Persistent pain and the injured worker: Integrating biomedical, psychosocial, and behavioral factors in assessment

The Functional Barometer - An analysis of a self-assessment questionnaire with ICF-coding regarding functional/activity limitations and quality of life due to pain - Differences in age gender and origin of pain

Long standing non-malignant pain leads to a variety of limitations which can be assessed by means of the self-assessment questionnaire Functional Barometer. It is designed to assess the extent and limitations in function, activity and decreased quality-of-life and is adapted to the International Classification of Functioning and Health.

AIM

To investigate the outcome and differences in age, gender and origin of pain in patients with long-standing non-malignant pain regarding the subjective experience of functional-, activity- and quality-of-life limitations.

METHOD

300 patients with a median duration of pain of 49 months referred to a Pain Management Centre filled out the Functional Barometer questionnaire, adapted to the International Classification of Functioning and Health.

RESULTS

66% patients were women and 34% were men. Seventy-five percent were in working age, 18-64 years. The duration before being referred to a pain specialist was over 4 years and 65% reported pain from more than three origins. Significant differences in functioning, activity and quality-of-life were found in comparing gender, age and origin of pain. Men more often reported physiological limitations while women more often reported psychological limitations of functioning, activity and quality-of-life. The most important were that men more often had difficulties in walking and climbing stairs, while women reported problems with concentration, stress and psychological demands, family relations and contact with friends.

CONCLUSION

The significant differences regarding functioning, activity and quality-of-life between women and men as age and origin of pain must be taken into account when tailoring individual treatment and rehabilitation programmes.

Assessment of Psychosocial Factors in Functional Capacity Evaluation of Clients with Chronic Back Pain

Psychosocial factors have been shown to be major determinants in the return to work of individuals with chronic back pain. It is important, therefore, for occupational therapists to have an understanding of these factors and to include an evaluation of them when assessing function for work.

This article presents an overview of the influence of some of these factors on function and, in particular, return to work in individuals with chronic back pain. It also provides an introduction to tools occupational therapists may use to assess these factors within a comprehensive functional capacity evaluation. Variables discussed include perceived disability, expectation of return to work, self-efficacy, perceived effort, pain intensity, pain location and pain behaviour. Consideration is given to the reliability and validity of the tools reviewed.

Using Locus of Control to Predict the Return-to-Work Achievements of Back-Injured Occupational Rehabilitation Clients

It has been proposed that perceived control plays an important role in influencing health-related behaviour. This study examined the relationship between locus of control and the return-to-work achievements of a group of back-injured workers' compensation claimants. The obtained results supported the hypothesised relationships between both ‘internal’ and ‘powerful others’ locus of control, and the return-to-work criterion variables. It was concluded that use of rehabilitation-specific measures of locus of control (such as were employed in the present study) could guide the program planning efforts of rehabilitation personnel dealing with this client group.

The Role of the Rehabilitation Provider in Occupational Rehabilitation: Providing for Whom? Part 1: Self-perceptions

Rehabilitation providers were the product of the 1987 Workers' Compensation Act in NSW, Australia. They operate in a complex environment and serve many masters. This paper assesses how rehabilitation providers are faring in the management of workplace injury. Using in depth semi-structured interviews, the self-perceptions of rehabilitation providers are presented. Results indicate that the current practice of rehabilitation providers labours under a heavy load of competing responsibilities, difficult clientele, adversarial stakeholders, economic restraints, and an unwieldy and clumsy workers' compensation system. Specific problems highlighted by rehabilitation providers included the identification of their core business and client group; misconceptions, lack of information and failure of communication among stakeholders; and lack of co-operation and overt and covert obstruction to the rehabilitation process. Rehabilitation providers perceived that they could function most effectively if they developed a genuine, trusting relationship with the injured worker, and educated and supported the treating doctor and employer in the rehabilitation and return to work process. Rehabilitation providers linked employer support of the injured worker to their willingness to provide suitable duties. Early referral was also considered an essential element in successful return to work. It was argued that rehabilitation providers should conceptualise themselves asadvocates for the rehabilitation processrather than for any stakeholder group. This conceptualisation allows the provider to move comfortably between groups of stakeholders, addressing their diverse needs while maintaining their focus on their core business.

The functional barometer -a self-report questionnaire in accordance with the International Classification of Functioning, Disability and Health for pain related problems; validity and patient-observer comparisons

Background

The International Classification of Functioning, Disability and Health, (ICF) provides a unified, international standardized framework for describing and classifying health and health-related functioning and disability. Based on an ICF core sets the Functional Barometer, (FB), was developed for assessments of perceived pain-related problems with functions, activity and quality-of-life by patients suffering from long-term pain. The aim was to evaluate the construct validity, and to compare the assessments of a patient’s problems from the perspectives of the patient and of the examining professional when using the validated FB and corresponding ICF-classification form, respectively.

