An increased response to experimental muscle pain is related to psychological status in women with chronic non-traumatic neck-shoulder pain

Tonic cuff pressure pain sensitivity in chronic pain patients and its relation to self-reported physical activity

OBJECTIVES

Physical inactivity is a global health concern and a significant problem among chronic pain patients. They often experience pain flare-ups when they try to increase their physical activity level. Most research on the relationship between pain sensitivity and physical activity has been on healthy participants. Data on chronic pain patients are lacking. Using cuff pressure algometry, this study investigated tonic cuff pressure pain sensitivity and its associations to self-reported physical activity and other patient-reported outcomes in chronic pain patients.

METHODS

Chronic pain patients (n=78) were compared to healthy controls (n=98). Multivariate data analysis was used to investigate the associations between tonic cuff pressure pain sensitivity, physical activity, and other patient-reported outcome measures.

RESULTS

The three most important variables for group discrimination were perceived health status (EQVAS: p(corr)=-0.85, i.e., lower in patients), depression (HADS-D: p(corr)=0.81, i.e., higher in patients), and the tonic cuff pressure pain sensitivity variable maximum pain intensity (VAS-peak-arm: p(corr)=0.75, i.e., higher in patients). In patients, the most important predictors for high VAS-peak-arm were female sex (p(corr)=-0.75), higher number of painful regions (p(corr)=0.72), higher pain intensity (p(corr)=0.55), followed by lower level of self-reported physical activity (p(corr)=-0.39). VAS-peak-arm in patients correlated negatively with self-reported physical activity (rho=-0.28, p=0.018).

CONCLUSIONS

Physical activity may be the most important patient-changeable variable correlating to pain sensitivity. This study highlights the importance of more research to further understand how increased physical activity may decrease pain sensitivity in chronic pain patients.

Neck and shoulder pain and inflammatory biomarkers in plasma among forklift truck operators - A case-control study

OBJECTIVES

The aim of this study was to investigate a panel of inflammatory biomarkers in plasma from forklift truck operators (FLTOs) and healthy controls, and their relation to neck pain characteristics.

METHODS

From employees in a warehouse, 26 FLTOs were recruited and 24 healthy age- and sex-matched controls (CONs) were recruited via advertisement. The inclusion criterion for FLTOs was that they should operate reach decker and/or counterbalanced tilting mast forklift trucks. All participants were asked to answer a questionnaire covering demographic data, pain intensity numeric rating scale (NRS), anatomical spread, psychological distress, and health aspects. Pain sensitivity was measured using a pressure algometer. Blood samples were collected and analyzed for inflammatory proteins in plasma using a panel of 71 cytokines and chemokines. Multivariate data analysis including orthogonal partial least square-discriminant analysis (OPLS-DA) was performed to identify significant biomarkers.

RESULTS

Thirty percent of FLTOs reported NRS > 3 in the neck. Shoulder pain was common in 26% of the FLTOs. Pain and discomfort that most often prevented completion of activities were in the neck (20%), lower back (32%), and hips (27%). The FLTOs reported significantly (p = 0.04) higher levels of anxiety than the CON group and they had significantly lower pressure pain thresholds in the trapezius muscle on both right (p < 0.001) and left sides (p = 0.003). A significant OPLS-DA model could discriminate FLTOs from CON based on nine inflammatory proteins where the expression levels of four proteins were upregulated and five proteins were downregulated in FLTOs compared to CONs. Twenty-nine proteins correlated multivariately with pain intensity.

CONCLUSIONS

The profile of self-reported health, pain intensity, sensitivity, and plasma biomarkers can discriminate FLTOs with pain from healthy subjects. A combination of both self-reported and objective biomarker measurements can be useful for better understanding the pathophysiological mechanisms underlying work-related neck and shoulder pain.

Pain catastrophizing in the elderly: An experimental pain study

OBJECTIVES

Pain catastrophizing in the aging population has not been studied in great detail. Existing investigations have reported conflicting results on the effects of age on pain catastrophizing in relation to pain responses. This study investigated the relationship between pain catastrophizing, and its individual components (rumination, magnification, and helplessness), and the responses to standardized experimental pain stimuli in old and young, healthy adults.

METHODS

Sixty-six volunteers (32 old: 65-87, 18 females; 34 young: 20-35, 17 females) participated in the study. Pain catastrophizing including the components of rumination, magnification, and helplessness was assessed with the pain catastrophizing scale (PCS). Experimental pain was induced by applying predefined pressure stimulations to the trapezius muscle. Pain intensity and unpleasantness were assessed using numerical rating scales. Pain catastrophizing levels and pain responses were statistically compared between the two age groups.

RESULTS

Elderly individuals reported significantly (p = 0.028) lower scores of pain catastrophizing (Med = 5; interquartile range [IQR] = 14) than younger individuals; this difference was driven by the significantly lower components of rumination (Med = 2; IQR = 4; p = 0.017) and helplessness (Med = 2; IQR = 7; p = 0.049). A larger proportion of young (57.8%) rated pain catastrophizing at high levels, with scores above the 75th percentile (Med = 20). Additionally, elderly reported the lowest pain intensity (Med = 5; p = 0.034) and pain unpleasantness (Med = 4.5; p = 0.011) responses to the experimental pressure stimuli. In the elderly group, pain unpleasantness was positively and significantly associated with pain catastrophizing (r s = 0.416, p = 0.021), rumination (r s = 0.42, p = 0.019), and helplessness (r s = 0.434, p = 0.015), respectively. No associations were found in the young group.

CONCLUSIONS

Elderly reported lower PCSs than young adults. Rumination and helplessness were reduced in the elderly group. The elderly population showed positive correlations between catastrophizing levels and pain unpleasantness to standardized pressure pain stimuli. Results supported the view that elderly possess resilience over specific domains of pain catastrophizing that could counteract pain perception due to physiological decline.

Effects of sleep quality on pain, cognitive factors, central sensitization, and quality of life in patients with chronic low back pain

BACKGROUND

Sleep quality in patients with chronic low back pain (CLBP) may affect quality of life (QoL), possibly due to worsening pain, central sensitization (CS), and cognitive factors. However, causal relationship among the factors has not been confirmed yet.

OBJECTIVE

The purpose of this study was to test the hypothesis that sleep quality in patients with CLBP is attributable to pain, cognitive factors, and CS, and influences QoL, by structural covariance analysis.

METHODS

This is a cross-sectional study. Participants were recruited from six health care facilities and 101 patients with CLBP were included. Structural covariance analysis assessed the fit of data to the model using goodness of fit index (GFI), adjusted goodness of fit index (AGFI), comparative fit index (CFI), and mean squared approximation error (RMSEA).

RESULTS

The structural covariance analysis showed that the goodness-of-fit indices were high (GFI = 0.993, AGFI = 0.964, CFI = 1.00, RMSEA < 0.01). Sleep quality was not directly influenced by QoL but rather by CS and cognitive factors.

CONCLUSION

This study suggests that sleep quality in patients with CLBP is indirectly mediated through multiple pathways, including cognitive factors and CS, which may influence QoL.

Pressure Pain Thresholds and Central Sensitization in Relation to Psychosocial Predictors of Chronicity in Low Back Pain

(1) Background: Peripheral, as well as central, sensitization have been described in chronic low back pain (cLBP). The purpose of this study is to investigate the influence of psychosocial factors on the development of central sensitization. (2) Methods: This prospective study investigated local and peripheral pressure pain thresholds and their dependence on psychosocial risk factors in patients with cLBP receiving inpatient multimodal pain therapy. Psychosocial factors were assessed using the Örebro Musculoskeletal Pain Screening Questionnaire (ÖMPSQ). (3) Results: A total of 90 patients were included in the study, 61 (75.4% women, 24.6% men) of whom had significant psychosocial risk factors. The control group consisted of 29 patients (62.1% women, 37.9% men). At baseline, patients with psychosocial risk factors showed significantly lower local and peripheral pressure pain thresholds, suggesting central sensitization, compared to the control group. Sleep quality, measured by the Pittsburgh Sleep Quality Index (PSQI), was also correlated with altered PPTs. After multimodal therapy, all participants reported increased local pain thresholds compared to at admission, independent of psychosocial chronification factors. (4) Conclusions: Psychosocial chronicity factors measured using the ÖMPSQ have a significant influence on pain sensitization in cLBP. A 14-day multimodal pain therapy increased local, but not peripheral, pressure pain thresholds.

Combined effects of lifestyle and psychosocial factors on central sensitization in patients with chronic low back pain: A cross-sectional study

BACKGROUND

Central sensitization is one cause of chronic low back pain. Lifestyle and psychosocial factors are involved in the exacerbation of central sensitization. However, the combined effects of these factors on central sensitization in patients with chronic low back pain are unclear. The objective of this study was to investigate the combined effects of lifestyle and psychosocial factors on central sensitization in patients with chronic low back pain.

