Psychosocial Profiles of People With Pain Associated With Spinal Cord Injury

Machine learning suggests sleep as a core factor in chronic pain

Patients with chronic pain have complex pain profiles and associated problems. Subgroup analysis can help identify key problems. We used a data-based approach to define pain phenotypes and their most relevant associated problems in 320 patients undergoing tertiary pain management. Unsupervised machine learning analysis of parameters "pain intensity," "number of pain areas," "pain duration," "activity pain interference," and "affective pain interference," implemented as emergent self-organizing maps, identified 3 patient phenotype clusters. Supervised analyses, implemented as different types of decision rules, identified "affective pain interference" and the "number of pain areas" as most relevant for cluster assignment. These appeared 698 and 637 times, respectively, in 1000 cross-validation runs among the most relevant characteristics in an item categorization approach in a computed ABC analysis. Cluster assignment was achieved with a median balanced accuracy of 79.9%, a sensitivity of 74.1%, and a specificity of 87.7%. In addition, among 59 demographic, pain etiology, comorbidity, lifestyle, psychological, and treatment-related variables, sleep problems appeared 638 and 439 times among the most important characteristics in 1000 cross-validation runs where patients were assigned to the 2 extreme pain phenotype clusters. Also important were the parameters "fear of pain," "self-rated poor health," and "systolic blood pressure." Decision trees trained with this information assigned patients to the extreme pain phenotype with an accuracy of 67%. Machine learning suggested sleep problems as key factors in the most difficult pain presentations, therefore deserving priority in the treatment of chronic pain.

Profiles of Subjective Well-being in Patients with Chronic Back Pain: Contrasting Subjective and Objective Correlates

OBJECTIVE

The detrimental impact of nonspecific chronic low back pain (CLBP) on quality of life is well known. However, patients with CLBP represent a remarkably heterogeneous group, and not all of them report compromised well-being.

METHODS

In this study, we investigated this heterogeneity by identifying profiles (or clusters) of well-being and their correlates in 239 CLBP patients. To take the multidimensionality of subjective well-being into account, we included multiple well-being indicators (depression, anxiety, affective distress, perceived control over life). For an in-depth characterization of the well-being profiles, we assessed 1) sociodemographic indicators (age, gender, education, marital status, occupational status), 2) pain-related measures (pain intensity, subjective and objective pain disability, number of pain locations), 3) psychosocial resources (mental health, resilience, perceived support), 4) biographical factors (trauma), and 5) somatosensory profiles based on quantitative sensory testing.

RESULTS

Based on two-step cluster analysis, we identified three distinct well-being profiles, characterized by either generally high well-being (cluster 1, n = 51), moderate well-being (cluster 2, n = 104), or consistently low well-being (cluster 3, n = 77), respectively. Most differences between the derived well-being profiles regarding sociodemographic, psychosocial, and biographical measures were of weak to moderate effect size. Larger effect sizes were observed for differences in pain intensity and subjective, but not objective, pain disability. Finally, the largest effects were found for differences in psychosocial resources.

CONCLUSIONS

Our findings suggest that not only in nonclinical samples, but also in patients with chronic pain, well-being is more closely associated with psychological resources and subjective evaluations than with objective parameters.

Beyond solicitousness: a comprehensive review on informal pain-related social support

Adults with chronic pain cite social support (SS) as an important resource. Research has mostly focused on general SS or pain-specific solicitousness, resulting in a limited understanding of the role of SS in pain experiences. Drawing on SS theoretical models, this review aimed to understand how pain-related SS has been conceptualized and measured and how its relationship with pain experiences has been investigated. Arksey and O'Malley scoping review framework guided the study. A database search (2000-2015) was conducted in PsycINFO, CINAHL, MEDLINE, and EMBASE using a combination of subject headings/keywords on pain and SS; 3864 citations were screened; 101 full texts were assessed for eligibility; references of 52 papers were hand searched. Fifty-three studies were included. Most studies were either a-theoretical or drew upon the operant conditioning model. There are several self-report measures and observational systems to operationalize pain-related SS. However, the Multidimensional Pain Inventory remains the most often used, accounting for the centrality of the concept of solicitousness in the literature. Most studies focused on individuals with chronic pain self-report of spousal pain-related SS and investigated its main effects on pain outcomes. Only a minority investigated the role of pain SS within the stress and coping process (as a buffer or mediator). Little is known about mediating pathways, contextual modulation of the effectiveness of SS exchanges, and there are practically no SS-based intervention studies. Drawing on general SS models, the main gaps in pain-related SS research are discussed and research directions for moving this literature beyond solicitousness are proposed.

