Affect balance style, experimental pain sensitivity, and pain-related responses

Individuals with fibromyalgia report greater pain sensitivity than healthy adults while listening to their favorite music: the contribution of negative affect

OBJECTIVE

We investigated the impact of favorite music on pain processing among individuals with fibromyalgia. We also examined differences in pain processing between individuals with fibromyalgia and healthy controls (HC) while listening to favorite music and explored whether psychosocial factors contributed to these differences.

METHODS

Individuals with fibromyalgia and HC completed baseline psychosocial questionnaires and then underwent quantitative sensory testing (QST) during 3 randomized music conditions (meditative music, favorite music, white noise). Among individuals with fibromyalgia, Friedman tests were used to investigate differences in QST across conditions. Analyses of Covariance were used to examine group (HC vs fibromyalgia) differences in QST during favorite music. Correlations were conducted to explore associations of baseline psychosocial factors with QST during favorite music. Mediation analyses were conducted to explore whether psychosocial factors contributed to greater pain sensitivity among individuals with fibromyalgia compared to HC during favorite music.

RESULTS

Individuals with fibromyalgia were less sensitive to pressure pain while listening to their favorite music compared to white noise. Compared to HC, individuals with fibromyalgia reported higher baseline negative affect and lower pain thresholds and tolerances during favorite music. Negative affect partially mediated the relationship between pain status (HC vs fibromyalgia) and pain sensitivity during favorite music.

CONCLUSIONS

Individuals with fibromyalgia were less pain sensitive while listening to favorite music than white noise, although they were more sensitive than HC. Greater negative affect endorsed by individuals with fibromyalgia contributed to their greater pain sensitivity. Future studies should explore the impact of favorite music on clinical pain.

CLINICAL TRAILS REGISTRATION

This study was registered with ClinicalTrials.gov (NCT04087564) and began on 6/13/2019.

Dispositional traits help explain individual differences in relationships between a radiographic knee osteoarthritis measure, pain, and physical function

Background

The concordance between radiograph-derived Kellgren-Lawrence (KL) scores for knee osteoarthritis (KOA) and experimental and clinical pain and KOA-related physical function is conflicting.

Objectives

We investigate whether the inclusion of dispositional traits reduces variability between KOA radiographic findings, experimental pain, clinical pain, and function in individuals with knee pain.

Design

This study is a cross-sectional, secondary analysis of data collected from the UPLOAD-II study.

Methods

Adults aged 45-85 years with and without knee pain were enrolled. Data collected included sociodemographics, knee radiographs, experimental pain, clinical pain and function, and trait affect. Vulnerable and protective dispositional traits were classified from combined positive and negative trait affect measures. KL scores were determined from the knee radiographs. Unadjusted and adjusted (age, sex, comorbidities, and body mass index) regression analyses were completed with SAS version 9.4 (Cary, NC, USA).

Results

The study included 218 individuals with a mean age of 58 years, 63.6% women, and 48.2% non-Hispanic black adults. Dispositional traits were associated with the experimental pain measures. No association between radiographic KOA and experimental pain was observed. In a combined and adjusted analysis, dispositional traits were predictive of knee punctate pain temporal summation (p = 0.0382). Both dispositional traits and radiographic KOA scores independently and combined were predictive of Graded Chronic Pain Scale pain and function, and Western Ontario and McMaster University pain and function (ps ⩽ 0.01). Improvements in R2 were noted across all models with the inclusion of dispositional traits.

Conclusion

Consideration of dispositional traits reduces the variability between radiographic KOA and pain and function. Non-pathological and associated pain-related psychological factors and dispositional traits might serve as parsimonious proxy tools to improve clinical assessments.

Registration

N/A.

Resilient, but for how long? The relationships between temperament, burnout, and mental health in healthcare workers during the Covid-19 pandemic

Introduction

Dispositional traits of wellbeing and stress-reaction are strong predictors of mood symptoms following stressful life events, and the COVID-19 pandemic introduced many life stressors, especially for healthcare workers.

