The reliability and validity of pain interference measures in persons with cerebral palsy

OBJECTIVE: To evaluate the reliability and validity of 2 measures of pain interference in persons with cerebral palsy (CP). DESIGN: Standardized interviews to assess pain and impact of pain on activities. SETTING: University medical center. PARTICIPANTS: Fifty adults with CP. INTERVENTIONS: Patients asked to rate pain's intensity, interference with general activities, and depression levels. MAIN OUTCOME MEASURES: Pain interference scales: Chronic Pain Grade (CPG) and Brief Pain Inventory (BPI); rating of disability: Craig Handicap Assessment and Reporting Technique (CHART); rating of depression: Center for Epidemiologic Studies Depression (CES-D) Scale. RESULTS: Mean interference of pain on 3 CPG items (pain interference with daily activities, social activities, work) were 1.74 +/- 2.45, 1.06 +/- 2.05, and.89 +/- 1.84 (out of 10), respectively. Mean interference on 10 modified BPI interference items ranged from 2.28 +/- 3.01 to 3.67 +/- 3.15 (out of 10). The composite CPG interference score did not correlate significantly with pain intensity. However, the composite BPI interference score did correlate significantly with pain intensity (r = .66, P < .01). There was no significant association shown between average pain and the CHART score (r = -.21, NS). Pain showed a significant association with CES-D score (r = .45, P < .05). Internal consistency of the 3 CPG items was inadequately low (Cronbach alpha = .59), whereas that of the 10 BPI items was excellent (.89). CONCLUSIONS: The pain interference items of the BPI serve as a reliable and valid measure of pain's impact on persons with CP-related pain.     

Pain in cerebral palsy: the relation of coping strategies to adjustment

Pain is a serious secondary problem for many persons with cerebral palsy (CP). Cognitive-behavioral models of pain hypothesize that how patients cope with painful episodes plays an important role in their adjustment to chronic pain. The utility of this model, however, has never been tested in persons with CP-related pain. Fifty adults with CP and chronic pain were interviewed to assess pain experience, the interference of pain on activities (BPI), depressive symptoms (CES-D), and coping strategies used for the pain (CSQ and CPCI). The results indicated that pain-contingent rest and catastrophizing were both significantly associated with pain interference and depressive symptoms even when controlling for pain severity. These findings support a cognitive-behavioral model of chronic pain as it might be applied to persons with CP. The results also support the need for research to determine if, and to what extent, cognitive-behavioral interventions that provide training in specific coping responses reduce depressive symptoms and pain interference in persons with CP.     

The reliability and validity of pain interference measures in persons with multiple sclerosis

Valid measures of pain-related interference with functioning could serve as useful outcome measures in much needed clinical trials of pain treatments for persons with multiple sclerosis (MS). The purpose of this study was to examine the psychometric properties of two pain interference measures in persons with MS and chronic pain. Modified versions of the Interference scale of the Brief Pain Inventory (BPI) and the Disability scale of the Graded Chronic Pain Scale were administered via a mailed survey to 187 community-dwelling persons with MS. Data from the 125 participants who reported pain were analyzed. Although both measures demonstrated excellent internal consistency, in the current sample, evidence regarding the construct and concurrent validity was stronger for the modified versions of the BPI Interference scale. These results provide preliminary support for the reliability and validity of modified versions of the BPI Interference scale in persons with MS and chronic pain.     

Pain belief assessment: A comparison of the short and long versions of the surgery of pain attitudes

Reliable and valid measures of pain-related beliefs are necessary to test and refine cognitive-behavioral models of chronic pain and may be used by clinicians to identify and monitor changes in beliefs during treatment. The Survey of Pain Attitudes (SOPA) has shown good psychometric properties (reliability and validity) and has been used in a number of studies. The current study sought to determine the reliability and validity of 2 brief versions of the SOPA. The original SOPA (SOPA-57) was completed by 126 patients with chronic pain before multidisciplinary pain treatment, after treatment, and at 2-week and 1-month follow-ups. Measures of pain coping, disability, physician visits for pain, and depression also were administered before treatment. A 35-item SOPA (SOPA-35) was created using criteria similar to those used to develop the original SOPA, and the content and psychometric properties of this brief version were compared with those of the original SOPA and a previously developed 30-item version (SOPA-30). Although the reliabilities of most of the scales were adequate to excellent, low reliabilities were found for the SOPA-30 Disability and Medication scales and the SOPA-35 Harm scale. With the exception of the Medical Cure scale, the correlations between the SOPA scales and the criterion measures supported the validity of each version of the SOPA. The SOPA-35 was more similar to the SOPA-57 than was the SOPA-30. Implications for use of the measures are discussed.     

