Sickle cell bone disease and response to intravenous bisphosphonates in children.

Children with sickle cell disease (SCD) have the potential for extensive and early-onset bone morbidity. This study reports on the diversity of bone morbidity seen in children with SCD followed at three tertiary centers. IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications. INTRODUCTION: To evaluate bone morbidity and the response to intravenous (IV) bisphosphonate therapy in children with SCD. METHODS: We conducted a retrospective review of patient records from 2003 to 2019 at three Canadian pediatric tertiary care centers. Radiographs, magnetic resonance images, and computed tomography scans were reviewed for the presence of avascular necrosis (AVN), bone infarcts, and myositis. IV bisphosphonates were offered for bone pain management. Bone mineral density was assessed by dual-energy X-ray absorptiometry (DXA). RESULTS: Forty-six children (20 girls, 43%) had bone morbidity at a mean age of 11.8 years (SD 3.9) including AVN of the femoral (17/46, 37%) and humeral (8/46, 17%) heads, H-shaped vertebral body deformities due to endplate infarcts (35/46, 76%), and non-vertebral body skeletal infarcts (15/46, 32%). Five children (5/26, 19%) had myositis overlying areas of AVN or bone infarcts visualized on magnetic resonance imaging. Twenty-three children (8/23 girls) received IV bisphosphonate therapy. They all reported significant or complete resolution of bone pain. There were no reports of sickle cell hemolytic crises, pain crises, or stroke attributed to IV bisphosphonate therapy. CONCLUSION: Children with SCD have the potential for extensive and early-onset bone morbidity. In this series, IV bisphosphonates were effective for bone pain analgesia and did not trigger sickle cell complications.

Somatosensory function in old age.

Sensory decline is viewed as an inevitable consequence of the ageing process. However, reports of declines have not been a consistent finding across the sensory systems. Reports from psychophysical studies indicate that the most common declines with ageing are in vision and audition and, to a lesser degree, olfaction and gustation. Findings for the somatosensory system (mechanoreception, warming and cooling thermoreception and pain) are less conclusive. Factors that contribute to individual differences in sensory ratings beyond chronological ageing include stimulus factors including stimulus type and body location, response measures and instructions, systemic disease that may affect the peripheral or central nervous system and environmental factors that may affect the skin integrity.

Investigating dynamic pain sensitivity in the context of the fear-avoidance model.

BACKGROUND: Although nearly everyone at some point in their lives experiences back pain; the amount of interference with routine activity varies significantly. The fear-avoidance (FA) model of chronic pain explains how psychological variables, such as fear, act as mediating factors influencing the relationship between clinical pain intensity and the amount of interference with daily activities. What remains less clear is how other mediating factors fit within this model. The primary objective of this report was to examine the extent to which a dynamic measure of pain sensitivity provides additional information within the context of the FA model. METHOD: To address our primary objective, classic mediation and moderated mediation analyses were conducted on baseline clinical, psychological and quantitative sensory measures obtained on 67 subjects with back pain (mean age, 31.4 ± 12.1 years; 70% female). RESULTS: There was a moderately strong relationship (r = 0.52; p < 0.01) between clinical pain intensity and interference, explaining about 27% of the variance in the outcome. Mediation analyses confirmed fear partially mediated the total effect of clinical pain intensity on interference (Δß = 0.27; p < 0.01), and accounted for an additional 16% of the variance. In our FA model, pain sensitivity did not demonstrate additional indirect effects; however, it did moderate the strength of indirect effects of fear. CONCLUSION: This preliminary modelling suggests complex interactions exist between pain-related fear and pain sensitivity measures that further explain individual differences in behaviour.

Sex differences in the perception of noxious experimental stimuli: a meta-analysis.

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.

Perceived spouse responsiveness to chronic pain: three empirical subgroups.