METHODS

This was a cross-sectional study. The participants were recruited from three orthopedic clinics for a total of 70 patients with chronic low back pain. Data were analyzed using hierarchical multiple regression analysis. In Model 1, lifestyle factors such as sleep quality, physical activity, sitting time, and perceived stress were included. Model 2 included psychosocial factors (pain catastrophizing, anxiety, and depression).

RESULTS

The data showed that sleep (b = 0.30) and perceived stress (b = 0.47) were significantly correlated in Model 1, and anxiety (b = 0.41) and perceived stress (b = 0.27) were significantly correlated in Model 2. Furthermore, contributions from sleep (b = 0.14) decreased, and no significant correlations were observed. The coefficient of determination increased significantly from Model 1 to Model 2 (ΔR ² = 0.12, p < 0.05).

CONCLUSIONS

In this study, we clarified that perceived stress and anxiety were correlated with central sensitization in patients with chronic low back pain. In addition, sleep quality mediates anxiety and may be associated with central sensitization.

In the Shoulder or in the Brain? Behavioral, Psychosocial and Cognitive Characteristics of Unilateral Chronic Shoulder Pain with Symptoms of Central Sensitization

The recognition of central sensitization (CS) is crucial, as it determines the results of rehabilitation. The aim of this study was to examine associations between CS and catastrophizing, functionality, disability, illness perceptions, kinesiophobia, anxiety, and depression in people with chronic shoulder pain (SP). In this cross-sectional study, 64 patients with unilateral chronic SP completed a few questionnaires including the Central Sensitization Inventory, the Oxford Shoulder Score, the Tampa Scale for Kinesiophobia, the Hospital Anxiety and Depression Scale, the Pain Catastrophizing Scale, the Brief Illness Perception Questionnaire and the “arm endurance” test. On the basis of three constructed linear regression models, it was found that pain catastrophizing and depression (model 1: p < 0.001, R = 0.57, R2 = 0.33), functionality (model 2: p < 0.001, R = 0.50, R2 = 0.25), and helplessness (model 3: p < 0.001, R = 0.53, R2 = 0.28) were significant predictors for CS symptoms in chronic SP. Two additional logistic regression models also showed that depression (model 4: p < 0.001, Nagelkerke R2 = 0.43, overall correct prediction 87.5%) and functionality (model 5: p < 0.001, Nagelkerke R2 = 0.26, overall correct prediction 84.4%) can significantly predict the classification of chronic SP as centrally sensitized. Patients who were classified as centrally sensitized (n = 10) were found to have significantly worse functionality, psychological factors (anxiety, depression, kinesiophobia, catastrophizing), and pain intensity (p < 0.05). Catastrophizing, depression, and functionality are predictive factors of CS symptoms in patients with chronic shoulder pain. Health care providers should adopt a precision medicine approach during assessment and a holistic rehabilitation of patients with unilateral chronic SP.

Influencing factors of pressure pain hypersensitivity of the upper trapezius in food service workers with nonspecific neck/shoulder myofascial pain: A cross-sectional study

It is unclear which factors contribute to the developing pressure pain hypersensitivity of the upper trapezius, a type of neurophysiological hyperexcitability. The present study investigated the relationship between physical and psychological factors and pressure pain hypersensitivity of the upper trapezius for each sex. In total, 154 individuals with neck/shoulder myofascial pain participated, among 372 food service workers. Participants completed a questionnaire (Beck Depression Inventory, and Borg Rating of Perceived Exertion scale) and were photographed to measure posture. Pressure pain sensitivity, 2 range of motions (cervical lateral bending and rotation), and 4 muscle strengths (serratus anterior, lower trapezius [LT], biceps, and glenohumeral external rotator) were measured by a pressure algometer, iPhone application, and handheld dynamometer, respectively. For each sex, forward multivariate logistic regression was used to test our a priori hypothesis among selected variables that a combination of psychosocial and physical factors contributed to the risk for pressure pain hypersensitivity. In multivariate analyses, LT strength (odds ratio = 0.94, 95% confidence interval = 0.91-0.97, P = .001) was the only significant influencing factor for pressure pain hypersensitivity in men. Dominant painful ipsilateral cervical rotation range of motion (odds ratio = 0.96, 95% confidence interval = 0.92-0.99, P = .037) was the only influencing factor for pressure pain hypersensitivity in women. LT strength and dominant painful ipsilateral cervical rotation range of motion could serve as guidelines for preventing and managing pressure pain hypersensitivity of the upper trapezius in food service workers with nonspecific neck/shoulder myofascial pain.

Age-Limited Effects of Low-Frequency Transcutaneous Electric Nerve Stimulation on Insomnia: A 4-Week Multi-Center, Randomized Controlled Study

OBJECTIVE

Insomnia disorder is a common condition with considerable harmful effects on health. We investigated the therapeutic efficacy and safety of low-frequency transcutaneous electric nerve stimulation (LF-TENS) as an alternative treatment option for insomnia disorder.

METHODS

A 4-week, multi-center, randomized controlled study was conducted. A total of 160 individuals aged 40 to 80 years with insomnia disorder were included and randomized to the experimental group receiving active device (n=81) or control group receiving sham device (n=79). Both groups used the device for four weeks, more than five days a week. The participants also completed pre- and post-intervention assessment with questionnaires, sleep diaries, wrist actigraphy, and blood tests.

RESULTS

There was no significant between-group difference in the changes of mood and sleep parameters and blood test results among the two study groups. Meanwhile, in the exploratory sub-group analysis of patients aged over 60 years, the experimental group showed better improvement after intervention in the change of Pittsburgh Sleep Quality Index (PSQI) score (-2.63±3.25 vs. -1.20±2.28, p=0.039; Cohen's d=0.99 vs. 0.45) and blood cortisol level (-1.65±3.37 μg/dL vs. -0.16±3.49 μg/dL, p=0.007; Cohen's d=0.56 vs. 0.05). In addition, no serious adverse reaction occurred during the study period in both groups.

CONCLUSION

The effect of LF-TENS was limited to older patients aged over 60 years, which might be related to the modulation of hypothalamic-pituitary-adrenal axis activity.

Bedside clinical tests to assess sensitization in office workers with chronic neck pain

OBJECTIVE

This study aimed to assess pain sensitization in individual office workers with chronic neck pain through simple bedside quantitative sensory tests (QST) and to associate the findings with pain intensity and pain catastrophizing.

METHODS

One hundred-and-four office workers with chronic neck pain were assessed using pressure pain threshold (PPT) considering pain sensitive if PPTs were lower than 155 kPa in the upper trapezius and 245 kPa in the tibialis anterior. Pain sensitive to temporal summation of pain (TSP) was considered if there was a difference of two points in the visual analogue scale (VAS) comparing the first and last stimulus. Pain sensitive was considered to conditioned pain modulation (CPM) if the CPM-effect was less than -7.5%. Pain intensity and catastrophizing were measured using VAS and with the Pain Catastrophizing Scale.

RESULTS

There was at least one pain sensitive QST finding in 66 office workers (63.5%). TSP findings were the most common (48.1%), followed by PPT's (31.7%) and CPM (20.2%). Based on the QST findings, office workers were divided based on the number of individual QST findings, and higher pain intensity and pain catastrophizing scores were found in office workers with one (N = 38, P < 0.05) or two (N = 28, P < 0.05) compared with office workers with no QST findings (N = 38).

CONCLUSION

This study demonstrated that most office workers with chronic neck pain exhibit either widespread pressure hyperalgesia, facilitated TSP or impaired CPM, indicating pain sensitization within the central nervous system. This was associated with increased clinical pain and pain catastrophizing rumination scores.

Sensitization in office workers with chronic neck pain in different pain conditions and intensities

OBJECTIVES

Office workers with chronic neck pain demonstrates signs of widespread hyperalgesia, less efficient descending pain modulation, which could indicate sensitization of central pain pathways. No studies have assessed a wide variety of office workers with different chronic neck pain disorders and assessed the impact of pain intensity on assessments of central pain pathways. This study aimed to assessed pressure pain thresholds (PPTs), temporal summation of pain (TSP) and conditioned pain modulation (CPM) and to associate these with pain intensity and disability in subgroups of office workers.

METHODS

One hundred-and-seventy-one office workers were distributed into groups of asymptomatic and chronic neck pain subjects. Chronic neck pain was categorized as chronic trapezius myalgia and chronic non-specific neck pain and as 'mild-pain' (Visual Analog Scale [VAS]≤3) and 'moderate-pain' (VAS>3) groups. PPTs, TSP, CPM, and Copenhagen Psychosocial Questionnaire II were assessed in all subjects. Neck Disability Index and Pain Catastrophizing Scale were assessed in all the symptomatic office workers.

RESULTS

PPTs were lower in moderate pain (n=49) and chronic trapezius myalgia (n=56) compared with asymptomatic subjects (n=62, p<0.05). TSP was facilitated in moderate pain group compared with mild pain (n=60, p<0.0001) group and asymptomatic subjects (p<0.0001). No differences were found in CPM comparing the different groups (p<0.05). Multiple regression analysis identified Neck Disability Index and TSP as independent factors for prediction of pain intensity in chronic trapezius myalgia (R²=0.319) and chronic non-specific neck pain (R²=0.208). Somatic stress, stress and sleep as independent factors in chronic non-specific neck pain (R²=0.525), and stress in moderate pain group (R²=0.494) for the prediction of disability.