Comparative reliability and validity of chronic pain intensity measures.

Reliable and valid measures of pain are essential for conducting research on chronic pain. The purpose of this longitudinal study was to compare the reliability and validity of several measures of pain intensity. One hundred twenty-three patients with chronic pain were administered telephone interview versions of 0-10 scales of current, worst, least and average pain, immediately prior to beginning a multidisciplinary treatment program. The measures were administered again to these subjects 2 weeks (n=108), 1 month (n=106) and 2 months (n=105) after the end of treatment. The validity (defined as ability to detect changes in pain intensity over the course of treatment up to the 2-month follow-up assessment) and reliability (defined as stability over time in the 2 months after treatment) of these four measures and of composite combinations of these measures were examined. Contrary to prediction, the composite measures did not show a statistically significant superiority to the individual ratings in terms of their ability to detect change in pain intensity from pre-treatment to various points after treatment. The composite scores did, however, show greater stability than did the individual ratings after treatment. The practical conclusions of this study are; (1), individual 0-10 pain intensity ratings have sufficient psychometric strengths to be used in chronic pain research, especially research that involves group comparison designs with relatively large sample sizes, but, (2), composites of 0-10 ratings may be more useful when maximal reliability is necessary, (e.g. in studies with relatively small sample sizes, or in clinical settings where monitoring of changes in pain intensity in individuals is needed).     

Cognitions, coping and social environment predict adjustment to phantom limb pain.

Biopsychosocial models of chronic pain hypothesize a role for psychological and environmental factors in adjustment to chronic pain. To test the utility of such models for understanding phantom limb pain, 61 persons with recent amputations were administered measures of average phantom limb pain intensity, pain interference, depression, pain coping use, pain cognitions and appraisals, and social environmental variables 1 month post-amputation, and the measures of pain intensity, pain interference, and depression again 5 months later. Multiple regression analyses showed that the psychosocial predictors made a statistically significant contribution to the concurrent prediction of average phantom limb pain, pain interference, and depression at the initial assessment, and a significant contribution to the prediction of subsequent change in pain interference and depression over the course of 5 months. The results support the utility of studying phantom limb pain from a biopsychosocial perspective, and identify specific biopsychosocial factors (e.g., catastrophizing cognitions, social support, solicitous responses from family members, and resting as a coping response) that may play an important role in adjustment to phantom limb pain.     

Relationships among alexithymia and pain intensity,pain interference,and vitality in persons with neuromuscular disease: Considering the effect of negative affectivity

Alexithymia, the inability to identify or label emotions, has been shown to be associated with pain in patients with a number of chronic pain conditions. We sought to: (1) replicate this association in samples of persons with chronic pain secondary to neuromuscular disease, (2) extend this finding to other important pain-related measures, and (3) to determine whether relationships among alexithymia and study variables existed after controlling for negative affect. One hundred and twenty-nine individuals with muscular dystrophy and chronic pain were administered measures of alexithymia (Toronto Alexithymia Scale, TAS-20), pain intensity (0–10 NRS), pain interference (Brief Pain Inventory Interference scale), mental health (SF-36 Mental Health scale; as a proxy measure of negative affect) and vitality (SF-36 Vitality scale). Higher TAS scores were associated significantly with higher pain intensity and interference, and less vitality. Although the strengths of these associations were reduced when mental health was used as a control, the associations between the Difficulty Identifying Feelings scale and vitality, and the Externally Oriented Thinking and Total TAS scales and pain intensity remained statistically significant. The findings replicate and extend previous findings concerning the associations between alexithymia and important pain-related variables in a sample of persons with chronic pain and neuromuscular disease. Future research is needed to determine the extent to which the associations are due to (1) a possible causal effect of alexithymia on patient functioning that is mediated via its effects on negative affect or (2) the possibility that alexithymia/outcome relationships reflect response bias caused by general negative affectivity.     

