Does self-perception of sensitivity to pain correlate with actual sensitivity to experimental pain?

Pain tolerance and threshold in suicide attempters: A systematic review and meta-analysis

It has been hypothesized that individuals less sensitive to pain could be at higher risk of suicide. However, data on pain sensitivity in suicide attempters (SA) obtained using experimental procedures are heterogeneous. The aim of this systematic review and meta-analysis was to investigate and compare pain tolerance and threshold in SA (patients with lifetime history of suicide attempt), non-attempters (psychiatric controls, PC), and healthy controls (HC). A random effects meta-analysis was used to estimate the standardized mean differences using data from 16 studies that compared physical pain tolerance and threshold in SA and PC or HC. Pain tolerance and threshold were not significantly different in SA and PC. However, pain tolerance, but not threshold, was higher in SA than HC. Our findings do not support the hypothesis of an altered pain perception related as a trait for suicidal vulnerability, but rather suggest altered pain perception related to psychiatric vulnerability.

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

ABSTRACT

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

Higher self-perceived stress reactivity is associated with increased chronic pain risk

Self-perceived stress reactivity—how a person cognitively and emotionally responds to a stressor—is longitudinally associated with increased odds for the development of chronic pain.

Introduction:

Experiencing stress can contribute to unfavorable pain experiences, but outcomes vary across individuals. Evidence suggests that a person's specific reactivity to stressful events may influence pain responses. Previous studies measuring physiological stress reactivity have found associations with pain both clinically and in the laboratory. However, the time and cost required for testing physiological stress reactivity may limit clinical application.

Objective:

Self-reported perception of one's own stress reactivity has been shown to correlate with physiological stress reactivity in relation to health outcomes and may represent a valuable tool in clinical pain assessment.

Methods:

Using data from the Midlife in the US survey, we selected participants who did not have chronic pain at baseline (n = 1512) and who had data at follow-up 9 years later. Stress reactivity was assessed using a subscale of the Multidimensional Personality Questionnaire. We conducted a binary logistic regression to determine the odds of developing chronic pain, controlling for demographics and other health-related variables.

Results:

Results indicate that higher reported stress reactivity at baseline increased the odds of developing chronic pain at follow-up (odds ratio (OR) = 1.085, 95% confidence interval (CI) (1.021, 1.153), P = 0.008), with the only other significant predictor being the number of chronic conditions (OR = 1.118, 95% CI (1.045, 1.197), P = 0.001).

Conclusion:

Findings provide evidence for the predictive criterion validity of self-reported stress reactivity in the context of chronic pain risk. More generally, with increased need for virtual assessment and care, self-reported stress reactivity may be a useful, time-efficient, and cost-efficient tool for predicting pain outcomes in research and clinical contexts.

Fearlessness about death and suicide planning predict lethality of adolescent suicide attempts during and following treatment

INTRODUCTION

The rate of adolescent suicide attempt has increased drastically over the past 10 years. However, little is known regarding what predicts a more versus less lethal attempt, which is of critical interest to clinicians managing this at-risk population. We sought to extend the study of lethality in adolescents by exploring its relationship with two recognized risk-factors for suicide attempt: fearlessness about death (FAD) and suicide planning.

METHODS

Participants (N = 254) were administered measures of FAD and depressive symptoms upon entering intensive outpatient treatment for adolescents exhibiting suicidal thoughts and behaviors. Attempts made between treatment entry and 6 months following discharge (n = 47) were scored on a 4-point ordinal scale of lethality. The resulting continuum ranged from no attempt to attempts of low to moderate levels of lethality.

RESULTS

FAD and suicide planning distinguished between levels of lethality of future attempt at the bivariate and multivariate level. FAD's predictive relationship with lethality while controlling for age, sex, depression, and prior attempt diminished when suicide planning was covaried.

CONCLUSION

FAD and suicide planning significantly predicted more versus less lethal future attempts in our sample of adolescents in a clinical setting. Our findings suggest that FAD influences the lethality of a future attempt by promoting planning for suicide. More studies are needed to assess whether the brief FAD scale might be a valuable adjunct in the clinical management of youth with suicidal thoughts and behaviors.