The spouse plays a fundamental role in day-to-day functioning and long-term well-being of the patient with chronic pain. Although spouses may respond differently to pain demonstrations, no study has examined patterns of perceived spouse responsiveness to chronic pain behavior. Yet perceived patterns of response to chronic pain may explain variability in pain behavior in the literature because studied samples may be drawn from any one subgroup. The purposes of this study were to run an exploratory cluster analysis to identify naturally occurring spouse response subgroups by using section 2 of the Multidimensional Pain Inventory and to examine pain-relevant variables between subgroups. It was hypothesized that subgroups would be identified and that they would differ on pain-relevant variables. Participants were 774 married pain patients from 2 University of Florida-affiliated pain clinics, 69% of whom experienced chronic low back pain. A hierarchical cluster analysis identified 3 subgroups that were labeled positively attentive, negatively attentive, and inattentive. A discriminant analysis yielded 2 significant discriminant functions that correctly classified 71.1% of subgroup membership. The support variable best differentiated between the positively and negatively attentive subgroups, whereas interference best distinguished between the negatively attentive and inattentive subgroups. Results suggest the profiles have conceptual and clinical validity, with the negatively and positively attentive subgroups exhibiting the poorest adjustment to pain. A controlled study is needed to determine the direction of causality.

Sex differences in negative emotional responses to chronic pain.

We proposed a sequential model of pain processing with pain intensity as stage 1, pain unpleasantness as stage 2, pain-related emotions (depression, anxiety, frustration, anger, fear) as stage 3, and overt behavioral expression of pain as stage 4. We tested hypotheses about relationships between sex and the first 3 stages of pain processing by conducting simultaneous regression analysis using LISREL-8 with data collected from 967 women and 680 men with chronic pain. We found the following results: (1) women reported higher pain-related frustration and fear; (2) frustration related most highly to pain intensity among women, as compared with anxiety and depression among men; (3) depression and frustration related most highly to usual and highest pain unpleasantness among women, as compared with frustration among men; and (4) contrary to expectations, pain-related emotions were more strongly related to pain for men. Consistent with the sequential model of pain processing, emotional response to pain was more closely related to pain unpleasantness than to pain intensity across sex. Anxiety and frustration were the emotions most highly related to pain. The current results highlight sex differences in the experience of chronic pain and the importance of assessing a range of emotions in patients with pain.

Gender role expectations of pain: relationship to sex differences in pain.

Empirical research supports the existence of sex differences in pain; yet these differences are poorly understood. Although biological mechanisms have been posited to explain variability, results of pain modeling manipulations suggest social learning may be a stronger influence on pain response. In this report we use the term sex to refer to the biological category of male or female. We use the term gender to refer to the socially acquired aspects of being male or female sometimes referred to as femininity and masculinity. This study investigated a new measure, the Gender Role Expectations of Pain questionnaire (GREP), which was designed to measure sex-related stereotypic attributions of pain sensitivity, endurance, and willingness to report pain. Subjects were 156 male and 235 female undergraduates at a southeastern university. Psychometric investigation of the questionnaire revealed a 5-factor solution that closely mirrored the theoretical construction of the items. Test-retest reliability was also shown for individual items on a separate sample of 28 subjects. Results supported hypotheses about gender role: both men and women rated men as less willing to report pain than women (F(1,389) = 336, P <.001); both men and women rated women more sensitive (F(1,389) = 9.5, P <.05) and less enduring of pain (F(1,389) = 65.7, P <.001) than men; and men rated their own endurance as higher than the typical man (F(1,389) = 65.7, P <.001). Sex accounted for 46% of the variance in willingness to report pain. Results suggest that the GREP distinguished between the socially learned reactions to pain for men and women. It is recommended that the influence of gender-related expectations for pain be assessed in all studies investigating human sex differences in pain.

Pain, disability, and psychological functioning in chronic low back pain subgroups: myofascial versus herniated disc syndrome.

A series of patients with chronic low back pain evaluated at a tertiary referral center were the subjects for this study. Of 250 consecutive patients, 94 were diagnosed as having myofascial pain and 57 as having herniated disc syndrome. Before evaluation and diagnosis, all patients completed the McGill Pain Questionnaire, ratings of pain and disability, and the Symptom Checklist 90-R. Patients were also grouped on the basis of previous surgical history and workers' compensation benefits. Patients suffering from myofascial pain were significantly less likely to report periods of pain relief than patients with herniated disc syndrome. Those receiving workers' compensation benefits reported significantly greater levels of pain, disability, and psychological distress than those not receiving benefits, irrespective of diagnosis. Patients who underwent previous surgery did not differ significantly from those who never underwent surgery. All patients had elevated scores on the Somatization subscale of the Symptom Checklist 90-R. Patients with myofascial pain and workers' compensation benefits demonstrated the highest levels of somatization and phobia. These findings suggest that the effects of low back pain of myofascial origin have comparable, if not worse, consequences than disc herniation. These findings also reaffirm the importance of workers' compensation in understanding the differences in patients with chronic low back pain.

