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Objectives: Despite its impact, individual factors associated with persistent low back pain (LBP) remain poorly understood. This study investigated static and dynamic pain sensitivity in adults with persistent LBP versus pain-free controls; and investigated associations between pain sensitivity and 3 clinical pain measures: recalled, resting, and movement-evoked pain (MEP)., Materials and Methods: A lifespan sample of 60 adults with persistent LBP and 30 age-matched/sex-matched controls completed 4 laboratory sessions. Static pain sensitivity (pressure pain threshold [PPT], heat pain threshold) and dynamic pain sensitivity (heat pain aftersensations [AS], temporal summation [TS] of second heat pain) were measured. Demographic and clinical factors collected were education, global cognition, and perceived health. Resting and recalled pain were measured via questionnaire, and MEP via the Back Performance Scale., Results: LBP participants demonstrated lower PPT remotely (hand; F1,84=5.34, P=0.024) and locally (low back; F1,84=9.55, P=0.003) and also had higher AS (F1,84=6.01, P=0.016). Neither static nor dynamic pain sensitivity were associated with recalled pain (P>0.05). However, static pain sensitivity (local PPT) explained an additional 9% variance in resting pain, while dynamic pain sensitivity (AS, TS) explained an additional 10% to 12% variance in MEP., Discussion: This study characterized pain sensitivity measures among individuals with persistent LBP and suggests static pain sensitivity plays a larger role in resting pain while dynamic pain sensitivity plays a larger role in MEP. Future studies will confirm these relationships and elucidate the extent to which changes in static or dynamic pain sensitivity predict or mediate clinical pain among adults with persistent LBP., Competing Interests: Supported by funding from NIH/NCATS Clinical and Translational Science Awards to the University of Florida (TL1 TR000066, UL1 TR000064), and the University of Florida Department of Physical Therapy, Gainesville, FL. NIH/NIA Award to Duke University (5P30AG0928716), Durham, NC. The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Chronic pain is associated with brain atrophy with limited evidence on its impact in the older adult's brain. We aimed to determine the associations between chronic pain and a brain aging biomarker in persons aged 60 to 83 years old. Participants of the Neuromodulatory Examination of Pain and Mobility Across the Lifespan (NEPAL) study (N = 47) completed demographic, psychological, and pain assessments followed by a quantitative sensory testing battery and a T1-weighted magnetic resonance imaging. We estimated a brain-predicted age difference (brain-PAD) that has been previously reported to predict overall mortality risk (brain-PAD, calculated as brain-predicted age minus chronological age), using an established machine-learning model. Analyses of covariances and Pearson/Spearman correlations were used to determine associations of brain-PAD with pain, somatosensory function, and psychological function. Individuals with chronic pain (n = 33) had "older" brains for their age compared with those without (n = 14; F[1,41] = 4.9; P = 0.033). Greater average worst pain intensity was associated with an "older" brain (r = 0.464; P = 0.011). Among participants with chronic pain, those who reported having pain treatments during the past 3 months had "younger" brains compared with those who did not (F[1,27] = 12.3; P = 0.002). An "older" brain was significantly associated with decreased vibratory (r = 0.323; P = 0.033) and thermal (r = 0.345; P = 0.023) detection, deficient endogenous pain inhibition (F[1,25] = 4.6; P = 0.044), lower positive affect (r = -0.474; P = 0.005), a less agreeable (r = -0.439; P = 0.020), and less emotionally stable personality (r = -0.387; P = 0.042). Our findings suggest that chronic pain is associated with added "age-like" brain atrophy in relatively healthy, community-dwelling older individuals, and future studies are needed to determine the directionality of our findings. A brain aging biomarker may help identify people with chronic pain at a greater risk of functional decline and poorer health outcomes.

This study examined the effects of interstimulus interval (ISI) on heat-evoked temporal summation of second pain (TSSP) and tested whether greatest maintenance of TSSP would occur at longer ISIs in older adults. Several lines of evidence support that TSSP is associated with central sensitization and is centrally mediated. The participants were 198 community-dwelling adults divided into 3 age cohorts (18-39, 40-59, and 60-78 years of age). Six TSSP trials used a train of 10 contacts with a preheated probe that made repetitive contact with the volar forearm. Participants completed 2 trials at each ISI of 2.5, 3.5, and 4.5 seconds. The intraclass correlations for each pair of trials support the reliability of the current methodology. Temporal summation of second pain scores declined in a time-dependent manner across ISI. In addition, greater maintenance of TSSP at longer ISIs was observed in middle-aged and older age groups compared with the younger cohort. Significant associations were found between TSSP and measures of recent pain. Greater summation at longer ISIs in older adults would suggest slower decay of excitability in spinal neurons and infer increased risk for central sensitization with advancing age.

Protocols of temporal summation (TS) of pain typically involve the delivery of brief repetitive noxious pulses of a constant intensity while measuring the perceived intensity of pain after each pulse. The size percept of noxious repetitive stimulation has been poorly characterized. Furthermore, no studies have investigated age differences in TS of cold pain. The current study examined TS of pain intensity and the perceived size of the painful area during repetitive noxious heat and cold pulses in healthy younger (n = 104) and older adults (n = 40). Trials of 10 brief repetitive noxious heat or cold pulses were delivered to the upper extremities. Participants rated the perceived size of the painful area or intensity of pain after each pulse. The magnitude of change for the size percept and intensity for pain were calculated for each trial. The results indicated that older adults experienced greater TS of the size percept of cold stimuli compared with younger adults. Additionally, older women experienced greater TS of the size percept of heat stimuli compared with older men and all younger participants. No overall age or sex differences were found in the TS of pain intensity for cold or heat trials. These results suggest dysfunctional modulation of the spatial percept of the painful stimuli by older adults, and in particular older women, during repetitive noxious thermal pulses.

Pain among individuals with knee osteoarthritis (OA) is associated with significant disability in older adults, and recent evidence demonstrates enhanced experimental pain sensitivity. Although previous research showed considerable heterogeneity in the OA clinical pain presentation, less is known regarding the variability in responses to experimental pain. The present study included individuals with knee OA (n = 292) who participated in the Understanding Pain and Limitations in Osteoarthritic Disease study and completed demographic and psychological questionnaires followed by a multimodal quantitative sensory testing (QST) session. Quantitative sensory testing measures were subjected to variable reduction procedures to derive pain sensitivity index scores, which in turn were entered into a cluster analysis. Five clusters were significantly different across all pain sensitivity index variables (P < 0.001) and were characterized by: (1) low pain sensitivity to pressure pain (N = 39); (2) average pain sensitivity across most modalities (N = 88); (3) high temporal summation of punctate pain (N = 38); (4) high cold pain sensitivity (N = 80); and (5) high sensitivity to heat pain and temporal summation of heat pain (N = 41). Clusters differed significantly by race, gender, somatic reactivity, and catastrophizing (P < 0.05). Our findings support the notion that there are distinct subgroups or phenotypes based on experimental pain sensitivity in community-dwelling older adults with knee OA, expanding previous findings of similar cluster characterizations in healthy adults. Future research is needed to further understand the pathophysiological mechanisms underlying pain within these subgroups, which may be of added value in tailoring effective treatments for people with OA.

