Multidimensional Pain Inventory profile classifications and psychopathology

Local myalgia compared to myofascial pain with referral according to the DC/TMD: Axis I and II results

BACKGROUND

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) categorized TMD muscle disorders into 3 subgroups: local myalgia, myofascial pain with spreading and myofascial pain with referral. However, the rationale for such division into subgroups and the pathogenesis and prognosis of muscle-related TMD are still poorly understood. The aim of this study was to explore the differences between local myalgia and myofascial pain with referral by means of a biopsychosocial model based on the DC/TMD.

METHODS

This retrospective study included all consecutive TMD patients who were diagnosed according to the DC/TMD in our institution between 2015 and 2018. The Axis I and II findings of patients diagnosed with local myalgia were compared to those of patients with myofascial pain with referral. A p value < 0.05 was considered statistically significant.

RESULTS

A total of 255 patients (61 men and 194 women, mean age 37.8 ± 15.34 years) were enrolled into the study, 114 in the local myalgia group and 83 in the myofascial pain with referral group. The levels of depression and nonspecific physical symptoms, headache attributed to TMD (HAattrTMD), and characteristic pain intensity (CPI) were significantly higher in the latter group. The significant differences for depression and nonspecific physical symptoms persisted after excluding patients diagnosed with HAattrTMD, however, the levels of significance were lower (p = 0.006 compared to p = 0.033 for depression total score, and p = 0.001 compared to p = 0.046 for nonspecific physical symptoms total score). CPI levels, extent of disability, and pain duration were similar for both groups when excluding for HAattrTMD.

CONCLUSION

The current study findings highlight the importance of differentiating between subgroups of myalgia according to the DC/TMD. The diagnosis of myofascial pain with referral may point to a significant Axis II component.

Trialing and Maintenance Dosing Using a Low-Dose Intrathecal Opioid Method for Chronic Nonmalignant Pain: A Prospective 36-Month Study

OBJECTIVE

To evaluate low-dose intrathecal opioid trialing and maintenance with regard to analgesia and psychometric functional capacity.

MATERIALS AND METHODS

Prospective cohort of subjects offered, trialed and maintained using low-dose opioid therapy via an intrathecal drug delivery system. Analgesia, measured by visual analog scale and the Global Pain Scale, and function, measured by Multidimensional Pain Inventory and Global Pain Scale, are evaluated. Population analysis by age, gender, oral opioid dose, diagnosis, and pain type is reported.

RESULTS

Fifty-eight subjects enrolled in the 36-month evaluation period with mean opioid intrathecal opioid dose less than 350 μg per day of morphine equivalent utilized. Primary nociceptive pain type were associated with lower intrathecal opioid doses and improved visual analog scale pain rating and improved pain severity and interference on the Multidimensional Pain Inventory.

CONCLUSIONS

This study adds to the growing body of literature suggesting that low-dose intrathecal analgesia without oral opioid supplementation can be efficacious. It appears that this approach may achieve analgesia with lower doses in those with primary nociceptive pain type.

The clinical utility of the Multidimensional Pain Inventory (MPI) in characterizing chronic disabling occupational musculoskeletal disorders

PURPOSE

The Multidimensional Pain Inventory (MPI) was designed to help capture unique characteristics of chronic pain patients. The present study examined the proportion of subgroups classified by the MPI in a chronic disabling occupational musculoskeletal disorder (CDOMD) patient cohort, and described characteristics of MPI profile groups in terms of other psychosocial variables.

METHODS

A cohort of 1,270 CDOMD patients undergoing an interdisciplinary functional restoration program was studied. Before the start of the program, all patients received a standard psychosocial assessment battery. A MPI computer program scored and identified pre-defined MPI subgroups: Adaptive Coper (AC); Interpersonally Distressed (ID); and Dysfunctional (DYS).

RESULTS

The distribution of MPI profiles for CDOMD patients was similar with those of highly disabled patients, with the largest proportion of patients having the DYS profile (44 %), followed by AC (33 %) and ID (23 %). The DYS profile group showed the highest level of pain severity, and psychosocial distress; the ID group had a moderate level; and the AC profile group had the lowest level. Higher rates of psychiatric disorders were also found in the DYS and ID groups. The DYS profile group was less likely to complete the treatment program.

