General Pain Sensitivity Research Articles

Pain Sensitivity Questionnaire: Cross-cultural adaptation and validation of the Greek version.

The Pain Sensitivity Questionnaire (PSQ) was developed to assess general pain sensitivity. This study aimed to validate the Greek version of PSQ. The questionnaire was translated into Greek (PSQ-GR) and piloted in a small sample of patients with chronic pain (n=35). A total of 146 chronic pain patients and healthy volunteers completed the PSQ-GR, the Pain Catastrophizing Scale (PCS), Hospital Anxiety and Depression Scale (HADS) and Central Sensitization Inventory (CSI). To evaluate the test-retest reliability, 36 volunteers completed the PSQ-GR twice over 7±2days. Internal consistency was excellent (Cronbach's alpha 0.90-0.96) for PSQ-total, PSQ-minor, and PSQ-moderate. The Intraclass Correlation Coefficient was estimated at 0.90-0.96 for PSQ-total, PSQ-minor and PSQ-moderate and the SEM was 0.59-0.90 for PSQ-total, PSQ-minor and PSQ-moderate approximately. The smallest detectable change was 0.48 for PSQ-total, 0.47 for PSQ-minor and 0.44 for PSQ-moderate. Positive and significant correlations were observed between PSQ-GR and HADS (r=0.38, p<0.01), PCS (r=0.41, p<0.01) and CSI (r=0.30, p<0.01). Statistically significant differences in PSQ-GR scores were identified between the healthy volunteers and the chronic pain patients. The PSQ-GR is a reliable and valid tool that can assess pain sensitivity in healthy individuals and chronic musculoskeletal pain patients.

Elevated pain sensitivity is associated with reduced rapid eye movement (REM) sleep in females with comorbid temporomandibular disorder and insomnia.

Patients with chronic pain disorders, including Temporomandibular Disorders (TMDs) endorse high levels of sleep disturbances, frequently reporting reduced sleep quality. Despite this, little is known about the effect that daytime pain has on the microstructure and macro-architecture of sleep. Therefore, we aimed to examine the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST), is associated with objective sleep parameters the following night, including sleep architecture and power spectral density, in women with TMD. 144 females with myalgia and arthralgia by examination using the Diagnostic criteria for TMD completed a comprehensive QST battery consisting of General Pain Sensitivity, Central Sensitization Index, and Masseter Pressure Pain Threshold assessments. Polysomnography was collected the same night to measure sleep architecture and calculate relative power in delta, theta, alpha, sigma, and beta power bands. Central Sensitization (B = -3.069, P = .009), General Pain Sensitivity Indices (B = -3.069, P = .007), and Masseter Pain Pressure Threshold (B = 0.030, P = .008) were significantly associated with lower REM% both before and after controlling for covariates. Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands nor with any other sleep architectural stages. Our findings demonstrate that higher generalized pain sensitivity, masseter pain pressure threshold, as well as central sensitization were associated with a lower percentage of REM in participants with myofascial pain and arthralgia of the masticatory system. These findings provide an important step toward understanding the mechanistic underpinnings of how chronic pain interacts with sleep physiology.

Breastfeeding-related Pain, Sensory Over-responsiveness, and Exclusive Breastfeeding at 6 Months: A Prospective Cohort Study

BackgroundExclusive breastfeeding (EBF) is recommended for the first 6 months of life, yet EBF rates at 6 months (T3) in most developed countries are low. Painful and nonpainful sensory stimuli processing is linked, and while pain has been suggested to restrict breastfeeding, its coupling with sensory over-responsiveness (SOR) in relation to breastfeeding has not yet been reported. ObjectiveWe aimed to explore whether breastfeeding-related pain, SOR, and general pain sensitivity predict nonexclusive breastfeeding (NEBF) at T3. Study DesignIn this prospective study, participants were recruited at 2 days postpartum (enrollment). For the assessment of breastfeeding-related pain, participants completed the visual analogue scale and the Short-Form McGill Pain Questionnaire at enrollment, and at 6 weeks after birth. At T3, they completed the Pain Sensitivity Questionnaire and the Sensory Responsiveness Questionnaire-Intensity Scale and then provided information about their breastfeeding status. Participants were divided into two groups accordingly: EBF and NEBF. ResultsA total of 164 participants were reached at T3: EBF (n = 105) and NEBF (n = 59). The incidence of SOR was significantly higher among NEBF compared with EBF participants (25.4% vs. 11.4%; p = .020). Between enrollment and 6 weeks after birth, 72.3% of the EBF participants had reported a ≥30% pain reduction, compared with 44.8% of the NEBF participants (p = .001). Logistic regression modeling revealed that both breastfeeding-related pain reduction and SOR predicted NEBF at T3 (p < .001), indicating a 3.2 times (p = .001) and 2.5 times (p = .041) odds ratio for NEBF, respectively. ConclusionsSOR and sustained breastfeeding-related pain predict NEBF at T3 and may emerge as substantial breastfeeding barriers.