Objectives: The prevalence of knee osteoarthritis (OA) is increasing with the aging population and is exacerbated by the growing numbers of obese older adults. Low levels of vitamin D, measured by serum 25-hydroxyvitamin D (25(OH)D), in older adults and obese individuals are correlated with several negative health conditions, including chronic pain. This cross-sectional study sought to examine the interactive influence of 25(OH)D levels and obesity on knee OA pain and functional performance measures., Methods: The sample consisted of 256 (63% female) racially diverse (55% black/African Americans) middle-aged and older adults (mean age 56.8 y). Blood was collected for analysis of 25(OH)D by high-performance liquid chromatography. Participants provided self-report regarding knee OA pain and underwent a lower extremity functional performance test., Results: Results demonstrated that obesity was associated with lower levels of 25(OH)D. Participants with adequate 25(OH)D levels reported significantly less knee OA pain compared with participants with deficient or insufficient levels, regardless of obesity status. Furthermore, there was a significant interaction between obesity and 25(OH)D levels for lower extremity functional performance, such that obese individuals with adequate 25(OH)D levels demonstrated better performance than those obese participants with deficient or insufficient 25(OH)D levels., Discussion: The mechanisms by which adequate 25(OH)D levels are associated with pain severity and improved function have not been completely elucidated. It may be that the pleiotropic role of biologically active 25(OH)D influences pain and pain processing through peripheral and central mechanisms. Alternatively, higher levels of pain may lead to reduced outdoor activity, which may contribute to both obesity and decreased vitamin D. Thus, investigating vitamin D status in obese and nonobese individuals with knee OA warrants further study.

Introduction: Despite many studies investigating exercise-induced hypoalgesia, there is limited understanding of the optimal intensity of aerobic exercise in producing hypoalgesic effects across different types of pain stimuli. Given that not all individuals are willing or capable of engaging in high-intensity aerobic exercise, whether moderate-intensity aerobic exercise (MAE) is associated with a hypoalgesic response and whether this response generalizes to multiple pain induction techniques needs to be substantiated., Purpose: This study's purpose is to test for differences in the magnitude of pressure and heat pain modulation induced by MAE and vigorous-intensity aerobic exercise (VAE)., Methods: Twelve healthy young males and 15 females completed one training session and three testing sessions consisting of 25 min of 1) stationary cycling at 70% HR reserve, 2) stationary cycling at 50% HR reserve, or 3) quiet rest (control). Pain testing was conducted on both forearms before and immediately after each condition and included the following tests: pressure pain thresholds, suprathreshold pressure pain test, static continuous heat test, and repetitive pulse heat pain test. Repeated-measures ANOVA was conducted on each pain measure., Results: VAE and MAE reduced pain ratings during static continuous heat stimuli and repetitive heat pulse stimuli, with VAE producing larger effects. VAE also increased pressure pain thresholds, whereas neither exercise influenced suprathreshold pressure pain ratings., Conclusion: These results suggest that MAE is capable of producing a hypoalgesic effect using continuous and repetitive pulse heat stimuli. However, a dose-response effect was evident as VAE produced larger effects than MAE.

Unlabelled: Considerable evidence suggests regular physical activity can reduce chronic pain symptoms. The dysfunction of endogenous facilitatory and inhibitory systems has been implicated in multiple chronic pain conditions. However, few studies have investigated the relationship between levels of physical activity and descending pain modulatory function., Purpose: The purpose of this study was to determine whether self-reported levels of physical activity in healthy adults predicted 1) pain sensitivity to heat and cold stimuli, 2) pain facilitatory function as tested by temporal summation (TS) of pain, and 3) pain inhibitory function as tested by conditioned pain modulation (CPM) and offset analgesia., Methods: Forty-eight healthy adults (age range = 18-76 yr) completed the International Physical Activity Questionnaire (IPAQ) and the following pain tests: heat pain thresholds, heat pain suprathresholds, cold pressor pain, TS of heat pain, CPM, and offset analgesia. The IPAQ measured levels of walking, moderate, vigorous, and total physical activity over the past 7 d. Hierarchical linear regressions were conducted to determine the relationship between each pain test and self-reported levels of physical activity while controlling for age, sex, and psychological variables., Results: Self-reported total and vigorous physical activity predicted TS and CPM (P < 0.05). Individuals who self-reported more vigorous and total physical activity exhibited reduced TS of pain and greater CPM. The IPAQ measures did not predict any of the other pain measures., Conclusions: These results suggest that healthy older and younger adults who self-report greater levels of vigorous and total physical activity exhibit enhanced descending pain modulatory function. Improved descending pain modulation may be a mechanism through which exercise reduces or prevents chronic pain symptoms.

Objectives: To describe and understand varieties and characteristics of sensitization contributing to hyperalgesia in participants with chronic pain conditions., Methods: Thermal stimulation was delivered to the face, forearm, and calf of pain-free participants and individuals with irritable bowel syndrome, temporomandibular pain disorder (TMD), and fibromyalgia syndrome (FM). Three-second contacts by a preheated thermode occurred at 30-second intervals in ascending and then in descending series (0.7°C steps)., Results: Thermal pain ratings during ascending series were greater at each site in individuals diagnosed with chronic pain. Intense pain at the time of testing further enhanced the ratings at all sites, but mild or moderate clinical pain did not have this effect. Thermal pain in all participants was greater during descending series compared with the ascending series of arm and leg stimulation. The hypersensitivity during the descending series was comparable in pain-free, FM and TMD participants but was increased in duration for arm or leg stimulation of FM participants., Discussion: The widespread sensitization for irritable bowel syndrome and TMD participants does not rely on mechanisms of spatial and temporal summation often invoked to explain widespread hyperalgesia associated with chronic pain. Increased sensitivity during descending series of stimulation of an arm or leg but not the face indicates a propensity for sensitization of nociceptive input to the spinal cord. Abnormally prolonged sensitization for FM participants reveals a unique influence of widespread chronic pain referred to deep somatic tissues.

