinal and hip extensors would result in increased pressure pain threshold (PPT) at sites local to and remote from the exercised muscles in healthy men and women and whether there is a relationship between central sensitization, psychosocial factors, and PPT.

Subjects

35 healthy adults (age 27.1 ± 4.5 years, 22 women).

Methods

This was a within-subjects cohort study. Participants completed questionnaires quantifying central sensitization, pain catastrophizing, sleepiness/insomnia, anxiety, and depression. PPT was assessed at the lumbar and thoracic paraspinals, hamstrings, gastrocnemius, wrist, and third digit before and immediately after participants performed the Biering-Sorensen test to failure.

Results

PPT increased postexercise in the thoracic paraspinals, hamstrings, and gastrocnemius in men and women and in the lumbar paraspinals in men only but did not change at the wrist and digit sites. A lower average PPT at baseline was associated with a higher central sensitization scores. A greater increase in average PPT postfatigue was significantly associated with higher average PPT at baseline.

Conclusions

Exercise-induced hypoalgesia occurs at sites overlying the muscles involved in fatiguing exercise, but not at remote sites, and is more evident in males than females. The magnitude of EIH depends upon baseline PPT. Even in healthy individuals, greater central sensitization is associated with lower baseline PPT.

Association between Experimental Pain Measurements and the Central Sensitization Inventory in Patients at Least 3 Months after COVID-19 Infection: A Cross-Sectional Pilot Study

Fatigue, pain, headache, brain fog, anosmia, ageusia, mood symptoms, and sleep disorders are symptoms commonly experienced by people with post-COVID-19 condition. These symptoms could be considered as manifestations of central sensitization. The aim of this study is to evaluate whether there are indicators of central sensitization by using experimental pain measurements and to determine their association with patient-reported outcome measures (PROMs). A cross-sectional study including 42 patients after COVID-19 infection was conducted. The central sensitization inventory (CSI) was administered as a PROM to evaluate central-sensitization-associated symptoms. Pressure pain thresholds (PPT), temporal summation, and descending nociceptive pain inhibition (CPM) were assessed as experimental pain measurements. The median score on the CSI was 46.5 (Q1-Q3: 33-54). The presence of central-sensitization-associated symptoms was seen in 64.3% of patients based on the CSI (≥40/100 points). A deficient CPM was seen in 12% and 14% of patients when measured at the trapezius and rectus femoris, respectively. A negative correlation between pressure sensitivity on the rectus femoris and the CSI score (r = -0.36, 95%CI -0.13 to -0.65, p = 0.007) was observed. Central-sensitization-associated symptoms were present in up to 64.3% of patients post-COVID-19 infection, based on a PROM, i.e., the CSI. A more objective evaluation of nociceptive processing through experimental pain measurements was less suggestive of indicators of central sensitization. Only a small negative correlation between pressure sensitivity and the CSI was observed, thereby pointing towards the discrepancy between the CSI and experimental pain measurements and presumably the complementary need for both to evaluate potential indicators of central sensitization in this population.

Characteristics and Outcomes of Patients Receiving Physical Therapy for Low Back Pain with a Nociplastic Pain Presentation: A Secondary Analysis

Introduction

Individuals with low back pain (LBP) may be classified based on mechanistic descriptors, such as a nociplastic pain presentation (NPP). The purpose of this secondary analysis was to examine the frequency and characteristics of patients with a NPP referred to physical therapy with LBP. Additionally, we characterized patients with LBP meeting the criteria for NPP by demographic, clinical, psychological, and pain sensitivity variables. Finally, we examined short- and long-term clinical outcomes in patients with a NPP compared to those without a NPP.

Materials and Methods

Patients referred to physical therapy for LBP completed the Patient Self-report Survey for the Assessment of Fibromyalgia. Participants were categorized as "LBP with NPP" or "LBP without NPP" based on the threshold established in this measure. A rank sum test examined for differences in pain-related psychological factors and pressure-pain threshold between groups. Next, a Friedman test examined if LBP intensity and disability trajectories differed by groups at one and six months after initiation of physical therapy.

Results

22.2% of patients referred to physical therapy for LBP met the criteria for a NPP. Patients with a NPP reported significantly greater disability, pain catastrophizing, depression, anxiety, and somatization compared to individuals without a NPP (p < 0.05). Pressure-pain threshold did not differ between groups (p > 0.05). Individuals with LBP with a NPP demonstrated nonsignificant, small to medium reductions in pain and disability at one and six months. Individuals experiencing LBP without a NPP demonstrated significant reductions in pain and disability in the short- and long term.

Conclusion

Patients with LBP with a NPP displayed greater negative pain-related psychological factors but similar pain sensitivity compared to LBP without NPP.

Immediate effects of dry needling on pain sensitivity and pain modulation in patients with chronic idiopathic neck pain: a single-blinded randomized clinical trial

BACKGROUND

Dry needling is frequently used for the treatment of neck pain but knowledge about its neurophysiological central effects is scarce.

OBJECTIVES

To compare the immediate effects of a single session of dry needling (DN) and sham needling (SN) on local and distant pressure pain thresholds and conditioned pain modulation in patients with chronic idiopathic neck pain.

METHOD

Participants with chronic idiopathic neck pain were randomly allocated to a DN or SN group. The primary outcome measure was the pressure pain threshold (PPT) at one peripheral location: quadriceps muscle (Q). Secondary outcome measures were local PPTs at the treated (most painful) (tUT) and non-treated upper trapezius muscle (ntUT), absolute and relative conditioned pain modulation (CPM) effects and pain during hot water immersion. Patients were assessed at baseline and immediately post intervention. Linear mixed models were used to examine interaction effects as well as between- and within-group differences.