CONCLUSIONS

Office workers with chronic trapezius myalgia and moderate pain intensity showed significant signs of widespread pressure hyperalgesia. Moreover, the moderate pain group demonstrated facilitated TSP indicating sensitization of central pain pathways. Neck Disability Index and TSP were independent predictors for pain intensity in pain groups. Sleep and stress were independent predictors for disability.

Vulvodynia-It Is Time to Accept a New Understanding from a Neurobiological Perspective

Vulvodynia is one the most common causes of pain during sexual intercourse in premenopausal women. The burden of vulvodynia in a woman's life can be devastating due to its consequences in the couple's sexuality and intimacy, in activities of daily living, and psychological well-being. In recent decades, there has been considerable progress in the understanding of vulvar pain. The most significant change has been the differentiation of vulvar pain secondary to pathology or disease from vulvodynia. However, although it is currently proposed that vulvodynia should be considered as a primary chronic pain condition and, therefore, without an obvious identifiable cause, it is still believed that different inflammatory, genetic, hormonal, muscular factors, etc. may be involved in its development. Advances in pain neuroscience and the central sensitization paradigm have led to a new approach to vulvodynia from a neurobiological perspective. It is proposed that vulvodynia should be understood as complex pain without relevant nociception. Different clinical identifiers of vulvodynia are presented from a neurobiological and psychosocial perspective. In this case, strategies to modulate altered central pain processing is necessary, changing the patient's erroneous cognitions about their pain, and also reducing fear avoidance-behaviors and the disability of the patient.

Association between central sensitivity syndrome and psychological factors in people with presurgical low back pain: A cross-sectional study

BACKGROUND

Low back pain (LBP) is a major problem; it causes significant burden, incurs considerable economic and human costs, and adversely affects the quality of life (QoL). Central sensitivity syndrome (CSS) is known as a group of overlapping conditions that share a common pathophysiological mechanism of central sensitization. Previous studies have shown that CSS is present in several disorders. However, it has been studied for people with presurgical LBP. The purpose of the study was to investigate the proportion of patients with CSS for presurgical LBP and to analyse the association of CSS with clinical symptoms and psychological factors.

METHODS

Data of demographics, the central sensitization inventory (CSI), psychological measures, clinical symptoms of 238 patients with presurgical LBP were evaluated. The patients were divided into two groups depending on the CSI scores (≥40 and < 40). The two groups were compared, and the correlation between the CSI scores and other outcomes was analysed. Furthermore, multiple regression analysis was performed to identify factors contributing to the CSI scores.

RESULTS

13.0% of participants were CSS. All outcomes were significantly different between the groups and significant associations were found between the CSI scores and all other outcomes. In addition, Pain Catastrophizing Scale (PCS) was most significant associated scale for the CSI scores.

CONCLUSION

We found that certain patients had CSS with presurgical LBP. The CSI scores were significantly associated with the majority of the factors. The PCS was the factor with the most influence on the CSI scores.

Enhanced Pronociceptive and Disrupted Antinociceptive Mechanisms in Nonspecific Chronic Neck Pain

OBJECTIVE

Evidence suggests altered pronociceptive and antinociceptive mechanisms in many chronic pain conditions. Knowledge about these mechanisms in nonspecific chronic neck pain (NSNP) would improve understanding of the causes and the design of more effective treatments. Pressure pain threshold (PPT) is often used to assess presence of altered nociceptive processing in NSNP; however, its usefulness to detect this is yet to be established. The purpose of this study was to determine the functional status of temporal summation of second pain (TSSP) and conditioned pain modulation (CPM) in NSNP and to characterize the association of both measures with PPT and clinical features of NSNP.

METHODS

Thirty-two participants with NSNP (mean [SD] age = 44 [11] years; 27 female) and 32 age- and sex-matched healthy controls were recruited. TSSP was assessed using an electrical stimulus at the dorsum of the hand, and CPM was evaluated with the Cold Pressor Test. PPT was assessed bilaterally at the neck and tibialis anterior muscles.

RESULTS

Participants with NSNP showed greater TSPP (mean difference = 0.23; 95% CI = 0.46-0.01; Cohen d = 0.51) and lower CPM (mean difference = 19.44; 95% CI = 10.42-28.46; Cohen d = 1.09). Pooled data from all participants showed lower PPTs at the neck than the tibialis anterior. However, PPT measures did not differ between groups at either location. PPT measures were not correlated with CPM and TSP.

CONCLUSION

NSNP is associated with enhanced pronociceptive and impaired antinociceptive mechanisms, which may explain long-lasting pain and failure of some treatments to resolve symptoms. However, due to the observational nature of this study, a clear cause-effect relationship cannot be established. Normal PPT values in the clinic should not be interpreted as absence of altered nociceptive processing.

IMPACT

This study fills in some gaps in knowledge. Changes in central nociceptive processing may explain persistent and recurrent symptoms in NSNP and failure of treatments to obtain long-lasting relief. Further research is required to ascertain if TSSP and CPM assessment in the clinic may help predict physical therapy treatment outcome. Whether symptomatic relief with physical therapy is mediated by an improvement in TSSP and CPM should also be explored. PPTs were unaltered in participants with NSNP despite evidence of impairment in the central pain modulatory systems. Normal PPTs should not be interpreted as evidence of unaltered central pain-related processing.

Development of a Short Form of the Negative Pain Thoughts Questionnaire (NPTQ)

BACKGROUND

Thoughts affect pain intensity and the magnitude of activity intolerance for a given nociception. The Negative Pain Thoughts Questionnaire (NPTQ) measures common unhelpful cognitive biases regarding pain. A shorter version of the NPTQ could be used in daily practice to improve health by identifying important misconceptions.

METHODS

One hundred and thirty-seven patients seeking specialty musculoskeletal care completed questionnaires addressing demographics, negative pain thoughts, worst-case thinking, resiliency, the magnitude of self-reported activity intolerance, and pain intensity. Patients were randomly allocated to a learning cohort (110 patients, 80%) and a validation cohort (27 patients, 20%). Based on factor analysis of the learning cohort, 4 questions were selected to create the NPTQ short form (NPTQ-SF). Floor and ceiling effects of the NPTQ and NPTQ-SF were analyzed. Psychometric properties of the NPTQ-SF were tested with use of Spearman correlations with the NPTQ. The internal consistency of the NPTQ and NPTQ-SF was analyzed with use of the Cronbach α coefficient. To test external validity, we calculated Spearman correlations with pain intensity, activity intolerance, the Pain Catastrophizing Scale, and the Brief Resiliency Scale in the validation cohort.

RESULTS

The Cronbach α was 0.90 for the NPTQ and 0.85 for the NPTQ-SF. The Spearman correlation between NPTQ and NPTQ-SF scores was 0.91 in the learning cohort and 0.93 in the validation cohort. In the validation cohort, there was no difference in the strength of the correlations of the NPTQ and NPTQ-SF with other questionnaires.

CONCLUSIONS

These findings support the use of a brief, 4-question measure of unhelpful cognitive biases regarding pain in both research and patient care. The NPTQ-SF would benefit from external validation in an independent cohort.

CLINICAL RELEVANCE

The notable influence of common misconceptions (i.e., cognitive bias) on musculoskeletal symptoms can be measured with a brief questionnaire and used as a point of discussion with patients.

The Dynamic Computer Workstation-A Pilot Study of Clinical and Biochemical Investigation during Work at Static Respectively Mobile Keyboards

A large and increasing number of the work force in the population spend their work hours at the keyboard. There is evidence that repetitive high levels of static work, or extreme working postures involving the neck-shoulder muscles are an increased risk for chronic neck-shoulder pain. The aim of this study was to investigate the effect of dynamic computer working (DCW), using a mobile application to the desk surface, on pain characteristics and biomarkers in office workers. We included 10 female subjects. All subjects answered questionnaires about general health, pain intensity and characteristics. The pressure pain threshold (PPT), neck range and motion, neck and shoulder strength were measured. Microdialysis was conducted in trapezius muscle. Measurements were performed before and 4 weeks after DCW. Multivariate analysis, orthogonal partial least square discriminate analysis (OPLS-DA) and univariate analysis paired test, Wilcoxon, was performed. There was significant improvement in reported neck pain, quality of life, and psychological distress after 4 weeks DCW. The PPT and strength in neck and shoulder were significantly increased after DCW. A significant OPLS-DA model showed clear separation between the samples collected before and after 4 weeks DCW. In conclusion, these results show that keyboard work at a movable desk application might decrease the risk of repetitive strain injuries in the neck and shoulder muscles.

Effects of Central Sensitivity Syndrome and Psychological Factors on the Clinical Features of Patients with Cervical Degenerative Disease: A Cross-Sectional Study

Study Design

Single-center cross-sectional study.