Recent studies indicate that aging is associated with dysfunctional changes in pain modulatory capacity, potentially contributing to increased incidence of pain in older adults. However, age-related changes in offset analgesia (offset), a form of temporal pain inhibition, remain poorly characterized. The purpose of this study was to investigate age differences in offset analgesia of heat pain in healthy younger and older adults. To explore the peripheral mechanisms underlying offset, an additional aim of the study was to test offset at 2 anatomical sites with known differences in nociceptor innervation. A total of 25 younger adults and 20 older adults completed 6 offset trials in which the experimental heat stimulus was presented to the volar forearm and glabrous skin of the palm. Each trial consisted of 3 continuous phases: an initial 15-second painful stimulus (T1), a slight increase in temperature from T1 for 5 seconds (T2), and a slight decrease back to the initial testing temperature for 10 seconds (T3). During each trial, subjects rated pain intensity continuously using an electronic visual analogue scale (0-100). Older adults demonstrated reduced offset compared to younger adults when tested on the volar forearm. Interestingly, offset analgesia was nonexistent on the palm for all subjects. The reduced offset found in older adults may reflect an age-related decline in endogenous inhibitory systems. However, although the exact mechanisms underlying offset remain unknown, the absence of offset at the palm suggests that peripheral mechanisms may be involved in initiating this phenomenon., (Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

A number of laboratory studies have confirmed the efficacy of opioid medication in reducing pain generated by a number of psychophysical modalities. However, one implicit assumption of clinical and experimental pain testing of analgesics is that the analgesic response is stable and will be comparable across repeated administrations. In the current study, the repeatability of opioid analgesia was assessed in a randomized, double-blinded study using 3 psychophysical pain modalities (e.g., thermal, pressure, and ischemic) over 4 medication sessions (2 with active drug, 2 with placebo). Psychophysical responses were evaluated before and after intravenous administration of either morphine (0.08mg/kg; n=52) or pentazocine (0.5mg/kg; n=49). To determine the ability of a drug to reduce pain, 4 analytic methods (i.e., absolute change, percent change, ratio, and residualized change scores) were calculated to generate separate analgesic index scores for each measure and drug condition. All analgesic index scores demonstrated a greater analgesic response compared to saline for both medications, but stability (i.e., test-retest correlations) of the opioid analgesic indices depended on the pain measurement. Ischemic pain outcomes were moderately stable across sessions for both opioid medications; however, heat and pressure analgesic index scores were moderately stable for only morphine and pentazocine, respectively. Finally, within stimulus modalities, analgesic index scores were highly correlated with each other, suggesting that the different methods for computing analgesic responses provided comparable results. These results suggest that analgesic measures are able to distinguish between active drugs. In addition, analgesic responses to morphine and pentazocine demonstrate at least moderate reliability., (Copyright © 2013. Published by Elsevier B.V.)

Robust interindividual variation in pain sensitivity has been observed, and recent evidence suggests that some of the variability may be genetically mediated. Our previous data revealed significantly higher pressure pain thresholds among individuals possessing the minor G allele of the A118G SNP of the mu-opioid receptor gene (OPRM1) compared with those with 2 consensus alleles. Moreover, ethnic differences in pain sensitivity have been widely reported. Yet, little is known about the potential interactive associations of ethnicity and genotype with pain perception. This study aimed to identify ethnic differences in OPRM1 allelic associations with experimental pain responses. A total of 247 healthy young adults from three ethnic groups (81 African Americans; 79 non-white Hispanics; and 87 non-Hispanic whites) underwent multiple experimental pain modalities (thermal, pressure, ischemic, cold pressor). Few African Americans (7.4%) expressed the rare allele of OPRM1 compared to non-Hispanic whites and Hispanics (28.7% vs. 27.8%, respectively). Across the entire sample, OPRM1 genotype did not significantly affect pain sensitivity. However, analysis in each ethnic group separately revealed significant genotype effects for most pain modalities among non-Hispanic-whites (P<.05) but not Hispanics or African Americans. The G allele was associated with decreased pain sensitivity among whites only; a trend in the opposite direction emerged in Hispanics. The reasons for this dichotomy are unclear; they may involve ethnic differences in haplotypic structure, or A118G may be a tag-SNP linked to other functional polymorphisms. These findings demonstrate an ethnicity-dependent association of OPRM1 genotype with pain sensitivity. Additional research is warranted to uncover the mechanisms influencing these relationships., (Copyright © 2012 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

Studies have demonstrated menstrual cycle influences on basal pain perception, but direct evidence of menstrual cycle influences on analgesic responses has not been reported in humans. Our aim was to determine whether the magnitude of morphine and pentazocine analgesia varied across the menstrual cycle. Sixty-five healthy women, 35 taking oral contraceptives (OC) and 30 normally cycling (NOC), underwent experimental pain assessment both before and after intravenous administration morphine (0.08mg/kg) or pentazocine (0.5mg/kg) compared to saline placebo. Both active drug and placebo were administered once during the follicular phase and once during the luteal phase. Measures of heat, ischemic, and pressure pain sensitivity were obtained before and after drug administration. Change scores in pain responses were computed to determine morphine and pentazocine analgesic responses, and medication side effects were recorded. The data were analyzed using mixed-model analyses of variance. NOC women showed slightly greater heat pain sensitivity in the follicular vs luteal phase, while the reverse pattern emerged for OC women (P=0.046). Also, OC women showed lower pressure pain thresholds compared to NOC women (P<0.05). Regarding analgesic responses, NOC women showed greater morphine analgesia for ischemic pain during the follicular vs the luteal phase (P=0.004). Likewise, side effects for morphine were significantly higher in NOC women in the follicular phase than in the luteal phase (P=0.02). These findings suggest that sex hormones may influence opioid responses; however, the effects vary across medications and pain modalities and are likely to be modest in magnitude. Limited menstrual cycle effects on baseline pain responses were observed; however, morphine analgesia and side effects were greater during the follicular phase., (Published by Elsevier B.V.)

This study supports the hypothesis that healthy older adults exhibit decreased endogenous pain inhibition compared to younger healthy controls. Twenty-two older adults (56-77years of age) and 27 controls aged 20-49 participated in five experimental sessions following a training session. Each experimental session consisted of five 60-s trials in which the experimental heat stimulus was presented to the thenar eminence of the left palm with or without a conditioning stimulus (cold-water immersion of the foot). The temperature for the palm (44-49 degrees C) and foot (8-16 degrees C) was customized for each subject. The intensity of experimental pain produced by the contact thermode was continuously measured during the 60-s trial with an electronic visual analogue scale. No significant associations were found between subjects rating of concentration and the overall inhibitory effect. Older subjects failed to demonstrate conditioned pain modulation (CPM) and showed facilitation in the trials using painful concurrent immersion of the foot. A novel aspect of the study was that we recorded "pain offset" (i.e., after-sensations) and found that ratings for the older sample decreased at a slower rate than observed for the group of younger adults suggesting increased central sensitization among the older sample. Decrements in CPM could contribute to the greater prevalence of pain in older age. Since a number of neurotransmitter systems are involved in pain modulation, it is possible age-related differences in CPM are due to functional changes in these systems in a number of areas within the neuroaxis., (Copyright 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.)