CONCLUSION

The present study further demonstrated the clinical utility of the MPI classification in a large cohort of CDOMD patients, indicating that the MPI profiles successfully distinguish among patients who may require extra psychosocial attention to achieve successful treatment gains and program completion.

Multi-modal examination of psychological and interpersonal distinctions among MPI coping clusters: a preliminary study

The Multidimensional Pain Inventory (MPI) is a widely used instrument to characterize distinct psychosocial subgroups of patients with chronic pain: Adaptive (AC), Dysfunctional (DYS), and Interpersonally Distressed (ID). To date, several questions remain about the validity and distinctiveness of the patient clusters, and continued scientific attention has strongly been recommended. It is unclear if AC patients experience better adjustment or merely present themselves favorably. Moreover, differences in psychological distress and interpersonal relations between DYS and ID patients are equivocal. The present study is the first to utilize comprehensive informant ratings to extend prior validity research on the MPI. We employed a multimodal methodology consisting of patient self-report, parallel informant ratings, and behavioral measures. Ninety-nine patients with chronic pain, their partners, and providers participated. They completed measures of patients' psychological distress and social relations. We also systematically observed patients' pain behavior. Results provided strong support for the validity of the AC cluster in that patients' positive adaptation was reliably corroborated by informants. The differentiating characteristics between the 2 maladaptive clusters, however, remain elusive. We found evidence that DYS patients' distress appeared to be illness specific rather than generalized; however, both clusters were equally associated with social distress and partner/caregiver burden.

PERSPECTIVE

An adaptive style of coping with chronic pain is reliably recognized by patients' partners and healthcare providers. Differences between a dysfunctional and an interpersonally distressed coping style, however, remain unclear. Patients with a dysfunctional style appear more distressed by their illness but both styles are characterized by social difficulties.

The Potential of Treatment Matching for Subgroups of Patients With Chronic Pain

A large and diverse number of treatments have been shown to be effective in reducing pain and other symptoms for a minority but statistically significant number of patients in different chronic pain syndromes. The means by which such different treatments achieve similar outcomes is not well understood. In this paper, the importance of considering patient heterogeneity for those who may be diagnosed with the same medical syndrome is discussed. The author suggests that the lack of satisfactory treatment outcomes for the treatments of chronic pain syndromes may be accounted for by the patient homogeneity myth--the assumption that all patients with the same medical diagnosis are similar on all important variables. The importance of subdividing (splitting) patients into meaningful groups is described. Studies presenting data on the identification of patient subgroups based on psychosocial and behavioral characteristics and the reliability and validity of this approach are presented. Some initial attempts to demonstrate the potential for matching treatments to patient subgroups are described.

An examination of the psychometric structure of the Multidimensional Pain Inventory

Factor analyses to create the Multidimensional Pain Inventory (MPI) warrant further examination due to small sample size, the use of separate factor analyses for each MPI section, and lack of evidence for the replicability of the factor model. The present study randomly assigned 972 respondents to one of three samples. Study 1 used data from Sample 1 (n = 452) to examine the replicability of the MPI factor structure reported by Kerns, Turk, and Rudy (1985), and to measure the internal consistencies of MPI scales. In Study 2, confirmatory factor analyses using Sample 2 data (n = 267) verified a revised MPI factor structure that was generated in Study 1; cross-validation was achieved using data from Sample 3 (n = 253). The revised MPI model differed from the original model in its number of scales and pattern of scale loadings. Recommendations for the refinement of the MPI are proposed.

Perceived future in chronic pain: the relationship between outlook on future and empirically derived psychological patient profiles

Perceived (subjective) future has been found to be a significant factor in explaining the relationship between pain and pain-related distress. The present study is based on the assumption that chronic pain patients with the three psychological profiles introduced by Turk and Rudy in 1988 could also be found in a sample of chronic pain patients and if so, these profiles have different perspectives on the future. The Multidimensional Pain Inventory (MPI) and The Future Scale were used to collect data from 569 patients with heterogeneous non-malignant chronic pain. A cluster analysis was conducted, where the resulting clusters closely resembled the profiles labelled by Turk and Rudy as 'dysfunctional', 'interpersonally distressed' and 'adaptive coper'. The results indicated that patients with adaptive coper profile have a more positive perception, while those with an interpersonally distressed profile have a more negative perception of the future. With an increased duration of pain, the proportion of the adaptive coper category decreased linearly, while an opposite trend was noted for the interpersonally distressed category. These results may better enable profiled psychological interventions in clinical pain treatment, e.g. by providing patients with therapies focused on positive future orientation, resulting in increased motivation for health-seeking behaviour and better abilities to cope with pain.