Purpose

The present study aimed to clarify the effects of central sensitivity syndrome (CSS) and psychological factors on the clinical features in patients with cervical degenerative disease (CDD).

Overview of Literature

The presence of CSS and psychological factors can influence the clinical features of patients with musculoskeletal disorders including CDD. However, the precise effects of CSS are unclear.

Methods

Patients admitted for surgical treatment of CDD were recruited. The following patient-reported outcome measures were recorded on the day before the surgery: the Numerical Rating Scale (NRS) for neck pain intensity, Neck Disability Index (NDI), EuroQol 5-Dimensions (EQ-5D) survey, Central Sensitization Inventory (CSI), Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, and the Hospital Anxiety and Depression Scale were used. We performed three multiple regression analyses to investigate the effects of CSS and psychological factors on the clinical features.

Results

Multiple regression analysis revealed that CSI had a significant effect on NRS (β, 0.50; 95% confidence interval [CI], 0.29 to 0.71), NDI (β, 0.64; 95% CI, 0.45 to 0.82), and EQ-5D (β, −0.55; 95% CI, −0.75 to −0.35). Multiple regression analysis revealed that psychological factors did not exert a significant effect on the clinical features.

Conclusions

Our results demonstrated that CSI was able to identify the clinical features in CDD patients, suggesting that CSS does affect the clinical features of such patients.

Plasma protein patterns are strongly correlated with pressure pain thresholds in women with chronic widespread pain and in healthy controls-an exploratory case-control study

Chronic widespread pain (CWP) is a complex pain condition characterized by generalized musculoskeletal pain and often associated with other symptoms. An important clinical feature is widespread increased pain sensitivity such as lowered pain thresholds for mechanical stimuli (pressure pain thresholds [PPT]). There is a growing interest in investigating the activated neurobiological mechanisms in CWP, which includes fibromyalgia. In CWP, strong significant correlations have been found between muscle protein patterns and PPT. This explorative proteomic study investigates the multivariate correlation pattern between plasma proteins and PPT in CWP and in healthy controls (CON). In addition, this study analyses whether the important proteins for PPT differ between the 2 groups.Using 2-dimensional gel electrophoresis, we analyzed the plasma proteome of the CWP (n = 15) and the CON (n = 23) and proteins were identified using mass spectrometry. For both the CWP and the CON, the associations between the identified proteins and PPT were analyzed using orthogonal partial least square in 2 steps.Significant associations between certain plasma proteins and PPT existed both in CWP (R = 0.95; P = .006) and in CON (R = 0.89; P < .001). For both groups of subjects, we found several proteins involved in PPT that reflect different biological processes. The plasma proteins as well as the biological processes involved in PPT differed markedly between the 2 groups of subjects.This study suggests that plasma protein patterns are associated with pain thresholds in CWP. Using the plasma proteome profile of CWP to study potential biomarker candidates could provide a snapshot of ongoing systemic mechanisms in CWP.

Convergent and Discriminant Validity of the Serbian Version of the Central Sensitization Inventory

OBJECTIVES

The goal of the present study was to explore additional evidence of validity of the Serbian version of the Central Sensitization Inventory (CSI), a patient-reported outcome measure of symptoms that have been found to be associated with central sensitization (CS). The CSI has been found to be psychometrically sound, and has demonstrated evidence of convergent and discriminant validity in numerous published studies and in multiple languages.

METHODS

CSI data were collected from 399 patients with chronic pain who had various diagnoses and from 146 pain-free controls. In addition, the patient sample completed a battery of validated patient-reported outcome measures of sleep problems, cognitive problems, pain catastrophizing, pain-related fear-avoidance, decreased quality of life, and decreased perception of social support. Six patient subgroups were formed, with presumably different levels of CS (including those with fibromyalgia, multiple pain sites, and localized pain sites).

RESULTS

Significant differences were found in total CSI scores among the controls and patient subgroups. Those with fibromyalgia and multiple pathologies scored highest and the control subjects scored lowest. Other patient-reported CS-related symptom dimensions were significantly correlated with total CSI scores. When the patients were divided into CSI severity subgroups (from subclinical to extreme), the severity of these other symptom dimensions increased with the severity of CSI scores.

CONCLUSIONS

The current study successfully demonstrated additional evidence of the convergent and discriminant validity of the Serbian version of the CSI.

Neural Tension Technique Improves Immediate Conditioned Pain Modulation in Patients with Chronic Neck Pain: A Randomized Clinical Trial

OBJECTIVE

To determine the immediate effect of neural tension technique (NTT) on conditioned pain modulation in patients with chronic neck pain. A secondary objective was to determine the immediate effect of neural tensioner technique on pain intensity and cervical range of movement.

DESIGN

Randomized clinical trial.

SETTING

University medical center.

SUBJECTS

Fifty-four patients with neck pain (13 males and 41 females; mean± SD age = 20.91 ± 2.64 years) were randomly allocated to two groups: NTT or sham technique.

METHODS

Participants received a visual analog scale (VAS) and neck disability index (NDI) after inclusion. Conditioned pain modulation (CPM) and active cervical range of motion were measured before and after the intervention. Each subject received one treatment session.

RESULTS

The results of the analysis of variance revealed a significant effect for the group × time interaction only for CPM (F = 11.09, P = 0.002, ηp2 = 0.176). No significant interactions were found for the other measures (VAS [F = 1.719, P = 0.195, ηp2 = 0.031], pressure pain threshold C2 [F = 0.731, P = 0.398, ηp2 = 0.018], flexion [F = 0.176, P = 0.677, ηp2 = 0.003], extension [F = 0.035, P = 0.852, ηp2 = 0.001], lateral flexions [F = 0.422, P = 0.519, ηp2 = 0.008], and rotations [F = 1.307 P = 0.258, ηp2 = 0.024]). Regarding CPM, intergroup interaction differences were found postintervention (P = 0.002) with a high effect size (d = 0.98).

CONCLUSIONS

This study suggests that neural tension technique enhances immediate conditioned pain modulation in patients with chronic neck pain, but not pain intensity or cervical range of movement.

Cross-Cultural Adaptation and Psychometric Properties of the European Portuguese Version of the Central Sensitization Inventory in Adolescents With Musculoskeletal Chronic Pain

BACKGROUND

Central sensitization (CS) is an important feature in musculoskeletal chronic pain, and associated symptoms can be assessed using the Central Sensitization Inventory (CSI).

OBJECTIVES

This study aimed to translate and cross-culturally adapt the CSI to the European Portuguese language and to assess its validity and reliability in adolescents with musculoskeletal chronic pain.

METHODS

The European Portuguese version of the CSI was established following the translation and testing processes recommended by international guidelines. Then, this version of the CSI was completed by 1,730 adolescents, who also completed the Nordic Musculoskeletal Questionnaire; the Pain Catastrophizing Scale; the Depression, Anxiety and Stress Scale; the Tampa Scale of Kinesiophobia; and the Basic Scale on Insomnia Complaints and Quality of Sleep. Test-retest reliability and measurement error, internal consistency, hypothesis testing, and factor analysis were assessed for the translated version of the CSI.

RESULTS

Cronbach's alpha was 0.91, the intraclass correlation coefficient was 0.94 (95% confidence interval: 0.90, 0.96), and the standard error of measurement and smallest detectable change were 4.15 and 11.50, respectively. Fair correlations were found between CSI and fear of movement (Spearman's correlation [r_s ] = 0.46), sleep (r_s  = 0.46), and catastrophizing (r_s  = 0.49). Moderate to good correlations were found between CSI and depression (r_s  = 0.60), anxiety (r_s  = 0.59), and stress (r_s  = 0.65).

CONCLUSION

The European Portuguese version of the CSI was considered easy to understand and showed very good internal consistency, excellent test-retest reliability, and excellent construct validity in a community sample of adolescents with musculoskeletal chronic pain.

Cross-cultural Adaptation and Psychometric Properties of the Greek Version of the Central Sensitization Inventory

OBJECTIVES

Recent studies support the opinion that central sensitization (CS) plays an important role in the pathophysiology of many chronic pain conditions. CS refers to hyperexcitability of the central nervous system, which can result in pain hypersensitivity and other somatosensory symptoms. Recognition of CS-related symptomology is crucial in chronic pain evaluation and rehabilitation. The Central Sensitization Inventory (CSI) was created to evaluate symptoms that have been found to be associated with CS. The aim of the current study was the cross-cultural adaptation of the CSI into Greek (CSI-Gr).

METHODS

To evaluate discriminate validity, 200 patients with chronic pain and 50 healthy control subjects participated. The sample was divided into 4 diagnostic groups (fibromyalgia, single pain complaints, multiple pain complaints, and a control group) and into 5 CSI severity subgroups, from subclinical to extreme. Convergent validity was determined by evaluation of the relationship between the CSI-Gr and the Pain Catastrophizing Scale (PCS). Additionally, 30 patients completed the CSI a second time for the purpose of a test/retest analysis.