RESULTS

Fifty-four participants were included for statistical analysis. Linear mixed model analyses showed no significant "group X time" interaction effects for any of the outcome measures. The relative CPM effect at the Q was significantly higher post-intervention, compared to baseline within the DN group (mean difference= 13.52%; 95% CI: 0.46, 26.59).

CONCLUSION

The present study shows no superior effect of DN, compared to SN, in the immediate effect on local and distant PPTs and CPM in patients with chronic idiopathic neck pain.

Autonomic Nervous System Function and Central Pain Processing in People With Frozen Shoulder: A Case-control Study

OBJECTIVES

The pathophysiology of a frozen shoulder (FS) is thought to be related to chronic inflammation. Chronic inflammation may disturb the immune system and consequently the nervous system as part of an overarching system. The aim of this study was to determine the presence of disturbed autonomic nervous system function and altered central pain processing (CPP) in patients with FS. Secondarily, the presence of psychological variables (catastrophizing and hypervigilance) and self-reported associated symptoms of altered CPP in patients with FS were investigated.

METHODS

Patients with FS and healthy controls completed the Composite Autonomic Symptom Score (autonomic function) and underwent quantitative sensory testing to assess tactile sensitivity (ie, allodynia), pressure pain thresholds (PPTs, ie, hyperalgesia), temporal summation of pain, and Conditioned Pain Modulation (CPM). Psychological issues were explored with the Pain Catastrophizing Scale and the Pain Vigilance and Awareness Questionnaire, and self-reported symptoms associated with altered CPP were determined with the Central Sensitization Inventory.

RESULTS

Thirty-two patients with FS and 35 healthy controls were analyzed in the study. Patients with FS showed more self-reported autonomic symptoms and symptoms of altered CPP, higher levels of pain catastrophizing and hypervigilance, and are more sensitive to tactile touches and mechanical pressure compared with controls.

DISCUSSION

On the basis of the effect sizes, between-group differences in allodynia, hyperalgesia, catastrophizing, and hypervigilance were clinically relevant, but only local allodynia, hyperalgesia, catastrophizing, and hypervigilance were statistically different. Therefore, obvious altered CPP was not present at the group level in patients with FS compared with controls.

Pain Management and Rehabilitation for Central Sensitization in Temporomandibular Disorders: A Comprehensive Review

Temporomandibular disorders (TMD) are a group of musculoskeletal diseases affecting masticatory muscles and temporomandibular joints (TMJ). In this context, the chronic TMD could be considered as a condition with chronic primary orofacial pain, presenting as myofascial TMD pain or TMJ arthralgia. In this context, myogenous TMD may present overlapping features with other disorders, such as fibromyalgia and primary headaches, characterized by chronic primary pain related to dysfunction of the central nervous system (CNS), probably through the central sensitization. This phenomenon could be defined as an amplified response of the CNS to sensory stimuli and peripheral nociceptive, characterized by hyperexcitability in the dorsal horn neurons in the spinal cord, which ascend through the spinothalamic tract. The main objectives of the management of TMD patients are: decreasing pain, increasing TMJ function, and reducing the reflex masticatory muscle spasm/pain. The first-line treatments are physical therapy, pharmacological drugs, occlusal splints, laser therapy, extracorporeal shockwave therapy, transcutaneous electrical nerve stimulation, and oxygen–ozone therapy. Although all these therapeutic approaches were shown to have a positive impact on the central sensitization of TMD pain, there is still no agreement on this topic in the scientific literature. Thus, in this comprehensive review, we aimed at evaluating the evidence on pain management and rehabilitation for the central sensitization in TMD patients.

Cross-Sectional Comparative Study on Central Sensitization-Psychosocial Associated Comorbidities and Psychological Characteristics in Breast Cancer Survivors with Nociceptive Pain and Pain with Neuropathic Features and without Pain

Simple Summary

Persistent pain after breast cancer treatment is still under research due to its complex and multifactorial underlying pathogenesis, including phycological factors. Further research is needed to elucidate more information about the factors that cause and perpetuate this pain. Thus, this study defined the influence of psychosocial and psychological factors on breast cancer survivors who report pain and those who do not. The psychosocial factors assessed were those that are associated with a central sensitization process, and the psychological factors were pain catastrophizing, fear of movement, anxiety and depression. Hence, the psychosocial symptom clusters were identified related to the clinical features of pain or to not reporting pain, which may encourage health clinicians to establish a customized biopsychosocial model focused on the management of pain-catastrophizing thoughts and fear of movement. Furthermore, anxiety and depression should be detected early by health professionals and referred to psychologists to be managed.

Abstract

The frequency of a high Central Sensitization Inventory (CSI) total score and the prevalence of pain have already been established among breast cancer survivors (BCS). However, the psychological factors’ influence based on the clinical features of pain is still unknown, as well as BCS characteristics with no pain. Thus, our main aim was to evaluate the presence of a high CSI total score in BCS with pain and compare it with BCS without pain and to evaluate the influence of psychosocial factors. A cross-sectional comparative study was designed to compare BCS with nociceptive pain (n = 19), pain with neuropathic features (n = 19) or no pain (n = 19), classified by the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS). CSI, pain catastrophizing, fear of movement, anxiety and depression symptoms were analyzed and compared among the three groups. The CSI total score was higher in both BCS pain groups compared to BCS without pain, but there were no statistical differences between the pain groups. The same observation was made when comparing pain catastrophizing. The neuropathic feature group showed greater levels of fear of movement, anxiety and depression compared to the no pain group. Thus, CS-psychosocial associated comorbidities and pain-catastrophizing thoughts were more prevalent among BCS with pain, regardless of the clinical features of pain. BCS with neuropathic pain features showed greater psychological disturbances.