Living With Chronic Pain After Spinal Cord Injury: A Mixed-Methods Study

OBJECTIVE

To identify the relative importance of positive (facilitators) and negative (barriers) contributors to living with chronic pain after spinal cord injury (SCI).

DESIGN

Mixed-methods: (1) Qualitative (n=35): individual, semistructured, open-ended interviews identifying facilitator/barrier themes; (2) Quantitative (n=491): converting the most common themes into statements and quantifying agreement with these in an online survey to determine relative importance, underlying dimensions, and their associations with perceived difficulty in dealing with pain.

SETTING

University-based research setting and general community.

PARTICIPANTS

Volunteers (N=526) with SCI experiencing moderate to severe chronic pain.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Interview guides, facilitator/barrier statements, and pain inventories.

RESULTS

Exploratory factor analyses reduced agreement ratings into 4 facilitators (information regarding pain and treatments, resilience, coping, medication use) and 5 barriers (poor health care communication, pain impact and limitations, poor communication about pain, difficult nature of pain, treatment concerns). Greater "pain impact and limitations," "difficult nature of pain," "poor communication from provider," lower "resilience," greater "medication use," and younger age predicted greater difficulty in dealing with pain (r=.75; F=69.02; P<.001).

CONCLUSIONS

This study revealed multiple facilitators and barriers to living with chronic pain after SCI. The principal barrier, "poor health care communication," indicated that consumers do not receive adequate information from their health care providers regarding pain. "Information regarding pain and treatments" had greater agreement scores and factor loadings than all other facilitators, indicating that most participants view provider-patient communication and educational efforts regarding pain and pain management as priorities and critical needs. Further initiatives in these areas are important for improving pain management post-SCI.

The impact of pain on spiritual well-being in people with a spinal cord injury

STUDY DESIGN

The study uses a cross-sectional, group comparison, questionnaire-based design.

OBJECTIVES

To determine whether spinal cord injury and pain have an impact on spiritual well-being and whether there is an association between spiritual well-being and measures of pain and psychological function.

SETTING

University teaching hospital in Sydney, New South Wales, Australia.

METHODS

Questionnaires evaluating pain, psychological and spiritual well-being were administered to a group of people with a spinal cord injury (n=53) and a group without spinal cord injury (n=37). Spiritual well-being was assessed using the Functional Assessment of Chronic Illness and Therapy - Spirituality Extended Scale (FACIT-Sp-Ex). Pain and psychological function were also assessed using standard, validated measures of pain intensity, pain interference, mood and cognition.

RESULTS

Levels of spiritual well-being in people with a spinal cord injury were significantly lower when compared with people without a spinal cord injury. In addition, there was a moderate but significant negative correlation between spiritual well-being and pain intensity. There was also a strong and significant negative correlation between depression and spiritual well-being and a strong and significant positive correlation between spiritual well-being and both pain self-efficacy and satisfaction with life.

CONCLUSION

Consequences of a spinal cord injury include increased levels of spiritual distress, which is associated, with higher levels of pain and depression and lower levels of pain self-efficacy and satisfaction with life. These findings indicate the importance of addressing spiritual well-being as an important component in the long-term rehabilitation of any person following spinal cord injury.

SPONSORSHIP

This study was supported by grant funding from the Australian and New Zealand College of Anaesthetists, and the National Health and Medical Research Council of Australia.