Stimulation of lateral parabrachial (LPB) to central amygdala (CeA) pituitary adenylate cyclase-activating polypeptide (PACAP) neurons induces anxiety-like behavior and mechanical allodynia

BackgroundAnxiety disorders are the most prevalent psychiatric disorders, and they are highly comorbid with chronic pain conditions. The central nucleus of the amygdala (CeA) is known not only for its role in the regulation of anxiety but also as an important site for the negative affective dimension of pain. Pituitary adenylate cyclase activating polypeptide (PACAP), a neuropeptide whose terminals are abundant in the CeA, is strongly implicated in the stress response as well as in pain processing. Here, using Cre-dependent viral vectors, we explored in greater detail the role of the PACAP projection to the CeA that originates in the lateral parabrachial nucleus (LPB). MethodsWe first performed a circuit mapping experiment by injecting an anterograde Cre-dependent virus expressing a fluorescent reporter in the LPB of PACAP-Cre mice and observing their projections. Then, we used a chemogenetic approach (a Cre-dependent Designer Receptors Activated by Designer Drugs, DREADDs) to assess the effects of the direct stimulation of the PACAP LPB to CeA projection on general locomotor activity, anxiety-like behavior (using a defensive withdrawal test), and mechanical pain sensitivity (using the von Frey test). ResultsWe found that the CeA, together with other areas, is one of the major downstream projection targets of PACAP neurons originating in the lateral parabrachial nucleus (LPB). In the DREADD experiment, we then found that the selective activation of this neuronal pathway is sufficient to increase both anxiety-like behavior and mechanical pain sensitivity in mice, without affecting general locomotor activity. ConclusionIn conclusion, our data suggest that the dysregulation of this circuit may contribute to a variety of anxiety disorders and chronic pain states, and that PACAP may represent an important therapeutic target for the treatment of these conditions.

Age-Related Changes in Corneal Sensitivity.

The aim of this prospective cross-sectional cohort study was to clinically test whether corneal sensation decreases with age, based on subject feedback (psychophysical method), and whether it correlates with general pain perception. Subjects were recruited from 2 equally large age groups: group A (18-30 years) and group B (50-70 years; n = 45 per group). The inclusion criteria were healthy eyes, Ocular Surface Disease Index ≤13, and no contact lens wear. Corneal sensitivity threshold (CST) measurements were performed twice during each of the 2 visits, with the aid of the new Swiss liquid jet esthesiometer for corneal sensitivity (SLACS) and Cochet-Bonnet (CB) esthesiometer. A general pain sensitivity score was obtained from all participants. Ninety subjects completed the study (n = 45 per age group, average age in group A: 24.2 ± 2.94 years, group B: 58.5 ± 5.71 years). Statistically higher CSTs for age group B were only observed for SLACS (mean difference: 1.58 dB, P < 0.001). No correlation was observed between the pain score and the CSTs obtained with either esthesiometry method (r = 0.11, P = 0.25 for liquid jet and r=-0.076, P = 0.61 CB). A statistically significant decrease in corneal sensitivity was observed for the older age group with SLACS in this study, with CB however only a trend in the same direction was noted. General pain perception was not found to correlate with ocular surface sensation.