Convergent Validity of the Central Sensitization Inventory in Women with Fibromyalgia: Association with Clinical, Psychological and Psychophysical Outcomes

BACKGROUND

To assess the relationship between demographic, clinical, psychological, and pressure pain sensitivity outcomes with the central sensitization inventory (CSI) in female with fibromyalgia (FMS).

METHODS

One hundred twenty-six (n=126) females with FMS completed demographic (age, body mass index, height, weight), clinical (pain history, pain intensity at rest and during daily living activities), psychological (depression/anxiety levels) outcomes and widespread pressure pain sensitivity as well as the central sensitization inventory (CSI). After conducting a multivariable correlation analysis to identify the association between variables, a multiple linear regression model was performed to identify CSI predictors.

RESULTS

The CSI was negatively associated with age (r=-0.262) and PPTs (r ranged from -0.221 to -0.372) and positively associated with anxiety (r=0.541), depression (r=0.415), mean intensity (r=0.305), worst pain (r=0.249), and pain during daily living activities (r= 0.398). The stepwise regression analysis revealed that 47.4% of CSI variance in this sample was explained by anxiety levels (27.8%), PPT at greater trochanter (10.5%), age (1.4%), years with pain (4.8%) and pain during daily living activities (2.9%).

CONCLUSION

The current study found that age, pain intensity at rest and pain during daily living activities, anxiety levels, and pressure pain sensitivity are associated with the CSI (associated sensitization symptoms) in women with FMS.

Digital pain extent is associated with pain intensity but not with pain-related cognitions and disability in people with chronic musculoskeletal pain: a cross-sectional study

Background

To evaluate whether digital pain extent is associated with an array of psychological factors such as optimism, pessimism, expectations of recovery, pain acceptance, and pain self-efficacy beliefs as well as to analyse the association between digital pain extent and pain intensity and pain-related disability in people with chronic musculoskeletal pain.

Methods

A descriptive cross-sectional study conducted in a primary health care setting was carried out including 186 individuals with chronic musculoskeletal pain. Patient-reported outcomes were used to assess psychological factors, pain intensity, and pain-related disability. Digital pain extent was obtained from pain drawings shaded using a tablet and analysed using novel customized software. Multiple linear regression models were conducted to evaluate the association between digital pain extent and the aforementioned variables.

Results

Digital pain extent was statistically significantly associated with pain intensity. However, digital pain extent was not associated with any psychological measure nor with pain-related disability.

Discussion

The results did not support an association between digital pain extent and psychological measures.

"Convergent validity of the central sensitization inventory and experimental testing of pain sensitivity"

OBJECTIVES

The aim of the current study was to examine the convergent validity of the Central Sensitization Inventory by quantifying the correlation with experimental measures of pain sensitivity and self-reported psycho-social questionnaires, in a low back pain population.

METHODS

All participants were recruited from an outpatient hospital spine care clinic (Spine Centre of Southern Denmark). Participants underwent a standardized experimental pain test protocol and completed the Central Sensitization Inventory (CSI) along with additional self-reported questionnaires to assess psycho-social constructs across different domains. The association between the CSI, experimental pain measures and other self-reported psycho-social questionnaires were analyzed using correlation and contingency tests. ROC-curve analysis was used to determine sensitivity and specificity for CSI.

RESULTS

One hundred sixty-eight (168) participants were included. The CSI was weakly correlated with nine out of 20 variables in the experimental pain test protocol (rho range -0.37 to 0.22). The CSI was more closely correlated with psycho-social factors such as work ability, disability, and symptoms of exhaustion disorder. ROC-analysis identified an optimal cut-point of 44 on CSI (Sn=39.1% Sp=87.4%). The CSI had an area under the ROC curve of 0.656. Fisher's exact test demonstrated a statistically significant association between participants scoring ≥40 on CSI and participants categorized as sensitized by experimental pain tests (p-value=0.03).

CONCLUSIONS

Our findings are consistent with previous studies, indicating that the CSI is related to psycho-social constructs. However, the convergent validity with experimental pain measures is small and probably not clinically meaningful.

Differences in Quantitative Sensory Testing Outcomes Between Patients With Low Back Pain in Primary Care and Pain-free Controls

OBJECTIVES

Quantitative Sensory Testing (QST) is used to test somatosensory functioning in on people with chronic LBP in secondary/tertiary health care facilities. Studies using QST-testing on LBP populations in primary care are scarce. Central Sensitization Inventory (CSI) measures central sensitization (CS)-related symptoms and studies investigating the differences between QST-testing and participants with LBP with a positive and negative score on the CSI questionnaire are also rare. This case-control study investigates differences of an extensive QST-measurement between patients with acute, chronic LBP, and pain-free controls (PFCs) in primary care. Secondary aim is to investigate differences of an extensive QST-measurement between "CS" and "no-CS" group.

MATERIALS AND METHODS

Participants with LBP were recruited from November 2016 to October 2019. Demographic and clinical information was collected and a standardized QST protocol was taken. Data analysis involved determining differences between groups.

RESULTS

Data of 100 participants with LBP and 50 PFCs were analyzed. Heat pain thresholds, pressure pain threshold, and conditioned pain modulation local and remote were significantly moderately to relatively strongly affected by acute, chronic LBP and PFCs (P<0.001 to 0.001). Lumbar temporal summation was significantly moderately affected by acute, chronic LBP, and PFCs (P=0.001). Only pressure pain threshold showed significant difference between "CS" and "no-CS" group (P=0.001 to 0.002).