RESULTS

The results showed high internal consistency (Cronbach's alpha = 0.994) and test-retest reliability (intraclass correlation coefficient = 0.993). The standard error of measurement was 2.1. The CSI-Gr correlated moderately with the PCS (r = 0.68). Statistically significant differences were found among the 3 comparison groups, with patients who had fibromyalgia reporting the highest CSI severity and healthy control subjects reporting the lowest severity.

CONCLUSIONS

As determined in the present study, the CSI-Gr was found to be a reliable and valid tool for recognition of CS-related symptomology.

Local and Widespread Pressure Pain Hyperalgesia Is Not Side Specific in Females with Unilateral Neck Pain that Can Be Reproduced during Passive Neck Rotation

Current evidence for widespread hyperalgesia in non-specific neck pain (NSNP) is unclear. It is currently recommended to group NSNP patients according to pain-provoking movements. The aim of this study was to investigate local and widespread pain sensitivity in females with unilateral NSNP that is reproducible during passive neck rotation compared with matched controls, and to compare the side specific effect of pain location on pressure pain sensitivity among females with unilateral NSNP. Thirty-six females with unilateral NSNP evoked during passive ipsilateral (n = 20) or contralateral (n = 16) rotation toward the painful side were compared with 20 controls. Participants reported their pain intensity at rest and during passive neck rotation and completed the Neck Disability Index. Pressure pain thresholds (PPTs) were assessed bilaterally over the anterior scalene; the sternocleidomastoid; the levator scapulae; lateral to the spinous process of C6; the median, ulnar, and radial nerves; and the tibialis anterior. The ANOVA revealed lower PPTs in females with unilateral NSNP compared with the controls (all at p < 0.001), but no differences were found between the sides, nor was there any Group × side interaction. Among females with NSNP, those with higher pain intensity during ipsilateral rotation toward the painful side showed lower PPTs over the anterior scalene, median nerve, ulnar nerve, and tibialis anterior (all, p < 0.05) than females with higher pain intensity during contralateral rotation toward the painful side. These findings demonstrated bilateral local and widespread pressure pain hyperalgesia in females with unilateral NSNP that was reproducible during passive neck rotation compared with controls. There was no side specific effect of pain location on PPTs among females with unilateral NSNP.

Racial/ethnic differences in experimental pain sensitivity and associated factors - Cardiovascular responsiveness and psychological status

This study evaluated the contributions of psychological status and cardiovascular responsiveness to racial/ethnic differences in experimental pain sensitivity. The baseline measures of 3,159 healthy individuals-non-Hispanic white (NHW): 1,637, African-American (AA): 1,012, Asian: 299, and Hispanic: 211-from the OPPERA prospective cohort study were used. Cardiovascular responsiveness measures and psychological status were included in structural equation modeling based mediation analyses. Pain catastrophizing was a significant mediator for the associations between race/ethnicity and heat pain tolerance, heat pain ratings, heat pain aftersensations, mechanical cutaneous pain ratings and aftersensations, and mechanical cutaneous pain temporal summation for both Asians and AAs compared to NHWs. HR/MAP index showed a significant inconsistent (mitigating) mediating effect on the association between race/ethnicity (AAs vs. NHWs) and heat pain tolerance. Similarly, coping inconsistently mediated the association between race/ethnicity and mechanical cutaneous pain temporal summation in both AAs and Asians, compared to NHWs. The factor encompassing depression, anxiety, and stress was a significant mediator for the associations between race/ethnicity (Asians vs. NHWs) and heat pain aftersensations. Thus, while pain catastrophizing mediated racial/ethnic differences in many of the QST measures, the psychological and cardiovascular mediators were distinctly restrictive, signifying multiple independent mechanisms in racial/ethnic differences in pain.

The Fear-Avoidance Components Scale (FACS): Responsiveness to Functional Restoration Treatment in a Chronic Musculoskeletal Pain Disorder (CMPD) Population

OBJECTIVES

To assess the clinical validity and factor structure of the Fear-Avoidance Components Scale (FACS), a new fear-avoidance measure.

MATERIALS AND METHODS

In this study, 426 chronic musculoskeletal pain disorder patients were admitted to a Functional Restoration Program (FRP). They were categorized into 5 FACS severity levels, from subclinical to extreme, at admission, and again at discharge. Associations with objective lifting performance and other patient-reported psychosocial measures were determined at admission and discharge, and objective work outcomes for this predominantly disabled cohort, were assessed 1 year later.

RESULTS

Those patients in the severe and extreme FACS severity groups at admission were more likely to "drop out" of treatment than those in the lower severity groups (P=0.05). At both admission and discharge, the FACS severity groups were highly and inversely correlated with objective lifting performance and patient-reported fear-avoidance-related psychosocial variables, including kinesiophobia, pain intensity, depressive symptoms, perceived disability, perceived injustice, and insomnia (Ps<0.001). All variables showed improvement at FRP discharge. Patients in the extreme FACS severity group at discharge were less likely to return to, or retain, work 1 year later (P≤0.02). A factor analysis identified a 2-factor solution.

DISCUSSION

Strong associations were found among FACS scores and other patient-reported psychosocial and objective lifting performance variables at both admission and discharge. High discharge-FACS scores were associated with worse work outcomes 1 year after discharge. The FACS seems to be a valid and clinically useful measure for predicting attendance, physical performance, distress, and relevant work outcomes in FRP treatment of chronic musculoskeletal pain disorder patients.

Pain Sensitivity and its Relation to Spreading on the Body, Intensity, Frequency, and Duration of Pain: A Cross-Sectional Population-based Study (SwePain)

OBJECTIVES

Individuals with chronic pain often report increased pain sensitivity compared with pain-free individuals; hence, it is crucial to determine whether and how different pain characteristics influence or interact with pain sensitivity. An alternative to experimental pain sensitivity testing is the self-reported pain sensitivity questionnaire (PSQ), which captures pain sensitivity in various body areas.This study compares PSQ in individuals with and without pain and clarifies how pain sensitivity relates to spreading of pain on the body, and to intensity, frequency, duration of pain and to age and sex.

MATERIALS AND METHODS

A total of 5905 individuals with pain and 572 individuals without pain from the general population in southeastern Sweden completed and returned a postal questionnaire.

RESULTS

The mean PSQ score was 3.9 (95% confidence interval [CI], 3.88-3.98) in individuals with pain and 3.5 (95% CI, 3.38-3.64) in pain-free individuals. Hence, PSQ was the highest among individuals with pain, with a difference of 0.4 (95% CI, 0.30-0.56). There was a considerable variation in the PSQ values (mean=3.5; SD=1.54) among pain-free individuals. Pain sensitivity was positively related to spreading, intensity, and frequency of pain, with a correlation coefficient of 0.3. PSQ was higher in widespread pain, 4.5 (95% CI, 4.27-4.69) in women and 4.3 (95% CI, 3.94-4.71) in men, than in local pain, 3.7 (95% CI, 3.61-3.91) in women and 3.8 (95% CI, 3.66-3.95) in men. The score for women with regional pain was between local and widespread pain at 4.0 (95% CI, 3.95-4.11) and that for men with regional pain was 3.8 (95% CI, 3.69-3.87), which is equal to that of local pain.

DISCUSSION

The positive association between pain sensitivity and spreading of pain on the body provides some evidence that the extent of spreading may be related to the degree of pain sensitivity. Before clinical use of PSQ, psychometric development and further research are needed.

Association Between Symptoms of Central Sensitization and Cognitive Behavioral Factors in People With Chronic Nonspecific Low Back Pain: A Cross-sectional Study

OBJECTIVE

The objective of this cross-sectional study was to analyze the relationship between symptoms of central sensitization (CS) and important cognitive behavioral and psychosocial factors in a sample of patients with chronic nonspecific low back pain.

METHODS

Participants with chronic nonspecific low back pain for at least 3 months were included in the study. They completed several questionnaires and a functional test. Pearson's correlation was used to analyze associations between symptoms of CS and pain behavior, functioning, pain, pain catastrophizing, kinesiophobia, and illness perceptions. Additionally, a between-group analysis was performed to compare patients with and without clinically relevant symptoms of CS.

RESULTS

Data from 38 participants were analyzed. Significant associations were found between symptoms of CS and all other outcomes, especially current pain (r = 0.510, P = .001), mean pain during the past 7 days (r = 0.505, P = .001), and pain catastrophizing (r = 0.518, P = .001). Patients with clinically relevant symptoms of CS scored significantly worse on all outcomes compared with persons without relevant symptoms of CS, except on functioning (P = .128).

CONCLUSIONS

Symptoms of CS were significantly associated with psychosocial and cognitive behavioral factors. Patients exhibiting a clinically relevant degree of symptoms of CS scored significantly worse on most outcomes, compared with the subgroup of the sample with fewer symptoms of CS.