Multidimensional clinical pain phenotypes after spinal cord injury

SUMMARY Persistent neuropathic pain after spinal cord injury (SCI) is a serious problem that significantly affects general health and wellbeing over and above what is caused by other medical consequences after SCI. The ideal approach to the management of the neuropathic pain conditions after SCI would be to identify the primary contributing mechanisms of pain in each person and tailor the treatment to these. However, despite significant basic and clinical research progress, this approach remains elusive. One strategy to further this effort is to define neuropathic pain phenotypes based on pain symptoms, sensory function/dysfunction and psychosocial factors, and determine the relationship between these and treatment outcomes and biomarkers including brain imaging. This approach will facilitate the interaction between basic and clinical science and translational research, further the understanding of the mechanisms that contribute to the development and maintenance of neuropathic pain after SCI, and thus the development of effective mechanisms-based pain treatment strategies.

Evaluation of an interdisciplinary program for chronic pain after spinal cord injury

OBJECTIVE

To assess efficacy of an interdisciplinary pain program adapted for persons with spinal cord injury (SCI) and chronic pain.

DESIGN

Prospective cohort.

SETTING

University-affiliated rehabilitation hospital.

PARTICIPANTS

Twenty-two persons with traumatic or nontraumatic SCI and chronic pain of at least 6 months' duration.

METHODS

Subjects participated in an interdisciplinary pain program consisting of biweekly group sessions for 10 consecutive weeks. Sessions incorporated patient education on chronic pain and associated pain mechanisms, cognitive behavioral therapy, self-management strategies (eg, energy conservation, ergonomics, goal setting, stress management, anger management, and coping skills), group discussions and activities, and either exercise or guided relaxation at the end of each session.

MAIN OUTCOME MEASURES

Multidimensional Pain Inventory SCI, Coping Inventory of Stressful Situations, Pain Stages of Change Questionnaire, and Life Satisfaction Questionnaire.

RESULTS

After participation in an interdisciplinary pain program, persons with SCI and chronic neuropathic pain demonstrated increased involvement in learning and maintenance of coping strategies for chronic pain. Participation also led to less pain interference in daily life and a greater sense of control over one's life.

CONCLUSIONS

Participation in an interdisciplinary pain program does not reduce pain severity, but it can help persons with SCI and chronic neuropathic pain cope with pain, lessen interference of pain, and improve their sense of control.

Metabolite concentrations in the anterior cingulate cortex predict high neuropathic pain impact after spinal cord injury

Persistent pain is a common reason for reduced quality of life after a spinal cord injury (SCI). Biomarkers of neuropathic pain may facilitate translational research and the understanding of underlying mechanisms. Research suggests that pain and affective distress are anatomically and functionally integrated in the anterior cingulate cortex and can modulate sensory and affective aspects of pain. We hypothesized that severe neuropathic pain with a significant psychosocial impact would be associated with metabolite concentrations (obtained by magnetic resonance spectroscopy) in the anterior cingulate cortex, indicating neuronal and/or glial dysfunction. Participants with SCI and severe, high-impact neuropathic pain (SCI-HPI; n=16), SCI and moderate, low-impact neuropathic pain (SCI-LPI; n=24), SCI without neuropathic pain (SCI-noNP; n=14), and able-bodied, pain-free control subjects (A-B; n=22) underwent a 3-T magnetic resonance imaging brain scan. Analyses revealed that the SCI-HPI group had significantly higher levels of myoinositol (Ins) (P<.000), creatine (P=.007), and choline (P=.014), and significantly lower levels of N-acetyl aspartate/Ins (P=.024) and glutamate-glutamine (Glx)/Ins (P=.003) ratios than the SCI-LPI group. The lower Glx/Ins ratio significantly discriminated between SCI-HPI and the A-B (P=.006) and SCI-noNP (P=.026) groups, displayed excellent test-retest reliability, and was significantly related to greater pain severity, interference, and affective distress. This suggests that the combination of lower glutamatergic metabolism and proliferation of glia and glial activation are underlying mechanisms contributing to the maintenance of severe neuropathic pain with significant psychosocial impact in chronic SCI. These findings indicate that the Glx/Ins ratio may be a useful biomarker for severe SCI-related neuropathic pain with significant psychosocial impact.