CSQ: five factors or fiction?

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.

Validity of MMPI-2 profiles in chronic back pain patients: differences in path models of coping and somatization.

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.

The Coping Strategies Questionnaire and chronic pain adjustment: a conceptual and empirical reanalysis.

OBJECTIVE: Some studies have found significant relations between both the factor scores and subscales of the Coping Strategies Questionnaire (CSQ) and various measures of adjustment to chronic pain. In their review of the literature on coping with chronic pain, Jensen et al. (Pain 1991;47:249-83) suggest that conceptual overlap between the subscales may inflate these observed correlations. In the present study, we examine the factor structure of the CSQ subscales which reflect coping, excluding the CSQ subscales which measure appraisal or activity. We then examine the relationship between the CSQ factors and subscales and pain adjustment, while controlling for selected variables. DESIGN AND SUBJECTS: One hundred fifty-two chronic pain patients were administered the CSQ. Seventy-three were also administered the Multidimensional Pain Inventory (MPI). Adjustment to chronic pain was defined based on patients' cluster membership on the MPI and responses to the Interference, Pain Severity, and Negative Affect subscales. SETTING: Tertiary care center. RESULTS: Multiple regression analyses revealed that the Pain Avoidance factor was positively related to pain severity, interference, and MPI cluster membership. In addition, the catastrophizing subscale was positively related to negative affect and MPI cluster membership even when controlling for level of depression, ability to decrease pain was related to lower levels of pain severity, and ability to control pain was related to MPI cluster membership. Neither the Conscious Cognitive Coping factor nor the Increasing Activities subscale was related to the adjustment measures. Follow-up analyses revealed that the Praying/Hoping subscale appeared to account for the relationship between pain avoidance and adjustment. CONCLUSION: The results suggest that praying/hoping and catastrophizing are related to poorer adjustment to chronic pain, that ability to control and decrease pain are related to better adjustment, and that catastrophizing appears to be a separate construct from depression. The results also suggest that the individual CSQ subscales may have greater utility in terms of examining coping, appraisals, and pain adjustment compared to the composite scores.

The relationship of cognitive distortion to depression in chronic pain: the role of ambiguity and desirability in self-ratings.

OBJECTIVE: This study attempts to clarify the relationship between depression and the cognitions of chronic pain patients. It was hypothesized that the ambiguity and desirability of self-rated traits would significantly predict level of depression. DESIGN: The study incorporated a correlational design in which subjects rated a number of traits as they pertained to themselves and completed questionnaires on negative affect and pain. SETTING: Subjects were recruited from a Spine Program and the Orthopaedic Clinic, at a tertiary care facility at the University of Florida. SUBJECTS: Fifty-eight chronic pain patients, two thirds of whom had primary back pain, were recruited for the study. OUTCOME MEASURE(S): All subjects completed a Beck Depression Inventory and McGill Pain Questionnaire, and rated themselves on 28 traits characterized by the dimensions of desirability and ambiguity. RESULTS: A hierarchical regression analysis indicated that the subjects' self-ratings on ambiguous negative traits significantly predicted level of depression. CONCLUSIONS: Patients with chronic pain are more likely to acknowledge undesirable traits in themselves when they have higher levels of depression when the pain level was controlled. These findings may have important implications for the cognitive-behavioral treatment of chronic pain patients.

Relationship of MMPI cluster type, pain coping strategy, and treatment outcome.