The Minnesota Multiphasic Personality Inventory and chronic pain: a conceptual analysis of a long-standing but complicated relationship

The Minnesota Multiphasic Personality Disorder (MMPI) and its successor, the MMPI-2, have a long-standing tradition in the assessment of patients with chronic pain. With the introduction of more narrowly defined and factor-analyzed pain inventories, however, the utility of the MMPI-2 for pain assessment has been brought into question. In this review, the relevant literature is carefully scrutinized from a conceptual and historical perspective. It is concluded that many of the (recent) criticisms are largely ungrounded. Rather than the test itself being at fault or of little utility in the field of pain assessment, it has simply been applied inappropriately (i.e., for determination of pain etiology or underlying personality structure "explaining" the chronic pain). In conclusion, it is suggested that the application of the MMPI-2 in the assessment of patients with chronic pain should correspond more closely to the original aims and psychometric properties of the tool--that is, for screening and the generation of hypotheses regarding comorbid psychopathology and personality features having the potential to complicate the treatment process. Guidelines for clinical interpretation of MMPI-2 profiles with regard to chronic pain are provided.

Coping profile differences in the biopsychosocial functioning of patients with temporomandibular disorder

OBJECTIVE

The objective of this study was to evaluate whether biopsychosocial functioning differences exist between samples of patients with temporomandibular disorder (TMD) who differ in coping profiles as assessed by the Multidimensional Pain Inventory.

METHODS

A total of 322 patients who presented with TMD were administered a comprehensive biopsychosocial assessment battery, and the acute or chronic status of their disorder was determined. A follow-up evaluation was conducted 6 months later to determine the status of their pain.

RESULTS

TMD patients with dysfunctional and interpersonally distressed coping profiles demonstrated more acute and chronic psychosocial difficulties than patients with adaptive coper profiles. The data also suggest that having a dysfunctional/distressed coping profile on the Multidimensional Pain Inventory has some predictive value in determining the likelihood of developing chronicity in the absence of treatment.

CONCLUSIONS

The presence of a dysfunctional/distressed coping profile in patients with TMD is likely to provide clinicians with important information about the biopsychosocial functioning of those patients, which, in turn, will help to determine the most effective treatment modalities to use with TMD patients.

Improving the rate of classification of patients with the multidimensional pain inventory (MPI): clarifying the meaning of "significant other"

OBJECTIVE

The Multidimensional Pain Inventory (MPI) has been used widely to assess the psychosocial adaptation in chronic pain patients. The MPI can also be used to classify patients into one of three primary subgroups. However, studies have reported that anywhere from 3% to 30% of patients are unclassifiable, mostly attributable to an excessive number of missing responses to questions. The purpose of this study was to examine the reasons for the large number of missing responses and subsequently to reduce the number of patients who cannot be classified within one of the three primary MPI subgroups.

DESIGN

Two versions of the MPI were evaluated on two samples of patients (N = 147; and N = 143) with persistent pain being evaluated by the Workers Compensation Board of British Columbia, Canada. One version used the published MPI instructions and the second modified the instructions to clarify the meaning of the term "significant other." In addition, patients were required to designate a significant other who would serve as the anchor for all responses related to a significant other.

RESULTS

Approximately 18% of patients could not be classified within one of the three primary profiles and were determined to be unanalyzable using the MPI standard classification procedure. Most patients who could not be classified had excessive missing data to those questions asking about support received from "significant other." Almost all of these patients with missing data were unmarried and living alone. Modifying the instructions of the MPI to specify the meaning of the term "significant other" resulted in an almost threefold (6.3% vs. 18%) reduction in the percentage of patients whose responses could not be analyzed and consequently classified into one of the three primary MPI subgroups. The revised instructions did not lead to any difference in the actual distribution of patients assigned to one of the three profiles. Thus, using the modified instruction did not alter the proportion of patients assigned to one of the three primary groups.