Cross-sectional study of pain-related variables before and during the COVID-19 pandemic in patients with COPD

BackgroundThe impact of the COVID-19 pandemic influences of COPD patients. The worsening of their health status may contribute to a higher pain prevalence. AimThe aim of this study was to analyze the pain-related variables before and during the COVID-19 pandemic in patients with chronic obstructive pulmonary disease. MethodsIn this cross-sectional case-control study, stable patients with chronic obstructive pulmonary disease without a COVID-19 diagnosis were evaluated before and during the pandemic. The main outcomes were the pronociceptive pain profile (general pain sensitivity, pain intensity, pain interference, and pressure pain sensitivity) and the psychological vulnerability (perceived health status, anxiety, and depression). ResultsOur results showed that patients with chronic obstructive pulmonary disease during COVID-19 pandemic experienced higher general pain sensitivity and intensity with statistical differences in pain interference (p < .001), being the overall perceived health status lower than before the pandemic (p < .05). ConclusionsWe concluded that patients with chronic obstructive pulmonary disease during the COVID-19 pandemic showed a rise the pronociceptive pain profile accompanied by increased psychological vulnerability.

Increased Pain Sensitivity Is Associated with Reduced REM Sleep in Females with Temporomandibular Joint Disorder (TMD)

Previous evidence demonstrates that the incidence of chronic sleep disturbance is high in patients with temporomandibular joint disorder (TMD). However, there has been little examination of whether heightened daytime pain sensitivity in this population is associated with alter sleep architecture at night. We aimed to test the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST) is associated with objective markers of sleep physiology, including sleep architecture and power spectral density bands, in patients with TMD. Female participants (n=149) with insomnia and TMD were recruited as part of a randomized-controlled trial. Pre-randomization, we performed a quantitative sensory testing (QST) battery to measure General Pain Sensitivity, a Central Sensitization Index, and Masseter Pressure Pain Threshold, and performed polysomnography (PSG) that night to calculate sleep architecture parameters (N1%, N2%, SWS%, REM%) and derive relative power in the Delta (0.5-3.5 Hz), Theta (3.5-8.0 Hz), Alpha (8.0-15.0 Hz), and Beta (15-30.0 Hz) spectral bands during sleep. We fit linear regression models with sleep parameters as the outcome, and pain sensitivity as the predictor, controlling for age, depressive symptom severity, and race. Higher Central Sensitization (B = -2.863, P = <0.01) and General Pain Sensitivity Indices (B = -3.069, P = <0.01) were significantly associated with lower REM% both before after controlling for covariates, however masseter pressure pain threshold was not significantly associated with REM% (B = -0.0259, P = 0.0743). Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands, or with any other sleep architectural stages. Heightened pain sensitivity, measured using QST is associated with objective features of sleep architecture in TMD patients, potentially due to heightened pain interfering with sleep. These findings may contribute to understanding of physiological mechanisms through which acute and chronic pain result in sleep disruption. Grant support from NIH Grant R01 DE019731. Previous evidence demonstrates that the incidence of chronic sleep disturbance is high in patients with temporomandibular joint disorder (TMD). However, there has been little examination of whether heightened daytime pain sensitivity in this population is associated with alter sleep architecture at night. We aimed to test the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST) is associated with objective markers of sleep physiology, including sleep architecture and power spectral density bands, in patients with TMD. Female participants (n=149) with insomnia and TMD were recruited as part of a randomized-controlled trial. Pre-randomization, we performed a quantitative sensory testing (QST) battery to measure General Pain Sensitivity, a Central Sensitization Index, and Masseter Pressure Pain Threshold, and performed polysomnography (PSG) that night to calculate sleep architecture parameters (N1%, N2%, SWS%, REM%) and derive relative power in the Delta (0.5-3.5 Hz), Theta (3.5-8.0 Hz), Alpha (8.0-15.0 Hz), and Beta (15-30.0 Hz) spectral bands during sleep. We fit linear regression models with sleep parameters as the outcome, and pain sensitivity as the predictor, controlling for age, depressive symptom severity, and race. Higher Central Sensitization (B = -2.863, P = <0.01) and General Pain Sensitivity Indices (B = -3.069, P = <0.01) were significantly associated with lower REM% both before after controlling for covariates, however masseter pressure pain threshold was not significantly associated with REM% (B = -0.0259, P = 0.0743). Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands, or with any other sleep architectural stages. Heightened pain sensitivity, measured using QST is associated with objective features of sleep architecture in TMD patients, potentially due to heightened pain interfering with sleep. These findings may contribute to understanding of physiological mechanisms through which acute and chronic pain result in sleep disruption. Grant support from NIH Grant R01 DE019731.