DISCUSSION

Signs of enhanced nociceptive processing and disturbed top-down nociceptive modulation are apparent in people with acute and chronic LBP in primary care. Results indicate existence of central mechanisms in LBP in primary care.

Questionnaire-based somatosensory profiling in breast cancer survivors: are we there yet? Associations between questionnaires and quantitative sensory testing

PURPOSE

Pain and sensory disturbances are common side effects of breast cancer treatment. Differential somatosensory functioning may reflect distinct pathophysiological backgrounds and therapeutic needs. Aim was to examine whether questionnaires evaluating signs and symptoms related to somatosensory functioning correlate sufficiently with quantitative sensory testing (QST) in breast cancer survivors to warrant consideration for somatosensory profiling in clinical practice.

METHODS

One year after breast cancer surgery, 147 women underwent QST and completed following questionnaires: Douleur Neuropathique en 4 questions (DN4), Central Sensitization Inventory, Margolis Pain Diagram and Visual Analog Scales (VAS). Associations between the questionnaires and QST were evaluated using Spearman correlation coefficients (rs).

RESULTS

Significant but weak (rs < 0.30) correlations were found between total DN4 score and QST results at the inner upper arm for detection of sharp stimuli (rs = 0.227), cold stimuli (rs = -0.186), and painful heat stimuli (rs = 0.179), as well as between QST evaluating conditioned pain modulation and the Margolis Pain Diagram on one hand (rs = 0.176) and minimum-maximum pain intensity differences (VAS) on the other (rs = -0.170).

CONCLUSION

Questionnaires evaluating signs and symptoms related to somatosensory functioning are insufficient for somatosensory profiling. Although somatosensory profiling may be valuable in a mechanism-based management, more research on the most appropriate clinical tools is needed.IMPLICATIONS FOR REHABILITATIONClinicians should be able to recognize that patients with persistent pain or sensory disturbances following breast cancer surgery may have a component of altered somatosensory processing as a significant contributor to their complaint in order to address it appropriately.Somatosensory profiling has yet to be implemented into clinical practice.No evidence-based recommendations can be made on the use of self-reported questionnaires to assess somatosensory processing in a breast cancer population based on the findings of this study.It is suggested to combine information on how individuals process and experience somatosensory stimulation with information from the patient interview or questionnaires to consider which biological, psychological and/or social factors may drive or sustain these neurophysiological processes.

Detection of altered pain facilitatory and inhibitory mechanisms in patients with knee osteoarthritis by using a simple bedside tool kit (QuantiPain)

Supplemental Digital Content is Available in the Text.

A simple bedside quantitative sensory testing tool kit demonstrated acceptable reliability and assessment validity for detecting altered pain facilitatory and inhibitory mechanisms in patients with painful osteoarthritis.

Purpose:

Altered pain facilitatory and inhibitory mechanisms have been recognized as an important manifestation in patients with chronic pain, and quantitative sensory testing (QST) can act as a proxy for this process. We have recently developed a simple bedside QST tool kit (QuantiPain) for more clinical use. The purpose of this study was to investigate its test–retest reliability and to evaluate its validity compared with the laboratory-based QST protocols in patients with knee osteoarthritis (OA).

Methods:

QuantiPain consists of 3 items: “pressure algometer” (for pressure pain thresholds [PPTs]), “pinprick” (for temporal summation of pain [TSP]), and “conditioning clamp” (for conditioned pain modulation [CPM]). In experiment-A, intrarater and interrater test–retest reliabilities were investigated in 21 young healthy subjects by using interclass correlation coefficient (ICC). In experiment-B, 40 unilateral painful patients with OA and 40 age-matched, healthy control subjects were included to compare the bedside tool kit against the computerized pressure algometry.

Results:

In experiment-A, excellent to moderate intrarater and interrater reliabilities were achieved in PPT and TSP (ICC: 0.60–0.92) while the agreements of CPM were good to poor (ICC: 0.37–0.80). In experiment-B, localized and widespread decrease of PPT, facilitated TSP, and impaired CPM was found by using the bedside tool kit in patients with OA compared with controls (P < 0.05). The data were significantly correlated with the established laboratory-based tools (R = 0.281–0.848, P < 0.05).

Conclusion:

QuantiPain demonstrated acceptable test–retest reliability and assessment validity with the sensitivity to separate patients with painful OA from controls, which has a potential to create more practical approach for quantifying altered pain mechanisms in clinical settings.

Pain catastrophizing, pain sensitivity and fear of pain are associated with early life environmental unpredictability: a path model approach

Background

Socioeconomic disadvantages in the childhood environment might strongly influence beliefs and behavior characterizing the adult years. When children experience unpredictable and adverse situations, they develop an unpredictability schema with the core belief that situations are unpredictable.

Methods

In two studies, we examined the association of childhood socioeconomic disadvantages with self-reported pain sensitivity, pain catastrophizing, and pain-related fear. Multidimensional survey measures were used to assess environmental conditions experienced in childhood. In addition, participants completed the Pain Catastrophizing Scale, Pain Sensitivity Questionnaire, Body Awareness Questionnaire, Unpredictability Schema Questionnaire, and Fear of Pain Questionnaire. In Study 1 (N = 252), in separate models, we examined pain sensitivity and pain catastrophizing of a community sample of pain-free young individuals in association with their childhood experiences. In Study 2 (N = 293), in a new sample, but with a wider age range, we examined the association of early life socioeconomic disadvantages with pain-related fear. In both studies, the predictions were tested with Structural Equation Modeling. Our models constituted a path from childhood socioeconomic status and household unpredictability to pain variables via the factors of family resources, unpredictability schemas, and body awareness.