Previous investigations of somatic hypersensitivity in IBS patients have typically involved only a single stimulus modality, and little information exists regarding whether patterns of somatic pain perception vary across stimulus modalities within a group of patients with IBS. Therefore, the current study was designed to characterize differences in perceptual responses to a battery of noxious somatic stimuli in IBS patients compared to controls. A total of 78 diarrhea-predominant and 57 controls participated in the study. We evaluated pain threshold and tolerance and sensory and affective ratings of contact thermal, mechanical pressure, ischemic stimuli, and cold pressor stimuli. In addition to assessing perceptual responses, we also evaluated differences in neuroendocrine and cardiovascular responses to these experimental somatic pain stimuli. A subset of IBS patients demonstrated the presence of somatic hypersensitivity to thermal, ischemic, and cold pressor nociceptive stimuli. The somatic hypersensitivity in IBS patients was somatotopically organized in that the lower extremities that share viscerosomatic convergence with the colon demonstrate the greatest hypersensitivity. There were also changes in ACTH, cortisol, and systolic blood pressure in response to the ischemic pain testing in IBS patients when compared to controls. The results of this study suggest that a more widespread alteration in central pain processing in a subset of IBS patients may be present as they display hypersensitivity to heat, ischemic, and cold pressor stimuli.

Recent meta-analyses find various magnitudes of placebo analgesia effects in placebo mechanism trials versus placebo control trials, which have led to debate. To further investigate the magnitude of placebo analgesia in placebo mechanism trials the databases "PubMed", "PsycINFO" and "Web of Science" (2002-2007) were searched with the term "placebo analgesia". Twenty-one articles including 24 studies fulfilled the selection criteria (concerning: mechanisms, control, placebo treatment, randomization and pain measures). The validity of studies was assessed by the authors and effect sizes were calculated via difference scores. The magnitude of placebo analgesia in placebo mechanism studies was large (d=1.00) and about five times larger than placebo analgesia effects in placebo control studies (d=0.15-0.27). Differences in magnitude between the two types of studies appear to result from different types of suggestions given for pain relief. The magnitude of placebo effects was larger in studies that used long-term pain stimuli >20s (d=0.96) as opposed to short-term stimuli (d=0.81) and the largest placebo effects were found in studies wherein hyperalgesia was present (d=1.88). These results replicate our previous finding that placebo analgesic effects are higher in mechanism studies than in placebo control studies. However, since magnitudes of placebo analgesic effects are highly variable it may be valuable to investigate the factors and mechanisms that contribute to this variability as well as differences in magnitudes across types of studies.

Females with Irritable Bowel Syndrome (IBS) and Temporomandibular Disorder (TMD) are characterized by enhanced sensitivity to experimental pain. One possible explanation for this observation is deficiencies in pain modulation systems such as Diffuse Noxious Inhibitory Control (DNIC). In a few studies that used brief stimuli, chronic pain patients demonstrate reduced DNIC. The purpose of this study was to compare sensitivity to prolonged heat pain and the efficacy of DNIC in controls to IBS and TMD patients. Heat pain (experimental stimulus; 44.0-49.0 degrees C), which was applied to left palm, was continuously rated during three 30-s trials across three separate testing sessions under the following conditions: without a conditioning stimulus; during concurrent immersion of the right foot in a 23.0 degrees C (control); and during noxious cold immersion in a (DNIC; 8.0-16.0 degrees C) water bath. Compared to controls, IBS and TMD patients reported an increased sensitivity to heat pain and failed to demonstrate pain inhibition due to DNIC. Controls showed a significant reduction in pain during the DNIC session. These findings support the idea that chronic pain patients are not only more pain sensitive but also demonstrate reduced pain inhibition by pain, possibly because of dysfunction of endogenous pain inhibition systems.

The aim of this study was to examine experimental pain sensitivity in three ethnic groups, African Americans, Hispanic Americans and non-Hispanic White Americans, and to determine whether ethnic identity is differentially associated with pain sensitivity across ethnic groups. Participants included sixty-three African American, sixty-one Hispanic and eighty-two non-Hispanic white participants who were assessed using three experimental pain measures: thermal, cold-pressor and ischemic. Participants' ethnic identity was assessed using the Multi-group Ethnic Identity Measure (MEIM). Ethnic group differences in pain responses were observed, with African American and Hispanic subjects showing lower cold and heat pain tolerances than non-Hispanic White Americans. In addition, pain range (i.e. tolerance-threshold) was computed for heat, cold and ischemic pain, and the two minority groups again had lower values compared to non-Hispanic White Americans. Ethnic identity was associated with pain range only for African American and Hispanic groups. Statistically controlling for ethnic identity rendered some of the group differences in pain range non-significant. These findings indicate that ethnic identity is associated with pain sensitivity in ethnic minority groups, and may partially mediate group differences in pain perception. The results of the present investigation provide evidence of ethnic group differences in responses to experimental pain across multiple noxious stimuli, with both minority groups exhibiting greater sensitivity to laboratory evoked pain compared to non-Hispanic White Americans.

Identifying individual differences in pain is an important topic; however, little is known regarding patterns of responses across various experimental pain modalities. This study evaluated subgroups emerging from multiple experimental pain measures. One hundred and eighty-eight individuals (59.0% female) completed several psychological instruments and underwent ischemic, pressure, and thermal pain assessments. Thirteen separate pain measures were obtained by using three experimental pain modalities with several parameters tested within each modality. The pain ratings and scores were submitted to factor analysis that identified four pain factors from which Pain Sensitivity Index (PSI) scores were computed: heat pain (HP), pressure pain (PP), ischemic pain (IP), and temporal summation of heat pain (TS). Cluster analyses of PSI scores revealed four distinct clusters. The first cluster demonstrated high overall pain sensitivity, the second cluster revealed high TS, the third cluster showed particular insensitivity to IP and low sensitivity across pain modalities except PP, and the fourth cluster demonstrated low sensitivity to PP. Significant correlations were found between psychological measures and Index scores and those differed by sex. Cluster membership was associated with demographic variables of ethnicity and sex as well as specific psychosocial variables, although cluster differences were only partially explained by such factors. These analyses revealed that groups respond differently across varied pain stimuli, and this was not related solely to demographic or psychosocial factors. These findings highlight the need for future investigation to identify patterns of responses across different pain modalities in order to more accurately characterize individual differences in responses to experimental pain.

Communication patterns with persons outside the health care system during a pain episode are poorly understood, yet can have a significant influence on patient behavior. This study examined associations between attitudes and beliefs about oral disease and dental care and talking about orofacial pain with laypersons and health care professionals. The subjects were 724 participants in the Florida Dental Care Study, a longitudinal study of oral health among community-dwelling adults. This study used a prospective design with data collected at baseline and the 42-month follow-up using a standardized interview format. Persons with negative attitudes and beliefs were more likely to have talked to a layperson about pain and less likely to have talked to a health care provider. In addition, the attitude that most consistently differentiated between respondents who had communicated only with a layperson from those who had talked to a health care provider was quality of recent visits, a variable representing more of the interpersonal aspects of a health care visit than the eventual outcomes from the treatment received. Our data are consistent with the hypothesis that lay consultation during a pain episode may substitute for formal care for persons with less positive views of the health care system. Intensity ratings and temporal characteristics of pain were also important determinants of these pain-related communication patterns. These findings emphasize the importance of understanding the communication between persons with pain and non-health care professionals, and how these attitudes and communication preferences relate to the management of pain.