Insomnia with objective short sleep duration in women with temporomandibular joint disorder: quantitative sensory testing, inflammation and clinical pain profiles

Objectives/backgroundTemporomandibular joint disorder (TMD) is a disabling facial pain syndrome with a high prevalence of insomnia that primarily affects women. Insomnia with objective short sleep duration (ISSD) is an emerging phenotype linked to cardiometabolic morbidity and increased mortality. The present report examines the association of ISSD on clinical and laboratory pain and systemic inflammation in TMD. MethodsWe collected baseline data from 128 women with TMD and insomnia as part of a clinical trial evaluating psychological interventions for sleep and pain. Participants completed self-report questionnaires, one-night polysomnography, a two-week actigraphy assessment, quantitative sensory testing (QST) to assess cold pain tolerance, pain sensitivity and central sensitization and circulating Interleukin-6 levels were measured to assess systemic inflammation. Results24.2% (n = 31) of the sample met criteria for ISSD [polysomnography (sleep duration <6 h)]. Compared to those with insomnia and normal sleep duration, ISSD were older (40.4 vs. 34.9,p < 0.05) and a greater proportion self-identified as Black (48.4% vs 11.3%,p < 0.001). Multivariate regressions revealed that ISSD endorsed higher self-report pain severity and functional limitation of the jaw. ISSD also demonstrated increased generalized pain sensitivity, enhanced central sensitization, cold pressor tolerance and higher resting interleukin-6 levels. ConclusionsThis is the first study to characterize the ISSD phenotype in a chronic pain sample and expand the scope of its negative health outcomes to chronic pain. ISSD may be an important chronic pain phenotype associated with a more severe clinical and laboratory pain profile, and future studies should focus on implications for treatment response and disease trajectory. Clinical trialClinicalTrials.gov Identifier: NCT01794624.

Pain sensitivity in men who have never experienced a headache: an observer blinded case control study

BackgroundHeadache affects 90–99% of the population. Based on the question “Do you think that you never ever in your whole life have had a headache?” 4% of the population say that they have never experienced a headache. The rarity of never having had a headache suggests that distinct biological and environmental factors may be at play. We hypothesized that people who have never experienced a headache had a lower general pain sensitivity than controls.MethodsWe included 99 male participants, 47 headache free participants and 52 controls, in an observer blinded nested case-control study. We investigated cold pain threshold and heat pain threshold using a standardized quantitative sensory testing protocol, pericranial tenderness with total tenderness score and pain tolerance with the cold pressor test. Differences between the two groups were assessed with the unpaired Student’s t-test or Mann-Whitney U test as appropriate.ResultsThere was no difference in age, weight or mean arterial pressure between headache free participants and controls. We found no difference in pain detection threshold, pericranial tenderness or pain tolerance between headache free participants and controls.ConclusionOur study clearly shows that freedom from headache is not caused by a lower general pain sensitivity. The results support the hypothesis that headache is caused by specific mechanisms, which are present in the primary headache disorders, rather than by a decreased general sensitivity to painful stimuli.Trial registrationRegistered at ClinicalTrials.gov (NCT04217616), 3rd January 2020, retrospectively registered.

Klinischer Vergleich eines neu entwickelten Prototyps zur Messung der Hornhautsensibilität zum aktuellen Goldstandard

Purpose. The aim of the study was to test a newly developed prototype for corneal sensitivity measurement (liquid jet (LJ) with saline as stimulus) for repeatability and correlation with the Cochet-Bonnet esthesiometer (CB). This is an excerpt of a master thesis, which was part of a larger study Material and Methods. Corneal sensitivity thresholds (CST) were determined for 30 subjects, in a clinical trial with 30 subjects, with each device on two separate dates (with inter- vals of at least one day and a maximum of fourteen days). In addition, the pain sensitivity questionnaire (PSQ) was applied to determine any possible correlation with corneal sensitivity. Results. Similar standard deviations of the CSTs for LJ and CB were obtained (LJ (M ± SD): 24.3 ± 2.0 dB; CB (M ± SD): 20.0 ± 2.0 dB). No statistically significant difference in CST was found between the two visits for LJ (mean differen- ce: -0.063 dB, p = 0.78), however there was a statistically significant difference for CB (mean difference: -0.641 dB, p = 0.003). LJ CSTs correlated moderately positively with CB CSTs and PSQ (LJ-CB: r = 0.476, p &lt; 0.001; LJ-PSQ: r = 0.437, p &lt; 0.001). Conclusion. LJ offers a significantly larger stimulus bandwidth than CB. Better reproducibility was observed for LJ, while correlation between the results for the two instruments was good. Significant moderate positive correlation was found between LJ CSTs and general pain sensitivity. Keywords esthesiometry, Cochet-Bonnet, Liquid Jet, prototype, PSQ