The purposes of the present study of chronic pain patients were to (a) assess whether cognitive and behavioral coping style is related to personality factors, (b) assess how coping styles differ across personality types, and (c) assess how outpatient interdisciplinary intervention affects the coping styles of various personality types. Four MMPI clusters (Depression/Pathological, V-type, Marginal Depression, and Marginal V-type) were derived using a hierarchical clustering procedure. Seventy subjects also completed the Coping Strategies Questionnaire before and after a 3-week outpatient pain management program. Pretreatment analyses indicated the Depression/Pathological and Marginal Depression groups used diverting attention less than either V-type group. The V-type group reported using praying/hoping significantly more than either of the marginal groups. At posttreatment the Depression/Pathological group used catastrophizing significantly more than either of the marginal groups. Results of pre-post analyses indicated that the Depression/Pathological group increased their use of diverting attention, reinterpreting pain sensations, and ignoring pain sensations, while decreasing catastrophizing. The V-type group increased their use of reinterpreting pain sensations, while decreasing praying/hoping and catastrophizing. Neither of the Marginal subtypes showed significant pre-post changes in coping strategies. These results suggest that different personality types use different pain coping strategies prior to multidisciplinary treatment. Groups showing more severe psychological distress, perhaps related to an underlying personality disorder, displayed greater changes in coping strategies with treatment, but remained more dysfunctional after treatment. These findings suggest that the alteration of coping strategies may be an important treatment effect needing more individualization to maximize treatment response.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessing depression among persons with chronic pain using the Center for Epidemiological Studies-Depression Scale and the Beck Depression Inventory: a comparative analysis.

OBJECTIVE: This study examined the ability of two self-report questionnaires, the Beck Depression Inventory (BDI) and the Center for Epidemiological Studies-Depression Scale (CES-D), to discriminate between chronic pain patients with and without major depression. Since previous research has suggested that medical conditions such as chronic pain can influence the endorsement of items that measure neurovegetative symptoms of depression, the accuracy of each of these questionnaires was also assessed eliminating these items. SUBJECTS: These included 132 consecutive patients with chronic pain, 44 of whom were diagnosed as suffering from major depression according to DSM-IV criteria. METHODS: Patients were administered a battery of questionnaires that included the CES-D and BDI. They were also interviewed by a clinical psychologist to determine the presence or absence of major depression. RESULTS: Both questionnaires were able to discriminate significantly between persons with and without major depression. Removal of the somatic items on each questionnaire did not improve their accuracy. Discriminant function analysis revealed an optimal cut-off score of 21 for the BDI, and 27 for the CES-D. Overall hit rates at these cut-offs for the two questionnaires were comparable, while the CES-D had somewhat better sensitivity (81.8% vs. 68.2%). Conversely, the BDI had slightly better specificity (78.4% vs. 72.7%). CONCLUSION: The results suggest that both questionnaires have good predictive validity among chronic pain patients, and decisions regarding the use of one questionnaire rather than the other may depend upon the goals of the user and the setting within which the questionnaire is used.

Clinical pain perception and hormone replacement therapy in postmenopausal women experiencing orofacial pain.

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.

Empirical subgroups of the Coping Strategies Questionnaire-Revised: a multisample study.

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.

Multivariate cluster analysis of the MMPI-2 in chronic low-back pain patients.

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.

The effects of depression and chronic pain on psychosocial and physical functioning.

OBJECTIVE: The present study employed causal modeling to examine the impact of somatic and cognitive symptoms of depression on the functioning of patients with chronic pain. DESIGN: Path analyses were conducted to determine whether pain level is directly related to the psychosocial and physical dimensions of functional status or whether this relationship is mediated by depression. SETTING: Subjects were recruited from a facial pain clinic at the University of Florida, an outpatient clinic associated with a tertiary-care health center. PATIENTS: Subjects were 70 patients with chronic pain, 53 of whom had primary facial pain. MAIN OUTCOME MEASURES: All subjects completed a packet of self-report questionnaires, including the Beck Depression Inventory, McGill Pain Questionnaire, and Sickness Impact Profile. RESULTS: Results of path analyses indicated that both somatic and cognitive symptoms of depression significantly correlate with psychosocial functioning even after controlling for the effects of pain level, trait anxiety, and trait anger. Somatic symptoms of depression were significantly correlated with physical functioning after pain level, anxiety and anger were controlled. CONCLUSIONS: This study indicates that depression is directly related to both the physical and the psychosocial functioning of facial pain patients, while self-reported level of pain is not. A better understanding of the impact of depression on chronic pain and the relationship of these two disorders could lead to improved assessment and treatment of chronic pain disorders.

Negative affect, self-report of depressive symptoms, and clinical depression: relation to the experience of chronic pain.

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.

Empirical test of the factor structure of the West Haven-Yale Multidimensional Pain Inventory.

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.