Sex-correlated differences in pain perception and behavior have been reported in several studies. Where such differences are found, they are most often in the direction of girls and women reporting more pain than is reported by boys and men. Although biologic, psychologic, and sociocultural factors act interdependently to influence pain responding, most efforts to explain sex-correlated differences in pain have focused on first-order biologic differences between the sexes. The current paper discusses empirical and theoretical literature addressing gender role socialization, cognitive factors, and affective factors associated with sex-correlated differences in pain. We affirm that there is convincing evidence that such psychosocial factors must be taken into account in research on sex-correlated differences in pain. We contend that the use of the dichotomous variable sex as a proxy for presumed biologic aspects of being female or male may obscure the contribution to sex-correlated differences that could be ascribed to the ways in which women and men are socialized with respect to pain perception and pain reporting.

The purpose of this study was to examine racial/ethnic-related differences in a four-stage model of the processing of chronic pain. The subjects were 1557 chronic pain patients (White=1084, African American=473) evaluated at a pain management clinic at a large southeastern university medical center. Using an analysis of covariance controlling for pain duration and education, African American patients reported significantly higher levels of pain unpleasantness, emotional response to pain, and pain behavior, but not pain intensity than Whites. Differences were largest for the unpleasantness and emotion measures, particularly depression and fear. The groups differed by approximately 1.0 visual analogue scale unit, a magnitude that may be clinically significant. Racial/ethnic differences in the linear relationship between stages were also tested using structural equation modeling and LISREL-8. The results indicate differences in linear associations between pain measures with African Americans showing a stronger link between emotions and pain behavior than Whites.

The purpose of this study was to describe race/ethnic differences in the use of formal health care services for painful oral symptoms by older adults. We also considered the sex of the respondent rather than assuming that males and females within a specific racial group would use health care services similarly. To our knowledge, these specific utilization patterns have never been reported before in the pain literature.Telephone interviews were conducted on a stratified random sample of 1,636 community dwelling older (65+) north Floridians. A total of 5,860 households were contacted and screened, with 75.3% participating to the point where their eligibility for the study could be determined. Overall race/ethnic differences in patterns of health care use for orofacial pain were not found. However, when we stratified race/ethnicity by sex, Black females (37.6%) were the least likely to have visited a health care provider, followed by non-Hispanic White females (47.2%), non-Hispanic White males (49.3%), and Black males (62.7%). Point estimates of odds ratio, adjusting for financial differences, indicate that more non-Hispanic White males (OR=1.79) and Black males (OR=2.74) visited a health care provider than Black females. Our results also suggest that for older Black adults, financial constraints have a more significant impact on decisions about health care for orofacial pain than they do for non-Hispanic Whites. For non-Hispanic White respondents, characteristics of the pain symptoms were significant determinates of health care use for their painful oral symptoms. Pain at its worst was a positive predictor for four of the five analyses (jaw joint pain, painful oral sores, temperature sensitivity, and toothache pain). The duration variable (years with pain) was a negative predictor of health care use. This is consistent with the conclusion that individuals seek care early in the course of the symptom, i.e. an active care seeking phase, make emotional or physical adjustments, and then resign themselves to the symptoms.

A previous meta-analysis of clinical analgesic trial studies showed generally low magnitudes of placebo analgesia (N. Engl. J. Med. 344 (2001) 1594). However, as studies included in their analysis used only placebo as a control condition, we conducted two meta-analyses, one in which 23 studies used only placebo as a control condition, and one in which 14 studies investigated placebo analgesic mechanisms. Magnitudes of placebo analgesic effects were much higher in the latter (mean effect size=0.95) as compared to the former (mean effect size=0.15) and were significantly different (P=0.003). This difference as well as differences in effect sizes within studies of placebo mechanisms may be parsimoniously explained by differences in expected pain levels produced by placebo suggestions and by conditioning. Furthermore, some of the studies of placebo analgesic mechanisms indicate that the magnitude of placebo analgesia is higher when the placebo analgesic effect is induced via suggestion combined with conditioning than via suggestion alone or conditioning alone. Based on these findings, we suggest that placebo analgesic effects are most optimally conceptualized in terms of perception of the placebo agent, and therefore a new definition of placebo response is proposed.

This study documented orofacial pain-related communication patterns among community-dwelling dentate adults, health care providers, and persons in the respondent's social network. We report communication patterns for orofacial pain by symptom (toothache pain, pain when chewing, temperature sensitivity of the teeth, painful oral sores, and jaw joint pain). The subjects for the study were 724 participants in the 42-month interview of the Florida Dental Care Study, a longitudinal study of oral health among dentate adults, age 45 and older at baseline. The data were collected using a standardized telephone interview. Pain was more likely to be discussed with a lay consultant (41-66% depending on the symptom) than a health care professional (21-62%). Consistent with studies that report females tend to rely on social networks to cope with pain, more female respondents than males reported having talked to a lay consultant about orofacial pain for most of the symptoms. We also found that rural Black adults were less likely to speak to a health care professional about their orofacial pain. The findings highlight the importance of family, friends, and neighbors within the lay consultation and support network for persons with pain. Recent interest in self-care and the use of complementary and alternative approaches to treatment suggest the importance of considering influences acting within the environment of persons with pain.

Objective: The current study investigated whether the relationship between sex and experimental pain report was explained by systolic blood pressure (SBP) at rest or during pain task, by gender-role socialization as assessed by the Bem Sex Role Inventory, or both. The influence of gender-role socialization on pain report is often inferred but rarely studied., Methods: Fifty female and 54 male healthy, young adults completed the Bem Sex Role Inventory and then underwent a cold pressor task. Blood pressure was assessed before and during pain testing., Results: Univariate analyses indicated significant sex-related differences in pain threshold and pain tolerance. Baseline SBP was positively related to pain tolerance but did not explain sex differences, in accord with previous research. The Bem Sex Role Inventory demonstrated a relationship with pain, but did not explain sex differences., Conclusions: We suggest that context-specific measures of gender are needed to assess gender-related pain behaviors in specific situations. Results from the current study support our contention that gender is part of sex as commonly measured. Also, blood pressure does not appear to fully account for sex-related differences in pain.