General pain perception sensitivity, lid margin sensitivity and gas permeable contact lens comfort

BackgroundThe non‐predictable variability in the capability of sensory adaptation to rigid gas permeable (RGP) contact lenses (CLs) represents a considerable challenge for CL practitioners and patients when choosing this CL type. This study explored if lid margin sensitivity and general pain sensitivity at baseline may help predict experienced subjective comfort of RGP CL wear.MethodsFor this prospective clinical cohort study, subjects filled in the Pain Sensitivity Questionnaire and lid margin sensitivity was measured at the lid wiper of the upper and lower lid at baseline, using the Cochet Bonnet aesthesiometer. RGP CL parameters were determined based on corneal topography, with additional use of fluorescein simulation. During the second visit, lid wiper sensitivity measurement was repeated and the RGP CLs were worn for 40-minutes. Upon removal of the CLs, lid wiper sensitivity measurement was repeated and spontaneous CL comfort was rated.ResultsThirty‐four subjects participated (mean age: 23.85 ± 5.39-years; 17 male). No correlation could be observed between the baseline lid margin sensitivity and spontaneous CL comfort (r = 0.013, p = 0.9417, upper lid; r = 0.016, p = 0.9277, lower lid). A decrease in lid margin sensitivity was obtained after CL wear (p = 0.0004, upper lid; p = 0.0001, lower lid). A good correlation was observed between Pain Sensitivity Questionnaire score and spontaneous CL comfort (r = 0.62, p = 0.0007).ConclusionThe results of this study suggest that lid margin sensitivity may not play an important role in spontaneous RGP CL comfort. The use of the Pain Sensitivity Questionnaire may well help select patients who are more likely to show good spontaneous tolerance of RGP CLs.

Static mechanical allodynia in post-surgical neuropathic pain after breast cancer treatments

Objectives Static mechanical allodynia (SMA), i.e., pain caused by normally non-painful static pressure, is a prevalent manifestation of neuropathic pain (NP). Although SMA may significantly affect the patient's daily life, it is less well studied in the clinical context. We aimed to characterize SMA in women with chronic post-surgical NP (CPSNP) after breast cancer surgery. Our objective was to improve understanding of the clinical picture of this prevalent pain condition. This is a substudy of a previously published larger cohort of patients with intercostobrachial nerve injury after breast cancer surgery (Mustonen et al. Pain. 2019;160:246-56). Methods We studied SMA in 132 patients with CPSNP after breast cancer surgery. The presence, location, and intensity of SMA were assessed at clinical sensory examination. The patients gave self-reports of pain with the Brief Pain Inventory (BPI). We studied the association of SMA to type of surgery, oncological treatments, BMI, other pains, and psychological factors. General pain sensitivity was assessed by the cold pressor test. Results SMA was prevalent (84%) in this cohort whereas other forms of allodynia were scarce (6%). Moderate-to-severe SMA was frequently observed even in patients who reported mild pain in BPI. Breast and the side of chest were the most common locations of SMA. SMA was associated with breast surgery type, but not with psychological factors. Severe SMA, but not self-reported pain, was associated with lower cold pain tolerance. Conclusions SMA is prevalent in post-surgical NP after breast cancer surgery and it may represent a distinct NP phenotype. High intensities of SMA may signal the presence of central sensitization. Implications SMA should be considered when examining and treating patients with post-surgical NP after breast cancer surgery.

Central mechanisms of pain in orofacial pain patients: Implications for management.