Methods

We longitudinally investigated the relationships among positive and negative temperament group status (created according to wellbeing and stress-reaction personality measures), burnout (exhaustion, interpersonal disengagement), COVID concern (e.g., health, money worries), and moral injury (personal acts, others' acts) as predictors of generalized anxiety, depression, and post-traumatic stress symptoms in 435 healthcare workers. Participants were employees in healthcare settings in North Central Florida who completed online surveys monthly for 8 months starting in October/November 2020. Multidimensional Personality Questionnaire subscale scores for stress-reaction and wellbeing were subjected to K-means cluster analyses that identified two groups of individuals, those with high stress-reaction and low wellbeing (negative temperament) and those with the opposite pattern defined as positive temperament (low stress-reaction and high wellbeing). Repeated measures ANOVAs assessed all time points and ANCOVAs assessed the biggest change at timepoint 2 while controlling for baseline symptoms.

Results and Discussion

The negative temperament group reported greater mood symptoms, burnout, and COVID concern, than positive temperament participants overall, and negative participants' scores decreased over time while positive participants' scores increased over time. Burnout appeared to most strongly mediate this group-by-time interaction, with the burnout exhaustion scale driving anxiety and depression symptoms. PTSD symptoms were also related to COVID-19 health worry and negative temperament. Overall, results suggest that individuals with higher stress-reactions and more negative outlooks on life were at risk for anxiety, depression, and PTSD early in the COVID-19 pandemic, whereas individuals with positive temperament traits became more exhausted and thus more symptomatic over time. Targeting interventions to reduce mood symptoms in negative temperament individuals and prevent burnout/exhaustion in positive temperament individuals early in an extended crisis may be an efficient and effective approach to reduce the mental health burden on essential workers.

Evaluation by Survival Analysis of Cold Pain Tolerance in Patients with Fibromyalgia and Opioid Use

Purpose

The cold pressor test (CPT) is a clinical pain research method used to measure cold pain tolerance. During this test, participants immerse an extremity (ie, hand or foot) into cold water for as long as tolerable. The duration of the test (traditionally up to an experimentally imposed cut-off at 2 minutes) indicates the amount of cold pain tolerance by the participant. Prior research studies have investigated cold pain tolerance in patients with chronic pain. However, few of these studies have used survival analysis, which allows for proper handling of data censoring and is therefore, an optimal statistical method for CPT data analysis. The goal of the present study was to use survival analysis to evaluate cold pain tolerance in patients with fibromyalgia. Furthermore, we aimed to model relationships between psychological and clinical variables as well as opioid medication use and cold pain tolerance.

Patients and Methods

A total of 85 patients with fibromyalgia (42 who were taking opioids) and 47 healthy pain-free controls provided CPT and questionnaire data (collected across 2 study sites) for a case-control study. We used survival analysis using Cox regression to evaluate group differences (patients vs controls) in cold pain tolerance and to evaluate cold pain tolerance relationships with psychological, clinical, and medication use.

Results

As compared to healthy controls, patients with fibromyalgia exhibited significantly lower CPT survival (HR = 2.17, 95% CI: [1.42, 3.31], p = 0.00035). As indicated by Cox regression models, the significant group difference in CPT survival did not relate to our selected psychological and clinical measures (p > 0.05). The groups of non-opioid-taking patients and healthy controls showed consistent CPT survival across study sites. However, patients taking opioid pain medications showed differences in CPT survival across study sites.

Conclusion

By using survival analysis, an optimal method for time-to-event pain measures such as the CPT, we confirmed previously identified reductions in cold pain tolerance in patients with fibromyalgia. While our selected psychological and clinical measures were not significantly associated with cold pain tolerance, our data suggest that opioid medication use may impart greater cold pain tolerance in some patients.

Personal influencing factors for pressure pain threshold in healthy people: A systematic review and meta-analysis

All studies that investigated personal factors influencing pressure pain threshold (PPT) in healthy people were synthesized. Data was summarized, and risk of bias (RoB) and level of evidence were determined. Results were pooled per influencing factor, grouped by body region and included in meta-analyses. Fifty-four studies were eligible. Five had low, nine moderate, and 40 high RoB. Following meta-analyses, a strong conclusion was found for the influence of scapular position, a moderate for the influence of gender, and a weak for the influence of age (shoulder/arm region) and blood pressure on PPT. In addition, body mass index, gender (leg region), alcohol consumption and pain vigilance may not influence PPT. Based on qualitative summary, depression and menopause may not influence PPT. For other variables there was only preliminary or conflicting evidence. However, caution is advised, since the majority of included studies showed a high RoB and several were not eligible to include in meta-analyses. Heterogeneity was high in the performed meta-analyses, and most conclusions were weak. More standardized research is necessary.