Are all pain tolerance tasks the same? Convergent validity of four behavioral pain tolerance tasks, self-reported capability for suicide, and lifetime self-injurious behaviors

OBJECTIVES

Discrepancies persist regarding the extent to which different pain measures provide similar information and relate to capability for suicide and self-injurious behaviors. This study examined pain threshold, tolerance, and persistence across four modalities (cold, heat, pressure, shock) and assessed associations with self-reported capability for suicide, non-suicidal self-injury (NSSI), and suicide attempts.

METHODS

A sample of 211 students who reported lifetime suicidal ideation completed four behavioral pain tasks and self-reported on capability for suicide, NSSI, and self-injurious behaviors.

RESULTS

All pain thresholds, tolerances, and persistences were positively correlated across the four tasks. Pain facets were related to self-reported capability for suicide with small effect sizes but generally did not differ across suicide attempt or NSSI histories.

CONCLUSIONS

Pain thresholds, tolerances, and persistences demonstrated convergent validity across the four modalities, suggesting that these tasks provide similar information. Although the relation between pain and self-injurious behaviors remains unclear, these tasks can generally be used interchangeably.

Higher Pain Sensitivity Predicts Efficacy of a Wearable Transcutaneous Electrical Nerve Stimulation Device for Persons With Fibromyalgia: A Randomized Double-Blind Sham-Controlled Trial

OBJECTIVES

This study investigated the efficacy of a transcutaneous electrical nerve stimulation (TENS) device (Quell®) for persons with symptoms due to fibromyalgia (FM).

MATERIALS AND METHODS

One hundred nineteen (N = 119) subjects were randomly assigned to use an active (N = 62) or sham (N = 57) TENS for three months. All subjects completed baseline questionnaires and were administered quantitative sensory testing (QST). Subjects completed the Patients' Global Impression of Change (PGIC, primary outcome measure) and other mailed questionnaires (secondary outcome measures) at six weeks and three months.

RESULTS

The subjects averaged 50.4 ± 13.5 years of age, 93.3% were female, and 79.8% were Caucasian. Most showed benefit from using the TENS, but no differences between groups were found on the primary outcome measure after three months (active 3.87 ± 1.85, sham 3.73 ± 1.80, 95% confidence interval [CI] [-0.60, 0.88], p = 0.707). Those with more hypersensitivity showed most improvement on the PGIC at six weeks (0.22, 95% CI [0.01, 0.43], p = 0.042) and three months (0.20, 95% CI [0.00, 0.41], p = 0.049) and among those with higher sensitivity based on QST, the active TENS group showed the most benefit with TENS compared with the sham treatment (1.20, 95% CI [0.22, 2.18], p = 0.017). No TENS-related serious adverse events were reported. Subjects in the sham group correctly identified their treatment 87.5% of the time, while, surprisingly, subjects in the active group correctly identified their treatment only 17.4% of the time.

CONCLUSION

This study found no differences between those who were exposed to maximal-frequency active stimulation or minimal-frequency sham stimulation from a wearable TENS in reducing FM-related symptoms. However, those with greater hypersensitivity showed most benefit from TENS. Additional studies to help determine the role individual differences play in the use of TENS in managing FM-related symptoms are needed.

During capsaicin-induced central sensitization, brush allodynia is associated with baseline warmth sensitivity, whereas mechanical hyperalgesia is associated with painful mechanical sensibility, anxiety and somatization

BACKGROUND

Mechanical hyperalgesia and allodynia incidence varies considerably amongst neuropathic pain patients. This study explored whether sensory or psychological factors associate with mechanical hyperalgesia and brush allodynia in a human experimental model.

METHODS

Sixty-six healthy volunteers (29 male) completed psychological questionnaires and participated in two quantitative sensory testing (QST) sessions. Warmth detection threshold (WDT), heat pain threshold (HPT) and suprathreshold mechanical pain (STMP) ratings were measured before exposure to a capsaicin-heat pain model (C-HP). After C-HP exposure, brush allodynia and STMP were measured in one session, whilst mechanical hyperalgesia was measured in another session.