Results and conclusions

The findings converged on the conclusion that individuals experiencing disadvantageous early life conditions tended to have an elevated level of pain catastrophizing, higher perceived sensitivity to pain, and higher level of pain-related fear. These associations were mediated by an unpredictability schema and body awareness.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-022-00800-0.

The Onset of Chronic Musculoskeletal Pain in High School Adolescents: Associated Factors and the Role of Symptoms of Central Sensitization

OBJECTIVE

This study aimed to investigate the association between sociodemographic data, physical activity, depression, anxiety, and stress, sleep, and self-reported symptoms of central sensitization at baseline, in asymptomatic adolescents, and the onset of pain at 6-months follow-up.

METHODS

A total of 252 asymptomatic adolescents were assessed at baseline with an online questionnaire that included sociodemographic data, the Nordic Musculoskeletal Questionnaire; the International Physical Activity Questionnaire for Adolescents; the Depression, Anxiety and Stress Scale for Children; the Basic Scale on Insomnia complaints and Quality of Sleep; and the Central Sensitization Inventory. The same questionnaire was repeated at 6-months follow-up.

RESULTS

Of the 231 (91.7%) adolescents who completed the questionnaire at the follow-up, 127 (55.0%) remained asymptomatic and 88 (38.1%) reported a new onset of pain. At the 6-month follow-up, the mean (SD) number of painful body sites was 1.81 (1.04), and the neck region was the most reported (n = 29, 33%). Multivariable analysis showed that being female (OR = 2.34; 95% CI = 1.28-4.27) and reporting more self-reported symptoms of central sensitization (OR = 1.04; 95% CI = 1.01-1.07) were associated with the onset of chronic pain at follow-up.

CONCLUSION

Female sex and self-reported symptoms of central sensitization were considered risk factors for the onset of pain in adolescents but should be further explored in future studies.

IMPACT

Considering the increasing prevalence of chronic musculoskeletal pain in adolescents, understanding the factors that may be associated with its new onset may help to better design preventive strategies and thus minimize the appearance of this type of pain in adolescents.

Pain descriptors and determinants of pain sensitivity in knee osteoarthritis: a community-based cross-sectional study

Objectives

To explore pain characteristics in individuals with knee osteoarthritis (KOA), to compare pain sensitivity across individuals with KOA, chronic back pain (CBP) and pain-free individuals (NP), and to examine the relationship between clinical and pain characteristics with pain sensitivity in KOA.

Methods

Cross-sectional, community-based online survey. Two datasets were combined comprising Dutch individuals of ≥ 40 years of age, experiencing chronic knee pain (KOA, N = 445), chronic back pain (CBP, N = 504), or no pain (NP, N = 256). Demographic and clinical characteristics, global health, physical activity/exercise, and pain characteristics including intensity, spreading, duration, quality (SF-MPQ), and sensitivity (PSQ) were assessed. Differences between (sub)groups were examined using analyses of variance or Chi-square tests. Regression analyses were performed to examine determinants of pain sensitivity in the KOA group.

Results

Quality of pain was most commonly described as aching, tender, and tiring-exhausting. Overall, the KOA group had higher levels of pain sensitivity compared to NP group, but lower levels than the CBP group. Univariately, pain intensity, its variability and spreading, global health, exercise, and having comorbidities were weakly related to pain sensitivity (standardized betas: 0.12-0.27). Symptom duration was not related to pain sensitivity. Older age, higher levels of continuous pain, lower levels of global health, and exercise uniquely contributed, albeit modest, to pain sensitivity (P&lt;0.05).

Conclusion

Continuous pain such as aching and tenderness in combination with decreased physical activity may be indicative for a subgroup of individuals at risk for pain sensitivity and, ultimately, poor treatment outcomes.

Dispositional and situational personal features and acute post-collision head and neck pain: Double mediation of pain catastrophizing and pain sensitivity

Pain variability can be partially attributed to psycho-cognitive features involved in its processing. However, accumulating research suggests that simple linear correlation between situational and dispositional factors may not be sufficiently explanatory, with some positing a role for mediating influences. In addition, acute pain processing studies generally focus on a post-operative model with less attention provided to post-traumatic injury. As such, this study aimed to investigate a more comprehensive pain processing model that included direct and indirect associations between acute pain intensity in the head and neck, pain catastrophizing (using pain catastrophizing scale (PCS)), and pain sensitivity (using the pain sensitivity questionnaire (PSQ)), among 239 patients with post-motor vehicle collision pain. The effect of personality traits (using Ten Items Personality Inventory (TIPI)) and emotional status (using Hospital Anxiety and Depression Scale (HADS) and Perceived Stress Scale (PSS)) on that model was examined as well. To this end, three Structural Equation Modeling (SEM) analyses were conducted. Overall, the data had good fit to all the models, with only PSQ found to have a direct correlation with acute pain intensity. The SEM analyses conversely revealed several mediations. Specifically, that: first, PSQ fully mediated the relationship between PCS and pain intensity; second, PCS and PSQ together fully mediated the relationship between conscientiousness (personality trait) and pain intensity; and finally, emotional status had direct and indirect links with PSQ and pain intensity. In conclusion, these models suggest that during the acute post-collision phase, pain sensitivity intermediates between emotional states and personality traits, partially via elevated pain catastrophizing thoughts.