This study investigated sex and age cohort differences in the subjective report of orofacial pain symptoms in a stratified sample of community dwelling adults. The subjects were 724 participants in the Florida Dental Care Study, a longitudinal study of oral health among dentate adults, age 45 and older at baseline. Pain prevalence and subjective ratings were assessed for a range of orofacial pain sites using a standardized telephone interview. The results suggest that the 6-month prevalence of jaw joint pain (8.3%), face pain (3.1%), toothache pain (12.0%), painful oral sores (15.6%), and burning mouth (1.6%) found in the FDCS sample are similar to United States population estimates. In addition, prevalence for pain when chewing and temperature sensitivity were also reported as 23% and 24% respectively, suggesting that these two seldom documented painful experiences are common. Female respondents reported higher 6-month prevalence for multiple symptoms and painful oral sores, with trends also observed for female sex as a risk factor for jaw joint pain and face pain, whereas males were more likely to report temperature sensitivity. A higher percentage of females rated their pain as severe enough to impact behavior for jaw joint pain, toothache pain, and painful oral sores. Few overall age effects were found, with the exception of higher prevalence of temperature sensitivity and pain when chewing in the 45--64-year-old group, compared to respondents in the 65+ age cohort. However, the most interesting finding was that when sex by age cohort comparisons were made, with the exception of painful oral sores, all significant differences in pain ratings were found within the 45--64-year-old cohort and not the 65+ group. This finding clarified inconsistencies found in earlier studies in the orofacial pain literature where sex differences in pain ratings were found in several adult samples of a wide range of ages but not in a sample of older adults.

Objective: The purpose of this study was to examine the magnitude of the relation between a postmenopausal woman's hormonal replacement status and clinical pain report in a sample of women experiencing orofacial pain., Design: To accomplish this, pain ratings were collected during a routine chronic pain evaluation at an orofacial pain clinic from a sample of 87 postmenopausal women., Results: Results of ANCOVA (controlling for pain duration) demonstrated that postmenopausal women receiving hormone replacement therapy (HRT) reported higher levels of pain than postmenopausal women not taking HRT. Numeric pain rating scales revealed large effect sizes for worst pain report (0.62), moderate differences for average (0.48) and current (0.39) pain levels, and trivial differences for least pain (0.04). Effect sizes for the McGill Pain Questionnaire indicated somewhat smaller differences (0.35-0.24) between the two groups., Conclusions: This study is among the first to examine the relation between a woman's hormonal status and clinical pain perception and is the first to investigate the role of HRT in a postmenopausal woman's orofacial pain report in a clinical treatment setting. This area of inquiry is particularly salient given the high percentage of women who choose to initiate HRT either after hysterectomy or with the onset of menopause.

Objective: The goal of this study was to examine the relative importance of global affective distress, self-report of depressive symptoms, and presence or absence of major depression to the experience of chronic pain., Setting: A multidisciplinary pain program at a university medical center was the setting for this study., Patients: Subjects in this study were 211 consecutive patients with chronic pain., Outcome Measures: Pain duration, compensation, and litigation status were controlled for in the statistical analyses, as each correlated significantly with at least one of the measures of affect. Global affective distress was assessed using the Global Severity Index (GSI) from the Brief Symptom Inventory. The Beck Depression Inventory and the Center for Epidemiological Studies Depression Scale were used as measures of self-report of depressive symptoms. Presence or absence of major depression was based on DSM-IV criteria., Results and Conclusions: The GSI, Beck Depression Inventory, and Center for Epidemiological Studies Depression Scale were significantly correlated with each measure of the experience of pain, although clinical depression was only significantly related to self-reported disability and negative thoughts about pain. The self-report measures of depression maintained their relation to the dependent measures when the somatic items from the scales were removed, suggesting that the relations were not spuriously due to the influence of pain symptoms on the scales. When examining the unique contribution of each variable to the experience of pain (by simultaneously controlling for the other measures of affect), the GSI was uniquely related to the sensory and affective components of pain. Self-report of depressive symptoms was more highly related to a measure of the evaluative component of pain and uniquely related to self-reported disability and negative thoughts about pain. The results are discussed within the context of theoretical models of the relation between pain and affect, and suggestions for future research are presented.

The purpose of this article is to review the sixteen published studies that examine associations between the perception of experimentally induced pain across menstrual cycle phases of healthy females. We also performed a meta-analysis to quantitatively analyze the data and attempt to draw conclusions. The results suggest that there are relatively consistent patterns in the sensitivity to painful stimulation. These patterns are similar across stimulus modality with the exception of electrical stimulation. The magnitude of the effect was approximately 0.40 across all stimulation. For pressure stimulation, cold pressor pain, thermal heat stimulation, and ischemic muscle pain, a clear pattern emerges with the follicular phase demonstrating higher thresholds than later phases. When the effect size was pooled across studies (excluding electrical) comparisons involving the follicular phase were small to moderate (periovulatory phase, d(thr) = 0.34; luteal phase, d(thr) = 0.37; premenstrual phase, d(thr) = 0.48). The pattern of effects was similar for tolerance measures. Electrical stimulation was different than the other stimulus modalities, showing the highest thresholds for the luteal phase. When the effect size was pooled across studies for electrical stimulation, effect sizes were small to moderate (menstrual (d(thr) = -0.37), follicular d(thr) = -0.30) periovulatory d(thr) = -0.61), and premenstrual d(thr) = 0.35) phases. This paper raises several important questions, which are yet to be answered. How much and in what way does this menstrual cycle effect bias studies of female subjects participating in clinical trials? Furthermore, how should studies of clinical pain samples control for menstrual related differences in pain ratings and do they exist in clinical pain syndromes? What this paper does suggest is that the menstrual cycle effect on human pain perception is too large to ignore.

Objective: The purpose of this study was to examine the dimensions of coping, measured by the subscales of the new revised Coping Strategies Questionnaire (CSQ-R) using factor analysis, and to perform cluster analysis on these factors to explore the existence of distinct subgroups. No published studies have identifed subgroups of chronic pain patients based on the use of CSQ coping strategies., Source: A sample of 419 chronic low back pain patients from a multidisciplinary pain rehabilitation clinic and a sample of 556 chronic pain patients of mixed pain etiology presenting for treatment at an anesthesia pain clinic were used to establish reliability of factors and clusters., Results: Both samples yielded very similar two-factor solutions, with initial solutions accounting for 67.1% and 69.1% of the total variance. The factors were characterized as cognitive coping and distraction. Three homogeneous subgroups were then identified that consisted of a group high on cognitive coping, a group with low overall ratings of response CSQ-R items in general, and a group with frequent endorsement of catastrophizing and distraction-related items., Conclusion: This paper is the first to report empirically derived subgroups from scores on the CSQ or CSQ-R. In addition, the three clusters were significantly different across measures of pain, psychological distress, and levels of physical functioning, demonstrating validity for the clusters.