Preliminary Validation of Subjective Anchor Scales for Worry and Rumination

This research is a preliminary validation of two single-item visual analogue scales. The worry visual analogue scale (WVAS) and the rumination visual analogue scale (RVAS) are self-report measures developed to track state changes in worry and rumination. Each of these scales uses an idiographic anchor sheet, enabling each participant to quantify their personal scale of worry or rumination. We compared ratings on the WVAS and RVAS with self-report measures of trait worry and rumination as well as other constructs administered concurrently in two separate studies. In study 1 we compared results within an unselected undergraduate sample. In study 2 we compared results within a community-based sample of individuals with generalized anxiety disorder (GAD), individuals with GAD comorbid with unipolar depressive disorders, and healthy controls. Results from both studies indicate the WVAS is a reliable state-level measure of worry with acceptable discriminant and convergent validity. Results for the RVAS showed similar reliability and convergent validity but lacked as much discriminant validity. This difference is possibly due to all experimental groups having comorbid anxiety, which is associated more with worry than rumination. Regression analyses indicate the WVAS predicts trait-level anxiety measures more strongly than measures of depression and beyond the predictive ability of the RVAS. The RVAS predicts measures of depression more strongly than it does measures of anxiety but is not consistently a stronger predictor of depression than the WVAS. These findings suggest worry and rumination are distinct regulatory constructs. In study 2, participants with GAD, and GAD comorbid with unipolar depressive disorders, scored significantly higher than healthy controls in worry and rumination. The internal reliability of the measures is reported.     

Willing and Able: A Closer Look at Pain Willingness and Activity Engagement on the Chronic Pain Acceptance Questionnaire (CPAQ-8)

An 8-item version of the Chronic Pain Acceptance Questionnaire (CPAQ-8) has recently been proposed and validated. The aims of this study were to further investigate the reliability and validity of the CPAQ-8 in a new sample. Questionnaires were completed by 550 people with chronic pain (478 online survey, 72 paper survey). A demographic and pain history questionnaire was administered along with the CPAQ-8 and measures of pain self-efficacy, pain catastrophizing, psychological flexibility in pain, anxiety, and mood. In addition, 105 respondents completed the CPAQ-8 within 6 weeks to provide test-retest reliability data. The 2-factor structure of the CPAQ-8 (Activity Engagement [AE] and Pain Willingness [PW]) was confirmed and had reasonable-to-good scale score reliability and test-retest reliability. Pain acceptance as measured by the CPAQ-8 was associated with less depression, anxiety, pain interference, fear of reinjury, pain catastrophizing, and psychological inflexibility in pain, and higher levels of satisfaction with life, pain self-efficacy, and general acceptance. Furthermore, pain acceptance fully mediated the relationship between reported pain severity and emotional distress (anxiety and depression) and partially mediated the relationship between pain severity and pain interference in a structural equation model. The test-retest reliability after 4 to 6 weeks ranged from .68 for PW to .86 for AE; the overall score correlation was .81. We conclude that the CPAQ-8 is a reliable and valid measure of pain acceptance and that the 2 subscales of the measure each make an individual contribution to the prediction of adjustment in people with chronic pain.PerspectiveThe present study provides further evidence for the reliability and validity of the CPAQ-8. Support was found for the 2 related subscales, PW and AE, which appear to work in synergy to influence levels of pain interference and emotional distress in people living with chronic pain.     

The validity and reliability of pain measures in adults with cancer.

To be most useful, clinical trials of cancer pain treatments should use pain measures that are both reliable and valid. A great variety of measures are now available that may be used to assess cancer pain. However, there are not yet any clear guidelines for selecting one or more measures over the others. The purpose of this article is to summarize the evidence concerning the validity and reliability of cancer pain measures. One hundred sixty-four articles were identified that provided psychometric data of pain measures among patients with cancer. The results indicate that commonly used single-item ratings of pain intensity are all valid and adequately reliable as measures of pain intensity, although some scales appear to be easier for patients with cancer to understand and to use than others. Multiple-item measures of pain intensity are reliable, but evidence concerning their validity is lacking. There is a paucity of research examining the psychometric properties of measures of cancer pain interference, pain relief, pain site, the temporal aspects of pain, and pain quality. This lack of evidence limits the conclusions that may be drawn concerning the reliability and validity of these other pain measures. Composite measures that combine ratings of pain intensity and pain interference into a single score appear to be both valid and reliable for describing patient populations, although their usefulness in clinical trials may be limited because they can obscure the contributions of intensity and interference to the total score. Proxy measures of cancer pain (pain ratings made by someone other than the patient) may be useful when patients are not able to provide pain ratings, but they should not be used as replacements for patient ratings when patient self-report measures are available. The discussion includes specific recommendations for selecting from among the available pain measures, as well as recommendations for future research into the assessment of cancer pain.     