Central sensitization (CS) is a form of neuroplasticity characterized by changes in the neural sensitivity, responsiveness, and/or output that are not contingent on peripheral input nor activity-dependent. CS is characterized by activation of unmyelinated C-fibers resulting in a cascade of events at molecular and cellular levels which eventuate into generation of synaptic currents at rest. CS, therefore, contributes to heightened generalized pain sensitivity, further complicates the process of reaching a diagnosis, and increases the possibility of treatment failure. BODY: Trigeminal nerve is the main sensory supplier of the anterior part of the head, including the intraoral structures. Primary afferent nociceptors of the trigeminal nerve and low threshold mechanoreceptors synapse with wide dynamic range (WDR) neurons in the pons. This multifaceted network of nerve interactions which is further complicated by the modulatory circuits that can suppress or heighten the activity of WDR neurons is one of the main contributors to CS. The importance of CS in orofacial pain disorders is emphasized in the context of chronic pain development. As for all chronic pain conditions, it is crucial to consider the biopsychosocial aspects of chronic orofacial pain in managing this diverse group of conditions. This review highlights current understanding of the biopsychosocial model and central mechanisms contributing to the pathogenesis of chronic orofacial pain.

Ethnic Differences in Experimental Pain Responses Following a Paired Verbal Suggestion With Saline Infusion: A Quasiexperimental Study.

Ethnic differences in placebo and nocebo responses are an important, yet underresearched, patient factor that might contribute to treatment disparities. The purpose of this study was to examine ethnic differences in pain trajectories following a verbal suggestion paired with a masked, inert substance (i.e., saline). Using a quasiexperimental design, we examined differences between 21 non-Hispanic Black (NHB) participants and 20 non-Hispanic White (NHW) participants in capsaicin-related pain rating trajectories following a nondirectional verbal suggestion + saline infusion. All participants were told that the substance would "either increase pain sensation, decrease it, or leave it unchanged." A spline mixed model was used to quantify the interaction of ethnicity and time on ratings. There was a significant Ethnicity × Time interaction effect (β = -0.28, p = .002); NHB individuals reported significantly greater increases in pain following, but not before, the verbal suggestion + saline infusion. Sensitivity analyses showed no change in primary results based on differences in education level, general pain sensitivity, or condition order. The present results showed ethnic differences in pain response trajectories following a verbal suggestion + saline infusion and suggest that future research rigorously examining possible ethnic differences in placebo/nocebo responses is warranted.

The Effect of Stress on Repeated Painful Stimuli with and Without Painful Conditioning.

Stress and pain have been interrelated in clinical widespread pain conditions. Studies indicate that acute experimental stress in healthy volunteers has a negative effect on the descending inhibitory pain control system and thus the ability to inhibit one painful stimulus with another (conditioned pain modulation [CPM]) although without effect on general pain sensitivity. CPM effects can be assessed immediately after the stress induction, whereas some physiological stress responses (e.g., cortisol release) are delayed and longer lasting. It is unclear whether CPM may relate to stress-induced increases in cortisol. Twenty-five healthy men had CPM effects measured over a period of 10 minutes. Pain detection thresholds (PDTs) were assessed by repeated test stimuli with cuff algometry on one leg, with and without painful cuff pressure conditioning on the contralateral leg. CPM effects, assessed as the increase in PDT during conditioning stimulation compared with without, were measured before and after experimental stress and a control condition (Montreal Imaging Stress Task [MIST]). Saliva cortisol levels and self-perceived stress were collected. Participants reported the MIST to be more stressful compared with the MIST control, but cortisol levels did not change significantly from baseline. In all sessions, PDT increased during conditioning (P = 0.001), although the MIST compared with the MIST control had no significant effect on PDT or CPM effects. A negative correlation between changes in cortisol and conditioned PDT was found when applying the MIST (P < 0.03). No significant effect of stress was found on CPM compared with a matched control condition. Individual changes in experimental stress and in conditioned pain sensitivity may be linked with cortisol.

Structural Consistency of the Pain Sensitivity Questionnaire in the Cooperative Health Research In South Tyrol (CHRIS) Population-Based Study