RESULTS

WDT and HPT measured in sessions separated by 1 month demonstrated significant but moderate levels of reliability (WDT: ICC = 0.5, 95%CI [0.28, 0.77]; HPT: ICC = 0.62, 95%CI [0.40, 0.77]). Brush allodynia associated with lower WDT (z = -3.06, p = 0.002; ϕ = 0.27). Those with allodynia showed greater hyperalgesia intensity (F = 7.044, p = 0.010, η_p ²  = 0.107) and area (F = 9.319, p = 0.004, η_p ²  = 0.163) than those without allodynia. No psychological self-report measures were significantly different between allodynic and nonallodynic groups. Intensity of hyperalgesia in response to lighter mechanical stimuli was associated with lower HPT, higher STMP ratings and higher Pain Sensitivity Questionnaire scores at baseline. Hyperalgesia to heavier probe stimuli associated with state anxiety and to a lesser extent somatic awareness. Hyperalgesic area associated with lower baseline HPT and higher STMP ratings. Hyperalgesic area was not correlated with allodynic area across individuals.

CONCLUSIONS

These findings support research in neuropathic pain patients and human experimental models that peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

SIGNIFICANCE

We evaluated differential relationships of psychological and perceptual sensitivity to the development of capsaicin-induced mechanical allodynia and hyperalgesia. Fifty percent of healthy volunteers failed to develop mechanical allodynia. Baseline pain sensitivity was greater in those developing allodynia and was related to the magnitude and area of hyperalgesia. State psychological factors, whilst unrelated to allodynia, were related to mechanical hyperalgesia. This supports that the intensity of peripheral sensory input and individual sensibility are related to development of mechanical allodynia and hyperalgesia during central sensitization, whilst psychological factors play a lesser role.

The visual time analog scale: simple, novel measurement approach to assess pain in patients with chronic pain

Aim: We conducted a preliminary evaluation of a newly developed, time-based visual time analog (VITA) scale for measuring pain in chronic pain patients. Materials & methods: 40 patients with chronic back pain rated their pain over four visits using numerical (pain) rating scale (NRS) and VITA assessing pain intensity by distributing the amount of time spent on 'not aware of pain' (blue), 'aware of nothing but pain' (red) and time in between (yellow). Results: The NRS scores were correlated with the VITA Red but not with VITA Blue. The psychometric analyses revealed that VITA achieved greater reliability and sensitivity than did NRS. Conclusion: The results provide preliminary support for VITA scale for assessing pain intensity in patients with chronic pain.

Risk factors of pain, physical function, and health-related quality of life in elderly people with knee osteoarthritis: A cross-sectional study

Data on the precise mechanisms of the complex interactions of factors related to clinical impact of knee osteoarthritis (KOA) in the elderly population remain limited. To find predictors that explain pain intensity, physical function, and quality of life in elderly KOA subjects, we performed a cross-sectional analysis of the baseline data from a randomized trial. The trial included 104 subjects (aged ≥60) with KOA pain and dysfunctional endogenous pain-inhibitory system activity assessed by conditioned pain modulation (CPM). Three multiple linear regression models were performed to understand the independent predictors of Brief Pain Inventory (BPI), WOMAC function subscale (WOMACFunc), and SF-12 physical subscale (SF12-PCS). Model 1 showed that BPI pain score was predicted by low CPM response, high von-Frey light touch threshold, worse radiological severity as indexed by Kellgren-Lawrence grade (KL), high von-Frey punctate pain intensity and high levels of anxiety (adjusted R2 = 27.1%, F (6,95) = 7.27, P < 0.0001). In model 2, von-Frey light touch threshold, KL, depressive symptoms indexed by Beck Depression Inventory (BDI), level of sleepiness and pain pressure threshold were risk factors for SF12-PCS (adjusted R2 = 31.9%, F (5,96) = 10.5, P < 0.0001). Finally, model 3 showed that WOMACFunc was predicted by BDI, KL and BPI (adjusted R2 = 41%, F (3,98) = 24.42, P < 0.0001). Our data provides an interesting framework to understand the predictors of KOA pain in the elderly and highlights how its related outcomes are affected by disease-specific factors, somatosensory dysfunction and emotional factors.