Pain site and the effects of amputation pain: further clarification of the meaning of mild, moderate, and severe pain

Research among persons with cancer pain suggests that the association between pain intensity and pain interference is non-linear. That is, pain begins to have a serious impact on functioning when it reaches a certain threshold level (about 5 on 0--10 scales). Often, a second pain threshold can be identified which, once reached, shows an even greater proportional negative impact on functioning. This finding supports the potential clinical utility of classifying pain as mild, moderate, and severe based on the impact of pain on quality of life, and research among persons with cancer pain supports specific cutoffs (mild: 1--4, moderate: 5--6, severe: 7--10, see Pain 61 (1995) 277) for this classification. The current study sought to replicate the non-linear association between pain and pain interference in a non-cancer pain sample, determine whether the cutoffs that have been identified as optimal for cancer patients are also optimal for persons with pain associated with amputation, and determine whether the optimal cutoffs replicate across pain types (in this case, phantom limb, back, and general pain) within a single sample. Two-hundred and five persons with acquired amputation and phantom limb pain, back pain, or both, rated their average pain intensity and degree of pain interference for each type of pain. The results support a non-linear association between pain intensity and pain interference. However, the optimal cutoffs for classifying mild, moderate and severe pain in the present sample replicated the findings for persons with cancer pain only for back pain -- different optimal cutoffs were found for phantom limb and general pain. Moreover, the degree of pain interference appeared to vary as a function of pain type. The same level of back pain interfered more significantly with daily function than phantom limb pain did after pain levels reached five or more (on a 0--10 scale). These findings have implications for understanding the meaning of pain intensity levels, as well as for the assessment of pain intensity in persons with amputation-related pain.     

Psychometric update of the Functional Interference Estimate: a brief measure of pain functional interference

The Functional Interference Estimate (FIE) is a brief, 5-item self-report measure that assesses the degree to which pain interferes with daily functioning. While the FIE has demonstrated reliability and validity with a small normative sample, not much is known about its reliability and validity with a broad sample of individuals with pain. The current study presents FIE score means, variability estimates, reliability and validity data based on a large sample (n = 1,337) of primary care patients who report problematic pain. The FIE has excellent internal consistency and appears to have strong convergent validity with other well-established measures of function (e.g., SF-36 and Dartmouth COOP Charts). Because of its brevity and flexibility, the FIE may be a useful self-report measure of pain functional interference in clinical research on pain.     

Validation of the Chronic Pain Acceptance Questionnaire (CPAQ) in an Internet sample and development and preliminary validation of the CPAQ-8

This study investigated the psychometric properties of the Chronic Pain Acceptance Questionnaire (CPAQ) in a mixed chronic pain, Internet sample and sought to develop a valid and reliable short form. Questionnaires were completed by 428 respondents, comprising a sample accessed via the Internet (n = 319) and a sample who completed a paper and pencil version of the measures (n = 109). Using confirmatory factor analysis (CFA) the two-factor structure of the CPAQ in the Internet sample was supported, though a good model fit was only achieved following the removal of one item. The resultant 19 item CPAQ demonstrated good reliability and evidence of validity was obtained for this sample. Data from the Internet sample were used to derive an eight-item short form. The two four-item factors (activity engagement [AE] and pain willingness [PW]) were confirmed using CFA and found to be invariant across both samples with good scale reliability. Higher CPAQ-8 and subscale scores were correlated with less depression and anxiety, pain severity and pain interference, and fewer medical visits for pain. Using structural equation modelling both subscales were found to partially mediate the impact of pain severity on pain interference and emotional distress. In this model AE had stronger associations with outcomes while PW accounted for a small portion of the variance in pain interference and anxiety, but not depression. This study confirmed the two-factor structure of the CPAQ in a mixed chronic pain Internet sample and provides preliminary evidence for the psychometric soundness of the CPAQ-8.     