Signs Indicative of Central Sensitization Are Present but Not Associated with the Central Sensitization Inventory in Patients with Focal Nerve Injury

Objective: Carpal tunnel syndrome (CTS) is the most common focal nerve injury. People with CTS may show alterations in central processing of nociceptive information. It remains unclear whether the central sensitization inventory (CSI) is capable of detecting such altered central pain processing. Methods: Thirty healthy volunteers were matched with 30 people with unilateral CTS from the orthopaedic waitlist. Changes to central pain processing were established through psychophysical sensory testing (bilateral pressure pain thresholds (PPT), conditioned pain modulation, temporal summation) and pain distribution on body charts. Patients also completed pain severity and function questionnaires, psychological questionnaires and the CSI. Results: Compared to healthy volunteers, patients with CTS have lower PPTs over the carpal tunnel bilaterally (t = −4.06, p < 0.0001 ipsilateral and t = −4.58, p < 0.0001 contralateral) and reduced conditioned pain modulation efficacy (t = −7.31, p <0.0001) but no differences in temporal summation (t = 0.52, p = 0.60). The CSI was not associated with psychophysical measures or pain distributions indicative of altered central pain processing. However, there was a correlation of the CSI with the Beck Depression Inventory (r = 0.426; p = 0.019). Conclusion: Patients with CTS show signs of altered central pain mechanisms. The CSI seems unsuitable to detect changes in central pain processing but is rather associated with psychological factors in people with focal nerve injuries.

Use of the painDETECT to discriminate musculoskeletal pain phenotypes

Background

Musculoskeletal pain patients present similar pain characteristics regardless of the clinical diagnosis. PainDETECT questionnaire is useful for screening neuropathic-like symptoms in many musculoskeletal conditions. However, no previous studies compared pain phenotypes of patients with musculoskeletal pain using the painDETECT. Therefore, the current study aimed to compare the pain characteristics of patients with musculoskeletal pain classified according to the painDETECT as nociceptive pain, unclear, and neuropathic-like symptoms.

Methods

A cross-sectional study was conducted in 308 participants with musculoskeletal pain. Demographic and clinical characteristics of the participants were examined. Neuropathic-like symptoms, pain intensity, pain area, Central Sensitization-related sign and symptoms, functional limitation, and conditioned pain modulation were assessed in patients with musculoskeletal pain. Independent one-way analysis of variance (ANOVA) was used to test for between-group differences for the outcome measures with continuous variables and Pearson chi-square test verified between-group differences on the efficiency of the conditioned pain modulation.

Results

Participants had a mean age of 52.21 (±15.01) years old and 220 (71.42%) were females. One hundred seventy-three (56.16%) participants present nociceptive pain, 69 (22.40%) unclear, and 66 (21.42%) neuropathic-like symptoms. A one-way ANOVA showed differences for the pain intensity [F (2,305) = 20.097; p < .001], pain area [F (2,305) = 28.525; p < .001], Central Sensitization-related sign and symptoms [F (2,305) = 54.186; p < .001], and functional limitation [F (2,256) = 8.061; p < .001]. However, conditioned pain modulation was similarly impaired among the three groups (X² = 0.333, p = 0.847).

Conclusion

Patients with neuropathic-like symptoms revealed unfavorable pain characteristics compared to their counterparts, including pain intensity, generalized pain, Central Sensitization-related sign and symptoms, and functional limitation.

Characteristics of clusters with contrasting relationships between central sensitization-related symptoms and pain

The central sensitization inventory (CSI) evaluates the central sensitization (CS)-related symptoms associated with increased pain sensitivity. However, the CSI includes items that are not directly related to pain. In this study, 146 patients with pain were classified into subgroups by k-means cluster analysis based on the short form of the central sensitization inventory (CSI9) and pain scores. In addition, inter-group and multiple comparisons were performed to examine the characteristics of each group. As a result of this study, there were three subgroups (clusters 1, 2, and 3) in which the CSI9 and pain intensity were both low, moderate, and high, and one subgroup (cluster 4) in which only CSI9 was high and pain intensity was low. Two subgroups with high CSI9 scores but contrasting pain intensities (clusters 3 and 4) were extracted; the pattern of CS-related symptoms in these two groups was very similar, with no differences in most of the non-pain factors. It is necessary to consider these points when interpreting the clinical condition of a patient with pain when using the assessment of CS-related symptoms.

Biopsychosocial risk factors for pain and pain-related disability 1 year after surgery for breast cancer

PURPOSE

Knowledge regarding risk factors for pain in the long term after surgery for breast cancer may be of great value in preventing this prevalent and debilitating side effect. Despite the biopsychosocial nature of pain, the predictive value of both pre- and postoperative biopsychosocial functioning for long-term pain intensity and pain-related disability has not yet been studied.

METHODS

One hundred sixty-six women planned for unilateral breast cancer surgery were included in this prospective cohort study. Pre- and postoperative outcomes related to pain, psychosocial, and somatosensory functioning (questionnaires and quantitative sensory testing) were evaluated as risk factors for pain intensity (visual analog scale) and pain-related disability (pain disability index) 1 year after surgery for breast cancer. Both bivariable and stepwise linear regression analyses were performed.

RESULTS

The most consistent biopsychosocial risk factors were symptoms related to altered central somatosensory functioning (central sensitization inventory), psychological symptoms, and social support (psychological symptoms and support subscale of McGill Quality of Life Questionnaire). Results also showed that a pre- and postoperative disturbed functioning of the somatosensory nervous system in the surgical area could provide additional information regarding pain intensity or pain-related disability in the long term after surgery for breast cancer.