Pain symptom profiles in persons with spinal cord injury

OBJECTIVE

Persistent pain is a common consequence of spinal cord injury. A patient-specific assessment that combines both the identification of pain symptoms and psychosocial factors is needed for a tailored treatment approach. The aim of the study was to define pain symptom profiles and to determine their relationship with psychosocial factors in persons with spinal cord injury.

DESIGN

Face-to-face interview and examination.

SETTING

VA Medical Center and Miami Project to Cure Paralysis, Miami, Florida.

PATIENTS

Persons with spinal cord injury (135 men and 21 women) provided detailed descriptions of 330 neuropathic pains.

OUTCOME MEASURES

The American Spinal Injury Impairment Scale, pain history and measures of pain interference, life satisfaction, locus of control, social support and depression.

RESULTS

The exploratory factor analyses and regression analyses revealed three distinct symptom profiles: 1) aching, throbbing pain, aggravated by cold weather and constipation predicted by a combination of chance locus of control and lower levels of life satisfaction; 2) stabbing, penetrating, and constant pain of high intensity predicted by a combination of pain interference, localized pain, powerful others locus of control and depressed mood; and 3) burning, electric, and stinging pain aggravated by touch and muscle spasms predicted by pain interference.

CONCLUSIONS

Although these results need to be replicated in other spinal cord injury samples, our findings suggest that pain symptom profiles may be a useful way to further characterize pain in a comprehensive assessment strategy.

Pain catastrophizing and beliefs predict changes in pain interference and psychological functioning in persons with spinal cord injury

The current study sought to examine how changes in pain-related beliefs and coping responses are related to changes in pain interference and psychological functioning in individuals with spinal cord injuries (SCI) and pain. To measure longitudinal changes in these variables, respondents completed a survey that included measures of pain intensity, pain interference, and psychological functioning, as well as specific psychosocial variables (pain-related beliefs, coping, and social support) and then completed the same survey 6 months later; analyses included only the individuals who reported pain at both times (n = 40). Demographic and injury-related variables were also assessed, but none were found to be significantly associated with changes in functioning. Changes in catastrophizing and belief in one's ability to control pain were each significantly associated with changes in the outcome variables: Greater pain interference and poorer psychological functioning. Changes in specific coping strategies and social support were not predictors of changes in pain, interference, or psychological functioning. These findings support a biopsychosocial model of pain in persons with SCI. Intervention studies targeting maladaptive pain-related beliefs and catastrophizing may help to identify the causal nature of these relationships and may improve multidisciplinary treatment of pain in SCI.

PERSPECTIVE

Intervention studies targeting catastrophizing and maladaptive pain-related beliefs may be the next step in determining which variables play a causal role in the pain interference and psychological functioning of individuals with pain and SCI.

Spinal cord injury-related pain in rehabilitation: a cross-sectional study of relationships with cognitions, mood and physical function

Although psychological aspects of SCI-related pain have been investigated in those with chronic pain, little data is available regarding these factors in those early in the course of the injury. Using a sample admitted for SCI rehabilitation, this paper describes the relationships between usual pain intensity, mood, disability and both pain and SCI-related psychological factors. The sample were largely similar to other samples of individuals with SCI-related chronic pain in terms of mood, but were noted to be less catastrophic in their thinking about pain than a comparative pain clinic sample. They also reported SCI self-efficacy and acceptance scores consistent with other SCI samples. Compared with other SCI populations there were mixed findings in relation to physical disability. Consistent with previous findings in chronic pain SCI samples, usual pain intensity was found to have a strong relationship with symptoms of anxiety and depression, and pain-related life interference. SCI acceptance was significantly negatively associated with depression scores, pain catastrophizing was significantly positively associated with both anxiety and depression scores, and SCI self-efficacy was significantly negatively associated with both anxiety and depression scores. SCI self-efficacy was also significantly positively associated with physical function scores. These findings suggest that pain-related psychological factors may have importance even early in the clinical course following SCI, but that it is important, however, to consider more general SCI-related psychological factors alongside them. In addition, these findings suggest the possibility that early interventions based upon the cognitive behavioural treatment of pain may be integrated into SCI rehabilitation programmes.