The self-reported Pain Sensitivity Questionnaire (PSQ) is a valid supplement to experimental pain testing. However, the latent constructs determining the originally proposed 1 general score (PSQ-total) and 2 subscores (PSQ-moderate and PSQ-minor) have not been consistently investigated in population-based studies or between genders. Based on a single construct hypothesized by expert knowledge or alternative constructs upon empirical evidence, PSQ structures were explored and confirmed among 4,820 participants aged 18 to 93 years of the Cooperative Health Research In South Tyrol (CHRIS) study. By exploratory factor analysis, we identified 3 alternative sets of PSQ imagined painful situations comprising 14, 10, and 9 items, which displayed simple structures of the rotated factor loadings of direct interpretation. In confirmatory analysis (CFA) of 1 latent factor, the 10-item set yielded acceptable goodness-of-fit overall, better fit than the alternative sets and consistent structural properties between genders. Separate analyses based on 14- and 9-item sets returned considerable correlations between 2 latent constructs. In higher-order CFA with each set, 1 first-order general factor explained a large part of the variances of 2 second-order factors. One dominant construct consistently describes the factorial structure of the PSQ. Averaging across the 10-item set, the PSQ-short score represents a structurally robust, gender-consistent, and practical measure of general pain sensitivity. PerspectiveOne dominant latent construct of general pain sensitivity consistently determines responses to the self-reported PSQ. The PSQ-short score maintains similar psychometric properties to the PSQ-total and between genders. This measure is attractive for large-scale research and clinical screening of pain sensitivity.

Experimental pain sensitivity in women with vestibulodynia: a pilot study

Objective: Investigate pain sensitivity in women with vestibulodynia using two experimental pain assessments outside the vulvar region: intramuscular infusion of an acidic phosphate buffer and pressure pain thresholds (PPTs) of the lower limb. Methods: Three women with a history of vestibulodynia (all 24 years old) participated after providing written informed consent. PPTs of the lower limb were assessed using a hand-held Somedic digital algometer (30 kilopascal (kPa)/sec) at baseline (pre-infusion) and during the intramuscular infusion. The acidic phosphate buffer (pH 5.2) was infused into the anterior tibialis muscle at a rate of 40 ml/hr for 15 min (10 ml total). Peak local (infusion site) and referred (ankle) pain ratings were assessed verbally, as well as vulvar pain at the time of the infusion (0 – 10 Borg Scale). Results: Peak local pain was higher in two of the three subjects (2.5, 4.0, 9.5) than the average pain ratings in 34 healthy age-matched (21 – 27 years old) women from our laboratory, mean 3.0/10 (standard deviation (SD) 2.2; range 0.5 to 10). Peak referred pain was also higher in the same two subjects (0, 4.25, and 7.5) than the average of the controls (mean 1.5; SD 1.8; range 0 – 9.0). Similarly, vulvar pain patients all exhibited greater mechanical pain sensitivity (lower PPT values) than the average of the healthy controls (mean [SD] 246.3 [101.7] kPa in patients vs. 431.3 [109.33] in controls). Conclusion: Preliminary data suggests women with vestibulodynia may exhibit greater generalized pain sensitivity to noxious stimuli than the general population of women.

Multidimensional Neuropathic Pain Phenotypes after Spinal Cord Injury.

Identifying clinical neuropathic pain phenotypes is a first step to better understand the underlying pain mechanisms after spinal cord injury (SCI). The primary purpose of the present study was to characterize multidimensional neuropathic pain phenotypes based on quantitative sensory testing (QST), pain intensity, and utilization of catastrophizing coping strategies. Thermal perception, thermal pain, and vibratory perception thresholds were assessed above and below the level of injury (LOI) in 101 persons with SCI and neuropathic pain, 18 persons with SCI and no neuropathic pain, and 50 able-bodied, pain-free controls. Cluster analysis of QST z-scores below the LOI, pain intensity ratings, and the Coping Strategies Questionnaire (CSQ) catastrophizing subscale scores in subjects with neuropathic pain resulted in two phenotypes: severe neuropathic pain (SNP) with greater pain intensity (7.39 ± 1.57) and thermal and vibratory sensitivity compared with the moderate neuropathic pain (MNP; 5.40 ± 1.43). A factor analysis including all CSQ subscales, the Neuropathic Pain Symptom Inventory (NPSI) total score, and thermal pain sensitivity above and below the LOI resulted in three factors: (1) adaptive pain coping including increasing activities, diverting attention, and reinterpreting pain sensations; (2) catastrophizing, neuropathic pain, and thermal sensitivity including greater NPSI total score, thermal pain sensitivity below the LOI, and catastrophizing; and (3) general pain sensitivity including greater thermal pain sensitivity above the LOI and lower catastrophizing. Our results suggest that neuropathic pain symptom severity post-SCI is significantly associated with residual spinothalamic tract function below the LOI and catastrophizing pain coping.