Use of the Central Sensitization Inventory (CSI) as a treatment outcome measure for patients with chronic spinal pain disorder in a functional restoration program

BACKGROUND CONTEXT

The Central Sensitization Inventory (CSI) is a valid and reliable patient-reported instrument designed to identify patients whose presenting symptoms may be related to central sensitization (CS). Part A of the CSI measures a full array of 25 somatic and emotional symptoms associated with CS, and Part B asks if patients have previously been diagnosed with one or more specific central sensitivity syndromes (CSSs) and related disorders. The CSI has previously been validated in a group of patients with chronic pain who were screened by a trained psychiatrist for specific CSS diagnoses. It is currently unknown if the CSI can be a useful treatment-outcome assessment tool for patients with chronic spinal pain disorder (CSPD) who are not screened for comorbid CSSs. It is known, however, that previous studies have identified CS-related symptoms, and comorbid CSSs, in subsets of patients with CSPDs. Studies have also shown that CS-related symptoms can be influenced by cognitive and psychosocial factors, including abuse history in both childhood and adulthood, sleep disturbance, catastrophic and fear-avoidant cognitions, and symptoms of depression and anxiety.

PURPOSE

This study aimed to evaluate CSI scores, and their associations with other clinically relevant psychosocial variables, in a cohort of patients with CSPD who entered and completed a functional restoration program.

STUDY DESIGN/SETTING

A retrospective study of prospectively collected data from a cohort study of patients with CSPD, who completed the CSI at admission to, and discharge from, an interdisciplinary function restoration program (FRP) was carried out.

PATIENT SAMPLE

A cohort of 763 patients with CSPD comprised the study sample.

OUTCOME MEASURES

Clinical interviews evaluated mood disorders and abuse history. A series of self-reported measures evaluated comorbid psychosocial symptoms, including pain intensity, pain-related anxiety, depressive symptoms, somatization symptoms, perceived disability, and sleep disturbance, at FRP admission and discharge.

METHODS

Patients were grouped into five severity level groups, from mild to extreme, based on total CSI scores, at FRP admission, and then again at discharge. The FRP included a quantitatively directed and medically supervised exercise process, as well as a multimodal psychosocial disability management component.

RESULTS

The CSI severity groups were strongly associated with Major Depressive Disorder and previous abuse history (p<.01), which are known risk factors for CS-related symptoms and diagnoses. The CSI scores were also strongly associated with patient-reported CSS diagnoses on CSI Part B. The percentage of patients who reported a comorbid CSS diagnosis increased in each higher CSI-severity group, from 11% in the Subclinical group, to 56% in the Extreme group. The CSI severity groups were significantly related to other CS-related patient-reported symptoms, including pain intensity, pain-related anxiety, depressive symptoms, somatization symptoms, perceived disability, and sleep disturbance (p's<.001). The CSI scores, along with all other psychosocial measures, decreased at treatment discharge.

CONCLUSIONS

In the present study, admission CSI scores were highly associated with previous CSS diagnoses, CS-related symptoms, and clinically relevant patient-reported psychosocial variables. All psychosocial variables, as well as scores on the CSI, were significantly improved at FRP discharge. The CSI may have important clinical utility, as a screener and as a treatment outcome measure, for patients with CSPD participating in an interdisciplinary FRP.

Facilitatory and inhibitory pain mechanisms are altered in patients with carpal tunnel syndrome

Preliminary evidence from studies using quantitative sensory testing suggests the presence of central mechanisms in patients with carpal tunnel syndrome (CTS) as apparent by widespread hyperalgesia. Hallmarks of central mechanisms after nerve injuries include nociceptive facilitation and reduced endogenous pain inhibition. Methods to study nociceptive facilitation in CTS so far have been limited to quantitative sensory testing and the integrity of endogenous inhibition remains unexamined. The aim of this study was therefore to investigate changes in facilitatory and inhibitory processing in patients with CTS by studying hypersensitivity following experimentally induced pain (facilitatory mechanisms) and the efficacy of conditioned pain modulation (CPM, inhibitory mechanisms). Twenty-five patients with mild to moderate CTS and 25 age and sex matched control participants without CTS were recruited. Increased pain facilitation was evaluated via injection of hypertonic saline into the upper trapezius. Altered pain inhibition through CPM was investigated through cold water immersion of the foot as the conditioning stimulus and pressure pain threshold over the thenar and hypothenar eminence bilaterally as the test stimulus. The results demonstrated that patients with CTS showed a greater duration (p = 0.047), intensity (p = 0.044) and area (p = 0.012) of pain in response to experimentally induced pain in the upper trapezius and impaired CPM compared to the control participants (p = 0.006). Although typically considered to be driven by peripheral mechanisms, these findings indicate that CTS demonstrates characteristics of altered central processing with increased pain facilitation and reduced endogenous pain inhibition.

Pain threshold reflects psychological traits in patients with chronic pain: a cross-sectional study

Background

Chronic pain enhances sensory sensitivity and induces the biased development of psychological traits such as depression and pain catastrophizing, leading to the formation of heterogeneous conditions. Fluctuations in the sensory-related thresholds of non-injured sites (with normal peripheral tissue) in patients with chronic pain are thought to be related to central sensitization. The objectives of this study were to analyze the association between pain tolerance thresholds (PTTs) in non-injured sites and the psychological traits of patients with chronic pain and to evaluate the usefulness of PTT measures in assessments of pathological conditions related to chronic pain.

Methods

This study included 57 patients with chronic pain. The PTTs were measured in non-injured sites with quantitative sensory testing (QST) with electrical stimulation and then classified with cluster analysis. The Short-Form McGill Pain Questionnaire was used to subjectively assess pain in the injured sites. The Minnesota Multiphasic Personality Inventory (MMPI) was used to assess the patients’ psychological traits.

Results

Based on the cluster analysis of PTTs, the patients were classified into a High-Sensitivity group and an Others group consisting of the remaining patients. The results of the MMPI profiles showed that the High-Sensitivity group included significantly more patients with the Neurotic Triad pattern and no patients with the Conversion V pattern. The scores of the hypochondriasis and hysteria scales were significantly lower in the High-Sensitivity group than in the Others group.

Conclusions

This study indicated that patients with chronic pain can be classified according to PTTs in non-injured sites and suggests that patients with High-Sensitivity have characteristic psychological traits. Assessment of PTTs in non-injured sites would be useful for evaluating the psychological condition of patients with chronic pain.

Clear differences in cerebrospinal fluid proteome between women with chronic widespread pain and healthy women - a multivariate explorative cross-sectional study

Introduction

Frequent chronic local pain can develop into chronic widespread pain (CWP). The spread of pain is correlated with pain intensity, anxiety, and depression, conditions that ultimately lead to a poor quality of life. Knowledge is incomplete about CWP’s etiology, although it has been suggested that both central hyperexcitability and/or a combination with peripheral factors may be involved. Cerebrospinal fluid (CSF) could act as a mirror for the central nervous system as proteins are signal substances that activate the formation of algesics and control nociceptive processes. To this end, this study investigates the CSF protein expression in women with CWP and in female healthy controls.

Materials and methods

This study included 12 female patients with CWP diagnosed according to the American College of Rheumatology criteria with 13 healthy age- and sex-matched pain-free subjects. All subjects went through a clinical examination and answered a health questionnaire that registered sociodemographic and anthropometric data, pain characteristics, psychological status, and quality of life rating. CSF was collected by lumbar puncture from each subject. Two-dimensional gel electrophoresis in combination with mass spectrometry was used to analyze the CSF proteome. This study identifies proteins that significantly discriminate between the two groups using multivariate data analysis (MVDA) (i.e., orthogonal partial least squares discriminant analysis [OPLS-DA]).

Results

There were no clinically significant levels of psychological distress and catastrophization presented in subjects with CWP. MVDA revealed a highly significant OPLS-DA model where 48 proteins from CSF explained 91% (R²) of the variation and with a prediction of 90% (Q²). The highest discriminating proteins were metabolic, transport, stress, and inflammatory.

Conclusion

The highest discriminating proteins (11 proteins), according to the literature, are involved in apoptotic regulations, anti-inflammatory and anti-oxidative processes, the immune system, and endogenous repair. The results of this explorative study may indicate the presence of neuro-inflammation in the central nervous system of CWP patients. Future studies should be larger and control for confounders and determine which alterations are unspecific/general and which are specific changes.

Signs of ongoing inflammation in female patients with chronic widespread pain: A multivariate, explorative, cross-sectional study of blood samples

This cross-sectional study investigates the plasma inflammatory profile of chronic widespread pain (CWP) patients compared to healthy controls (CON). Rather than analyzing a relatively few substances at a time, we used a new multiplex proximity extension assay (PEA) panel that enabled the simultaneous analysis of 92 inflammation-related proteins, mainly cytokines and chemokines.Seventeen women with CWP and 21 female CON participated and a venous blood sample was drawn from all subjects. Pain intensity and pain thresholds for pressure, heat, and cold were registered. A PEA panel (92 proteins) was used to analyze the blood samples. Multivariate data analysis by projection was used in the statistical analyses.Eleven proteins significantly differentiated the CON and CWP subjects (R = 0.58, Q = 0.37, analysis of variance of cross-validated predictive residuals P = 0.006). It was not possible to significantly regress pain thresholds within each group (CON or CWP). Positive significant correlations existed between several proteins and pain intensities in CWP, but the model reliability of the regression was poor.CWP was associated with systemic low-grade inflammation. Larger studies are needed to confirm the results and to investigate which alterations are condition-specific and which are common across chronic pain conditions. The presence of inflammation could promote the spreading of pain, a hallmark sign of CWP. As it has been suggested that prevalent comorbidities to pain (e.g., depression and anxiety, poor sleep, and tiredness) also are associated with inflammation, it will be important to determine whether inflammation may be a common mediator.