Painful Life Events in Psychiatric Disorders: A Quantitative and Qualitative Analysis

We reported in a previous study the painful events experienced in the past in subjects with schizophrenia or major depression, in comparison to controls, and related them to the experimental pain sensitivity, anxiety, and the diagnosis. We present here the detailed analysis of these past painful events, with the aim of determining whether schizophrenic, depressive and control groups are qualitatively (type of painful events experienced, emotional or sensory components associated with pain) and quantitatively (duration, severity, and intensity) comparable concerning their past painful experiences. The questionnaire used relies on memory and feelings and will provide an indication about the way pain is experienced and memorized in daily life. The reported history of pain was not the same in the three groups. Depressed subjects differed from the others by the number of reported painful events. Painful events of everyday life, such as trauma without fracture and wounds, were the most highly reported painful events for all groups. Surprisingly, the daily pain events are associated to affective component of pain perception. Other kinds of event were differently reported between the groups. Experience of pain appears to be memorized and reported differently depending on the psychiatric disorder and type of event. The characteristics of each individual, their previous experience, contribute to the expression of psychiatric disorders, including in the field of pain. Past pain experience should be taken into account when attending someone for pain.

The relationship between sensitivity to pain and conditioned pain modulation in healthy people

BACKGROUND

The relationship between sensitivity to pain and conditioned pain modulation (CPM) - a paradigm reflecting the activity of the endogenous descending analgesic system - is still unclear. This study aimed at investigating CPM magnitude in two distinct subgroups of healthy subjects, presenting low vs. high sensitivity to pain (LSP vs. HSP, respectively), by employing two different thermal paradigms of CPM.

METHOD

Ninety-five healthy subjects (out of 293 tested) were identified as LSP (n = 48) or HSP (n = 47) according to their tolerance time to noxious cold stimulation (Cold Pressor Test, 1 °C). All subjects were exposed to two different paradigms of CPM: 1) Fixed temperature 'test-pain' (TP) where phasic, fixed painful heat stimuli of 47 °C were administered before and during a prolonged 'conditioning stimulus' (cold water at 12 °C for 30 s); and 2) Individually based 'pain-60' where TP was determined as the temperature that induced pain at a magnitude of 60 on a 0-100 rating scale (with the same conditioning stimulus).

RESULT

Using both thermal paradigms, LSP subjects showed decreased CPM magnitudes in comparison to HSP (p < 0.0001 in both paradigms). Within each group, no differences in the magnitudes of CPM were found between the two paradigms.

CONCLUSION

These findings show that regardless of the thermal CPM paradigm employed, healthy individuals exhibiting low sensitivity to pain have a low pain inhibition profile and vice-versa. It is suggested that in healthy subjects, pain sensitivity predisposes the magnitude of CPM and not the other way around.

Outcome of a High-Frequency Transcutaneous Electrical Nerve Stimulator (hfTENS) Device for Low Back Pain: A Randomized Controlled Trial

OBJECTIVE

This controlled trial examined the benefit of a high-frequency transcutaneous electrical nerve stimulation (hfTENS) device (the Quell, NeuroMetrix, Inc., Waltham, MA, U.S.A.) for patients with chronic low back pain (CLBP).

METHODS

Thirty-five (n = 35) participants were randomly assigned to use the device each day for 3 months (experimental group) and were compared with 33 subjects without the device (treatment-as-usual control group). All patients were instructed to complete baseline questionnaires and were assessed on thresholds of pressure pain and mechanical temporal summation as part of standardized quantitative sensory testing (QST). The subjects also uploaded smartphone applications (apps) for tracking use of the hfTENS and for daily pain assessment. Each participant completed weekly phone interviews, was prompted to complete daily pain app assessments, and was asked to repeat the baseline questionnaires again after 6 weeks and 3 months.