CONCLUSION

Modification of the MPI instructions clarifying the definition of a significant other can greatly reduce the number of patients who are classifiable within one of the three primary MPI profiles. Thus, the modified instructions of the MPI (hence the MPI-M) have a significant advantage over the original version. The mean scores on the individual scales of the MPI and the MPI-M are comparable. Moreover, the results demonstrate that the proportion of the previously unanalyzable patients classified within one of the three primary subgroups is comparable to the original proportion of patients assigned to each of the primary subgroups. Thus, it may not be necessary to reestablish the norm scores based on the modified instructions. Future studies and clinicians who wish to use the MPI for the purpose of classifying patients on the basis of psychosocial and behavioral factors should make use of the MPI-M that incorporates the clarification of the meaning of "significant other."

A model for predicting chronic TMD: practical application in clinical settings

BACKGROUND

Substantial cost is associated with the treatment of chronic temporomandibular disorders, or TMDs, and patients with TMDs often experience significant psychosocial distress. Early intervention based on identified risk factors has potential financial and functional benefits.

METHODS

Two hundred four patients with acute TMD were evaluated via an assessment battery that included physical, psychological and social measures. All participants were diagnosed as having TMD on the basis of the research diagnostic criteria for TMD, Axis I. At the six-month follow-up assessment, patients were considered to have chronic TMD if they continued to have TMD pain. This resulted in 144 of the patients being classified in the chronic group and 60 being classified in the nonchronic group.

RESULTS

A comparison of the acute TMD data demonstrated that the group that went on to develop chronic TMD and the group that did not differed significantly in their scores on numerous biopsychosocial indexes. Although several biopsychosocial measures were found to differentiate these two groups before the onset of chronic TMD, logistic regression analysis demonstrated that a two-variable predictive model consisting of the presence of a muscle disorder and characteristic pain intensity (that is, the mean of these three ratings: patient's report of current pain, worst pain in the last three months and mean pain in the last three months) accurately classified 91 percent of the subjects who went on to develop chronic TMD.

CONCLUSIONS

During the acute phase of TMD, two variables allowed for an accurate prediction rate of 91 percent among patients who went on to develop chronic TMD.

CLINICAL IMPLICATIONS

This model provides clinicians with the opportunity to identify at-risk patients early and initiate adjunctive or alternative treatments, thus reducing the likelihood of the development of TMD chronicity.

Psychosocial and behavioral assessment of patients with temporomandibular disorders: diagnostic and treatment implications

The literature on chronic pain reveals that several psychosocial and behavioral factors, in addition to physical pathology, play a role in reports of pain and disability. Therefore it is important to assess patients more broadly rather than focus exclusively on physical pathology. Understanding and treatment of temporomandibular disorders has been impeded by the lack of agreement on a classification system with which to make a differential diagnosis. Research supports the appropriateness of a dual-diagnostic approach for temporomandibular disorders based on physical and psychological axes. Treatment should be directed toward the physical diagnoses supplemented by treatment that targets relevant psychosocial characteristics. This approach encourages diagnosticians to think in terms of the two relevant axes and to customize treatment to physical and psychosocial characteristics and thus should foster better outcomes.

Management of chronic pain. Part II

Chronic pain is associated with substantial psychosocial and economic stress coupled with functional loss and various levels of vocational dysfunction. The role of a pain center is to focus on chronic pain in a multidisciplinary, comprehensive manner, providing the patient with the most effective opportunity to manage his or her chronic disease syndrome. This article focuses on methods to manage many types of chronic pain and describes a broad range of pharmacologic and non-pharmacologic interventions and options available to the patient. Part I of this two-part monograph described pharmacotherapeutic interventions and regional nerve blocks. Part II focuses on psychologic assessment and treatment and physical therapy. A multimodal management strategy offers patients the greatest improvement potential for specific chronic pain syndromes. Cognitive and behavioral therapies and physical therapies are described. This combination of therapies may provide patients with the skills and knowledge needed to increase their sense of control over pain. The integration of appropriate pharmacotherapeutic regimens, neural blockades, physical therapy, and psychologic techniques maximizes the patient's effectiveness in dealing with chronic pain. Three case studies are presented in Part II.