Is there a relationship between psychological stress or anxiety and chronic nonspecific neck-arm pain in adults? A systematic review and meta-analysis

PURPOSE

To systematically review and analyze the research evidence linking stress or anxiety to chronic nonspecific neck-arm pain (NSNAP) in adults.

SUBJECTS AND METHODS

Data were obtained from Pubmed, Scopus, PsycInfo, Web of Science, Physiotherapy Evidence Database (PEDro) and The Cochrane library database from their inception to July 2015. Two authors independently conducted the searches, extracted data, and completed methodological quality assessments. The methodological quality of the cohort and case-control studies was evaluated using the Newcastle-Ottawa scale, whilst the quality of the Randomized Controlled Trial (RCT) was evaluated using the PEDro scale.

RESULTS

Twenty-eight studies involving 39,166 participants met the inclusion criteria. Four studies, including 5 pair-wise comparisons, were included in the meta-analysis: Three were cohort studies and 1 was a cross-sectional study. The meta-analysis outcome demonstrated a relationship between chronic NSNAP and psychological stress. The estimate odds ratio for all studies combined was 2.33 (95% CI, 1.04-5.18; p=0.039). A high heterogeneity of the findings appeared (Q=28.94, I²=86% p=0.00).

CONCLUSION

This study shows that there is a strong relationship between stress and chronic NSNAP. Despite this finding, we cannot support that stress is a risk factor for chronic NSNAP due to the low quality of the results according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). It was not possible to make a quantitative analysis comparing the relationship between anxiety and chronic NSNAP. However, according to the qualitative analysis there is a strong relationship between anxiety and chronic NSNAP.

Increased Interstitial Concentrations of Glutamate and Pyruvate in Vastus Lateralis of Women with Fibromyalgia Syndrome Are Normalized after an Exercise Intervention - A Case-Control Study

BACKGROUND

Fibromyalgia syndrome (FMS) is associated with central alterations, but controversies exist regarding the presence and role of peripheral factors. Microdialysis (MD) can be used in vivo to study muscle alterations in FMS. Furthermore for chronic pain conditions such as FMS, the mechanisms for the positive effects of exercise are unclear. This study investigates the interstitial concentrations of algesics and metabolites in the vastus lateralis muscle of 29 women with FMS and 28 healthy women before and after an exercise intervention.

METHODS

All the participants went through a clinical examination and completed a questionnaire. In addition, their pressure pain thresholds (PPTs) in their upper and lower extremities were determined. For both groups, MD was conducted in the vastus lateralis muscle before and after a 15-week exercise intervention of mainly resistance training of the lower limbs. Muscle blood flow and interstitial muscle concentrations of lactate, pyruvate, glutamate, glucose, and glycerol were determined.

RESULTS

FMS was associated with significantly increased interstitial concentrations of glutamate, pyruvate, and lactate. After the exercise intervention, the FMS group exhibited significant decreases in pain intensity and in mean interstitial concentrations of glutamate, pyruvate, and glucose. The decrease in pain intensity in FMS correlated significantly with the decreases in pyruvate and glucose. In addition, the FMS group increased their strength and endurance.

CONCLUSION

This study supports the suggestion that peripheral metabolic and algesic muscle alterations are present in FMS patients and that these alterations contribute to pain. After an exercise intervention, alterations normalized, pain intensity decreased (but not abolished), and strength and endurance improved, all findings that suggest the effects of exercise are partially peripheral.

Factors associated with increased risk for pain catastrophizing in patients with chronic neck pain: A retrospective cross-sectional study

Pain catastrophizing is becoming increasingly recognized as a clinically important psychological factor in chronic musculoskeletal pain. In this retrospective cross-sectional study, we have identified factors associated with an increased risk for pain catastrophizing in chronic neck pain (CNP) patients. We obtained data from our medical database on 331 patients who were treated for neck pain as their chief complaint at our clinic. The Pain Catastrophizing Scale (PCS) was used to define a high pain catastrophizing state (PCS score ≥21) in this study. Patient demographics, pain-related factors, and psychological factors were evaluated with logistic regression analysis to identify risk factors of high pain catastrophizing among patients with CNP. A total of 256 patients with CNP satisfied the study inclusion criteria and were included in the analyses. The median PCS score was 16 (range, 0-45), and 86 of 256 patients (33.5%) reported a PCS score ≥21. In multivariate analysis, high pain intensity, clinical insomnia, and a high level of depression/anxiety were strongly associated with high pain catastrophizing in patients with CNP. Depression was the strongest predictor of high pain catastrophizing, with an odds ratio of 7.35 (95% confidence interval 2.23-24.22). High pain catastrophizing was not significantly related to age, gender, comorbidities, or neck pain-related physical symptoms. In conclusion, poor psychological states should be addressed as an important part of pain management in CNP patients who are susceptible to high pain catastrophizing.

Reduced Maximal Force during Acute Anterior Knee Pain Is Associated with Deficits in Voluntary Muscle Activation

Although maximal voluntary contraction (MVC) force is reduced during pain, studies using interpolated twitch show no consistent reduction of voluntary muscle drive. The present study aimed to test if the reduction in MVC force during acute experimental pain could be explained by increased activation of antagonist muscles, weak voluntary activation at baseline, or changes in force direction. Twenty-two healthy volunteers performed maximal voluntary isometric knee extensions before, during, and after the effects of hypertonic (pain) and isotonic (control) saline injections into the infrapatellar fat pad. The MVC force, voluntary activation, electromyographic (EMG) activity of agonist, antagonist, and auxiliary (hip) muscles, and pain cognition and anxiety scores were recorded. MVC force was 9.3% lower during pain than baseline (p < 0.001), but there was no systematic change in voluntary activation. Reduced MVC force during pain was variable between participants (SD: 14%), and was correlated with reduced voluntary activation (r = 0.90), baseline voluntary activation (r = − 0.62), and reduced EMG amplitude of agonist and antagonist muscles (all r > 0.52), but not with changes in force direction, pain or anxiety scores. Hence, reduced MVC force during acute pain was mainly explained by deficits in maximal voluntary drive.

Effect of verbal persuasion on self-efficacy for pain-related diagnostic sensory testing in individuals with chronic neck pain and healthy controls - a randomized, controlled trial

The aim of this study was to investigate the differences in cold pain threshold (CTh), pressure pain threshold (PPT), cold pain tolerance (CPTo) tests, and the level of self-efficacy when self-efficacy for diagnostic sensory testing was manipulated by verbal persuasion before a testing situation in persons with neck pain and in healthy controls. A randomized experimental design was used. Twenty-one healthy volunteers and 22 individuals with either traumatic or nontraumatic chronic neck pain were recruited to participate in the study. The intervention consisted of two experimental verbal persuasion conditions: Increase self-efficacy and Decrease self-efficacy. The PPT was measured using a pressure algometer, the CTh was measured using a thermo test system, and CPTo was measured by submerging the participant’s hand in ice water up to the elbow joint. On three occasions, the participants reported their self-efficacy level in performing the sensory tests. In the chronic neck pain group, there were no differences in pain threshold or tolerance. There was a difference in the self-efficacy level after verbal persuasion between the experimental conditions. In the healthy control group, the CThs increased following the condition that aimed to increase self-efficacy. No other differences were observed in the healthy controls. A short verbal persuasion in the form of manipulative instructions seems to have a marginal effect on the individual’s self-efficacy levels in the chronic neck pain group and a slight influence on the results of sensory testing in healthy controls.

A Comparison of the Sensitivity of Brush Allodynia and Semmes-Weinstein Monofilament Testing in the Detection of Allodynia Within Regions of Secondary Hyperalgesia in Humans

BACKGROUND

Two of the most common Quantitative Sensory Techniques (QST) employed to detect allodynia include mechanical brush allodynia and Semmes-Weinstein monofilaments. However, their relative sensitivity at detecting allodynia is poorly understood. The purpose of this study was to compare the sensitivity of brush allodynia against Semmes-Weinstein monofilament technique for detecting allodynia within regions of secondary hyperalgesia in humans.

METHODS

Twenty subjects (10 males, 10 females; 21.1 ± 0.9 years) were recruited and randomly allocated to allodynia or monofilament groups. Topical capsaicin (Zostrix 0.075%) was applied to a target region defined by C4-C7 dermatomes. Allodynia testing was performed at 0- (baseline) and 10 minutes postcapsaicin. The Semmes-Weinstein group assessed changes in skin sensitivity 8 cm inferior to target region and 2 cm lateral to the spinous process, while brush allodynia was employed to detect the point inferior to the target region where subjects reported changes in skin sensitivity. The distance (cm) from this point to the inferior border of the target region was termed the Allodynia Score.