Perceptual sensory attenuation in chronic pain subjects and healthy controls

We investigated whether sensory attenuation (or failure of) might be an explanation for heightened pain perceptions in individuals with chronic pain. N = 131 (50% chronic pain) individuals underwent a single experimental session, which included the force-matching task and several self-reported symptom and psychological measures. Individuals matched a force delivered to their finger, either by pressing directly on their own finger with their other hand (direct) or by using potentiometer to control the force through a torque motor (slider). All participants overestimated the target force in the direct condition reflecting the sensory attenuation phenomenon. No differences in the magnitude of sensory attenuation between chronic pain and control groups were observed (direct: Z = - 0.90, p = 0.37 and slider: Z = - 1.41, p = 0.16). An increased variance of sensory attenuation was observed in chronic pain individuals (direct: F(1, 129) = 7.22, p = 0.008 and slider: F(1, 129), p = 0.05). Performance in the slider condition was correlated with depressive symptoms (r = - 0.24, p = 0.05), high symptom count (r = - 0.25, p = 0.04) and positive affect (r = 0.28, p = 0.02). These were only identified in the chronic pain individuals. Overall, our findings reveal no clear differences in the magnitude of sensory attenuation between groups. Future research is needed to determine the relevance of sensory attenuation in neuro-cognitive models related to pain perception.

Vulnerable Dispositional Traits and Chronic Pain: Predisposing but not Predetermining

Dispositional traits can be protective or contribute to increased vulnerability in individuals with chronic pain. This study aims to evaluate the association between two dispositional trait measures, affect balance style and multi-domain trait groups, with psychosocial measures, clinical pain, functional pain, and experimental pain at two years in individuals with chronic knee pain. The study is a prospective analysis of 168 community dwelling individuals aged 45 to 85 years old with knee pain with or at risk for knee osteoarthritis. At baseline, affect balance style and multi-domain trait groups were associated with psychosocial measures, clinical pain, and functional status. At the two-year time point, the multi-domain trait groups were associated with the clinical pain measures. Interestingly, individuals with previously demonstrated vulnerable traits showed more variability in dispositional trait status at the two-year time point compared to those with dispositional traits previously demonstrated as more protective. Findings reiterate that dispositional traits are predisposing but are not predetermining regarding pain-related experiences. PERSPECTIVE: Vulnerable and protective dispositional traits are positively and negatively associated with clinical pain and functional limitations respectively. Although considered relatively stable, a 30-50% shift in dispositional traits was indicated over a two-year period. Findings highlight that dispositional trait are modifiable and thus, predisposing but not predetermining for persisting chronic pain.

Resilience, pain, and the brain: Relationships differ by sociodemographics

Chronic musculoskeletal (MSK) pain is disabling to individuals and burdensome to society. A relationship between telomere length and resilience was reported in individuals with consideration for chronic pain intensity. While chronic pain associates with brain changes, little is known regarding the neurobiological interface of resilience. In a group of individuals with chronic MSK pain, we examined the relationships between a previously investigated resilience index, clinical pain and functioning measures, and pain-related brain structures, with consideration for sex and ethnicity/race. A cross-sectional analysis of 166 non-Hispanic Black and non-Hispanic White adults, 45-85 years of age with pain ≥ 1 body site (s) over the past 3 months was completed. Measures of clinical pain and functioning, biobehavioral and psychosocial resilience, and structural MRI were completed. Our findings indicate higher levels of resilience associate with lower levels of clinical pain and functional limitations. Significant associations between resilience, ethnicity/race, and/or sex, and pain-related brain gray matter structure were demonstrated in the right amygdaloid complex, bilateral thalamus, and postcentral gyrus. Our findings provide compelling evidence that in order to decipher the neurobiological code of chronic pain and related protective factors, it will be important to improve how chronic pain is phenotyped; to include an equal representation of females in studies including analyses stratifying by sex, and to consider other sociodemographic factors.

Bouncing back after lumbar spine surgery: early postoperative resilience is associated with 12-month physical function, pain interference, social participation, and disability

BACKGROUND CONTEXT

Positive psychosocial factors early after surgery, such as resilience and self-efficacy, may be important characteristics for informing individualized postoperative care.