Evidence-based clinical practice guidelines for interdisciplinary rehabilitation of chronic nonmalignant pain syndrome patients

This is an update to evidence-based practice guidelines for chronic nonmalignant pain syndrome patients first published in 1995 and revised in 1999. The current guidelines recommend interdisciplinary-focused rehabilitation, which is goal-directed and time-limited. Emphasis is placed on educating patients in active self-management techniques that stress maximizing function. Integrated treatment involving medical, psychological/behavioral, physical/occupational therapy, and disability/vocational interventions are recommended on an outpatient basis whenever clinically possible. Patient selection criteria are delineated. Updated references providing evidence-based support for the recommendations are provided, including the use of opioids and sedative-hypnotic medications, injection and block procedures, acupuncture, implantable spinal infusion and stimulation devices, and other invasive spinal surgery procedures such as intradiscal electrothermal therapy. Guideline integration and early detection and intervention with chronic pain syndrome patients are encouraged.

Spinal Cord Injury Pain: The Influence of Psychologic Factors and Impact on Quality of Life

OBJECTIVES

To examine chronic pain prevalence in a spinal cord injury (SCI) population, and to determine the influence of psychologic factors on SCI pain and impact of SCI pain on quality of life.

METHODS

Five hundred seventy-five persons with SCI were asked to participate in the study. Demographic, SCI, and pain characteristics were obtained. The Chronic Pain Grade, anger items of the Profile of Mood States, Illness Cognition Questionnaire, Pain Coping and Cognition List, and Patient Health Questionnaire were used. General health and well-being were assessed with 0-10 scales. The influence of psychologic factors was assessed with regression analyses controlling for person and injury characteristics and pain intensity.

RESULTS

Response rate was 49%. SCI pain prevalence was high (77.1%). More internal pain control and coping, less catastrophizing, higher level of lesion, and nontraumatic SCI cause were associated with less pain intensity. More pain was associated with higher pain-related disability. Lower catastrophizing was related to better health. Less SCI helplessness and catastrophizing, greater SCI acceptance and lower anger levels were related to higher well-being. Higher levels of SCI helplessness, catastrophizing, and anger were related to higher depression levels. Pain intensity showed no independent relationships with health, well-being, and depression in the regression analyses.

DISCUSSION

Chronic SCI pain and quality of life were both largely associated with several psychologic factors of which pain catastrophizing and SCI helplessness were most important. Psychologic intervention programs may be useful for persons suffering from chronic SCI pain to improve their quality of life.

Pain after spinal cord injury: an evidence-based review for clinical practice and research. Report of the National Institute on Disability and Rehabilitation Research Spinal Cord Injury Measures meeting

BACKGROUND/OBJECTIVES

To examine the reliability, validity, sensitivity, and practicality of various outcome measures for pain after spinal cord injury (SCI), and to provide recommendations for specific measures for use in clinical trials.

DATA SOURCES

Relevant articles were obtained through a search of MEDLINE, EMBASE, CINAHL, and PubMed databases from inception through 2006.

STUDY SELECTION

The authors performed literature searches to find articles containing data relevant to the reliability and validity of each pain outcome measure in SCI and selected non-SCI populations.

DATA EXTRACTION

After reviewing the articles, an investigator extracted information utilizing a standard template. A second investigator reviewed the chosen articles and the extracted pertinent information to confirm the findings of the first investigator.

DATA SYNTHESIS

Taking into consideration both the quantity and quality of the studies analyzed, judgments on reliability and validity of the measures were made by the two investigators. Based upon these judgments, recommendations were formulated for use of specific measures in future clinical trials. In addition, for a subset of measures a voting process by a larger group of SCI experts allowed formulation of recommendations including determining which measures should be incorporated into a minimal dataset of measures for clinical trials and which ones need revision and further validity and reliability testing before use.