RESULTS

Statistically significant increases in the Allodynia Score were observed at 10 minutes postcapsaicin compared to baseline (P < 0.001). No differences in monofilament scores were observed between 10 minutes postcapsaicin and baseline (P = 0.125). Brush allodynia also demonstrated superior sensitivity, detecting allodynia in 100% of cases compared to 60% in the Semmes-Weinstein group.

CONCLUSION

Brush allodynia is more sensitive than Semmes-Weinstein monofilaments for detecting mechanical allodynia in regions of secondary hyperalgesia. Brush allodynia may be preferred over Semmes-Weinstein monofilaments for clinical applications requiring reliable detection of allodynia.

Psychosocial, Physical, and Neurophysiological Risk Factors for Chronic Neck Pain: A Prospective Inception Cohort Study

The purpose of this investigation was to identify modifiable risk factors for the development of first-onset chronic neck pain among an inception cohort of healthy individuals working in a high-risk occupation. Candidate risk factors identified from previous studies were categorized into psychosocial, physical, and neurophysiological domains, which were assessed concurrently in a baseline evaluation of 171 office workers within the first 3 months of hire. Participants completed monthly online surveys over the subsequent year to identify the presence of chronic interfering neck pain, defined as a Neck Disability Index score ≥5 points for 3 or more months. Data were analyzed using backward logistic regression to identify significant predictors within each domain, which were then entered into a multivariate regression model adjusted for age, sex, and body mass index. Development of chronic interfering neck pain was predicted by depressed mood (odds ratio [OR] = 3.36, 95% confidence interval [CI] = 1.10-10.31, P = .03), cervical extensor endurance (OR = .92, 95% CI, .87-.97, P = .001), and diffuse noxious inhibitory control (OR = .90, 95% CI, .83-.98, P = .02) at baseline. These findings provide the first evidence that individuals with preexisting impairments in mood and descending pain modulation may be at greater risk for developing chronic neck pain when exposed to peripheral nociceptive stimuli such as that produced during muscle fatigue.

PERSPECTIVE

Depressed mood, poor muscle endurance, and impaired endogenous pain inhibition are predisposing factors for the development of new-onset chronic neck pain of nonspecific origin in office workers. These findings may assist with primary prevention by allowing clinicians to screen for individuals at risk of developing chronic neck pain.

Short-term effects of thoracic spinal manipulations and message conveyed by clinicians to patients with musculoskeletal shoulder symptoms: a randomized clinical trial

STUDY DESIGN

Randomized clinical trial.

OBJECTIVES

To evaluate the effects of high-velocity, low-amplitude thrust manipulations (HVLATMs) and various messages on patients with musculoskeletal shoulder symptoms.

BACKGROUND

Previous studies indicated that HVLATM directed at the thoracic spine and ribs resulted in improvements of shoulder range of motion, pain, and disability in patients with musculoskeletal shoulder symptoms. These studies did not explore if the outcome was dependent on thrust location, clinician communication with the patient, or if there were any lasting effects.

METHODS

A consecutive sample of 100 patients with shoulder pain was randomized into four groups. Patients received one intervention session including: six thoracic HVLATM (spine versus scapula), a message about HVLATM (neutral versus positive), and standardized home exercises. Outcome measures included shoulder Numeric Pain Rating Scale (NPRS), NPRS with impingement testing, and Shoulder Pain and Disability Index (SPADI). Measurements were recorded prior to intervention, immediately following intervention, and at short-term follow-up. Kruskal-Wallis statistics were used for between-group comparisons and Wilcoxon signed ranks for within-group comparisons.

RESULTS

Eighty-eight patients (22 per group) completed the study. Statistically significant differences were found for within-group comparisons for most time points assessed. No statistical differences were found for between-group comparisons.

CONCLUSION

Patients improved following the interventions. Neither the type of HVLATM nor the message conveyed to the patients had a significant effect on the patients' improvements.

LEVEL OF EVIDENCE

1b.

The Fear-avoidance Components Scale (FACS): Development and Psychometric Evaluation of a New Measure of Pain-related Fear Avoidance

Pain-related fear avoidance (FA), a common problem for patients with painful medical conditions, involves pain-related catastrophizing cognitions, hypervigilance, and avoidance behaviors, which can ultimately lead to decreased functioning, depression, and disability. Several patient-reported instruments have been developed to measure FA, but they have been criticized for limited construct validity, inadequate item specificity, lack of cutoff scores, and missing important FA components. The Fear-Avoidance Components Scale (FACS) is a new patient-reported measure designed to comprehensively evaluate FA in patients with painful medical conditions. It combines important components of FA found in prior FA scales, while trying to correct some of their deficiencies, within a framework of the most current FA model. Psychometric evaluation of the FACS found high internal consistency (α = 0.92) and high test/retest reliability (r = 0.90-0.94, P < 0.01). FACS scores differentiated between 2 separate chronic pain patient samples and a nonpatient comparison group. When clinically relevant severity levels were created, FACS severity scores were highly associated with FA-related patient-reported psychosocial and objective lifting performance variables. These results suggest that the FACS is a psychometrically strong and reliable measure that can help healthcare providers assess FA-related barriers to function and recovery.

Cardiovascular responses to an acute psychological stressor are associated with the cortisol awakening response in individuals with chronic neck pain

INTRODUCTION

Dysregulation of the hypothalamic-pituitary-adrenal axis (HPA-axis) is common in individuals who experience chronic psychological stress, as well as individuals with chronic pain. Changes in cortisol availability in the presence of a chronic stressor such as pain may influence the sympathetic-adrenal-medullary (SAM) system, which contributes to cardiovascular responses to stress and also exhibits altered responsiveness in the presence of pain. The purpose of this study was to investigate the relationship between HPA activity during the cortisol awakening response and cardiovascular reactivity during exposure to an acute psychological stressor in individuals with chronic neck pain.

METHODS

Area under the curve (AUC) of the salivary cortisol awakening response was assessed in 41 individuals with chronic neck pain aged 19-80 years (22 men, 23 women). Slopes representing the change in mean arterial pressure and heart rate during a baseline quiet sitting condition, a low stress condition with mental concentration, and a high stress condition combining mental concentration with social evaluative threat were calculated for each individual as an index of cardiovascular responsiveness to the acute stressor. Cardiovascular responses were regressed on cortisol awakening AUC and pain duration, adjusting for age and sex.

RESULTS

Greater mean arterial pressure (β = -0.33, p = 0.02) and heart rate responses (β = -0.41, p = 0.007) to the acute psychological stressor were associated with lower cortisol awakening responses after adjusting for age and sex. Individuals with a shorter duration of chronic pain also demonstrated a larger increase in mean arterial pressure during the laboratory stressor (β = -0.39, p = 0.01), but there was no relationship between pain duration and changes in heart rate (p = 0.25).

CONCLUSIONS

Individuals with a shorter duration of chronic neck pain who demonstrate heightened cardiovascular responsiveness to an acute psychological stressor also exhibit lower cortisol awakening response. These results are consistent with time-dependent adaptations across the two major stress systems in the presence of chronic pain.

Gender differences in acute and chronic pain in the emergency department: results of the 2014 Academic Emergency Medicine consensus conference pain section

Pain is a leading public health problem in the United States, with an annual economic burden of more than $630 billion, and is one of the most common reasons that individuals seek emergency department (ED) care. There is a paucity of data regarding sex differences in the assessment and treatment of acute and chronic pain conditions in the ED. The Academic Emergency Medicine consensus conference convened in Dallas, Texas, in May 2014 to develop a research agenda to address this issue among others related to sex differences in the ED. Prior to the conference, experts and stakeholders from emergency medicine and the pain research field reviewed the current literature and identified eight candidate priority areas. At the conference, these eight areas were reviewed and all eight were ratified using a nominal group technique to build consensus. These priority areas were: 1) gender differences in the pharmacological and nonpharmacological interventions for pain, including differences in opioid tolerance, side effects, or misuse; 2) gender differences in pain severity perceptions, clinically meaningful differences in acute pain, and pain treatment preferences; 3) gender differences in pain outcomes of ED patients across the life span; 4) gender differences in the relationship between acute pain and acute psychological responses; 5) the influence of physician-patient gender differences and characteristics on the assessment and treatment of pain; 6) gender differences in the influence of acute stress and chronic stress on acute pain responses; 7) gender differences in biological mechanisms and molecular pathways mediating acute pain in ED populations; and 8) gender differences in biological mechanisms and molecular pathways mediating chronic pain development after trauma, stress, or acute illness exposure. These areas represent priority areas for future scientific inquiry, and gaining understanding in these will be essential to improving our understanding of sex and gender differences in the assessment and treatment of pain conditions in emergency care settings.