Psychometric properties of three medication adherence scales in patients with rheumatoid arthritis

Patient adherence to their health care protocols is important to encourage the best health outcomes in rheumatoid arthritis (RA); however, little attention has been given to assessing the psychometric properties of adherence measures in this patient population. The purpose of this study was to evaluate the psychometric properties of three existing self-report measures of medication adherence in a sample of patients with RA--the compliance-questionnaire-rheumatology (CQR), the Medication Adherence Report Scale (MARS), and the medication adherence scale (MAS). A cross-sectional study of 108 clinic patients with rheumatoid arthritis was conducted to evaluate the reliability and validity of the measures. Cronbach's alpha was .77 for both the CQR and a modified version of the MARS. For the MAS, the Kuder-Richardson 20 reliability was .25. Although not strong, test-retest reliability was adequate for all measures. Factor analysis indicated that both the MARS and the CQR measure two factors. All three instruments were moderately correlated with each other, with correlations ranging between .48 and .56. Although these scales were significantly correlated, moderate correlations among the scales indicate that they may not measure the same aspects of adherence. Among the three adherence measures, the modified MARS demonstrated the best evidence of reliability and validity and ease of administration in this sample of persons with RA.     

Initial development and validation of a multidimensional pain readiness to change questionnaire.

Psychometric instruments that assess patient readiness to adopt pain management skills taught in multidisciplinary pain management programs have the potential to clarify interindividual responses to treatment. To date, however, such questionnaires have examined overall readiness to self-manage pain in general rather than readiness to adopt the various specific skills that are taught in multidisciplinary pain treatment. The present study describes the initial construction and evaluation of a Multidimensional Pain Readiness to Change Questionnaire (MPRCQ) that measures readiness to adopt adaptive and avoid maladaptive pain coping strategies. The MPRCQ was initially administered to patients with fibromyalgia syndrome (n = 93) and then to a replication sample of persons with acquired amputations and spinal cord injuries who have chronic pain (n = 88). The results provide preliminary support for the reliability and validity of this instrument. Further research is needed to clarify the construct validity of the MPRCQ and its clinical utility.     

Desire for hastened death, cancer pain and depression: report of a longitudinal observational study

Desire for hastened death (DHD) is reported in the literature as being common in patients with cancer pain. However, there is currently little evidence to suggest that improvement in pain results in improvement in DHD. Our objectives were to assess 1) the impact of improvements in cancer pain severity and pain's interference with daily functioning and depression on DHD, and 2) the role of factors such as social and spiritual well-being, educational level, and patient age in moderating the impact of pain and depression on DHD. This observational study included patient-rated and clinician-rated scales administered twice at 4-week intervals. We enrolled 131 newly-referred patients to the Pain and Palliative Care Service at Memorial Sloan-Kettering Cancer Center or newly-admitted patients to Calvary Hospital in New York. One hundred and sixteen patients completed the baseline measures and 64 patients completed both baseline and follow-up measures. The main outcome measures included the Brief Pain Inventory (BPI), Beck Depression Inventory (BDI), and the Desire for Hastened Death Scale (DHD). Sixty-six percent of patients had no DHD at baseline and 45% of patients had BDI scores of 14 or greater ('mild' depression). Only 40% of patients with moderate/severe depression were receiving antidepressants. BPI scores improved significantly from baseline to follow-up (6.36 vs. 4.86, P < 0.01). DHD scores increased significantly from baseline to follow-up (0.84 to 1.38, P = 0.03). All other measures including depression were stable. DHD scores were moderately correlated with depression (r = 0.43), low social support (r = 0.38), poor spiritual well-being (r = -0.38), religious well being (r = -0.25), pain interference (r = 0.27), higher educational level (F = 4.50, P = 0.02) and lower physical functioning (KPRS, r = -0.40), but were unrelated to sex, age, race, or marital status. In multivariate regression analyses, baseline DHD (beta = 0.30, P = 0.05) and change in depression (beta=0.36, P = 0.02) were predictive of follow-up DHD. Improvement in pain interference was not predictive of follow-up DHD. The results suggest that improvement in depression moderated the severity of desire for hastened death in a population of patients with cancer pain. Depression was common in this population and was often untreated. Improvements in functional impairment due to pain did not moderate the severity of DHD in a setting of aggressive pain management. Strategies to preemptively screen for depression in the routine assessment of patients with cancer pain may be important to address DHD.     