CONCLUSIONS

A 0-10 Point Numerical Rating Scale (NRS) is recommended as the outcome measure for pain intensity after SCI, while the 7-Point Guy/Farrar Patient Global Impression of Change (PGIC) scale is recommended as the outcome measure for global improvement in pain. The SF-36 single pain interference question and the Multidimensional Pain Inventory (MPI) or Brief Pain Inventory (BPI) pain interference items are recommended as the outcome measures for pain interference after SCI. Brush or cotton wool and at least one high-threshold von Frey filament are recommended to test mechanical allodynia/hyperalgesia while a Peltier-type thermotester is recommended to test thermal allodynia/hyperalgesia. The International Association for the Study of Pain (IASP) or Bryce-Ragnarsson pain taxonomies are recommended for classification of pain after SCI, while the Neuropathic Pain Scale (NPS) is recommended for measuring change in neuropathic pain and the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) for quantitating neuropathic and nociceptive pain discrimination.

Internal Consistency, Stability, and Validity of the Spinal Cord Injury Version of the Multidimensional Pain Inventory

OBJECTIVE

To evaluate the internal consistency, stability, and construct validity of a spinal cord injury (SCI) version of the Multidimensional Pain Inventory (MPI-SCI).

DESIGN

Interview.

SETTING

Veterans Affairs medical center and university-based institute.

PARTICIPANTS

Community sample of persons with SCI and chronic pain (N=161).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

The MPI-SCI.

RESULTS

The internal consistency of the MPI-SCI subscales ranged from fair (.60) for affective distress to substantial (.94) for pain interference with activities. The subscales of the MPI-SCI (ie, life interference [r=.81], affective distress [r=.71], solicitous responses [r=.86], distracting responses [r=.85], general activity [r=.69], pain interference with activities [r=.78], pain severity [r=.69], negative responses [r=.69]) showed adequate stability. In contrast, the stability of the support (r=.59) and the life control subscales (r=.31) was unacceptably low. All MPI-SCI subscales with the exception of the perceived responses by significant others subscales showed good convergent, discriminant, and concurrent validity.

CONCLUSIONS

The MPI-SCI appears to be a reasonable measure for evaluating chronic pain impact after SCI. In clinical trials, however, supplementary instruments should be included to assess changes in affect, social support, and perceptions of life control.

Exacerbation of Chronic Pain following Spinal Cord Injury

Because of the high prevalence and the refractory nature of pain following spinal cord injury (SCI), it is important to increase the understanding of what factors aggravate different types of pain. This information is related to pain generating mechanisms and may thus be useful in the diagnosis and management of these difficult pain conditions. The aims of the present study were to (1) identify variables (factors) that exacerbate chronic pain associated with SCI and (2) define the relationships among these patterns of pain exacerbation, specific pain characteristics, and psychological features. A sample out of 159 (75.5%) people with SCI and chronic pain, volunteered to participate in a mail survey. Over 50% of the sample indicated that prolonged sitting, infections, fatigue, muscle spasms, cold weather, and sudden movements exacerbated their pain. A principal components analysis detected five sets of factors that were reported to magnify pain: negative mood, prolonged afferent activity (bowel, bladder, somatic), weather, voluntary physical activity, and transient somatic afferent activity. Negative mood and prolonged afferent activity were frequently and significantly associated with both pain characteristics and psychosocial issues. A multiple regression analysis revealed that a combination of decreased activity levels due to pain (t = 3.54; p < 0.001), pain located in the frontal aspects of torso (including genitals) (t = 2.29; p < 0.05), "burning" (t = 2.26; p < 0.05), or "electric" (t = 2.09; p < 0.05) pain, and a limited perception of life control (t = -2.16; p < 0.05) was significantly associated with a high extent of pain aggravation (R2 = 0.39; p < 0.000).