PURPOSE

To examine the association of early postoperative resilience and self-efficacy on 12-month physical function, pain interference, social participation, disability, pain intensity, and physical activity after lumbar spine surgery.

STUDY DESIGN/SETTING

Pooled secondary analysis of prospectively collected trial data from two academic medical centers.

PATIENT SAMPLE

Two hundred and forty-eight patients who underwent laminectomy with or without fusion for a degenerative lumbar condition.

OUTCOME MEASURES

Physical function, pain inference, and social participation (ability to participate in social roles and activities) were measured using the Patient Reported Outcomes Measurement Information System. The Oswestry Disability Index, Numeric Rating Scale, and accelerometer activity counts were used to measure disability, pain intensity, and physical activity, respectively.

METHODS

Participants completed validated outcome questionnaires at 6 weeks (baseline) and 12 months after surgery. Baseline positive psychosocial factors included resilience (Brief Resilience Scale) and self-efficacy (Pain Self-Efficacy Questionnaire). Multivariable linear regression analyses were used to assess the associations between early postoperative psychosocial factors and 12-month outcomes adjusting for age, sex, study site, randomized group, fusion status, fear of movement (Tampa Scale for Kinesiophobia), and outcome score at baseline. This study was funded by Patient-Centered Outcomes Research Institute and Foundation for Physical Therapy Research. There are no conflicts of interest.

RESULTS

Resilience at 6 weeks after surgery was associated with 12-month physical function (unstandardized beta=1.85 [95% confidence interval [CI]: 0.29; 3.40]), pain interference (unstandardized beta=-1.80 [95% CI: -3.48; -0.12]), social participation (unstandardized beta=2.69 [95% CI: 0.97; 4.41]), and disability (unstandardized beta=-3.03 [95% CI: -6.04; -0.02]). Self-efficacy was associated with 12-month disability (unstandardized beta=-0.21 [95% CI: -0.37; -0.04].

CONCLUSIONS

Postoperative resilience and pain self-efficacy were associated with improved 12-month patient-reported outcomes after spine surgery. Future work should consider how early postoperative screening for positive psychosocial characteristics can enhance risk stratification and targeted rehabilitation management in patients undergoing spine surgery.

Optimism and Psychological Resilience are Beneficially Associated With Measures of Clinical and Experimental Pain in Adults With or at Risk for Knee Osteoarthritis

OBJECTIVES

This cross-sectional study examined the associations among optimism, psychological resilience, endogenous pain inhibition, and clinical knee pain severity. Two hypotheses were tested. First, we hypothesized that experimentally tested endogenous pain inhibition would mediate the relationship between optimism and clinical knee pain severity. Second, it was also hypothesized that optimism would moderate the relationships of psychological resilience with endogenous pain inhibition and clinical knee pain severity, particularly for individuals with high optimism.

METHODS

A total of 150 individuals with or at risk for symptomatic knee osteoarthritis completed the Life Orientation Test-Revised, the Brief Resilience Scale, and the revised Short-Form McGill Pain Questionnaire-2 to assess optimism, psychological resilience, and clinical knee pain severity, respectively. Endogenous pain inhibition was examined experimentally using a conditioned pain modulation (CPM) protocol with algometry (test stimulus) and a cold pressor task (conditioning stimulus).

RESULTS

As hypothesized, results showed that increased CPM significantly mediated the association between higher optimism and lower clinical knee pain severity. Further, optimism moderated the association between psychological resilience and CPM. However, contrary to our hypothesis, greater psychological resilience was associated with enhanced CPM in individuals with low optimism only.

DISCUSSION

This study suggests that an optimistic outlook may beneficially impact clinical pain severity by altering endogenous pain modulatory capacity. Furthermore, individuals with low optimism (ie, pessimists) may be more adept at engaging resources that promote psychological resilience, which in turn, enhances endogenous pain modulatory capacity. Therefore, this study supports consideration of psychological resilience factors when evaluating experimental and clinical pain outcomes.