CONCLUSION

This study revealed several biopsychosocial characteristics that might be used to identify women more vulnerable to have pain and pain-related disability in the long term after surgery for breast cancer, allowing for more effective pain management and prevention.

The Definition, Assessment, and Prevalence of (Human Assumed) Central Sensitisation in Patients with Chronic Low Back Pain: A Systematic Review

Central sensitisation is assumed to be one of the underlying mechanisms for chronic low back pain. Because central sensitisation is not directly assessable in humans, the term 'human assumed central sensitisation' (HACS) is suggested. The objectives were to investigate what definitions for HACS have been used, to evaluate the methods to assess HACS, to assess the validity of those methods, and to estimate the prevalence of HACS. Database search resulted in 34 included studies. Forty different definition references were used to define HACS. This review uncovered twenty quantitative methods to assess HACS, including four questionnaires and sixteen quantitative sensory testing measures. The prevalence of HACS in patients with chronic low back pain was estimated in three studies. The current systematic review highlights that multiple definitions, assessment methods, and prevalence estimates are stated in the literature regarding HACS in patients with chronic low back pain. Most of the assessment methods of HACS are not validated but have been tested for reliability and repeatability. Given the lack of a gold standard to assess HACS, an initial grading system is proposed to standardize clinical and research assessments of HACS in patients with a chronic low back.

Validation of the Turkish version of the Pain Sensitivity Questionnaire in patients with chronic pain

Objective

The Pain Sensitivity Questionnaire (PSQ) is a clinically beneficial instrument that has been proven to be correlated with various experimental pain sensitivity assessments in healthy people and in patients with chronic pain. In this study, we aimed to translate the PSQ into Turkish (PSQ-T) and validate it for the measurement of pain sensitivity among Turkish people.

Methods

Seventy-three patients with chronic back pain who were planning to undergo an interventional procedure completed the Brief Pain Inventory-Short Form (BPI-SF), Beck Depression Inventory (BDI), Beck Anxiety Inventory, Pain Catastrophizing Scale, and PSQ prior to their procedure. Subcutaneous infiltration of lidocaine was used as a standardized experimental pain stimulus. Pain was evaluated using a visual analog scale (VAS 1: infiltration in the hand, and VAS 2: infiltration in the procedure area)

Results

Scores on the PSQ-T were significantly correlated with those on the BPI-SF. A significant positive relationship was observed between VAS 1 and VAS 2 values and the PSQ-T score, BPI pain score, and BPI interference score.

Conclusions

The PSQ-T can be used as a valid and reliable tool for the assessment of pain sensitivity in the Turkish population.

Can Central Sensitization after injury persist as an autonomous pain generator? - A comprehensive search for evidence

OBJECTIVE

To conduct a comprehensive search for evidence whether Central Sensitization following an injury can act as a persistent autonomous pain generator after the inducing injury has healed.

METHODS

We searched Medline on PubMed and the Cochrane Library, screening 3,572 abstracts, from which 937 full text articles were obtained, with 186 of these discarded as irrelevant to the question being posed. The remaining 751 articles were studied for evidence.

RESULTS

Fourteen publications were judged to provide weak evidence for the hypothesis of central sensitization as a persisting autonomous pain generator, but none addressed the question directly. No strong evidence for the affirmative answer was found.Sixty-two publications were judged to provide weak evidence for a negative answer, and nine judged to provide strong evidence.Unexpectedly, serious weaknesses were discovered in the literature underpinning the validity of the clinical diagnosis of Central Sensitization in man:(i)  Inappropriate extrapolation, in many publications, of laboratory animal data to humans.(ii) Failure to demonstrate the absence of peripheral pain generators which might be perpetuating Central Sensitization.(iii) Many factors now shown to confound what is being measured by quantitative sensory testing, conditioned pain modulation, and Central Sensitization Inventory.

CONCLUSIONS

We found no evidence proving that central sensitization can persist as an autonomous pain generator after the initiating injury has healed.Our review has also shown that the evidential basis for the diagnosis of CS in individual patients is seriously in question.

Central sensitization in burning mouth syndrome: a practical approach using questionnaires

OBJECTIVES

Some experts have suggested that burning mouth syndrome (BMS) should be included in the family of central sensitivity syndromes, a group of similar medical disorders linked by the central sensitization (CS) mechanism. Our objective is to assess the presence of CS in patients with BMS by performing a clinical examination and administering questionnaires to measure the generalized extent of pain, the presence of associated symptoms, and the number of other concurrent chronic pain conditions.

STUDY DESIGN

We conducted a case-control study in 82 subjects (40 patients with BMS and 42 controls). Patients with BMS were diagnosed using The International Classification of Headache Disorders 3rd edition, beta version (ICHD-IIIβ) criteria. The Widespread Pain Index (WPI) and Symptom Severity (SS) Score questionnaires were used to determine the degree of central sensitivity. The number of other concurrent chronic pain conditions was determined with the Neblett inventory.

RESULTS

Data indicative of CS show a statistically significant association with BMS. Both SS Score and Widespread Pain Index scores higher in patients with BMS. Additionally, patients with BMS reported a significantly higher number of other central sensitivity syndromes.

CONCLUSIONS

Patients with BMS could present a CS component as well as other chronic pain conditions. The use of questionnaires may be useful to determine the degree of central sensitivity in patients with BMS.

Tests for central sensitization in general practice: a Delphi study

INTRODUCTION

Central sensitization (CS) may explain the persistence of symptoms in patients with chronic pain and persistent physical symptoms (PPS). There is a need for assessing CS in the consultation room. In a recently published systematic review, we made an inventory of tests for CS. In this study we aimed to assess which tests might have added value, might be feasible and thus be suitable for use in general practice.