Pain interference in persons with spinal cord injury: classification of mild, moderate, and severe pain.

Pain intensity is commonly measured by patient ratings on numerical rating scales (NRS). However, grouping such ratings into categories may be useful for guiding treatment decisions or interpreting clinical trial outcomes. The purpose of this study was to examine pain intensity classification in 2 samples of persons with spinal cord injuries (SCI) and chronic pain. The first sample (n = 307) rated the average intensity and activity interference of pain in general, and the second sample (n = 174) rated their worst pain problem. Pain intensity was categorized as mild, moderate, or severe using 4 possible classification systems; analyses were performed to determine the classification system that best distinguished the pain intensity groups in terms of activity interference. In both samples, the optimal mild/moderate boundary was lower (mild = 1-3 on a 0-10 NRS scale) than that reported previously for individuals with other pain problems. The possibility that pain may interfere with activity at lower levels for individuals with SCI requires further exploration. The moderate/severe boundary suggested by previous research was confirmed in only one of the samples. Implications for the assessment of pain intensity and functioning in persons with SCI and pain are discussed. PERSPECTIVE: Although pain in individuals with SCI is common, more research is needed regarding its characteristics and treatment. This study sought to develop an empirically based classification system for mild, moderate, and severe pain that could be useful for applying clinical treatment guidelines and for interpreting the results of much-needed clinical trials.     

The Bath Adolescent Pain--Parental Impact Questionnaire (BAP-PIQ): development and preliminary psychometric evaluation of an instrument to assess the impact of parenting an adolescent with chronic pain

When an adolescent has chronic pain many aspects of a parent’s life can be affected, including their emotional and social functioning. The assessment of this multidimensional parental impact is an essential, yet often neglected, clinical task. This study reports on the development and psychometric evaluation of the Bath Adolescent Pain – Parental Impact Questionnaire (BAP-PIQ), an assessment tool comprising multiple scales thought to be relevant for better understanding changes in functioning and behavior associated with parenting an adolescent with chronic pain. A sample of 194 parents of adolescents with chronic pain, recruited from three UK clinics, completed the 94 item draft inventory. Frequency and item correlation analyses resulted in a final inventory of 62 items. Internal consistency of all eight scales was established based on Cronbach’s alpha. Convergent validity was undertaken by comparison of individual scales with existing validated measures of parental stress, mood, parenting behavior, marital adjustment, and general functioning. The temporal reliability of each scale was established using a sub-sample of 46 participants over a 14-day period. Psychometric evaluation suggests that the inventory yields a reliable and valid assessment of the multiple impacts of parenting an adolescent with chronic pain. The BAP-PIQ may offer a comprehensive assessment of these impacts in both a research and a clinical setting. Further study of the validity of BAP-PIQ scales and their ability to detect clinically meaningful change would be of use. Additional data from samples comprising fathers of adolescents with chronic pain and parents of adolescents with non-musculoskeletal pain would be of benefit.     

The reliability and validity of pain interference measures in persons with spinal cord injury.

The current study compared the psychometric properties of 2 commonly used measures of pain-related interference, the Graded Chronic Pain (GCP) Disability scale and 3 modified versions of the Brief Pain Inventory (BPI) Interference scale. Participants were 127 persons with spinal cord injury (SCI) who reported pain on a survey. The results suggest that the GCP Disability scale and 3 versions of the BPI Interference scale are reliable and valid measures of pain-related interference in persons with SCI and pain. All 4 measures evidenced excellent internal consistency. The composite scores and individual items of the GCP Disability scale and each version of the BPI Interference scale were significantly related to average pain intensity during the past week and a global measure of psychological functioning. Finally, as pain intensity ratings increased (from mild to moderate to severe), so did the composite and item-level ratings of interference for each version of the BPI Interference scale and GCP Disability scale. Strengths and weaknesses of each measure for use with persons with disability and pain are discussed. PERSPECTIVE: The GCP Disability scale and 3 versions of the BPI Interference scale (modified for use in persons with disabilities) appear to be reliable and valid measures of pain-related interference in persons with SCI. Future research should examine their psychometric properties in other disability populations.