The purpose of this study was to determine which specific attributes of painful orofacial symptoms serve as predictors of health care utilization in a population based sample of elderly subjects. Furthermore, we documented patterns of health care utilization selection by type of health care provider. To our knowledge, these specific utilization patterns have never before been reported in the pain literature. Telephone interviews were conducted with a stratified random sample of 1636 community dwelling older (65+) north Floridians. A total of 5860 households were contacted and screened, with 75.3% participating to the point where their eligibility for the study could be determined. The percentage of subjects reporting health care utilization for a specific symptom ranged from 62 to 32%. One or more health care visits were reported by at least 50% of those reporting symptoms of toothache pain, facial pain, jaw joint pain and burning mouth in the past 12 months. These rates suggest that elderly individuals are willing and able to seek health care for painful orofacial symptoms. We found that pain intensity was the best predictor of whether an elderly individual utilized health care or not, which suggests that some pain intensity threshold may exist at which health care seeking behavior is initiated. The overall number of visits was not predicted by pain intensity but by other qualities more associated with time or level of dysfunction caused by the symptom. We also found that elderly adults, typically seek care for toothache from a dentist and from physicians for painful orofacial symptoms not associated with the teeth or mouth. These decisions regarding the selection of a health care professional may, in part, be a function of financial and insurance considerations, anatomical site and perception of the role of dentistry in orofacial care.

Objective: Although the West Haven-Yale Multidimensional Pain Inventory (MPI) is frequently used in clinical evaluation and research with chronic pain patients, few studies have reported item-level factor analyses. After performing such an analysis, Bernstein et al. (Spine 1995;20:956-63) reported lack of independence between the solicitous and distracting response scales in section II as well as the activities away from home and social activities scales in section III. They suggested that the combination of these scales would improve the internal structure of the MPI. The purpose of this study was to perform a confirmatory factor analysis testing whether the MPI would be improved by the consolidation of these scales. In addition, a third, empirical model was generated for comparison with the West Haven-Yale and Bernstein models., Design: This study used exploratory and confirmatory factor analysis on two independent samples of chronic pain patients (n = 472 and n = 346) to test hypotheses regarding the factor structure of the MPI., Results and Conclusion: Principal axis factor analysis resulted in an empirical model that suggested that the primary psychometric problem of the MPI was lack of item-factor discrimination for several items. When the three models were tested using confirmatory factor analysis, improvement in model fit occurred when cross loading items were excluded. Nevertheless, the goodness of fit of original factor structure was adequate, suggesting it would be premature to suggest changes in this instrument.

Objective: To show clinical utility and empirical validity of Minnesota Multiphasic Personality Inventory-2 (MMPI-2) chronic pain patient subgroups by identification of differential multivariate relationships across groups., Method: This study used structural equation modeling to test cognitive coping strategies and somatization as mediator variables in path models with pain severity and depression used as exogenous (independent) variables and patient's activity level as the final endogenous (dependent) variable, across MMPI-2 profiles., Results: Hierarchical cluster analysis, performed on a sample of 569 chronic low back patients, resulted in four cluster profiles identifiable as those found in previous work with the MMPI-2 (within normal limits, V-type, neurotic triad, and depressed-pathological). Somatization mediated the relationship between depression and activity level for the neurotic triad group but not the other three groups. A positive linear relationship was found between somatization and depression for the within normal limits, neurotic triad, and depressed-pathological groups, whereas their linear association was negative for the V-type group. Cognitive coping strategies mediated the relationship between depression and activity level for the within normal limits group. In addition, cognitive coping was predictive of activity level for the within normal limits, V-type, and neurotic triad groups but not for the depressed-pathological group., Conclusion: Consistent with previous cluster analytic studies, this study replicated four MMPI-2 cluster profile groups in chronic pain patients. These results have also shown that several multivariate relationships between variables are different across MMPI-2 groups, providing evidence for the validity for these MMPI-2 subgroups.

Previous studies have shown that in vitro culture of human CD4+ T cells with antibodies to CD3 and CD28 immobilized on beads induced an antiviral effect to HIV-1 infection. Herein, we have used CD4+ T cells from nonhuman primates to address issues critical for use of such cells for therapy and immune reconstitution of humans and nonhuman primates infected with HIV and simian immunovirus (SIV). These studies include definition of the kinetics of the antiviral effect, the relative stability of the acquired phenotype, and whether such activated and expanded CD4+ T cells retain their immune function. Results of our studies show that antiviral effect is induced rapidly following activation with anti-CD3/CD28-coated beads. Additionally, the antiviral effect is not stable in these cells and requires continuous culture with anti-CD3/CD28 beads. Removal of CD4+ T cells from anti-CD3/CD28 stimulation renders these cells susceptible to infection, demonstrating that the resistant phenotype is not stable in these cultures. However, anti-CD3/CD28 expanded CD4+ T cells do retain immune function. Thus, although these findings imply a note of caution for therapeutic strategies aimed at providing patients with virus-resistant CD4+ T cells, the present study suggests that transfusion of such cells with retained immune function may have immune restoration capability.

The existing literature on experimentally induced pain indicates that there are sex differences, with females displaying greater sensitivity. In epidemiological studies, sex differences are also noted in the prevalence of a number of pain syndromes, with females reporting more severe pain, more frequent pain, and pain of longer duration. Complicating the interpretation of pain differences between men and women in clinical samples are reports of sex differences in response to pain-reducing medications. Studies in human subjects suggest that women respond better to certain opioid analgesics than men following third molar extraction, but few studies have assessed sex effects in effectiveness of topical anesthetics. The purpose of this study was to test for sex differences in response to a topical anesthetic, Lidocaine, using double blind, placebo controlled experimental methodology, in combination with a magnitude matching psychophysical protocol using a pressure algometer. The subjects were 21 female and 23 male adult volunteers. Twenty-four subjects (12 males and 12 females) were randomly assigned to the Lidocaine condition and 20 subjects were randomly assigned to the placebo control condition (9 males and 11 females). The effect size across sex for subjects in the Lidocaine treatment condition on the response bias variable was large indicating the males rated the stimuli as less painful than the females. Sex differences were not observed for discriminability in the Lidocaine treatment condition. This study did not show sex differences in the placebo condition. These results are particularly interesting in light of previous work that has shown similar pain stimuli (pressure pain) to be the stimulation most sensitive to sex differences. Results of this study suggest that the protocol employed (pressure pain stimulus with magnitude matching task) is sensitive to both anesthetic treatment and sex differences and represents an improvement in pain assessment methodology for use in experimental studies and in the clinic.

This study investigated sex differences in orofacial pain symptoms in a sample of elderly adults. Furthermore, differences across sex were tested on symptom continuity, overall duration, pain severity, activity reduction, and health care utilization, related to each specific symptom. Telephone interviews were conducted with a stratified random sample of community dwelling older (65+) north Floridians. A total of 5860 households were contacted and screened, with 75.3% participating to the point where their eligibility for the study could be determined. Of the remaining households, 1636 completed the interview. Of the total sample, 17.4% reported experiencing at least one of the four target orofacial pain symptoms (jaw joint pain, face pain, oral sores, burning mouth) during the past year, suggesting that orofacial pain symptoms are common in older adults. Our findings for prevalence of each specific symptom (jaw joint pain, 7.7%; face pain, 6.9%; oral sores, 6.4%; toothache, 12.0%; burning mouth, 1.7%) are similar to those estimated by the 1989 National Health Interview Survey, for the US adult population. Consistent with other epidemiological and clinical studies, we found that females were more likely to report jaw joint pain and face pain than males. In contrast to clinical studies, no differences were found on subjective ratings of pain severity, for any symptom. Differences across sex were most likely to be reported for jaw joint pain related variables, suggesting undetermined sex-uniqueness for these symptoms. In contrast to previous studies, older females tended to report lower levels of health care utilization than older males. This is the first study to our knowledge that reports orofacial symptom-specific sex differences among the elderly.