RESULTS

Sixty percent of the subjects were female, 77.9% were Caucasian, and the average age was 46.2 years. Significant reductions in pain intensity (P < 0.01) and activity interference (P < 0.025) and significant improvements in pain catastrophizing (P < 0.025) were noted in the experimental group compared with the control group. No group differences were found on depression, anxiety, or pain-related disability. Older subjects with a longer duration of pain tended to use the hfTENS more often. Subjects who showed greater sensitivity based on QST results revealed increased use of the hfTENS (P < 0.025) and tended to believe that the hfTENS was more helpful in reducing their back pain, but these findings did not reach significance (P = 0.09).

CONCLUSION

These results suggest that hfTENS can have a moderate effect in reducing pain and improving quality of life in low back pain patients. Further trials designed to determine the mechanism of action of the hfTENS are needed.

Anchoring the Numeric Pain Scale Changes Pain Intensity Reports in Patients With Chronic But Not With Acute Pain

BACKGROUND

Despite enormous differences between acute and chronic pain, the numeric pain scale (NRS) is commonly used in pain research and clinical practice for assessing the intensity of both acute and chronic pain. The use of this scale has been challenged as it may fail to accurately reflect the pure intensity of chronic pain.

AIM

To compare the effect of anchoring the NRS on the intensity of pain reported by patients with acute vs. chronic pain.

METHODS

Patients with acute postoperative or chronic pain (n = 100/group) were requested to rate their: current clinical pain intensity on an NRS from 0 to 100; the intensity of an anchoring pain event on the same scale; and subsequently to rate again their current pain intensity while making reference to the reported intensity of the pain event. The magnitude of correction was compared between the 2 groups.

RESULTS

The anchoring pain was rated identically between the groups. However, following anchoring, patients with chronic pain made a significantly larger correction of their pain intensity than did those with acute pain (mean ± standard deviation = 9 ± 9, median [interquartile range] = 10 [0 to 10] vs. 3 ± 7, 0 [0 to 5], respectively; P < 0.0001). More patients in the chronic pain group corrected their pain intensity. Logistic regression showed that chronic pain and female gender significantly increased the likelihood of making the correction (chronic pain: odds ratio 7.2, 95% confidence interval 3.5 to 15.1, P < 0.0001; female gender: odds ratio 2.8, 95% confidence interval 1.4 to 5.5, P < 0.0001).

CONCLUSION

The results suggest that anchoring the NRS can potentially improve the accuracy of reported chronic pain intensity.

Association between self-perceived pain sensitivity and pain intensity after cardiac surgery

Background and purpose

Cardiac surgical pain remains a clinical challenge affecting about 40% of individuals in the first six months post-cardiac surgery, and continues up to two years after surgery for about 15–20%. Self-perceived sensitivity to pain may help to identify individuals at risk for persistent cardiac surgical pain to optimize health care responses. The purpose of this study was to assess the relationship between self-perceived pain sensitivity assessed by the Pain Sensitivity Questionnaire (PSQ) and postoperative worst pain intensity up to 12 months after cardiac surgery. Sex differences in baseline characteristics and the PSQ scores were also assessed.

Methods

This study was performed among 416 individuals (23% women) scheduled for elective coronary artery bypass graft and/or valve surgery between March 2012 and September 2013. A secondary data-analysis was utilized to explore the relationship between preoperative PSQ scores and worst pain intensity rated preoperatively, across postoperative Days 1–4, at 2 weeks, and at 1, 3, 6, and 12 months post-surgery. Linear mixed model analyses were performed to estimate changes in pain intensity during 1-year follow-up.

Results

The mean (±standard deviation) PSQ-total score was 3.3±1.4, with similar scores in men and women. The PSQ-total score was significantly associated with higher worst pain intensity ratings adjusted for participant characteristics (p=0.001).

Conclusion

Use of the PSQ before surgery may predict cardiac surgical pain intensity. However, previous evidence is limited and not consistent, and more research is needed to substantiate our results.