Resilience factors may buffer cellular aging in individuals with and without chronic knee pain

Telomere length, a measure of cellular aging, is inversely associated with chronic pain severity. While psychological resilience factors (e.g., optimism, acceptance, positive affect, and active coping) are associated with lower levels of clinical pain and greater physical functioning, it is unknown whether resilience may buffer against telomere shortening in individuals with chronic pain. Additionally, a broader conceptualization of resilience that includes social and biobehavioral factors may improve our understanding of the relationship between resilience, chronic pain, and health outcomes. In individuals with and without chronic knee pain, we investigated whether (1) psychological resilience would be positively associated with telomere length and if (2) a broader conceptualization of resilience including social and biobehavioral factors would strengthen the association. Seventy-nine adults, 45 to 85 years of age, with and without knee pain completed demographic, health, clinical pain, psychological, social, and biobehavioral questionnaires. Resilience levels were determined by summing the total number of measures indicating resilience based on published clinical ranges and norms. Blood samples were collected, and telomere length was determined. In regression analyses controlling for sex, race, age, and characteristic pain intensity, greater psychological resilience and psychosocial/biobehavioral resilience were associated with longer telomeres ( p = .0295 and p = .0116, respectively). When compared, psychosocial/biobehavioral resilience was significantly more predictive of telomere length than psychological resilience ( p < .0001). Findings are promising and encourage further investigations to enhance understanding of the biological interface of psychosocial and biobehavioral resilience factors in individuals with musculoskeletal chronic pain conditions.

Affect and Low Back Pain: More to Consider Than the Influence of Negative Affect Alone

OBJECTIVES

Affect balance style, a measure of trait positive affect (PA) and negative affect (NA), is predictive of pain and functioning in fibromyalgia and healthy individuals. The purpose of this study was to evaluate the distribution of affect balance styles and the relationship between these styles and clinical factors in low back pain.

METHODS

In this cross-sectional study, patients with low back pain (N=443) completed questionnaires and were categorized as having 1 of 4 distinct affect balance styles: Healthy (high levels of PA and low levels of NA), Low (low PA/low NA), Reactive (high PA/high NA), and Depressive (low PA/high NA). Comparisons between groups were made in regard to pain, functioning, and psychiatric comorbidity.

RESULTS

High NA was observed in 63% (n=281), whereas low PA was present in 81% (n=359). We found that having a Depressive style was associated with greater pain severity, increased odds for comorbid fibromyalgia, and worse functioning compared with having a Healthy or Low style. Yet, those with a Low style were at increased risk for depression compared with a Healthy style, whereas patients with a Reactive style had similar levels of pain, functioning, and depression as those with a Healthy affective style.

CONCLUSIONS

Our study revealed that there are important differences between trait affect balance styles in regard to pain, mood, and functioning in low back pain. Findings related to Reactive and Low affective styles suggest that relationships between affect, pain, and disability in low back pain extend beyond considering NA alone.

Optimism Moderates the Influence of Pain Catastrophizing on Shoulder Pain Outcome: A Longitudinal Analysis

Study Design Secondary analysis of prospectively collected data. Background An abundance of evidence has highlighted the influence of pain catastrophizing and fear avoidance on clinical outcomes. Less is known about the interaction of positive psychological resources with these pain-associated distress factors. Objective To assess whether optimism moderates the influence of pain catastrophizing and fear avoidance on 3-month clinical outcomes in patients with shoulder pain. Methods Data from 63 individuals with shoulder pain (mean ± SD age, 38.8 ± 14.9 years; 30 female) were examined. Demographic, psychological, and clinical characteristics were obtained at baseline. Validated measures were used to assess optimism (Life Orientation Test-Revised), pain catastrophizing (Pain Catastrophizing Scale), fear avoidance (Fear-Avoidance Beliefs Questionnaire physical activity subscale), shoulder pain intensity (Brief Pain Inventory), and shoulder function (Pennsylvania Shoulder Score function subscale). Shoulder pain and function were reassessed at 3 months. Regression models assessed the influence of (1) pain catastrophizing and optimism and (2) fear avoidance and optimism. The final multivariable models controlled for factors of age, sex, education, and baseline scores, and included 3-month pain intensity and function as separate dependent variables. Results Shoulder pain (mean difference, -1.6; 95% confidence interval [CI]: -2.1, -1.2) and function (mean difference, 2.4; 95% CI: 0.3, 4.4) improved over 3 months. In multivariable analyses, there was an interaction between pain catastrophizing and optimism (β = 0.19; 95% CI: 0.02, 0.35) for predicting 3-month shoulder function (F = 16.8, R² = 0.69, P<.001), but not pain (P = .213). Further examination of the interaction with the Johnson-Neyman technique showed that higher levels of optimism lessened the influence of pain catastrophizing on function. There was no evidence of significant moderation of fear-avoidance beliefs for 3-month shoulder pain (P = .090) or function (P = .092). Conclusion Optimism decreased the negative influence of pain catastrophizing on shoulder function, but not pain intensity. Optimism did not alter the influence of fear-avoidance beliefs on these outcomes. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2017;47(1):21-30. Epub 5 Nov 2016. doi:10.2519/jospt.2017.7068.