METHODS

We conducted a Delphi study consisting of two e-mail rounds to reach consensus among experts in chronic pain and PPS. We invited 40 national and international experts on chronic pain and PPS, 27 agreed to participate. We selected 12 tests from our systematic review and additional searches; panellists added three more tests in the first round. We asked the panellists, both clinicians and researchers, to rate these 15 tests on technical feasibility for use in general practice, added value and to provide an overall judgement for suitability in general practice.

RESULTS

In two rounds the panellists reached consensus on 14 of the 15 tests: three were included, eleven excluded. Included were the Central Sensitization Inventory (CSI), pressure pain thresholds (PPTs) and monofilaments. No consensus was reached on the Sensory Hypersensitivity Scale.

CONCLUSION

In a Delphi study among an international panel of experts, three tests for measuring CS were considered to be suitable for use in general practice: the Central Sensitization Inventory (CSI), pressure pain thresholds (PPTs) and monofilaments.

Psychological factors and trajectories of post-surgical pain: A longitudinal prospective study

A significant proportion of patients do not experience relief from pain during the early postsurgical period after joint arthroplasty and are at risk for developing chronic pain. The objectives of this study were to identify biopsychosocial factors associated with acute postsurgical pain trajectories and with pain intensity and interference after 1, 3, and 12 months. Two hundred ten patients listed for joint arthroplasty filled a presurgical battery of questionnaires assessing presurgical pain intensity, catastrophizing, emotional distress, state anxiety and depression, self-efficacy, central sensitization, and executive functions. From the day after surgery, they were asked to fill a 7-day diary, including questions about postsurgical pain and postsurgical state catastrophizing. Finally, they provided data about pain intensity and interference after 1, 3, and 12 months. Predictors of acute pain trajectories were investigated using multilevel growth curve analysis. Results showed that central sensitization was a predictor of the intercept of pain trajectories and daily postsurgical catastrophizing was a significant covariate of pain intensity in the acute phase. Analyses of follow-up data showed that central sensitization was a predictor of pain intensity and pain interference at 3 and 12 months, that emotional distress was related with pain intensity and interference at 1 month, and with pain interference at 3 months, and that cognitive flexibility was associated with pain interference at 1 month. Assessment of these factors could enable to identify patients at risk for worse outcomes and to plan targeted treatments to be implemented during the patient's inward stay.

Assessment of Central Sensitization in Breast Cancer Survivors: Convergent Validity and Use of the Central Sensitization Inventory (CSI) and Its Short-Form as a Clustering Tool

The Central Sensitization Inventory (CSI) measurement properties in patients having nonspecific, noncancer pain are well-established. However, studies examining the reliability and validity of either the CSI or the Central Sensitization Inventory short-form version (CSI-9) in breast cancer survivors (BCS) are scarce. The purpose was to evaluate convergent validity and internal consistency of the CSI and CSI-9. Additionally, the relevance of a new cluster calculator using the CSI was explored. The cross-sectional multi-center study included 65 BCS and 37 healthy volunteers. Patients filled out multiple questionnaires assessing pain, number of painful areas, anxiety, depression and quality of life. The relevance of a cluster calculator was explored by known-group comparisons and boxplot description. All hypotheses were formulated before data analysis. The majority of hypotheses on the correlations between the CSI or CSI-9 and other health outcomes were confirmed (22 out of 27). The CSI and CSI-9 have excellent (α = 0.92) and good (α = 0.86) internal consistency, respectively. The CSI cluster calculator might be an interesting tool to use to have a patient's overall condition snapshot. Generally, the study findings support the construct validity and internal consistency of the CSI, which underline the use of this self-reported instrument in BCS. The CSI-9 shows promising results, but should be further evaluated.

High Rate of Pain Sensitization in Musculoskeletal Shoulder Diseases: A Systematic Review and Meta-analysis

BACKGROUND

Pain sensitization, defined as an increased responsiveness of nociceptive neurons to normal input, is detected in several musculoskeletal diseases, but there are no systematic reviews or meta-analyses about pain sensitization in shoulder pain.

OBJECTIVES

The aim of the study was to document pain sensitization rate and its impact in patients with shoulder pain.

MATERIALS AND METHODS

PubMed, Cochrane Library, and Web of Science were searched on January 8, 2020. Level I-IV studies, evaluating pain sensitization in musculoskeletal shoulder disorders through validated methods (questionnaires/algometry) were included. The primary outcome was pain sensitization rate. Secondary outcomes were the pain sensitivity level measured as pressure pain threshold, temporal summation, conditioned pain modulation, and suprathreshold heat pain response. Associated demographic and psychosocial factors were evaluated.

RESULTS

The rate of abnormal pressure pain threshold in patients with shoulder pain varied from 29% to 77%. Questionnaires detected pain sensitization in 11% to 24% of patients. This meta-analysis showed no difference in pressure pain threshold and central pain modulation but documented a significant difference in terms of suprathreshold heat pain response, indicating a hypersensitivity state in patients with shoulder pain versus asymptomatic controls. The only factor that was constantly found to correlate with higher sensitivity was a lower postoperative outcome.

DISCUSSION

Pain sensitization has a high rate among patients with musculoskeletal shoulder pain, regardless of the specific etiology, and this may lead to worse clinical outcome after treatment of the primary disease. The best way to assess pain sensitization still needs to be identified as the assessment methods results in used high variability in the documented pain sensitization rate.