Reliability and validity of a simple and clinically applicable pain stimulus: sustained mechanical pressure with a spring-clamp

Abstract Background Generalized hyperalgesia, a widespread increased sensitivity to painful stimuli, has been demonstrated in a range of chronic pain conditions including low-back pain. The evidence suggests, that generalized hyperalgesia may be an important factor in the development of chronicity, but it is not commonly assessed in clinical practice. Whereas a range of tools and procedures for the quantitative sensory testing of pain sensitivity is available for laboratory pain research, most experimental pain stimuli are not well suited for clinical practice. In the current study, a simple and inexpensive mechanical spring-clamp was tested as a potential experimental pain stimulus. Methods Ten seconds of mechanical pressure was applied to the thumb of 242 study participants: Healthy volunteers and low-back-pain patients (hospital and primary care). Pain intensity was measured by visual analogue scale before and after conditioned pain modulation by cold-pressor test (CPT). Correlation to pressure pain threshold (PPT) of the infraspinatus muscle and cold-pressor test pain intensity, time to pain onset and time to non-tolerance, was examined. Test/re-test reliability of clamp pain was also assessed and the stimulus–response relationship was examined with a set of 6 different clamps. Conclusions Clamp pain was sensitive to changes in pain sensitivity provoked by conditioned pain modulation (CPM). Test/re-test reliability of the spring-clamp pain was better for healthy volunteers over a period of days, than for hospital patients over a period of weeks. A strong correlation (ρ = 0.73, P |003E; 0.0001) was found between clamp force and evoked pain intensity. Correlation to other pain stimuli varied, with a strong correlation between pre and post-CPM clamp pain intensity (ρ = 0.81, P &gt; 0.0001), moderate correlation between clamp pain and PPT (ρ = −0.43, P &gt; 0.0001), as well as CPT pain intensity (ρ = 0.32, P &gt; 0.0001) and a weak correlation with time to onset of CPT pain (ρ = −0.14, P &lt; 0.05). The application of mechanical pressure is commonly employed to assess general pain sensitivity, and a simple spring-clamp seems a potentially useful instrument for quantitative sensory testing in a clinical setting.

Reliability and validity of a simple and clinically applicable pain stimulus: sustained mechanical pressure with a spring-clamp

Generalized hyperalgesia, a widespread increased sensitivity to painful stimuli, has been demonstrated in a range of chronic pain conditions including low-back pain. The evidence suggests, that generalized hyperalgesia may be an important factor in the development of chronicity, but it is not commonly assessed in clinical practice. Whereas a range of tools and procedures for the quantitative sensory testing of pain sensitivity is available for laboratory pain research, most experimental pain stimuli are not well suited for clinical practice. In the current study, a simple and inexpensive mechanical spring-clamp was tested as a potential experimental pain stimulus. Ten seconds of mechanical pressure was applied to the thumb of 242 study participants: Healthy volunteers and low-back-pain patients (hospital and primary care). Pain intensity was measured by visual analogue scale before and after conditioned pain modulation by cold-pressor test (CPT). Correlation to pressure pain threshold (PPT) of the infraspinatus muscle and cold-pressor test pain intensity, time to pain onset and time to non-tolerance, was examined. Test/re-test reliability of clamp pain was also assessed and the stimulus–response relationship was examined with a set of 6 different clamps. Clamp pain was sensitive to changes in pain sensitivity provoked by conditioned pain modulation (CPM). Test/re-test reliability of the spring-clamp pain was better for healthy volunteers over a period of days, than for hospital patients over a period of weeks. A strong correlation (ρ = 0.73, P |003E; 0.0001) was found between clamp force and evoked pain intensity. Correlation to other pain stimuli varied, with a strong correlation between pre and post-CPM clamp pain intensity (ρ = 0.81, P > 0.0001), moderate correlation between clamp pain and PPT (ρ = −0.43, P > 0.0001), as well as CPT pain intensity (ρ = 0.32, P > 0.0001) and a weak correlation with time to onset of CPT pain (ρ = −0.14, P < 0.05). The application of mechanical pressure is commonly employed to assess general pain sensitivity, and a simple spring-clamp seems a potentially useful instrument for quantitative sensory testing in a clinical setting.