Methods

Patients with long-term pain for more than 3 months that visited one of four pain clinics during specified time periods of data collections were eligible. The self-report Balanced Inventory for Spinal disorders was used for validation of the FB. Correspondingly to the validated FB an ICF-classification form for professional’s assessment was developed. The data sets for these inter-scale and the patient-professional comparisons were collected adjacent to the clinical examination. By the statistical method used for evaluation of the pairs of ordinal data presence of systematic disagreement was identified and measured separately from additional individual variations.

Results

The validation process resulted in a revised FB(2.0) that meets the requirements of good construct and content validity. The professionals’ ICF-classifications of the patients’ problems disagreed with the patients’ assessments on the FB(2.0); the percentage agreements ranged from 18% to 51%. The main reason was that the practitioners systematically underestimated the patients’ levels of problems but the different professionals contributed also to a large individual variability (noise) in assessment.

Conclusions

This study presents an ICF-based validated self-report questionnaire, The FB, to be used for identifying and describing pain-related problems with current functioning, activities and quality-of-life as perceived by patients suffering from long-term pain. The strong evidences of underestimation of the patients’ problems and the variability in the professionals’ ICF-classifications demonstrated the importance of describing the patient’s problems both from the patient’s and the professional’s perspective beneficial for the patient’s rehabilitation.

The cross-sectional construct validity of the Waddell score

BACKGROUND

In 1980 the Waddell score, consisting of 8 non-organic or behavioural signs, was developed to measure illness behaviour in patients with low back pain. There is some debate about whether the Waddell score is a valid screening instrument for illness behaviour and psychological distress, or whether it merely reflects elevated pain levels and diminished functional physical capacities.

OBJECTIVE

The purpose of this study was to examine the construct validity of the Waddell score.

METHODS

In this cross-sectional study, a total of 20 hypotheses about the associations between the Waddell score and measures from different domains were formulated a priori, based on a Medline database search (1980-2010). These hypotheses were tested in a sample of 229 patients with chronic low back pain who attended an outpatient rehabilitation centre.

RESULTS

The percentage of hypotheses that were confirmed for the association between the Waddell score and the domain pain was 100%, for the domain physical 80%, for the domain illness behaviour 80% and 50% for the domain psychological. Correlation coefficients and kappa values varied between 0.06 and 0.44 for the measures that were expected to be associated with the Waddell score.

CONCLUSION

Most of our challenging a priori hypotheses were accepted, and the Waddell score was found to have satisfactory cross-sectional construct validity. However, the presence of Waddell signs does not indicate exactly what the specific problems are and must therefore be conceptualized and understood in the total clinical picture of the patient. The association between the Waddell score and measures from different domains is weak. The Waddell score cannot be regarded as a straightforward psychological "screener".

Psychological perspective on hand injury and pain

NARRATIVE REVIEW: Pain is considered a fundamental ramification of hand injury and has been identified as one of the most acutely stressful aspects of traumatic injuries and their treatment. Both comorbid psychiatric conditions and psychosocial factors have been shown to affect medical treatment outcome in patients with hand disorders and pain, further complicating recovery and potentially leading to significant psychological, social, and economic consequences for the individual. The purpose of this article was to assist hand therapists in developing a greater understanding of psychological constructs, psychosocial variables, and comorbid psychiatric conditions and thereby facilitate the more effective identification of such factors. A case study is included to illustrate these concepts. Circumstances in which referral for a comprehensive psychological evaluation is necessary are discussed. Many of the principles reviewed are also applicable to other upper extremity and musculoskeletal conditions.

A 6-year follow-up study of 122 patients attending a multiprofessional rehabilitation programme for persistent musculoskeletal-related pain

The aim of the study was to evaluate the outcome 6 years after completing a multiprofessional 8-week rehabilitation programme regarding the following objectives: (1) return to work, (2) level of activity and (3) pain intensity. Of 149 patients attending a rehabilitation programme, 122 were followed up after 6 years, through a structured telephone interview, and their present work situation, level of activity, sleeping habits, their estimated pain intensity and consumption of analgesics were recorded. The questions presented were the same as they had answered before entering the programme. The return-to-work rate was compared to 79 patients in a control group. At the 6-year follow-up, compared to before entering the programme, 52% had returned to work (P<0.001). In the control group the return-to-work rate was 13%. This difference was statistically significant (P<0.001). There was a statistically significant higher level of activity (P=0.037). A pain reduction was experienced by 58% of the patients (P<0.001) and 47% of the patients had decreased their consumption of analgesics (P<0.001). In conclusion, after completing the structured 8-week rehabilitation programme, the return-to-work rate was higher at a 6-year follow-up than in a control group. Furthermore, they had a higher level of activity and lower level of pain intensity than before entering the programme, indicating that the rehabilitation programme had a long-term positive effect on the return-to-work-rate, activity and pain as well as on the analgesic consumption.