Clinical and evoked pain, personality traits, and emotional states: can familial confounding explain the associations?

OBJECTIVES

Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample.

METHODS

99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain and b) whether genetics and common environment (i.e. familial factors) may account for the associations.

RESULTS

Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS negative affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain.

CONCLUSIONS

A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors.

A Comparison of Fibromyalgia Symptoms in Patients with Healthy versus Depressive, Low and Reactive Affect Balance Styles

BACKGROUND AND AIMS

Affect balance reflects relative levels of negative affect (NA) and positive affect (PA) and includes four styles: Healthy (low NA/high PA), Depressive (high NA/low PA), Reactive (high NA/high PA) and Low (low NA/low PA). These affect balance styles may have important associations with clinical outcomes in patients with fibromyalgia. Herein, we evaluated the severity of core fibromyalgia symptom domains as described by the Outcomes Research in Rheumatology-Fibromyalgia working group in the context of the four affect balance styles.

METHODS

Data from735 patients with fibromyalgia who completed the Brief Pain Inventory, Multidimensional Fatigue Inventory, Profile of Mood States, Medical Outcomes Sleep Scale, Multiple Ability Self-Report Questionnaire, Fibromyalgia Impact Questionnaire-Revised, Medical Outcomes Study Short Form-36, and Positive and Negative Affect Schedule were included in this analysis.

RESULTS

The majority (51.8%) of patients in our sample had a Depressive affect balance style; compared to patients with a Healthy affect balance style, they scored significantly worse in all fibromyalgia symptom domains including pain, fatigue, sleep disturbance, dyscognition, depression, anxiety, stiffness, and functional status (P = <.001 - .004). Overall, patients with a Healthy affect balance style had the lowest level of symptoms, while symptom levels of those with Reactive and Low affect balance styles were distributed in between those of the Depressive and Healthy groups.

CONCLUSIONS AND IMPLICATIONS

The results of our cross-sectional study suggest that having a Healthy affect balance style is associated with better physical and psychological symptom profiles in fibromyalgia. Futures studies evaluating these associations longitudinally could provide rationale for evaluating the effect of psychological interventions on affect balance and clinical outcomes in fibromyalgia.

Can quantitative sensory testing move us closer to mechanism-based pain management?

OBJECTIVE

This review summarizes the scientific literature relating to the use of quantitative sensory testing (QST) for mechanism-based pain management.

DESIGN

A literature search was undertaken using PubMed and search terms including quantitative sensory testing, pain, chronic pain, response to treatment, outcome measure.

SETTINGS AND PATIENTS

Studies including QST in healthy individuals and those with painful disorders were reviewed.

MEASURES

Publications reported on QST methodological issues including associations among measures and reliability. We also included publications on the use of QST measures in case-control studies, their associations with biopsychosocial mechanisms, QST measures predicting clinical pain, as well as predicting and reflecting treatment responses.

RESULTS

Although evidence suggests that QST may be useful in a mechanism-based classification of pain, there are gaps in our current understanding that need to be addressed including making QST more applicable in clinical settings. There is a need for developing shorter QST protocols that are clinically predictive of various pain subtypes and treatment responses without requiring expensive equipment. Future studies are needed, examining the clinical predictive value of QST including sensitivity and specificity for pain classification or outcome prediction. These findings could enable third-party payers' reimbursement, which would facilitate clinical implementation of QST.

CONCLUSIONS

With some developments, QST could become a cost-effective and clinically useful component of pain assessment and diagnosis, which can further our progress toward the goal of mechanism-based personalized pain management.