Fillingim and Maixner (Fillingim, R.B. and Maixner, W., Pain Forum, 4(4) (1995) 209-221) recently reviewed the body of literature examining possible sex differences in responses to experimentally induced noxious stimulation. Using a 'box score' methodology, they concluded the literature supports sex differences in response to noxious stimuli, with females displaying greater sensitivity. However, Berkley (Berkley, K.J., Pain Forum, 4(4) (1995) 225-227) suggested the failure of a number of studies to reach statistical significance suggests the effect may be small and of little practical significance. This study used meta-analytic methodology to provide quantitative evidence to address the question of the magnitude of these sex differences in response to experimentally induced pain. We found the effect size to range from large to moderate, depending on whether threshold or tolerance were measured and which method of stimulus administration was used. The values for pressure pain and electrical stimulation, for both threshold and tolerance measures, were the largest. For studies employing a threshold measure, the effect for thermal pain was smaller and more variable. The failures to reject the null hypothesis in a number of these studies appear to have been a function of lack of power from an insufficient number of subjects. Given the estimated effect size of 0.55 threshold or 0.57 for tolerance, 41 subjects per group are necessary to provide adequate power (0.70) to test for this difference. Of the 34 studies reviewed by Fillingim and Maixner, only seven were conducted with groups of this magnitude. The results of this study compels to caution authors to obtain adequate sample sizes and hope that this meta-analytic review can aid in the determination of sample size for future studies.

Objective: The Coping Strategies Questionnaire (CSQ), a rationally constructed pain coping assessment instrument, was conceived to measure the extent to which patients used six different cognitive coping strategies and two behavioral coping strategies. A number of studies have factor analyzed the original scales but have not found a reliable factor structure. Recent studies by Turtle et al. and Swartzman et al. have obtained a five-factor solution performing exploratory factor analysis on the individual items. Robinson and associates from the University of Florida performed an item level exploratory factor analysis on a much larger sample (n = 965) and found a six-factor solution that was relatively supportive of the original rationally derived scales. The purpose of the present investigation was to perform a confirmatory factor analysis using the LISREL structural equation modeling program to compare these three different factor structures., Patients: A sample of 472 chronic patients was used., Results and Conclusions: The results indicated that the Florida six-factor model was a better fit to the sample data than either of the five-factor models. Creation of the Coping Strategy Questionnaire Revised (CSQ-R), which retains 27 of the original items, is suggested.

Objective: The Coping Strategies Questionnaire (CSQ), a measure of coping in chronic pain patients, was subjected to item-level exploratory factor analysis., Subjects: A sample of 965 chronic pain patients were used in the analysis., Results: Principal components analysis using a varimax rotation procedure identified nine factors that accounted for 54.5% of the variance. Of these nine factors, the first five represent subscales of the original CSQ subscales. The catastrophizing subscale replicated with significant loadings for all six original items, and ignoring sensations replicated with five of six items. Factors representing reinterpreting pain sensations, coping self-statements, and diverting attention subscales also appeared. The items from the praying and hoping subscale split into separate praying and hoping factors (factors 6 and 8). When reliability coefficients were calculated, factors 7 through 9 had unacceptably low internal consistency and thus were not considered stable factors. Correlations between factors 1 through 6 and other measures of psychological and physical functioning were calculated in the construct validation portion of this study. Previously found relationships were replicated in that the correlations between CSQ factor scores and measures of pain, depression, and disability were in the same direction in this data set as those previously reported.

Objective: Past research has shown response biases to influence the accuracy of results from self-report measures. In pain assessment, where a percentage of patients have financial and other reasons to minimize or exaggerate psychological disturbance, it becomes especially important to identify the influence of response bias in self-report of adjustment. This study investigated the susceptibility of three commonly used self-report pain assessment measures to response bias., Design: This study used a within-subjects (asymptomatic subjects) design with two experimental conditions and nonequivalent control group (chronic pain patients)., Subjects: Experimental group: 40 students enrolled in an occupational therapy program at a major southeastern United States university., Control Group: 200 subjects referred to a multidisciplinary pain clinic at a major teaching hospital., Measures: Coping Strategies Questionnaire, Multidimensional Pain Inventory, and Pain Beliefs and Perceptions Inventory., Results: With few exceptions, asymptomatic subjects scored significantly differently on these measures while portraying themselves as either coping well or coping poorly. In addition, when using the "coping poorly" response set, asymptomatic subjects reproduced scores similar to those of symptomatic chronic pain patients., Conclusion: The susceptibility to manipulation appeared constant across the three measures, a finding that highlighted the difficulties clinicians and researchers encounter in accurate interpretation of results from these measures in the absence of validity indicators. This study also emphasizes the ease with which subjects with sufficient motivation can present themselves in an untruthful and manipulative manner and can generate scores that are, on their own, difficult to distinguish from those of a group of typical chronic pain patients.

The purpose of this study was to investigate back surgery outcome differences based on Minnesota Multiphasic Personality Inventory-2 (MMPI-2) profile types. Four homogenous subgroups were found from a hierarchical cluster analysis of 201 MMPI-2 profiles. These four clusters consisted of a Depressed-pathological profile, a conversion V profile (V-type), a neurotic Triad profile, and a within normal limit (WNL) profile. Patients in the WNL and Triad subgroups reported significantly more satisfaction with postsurgical improvement than did patients in the Depressed-pathological or V-type subgroups. The Triad subgroup also gave a more favorable subjective rating of surgical outcome than did patients in the Depressed-pathological or V-type subgroups. These groups also differed on measures of work status and nonwork-related physical activity levels but not on indices of pain.

Objective: The purpose of our study was to investigate whether Minnesota Multiphasic Personality Inventory-2 cluster solutions of chronic low-back pain patients would replicate those found in previous research with the Minnesota Multiphasic Personality Inventory., Setting: A multidisciplinary pain clinic in the southeastern United States., Patients: The subjects were 201 chronic low-back pain patients who had suffered a work-related back injury., Outcome Measures: The Minnesota Multiphasic Personality Inventory-2., Results: We found four relatively homogeneous subgroups of chronic low-back pain patients that were similar to those identified by previous researchers using data collected with the Minnesota Multiphasic Personality Inventory., Conclusion: These findings indicate that interpretations of the Minnesota Multiphasic Personality Inventory-2 should parallel those of the Minnesota Multiphasic Personality Inventory for chronic low-back pain patients. They further suggest that the results of Minnesota Multiphasic Personality Inventory-based studies are also applicable to Minnesota Multiphasic Personality Inventory-2.