Analysis of the acute postoperative pain experience following oral surgery: identification of 'unaffected', 'disabled' and 'depressed, anxious and disabled' patient clusters

BACKGROUND

Pain is defined as both a sensory and an emotional experience. Acute postoperative tooth extraction pain is assessed and treated as a physiological (sensory) pain while chronic pain is a biopsychosocial problem. The purpose of this study was to assess whether psychological and social changes occur in the acute pain state.

METHODS

A biopsychosocial pain questionnaire was completed by 438 subjects (165 males, 273 females) with acute postoperative pain at 24 hours following the surgical extraction of teeth and compared with 273 subjects (78 males, 195 females) with chronic orofacial pain. Statistical methods used a k-means cluster analysis.

RESULTS

Three clusters were identified in the acute pain group: 'unaffected', 'disabled' and 'depressed, anxious and disabled'. Psychosocial effects showed 24.8 per cent feeling 'distress/suffering' and 15.1 per cent 'sad and depressed'. Females reported higher pain intensity and more distress, depression and inadequate medication for pain relief (p < 0.001). Distress and depression were associated with higher pain intensity. The developed questionnaire had tested reliability (test-retest r = 0.89) and estimated validity.

CONCLUSION

Cluster analysis showed constituent groups with a range of psychosocial effects in acute postoperative dental extraction pain and is associated with an increase in pain intensity.

Functional capacity evaluation as a performance measure: evidence for a new approach for clients with chronic back pain

OBJECTIVES

To report the research and development of a new approach to Functional Capacity Evaluation, the Gibson Approach to Functional Capacity Evaluation (GAPP FCE) for chronic back pain clients.

METHODS

Four studies, including pilot and feasibility testing, expert review, and preliminary interrater reliability examination, are described here. Participants included 7 healthy young adults and 19 rehabilitation clients with back pain who underwent assessment using the GAPP FCE. Thirteen therapists were trained in the approach and were silently observed administering the Functional Capacity Evaluations by at least 1 other trained therapists or the first investigator or both. An expert review using 5 expert occupational therapists was also conducted.

RESULTS

Study 1, the pilot with healthy individuals, indicated that the GAPP FCE was a feasible approach with good utility. Study 2, a pilot using 2 trained therapists assessing 5 back pain clients, supported the clinical feasibility of the approach. The expert review in Study 3 found support for GAPP FCE. Study 4, a trial of the approach with 14 rehabilitation clients, found support for the interrater reliability of recommendations for return to work based on performance in the GAPP FCE.

DISCUSSION

The evidence thus far available supports the GAPP FCE as an approach that provides a sound method for evaluating the performance of the physical demands of work with clients with chronic back pain. The tool has been shown to have good face and content validity, to meet acceptable test standards, and to have reasonable interrater reliability. Further research is occurring to look at a larger interrater reliability study, to further examine content validity, and to examine predictive validity.

Chronic orofacial pain is associated with psychological morbidity and negative personality changes: A comparison to the general population

BACKGROUND

Chronic orofacial pain is a biopsychosocial problem. Pain description and intensity have been previously reported by the authors. This follow up study reports on the presence and severity of psychological morbidity presence and alseverity changes associated with chronic and personality changes associated with chronic orofacial pain.

METHODS

A total of 415 questionnaires for psychological morbidity (238 chronic orofacial pain patients and 175 controls) and 205 responses for personality changes (105 pain patients and 100 controls) were analyzed. Demographic and status, level of education include and current work status. status, level of education and current work status. Psychological variables tested were depression, anger, fear, distress, frustration and anxiety. Pain patients indicated descriptors of their personalities 'pre-pain' and 'with pain'.

RESULTS

The chronic pain group reported higher levels of 'feeling sad or miserable' p < 0.001 'feeling frustrated' p = 0.001 and 'feeling anxious, worried' p = 0.022 than the control group. Within the chronic pain group, patients unemployed due to pain or other reasons reported higher levels of 'feeling sad or miserable' and 'feeling frustrated' (p < 0.05) compared with patients engaged in full or part-time work. Negative personality changes due to pain were clearly evident with 'irritable' and 'sad' being frequently chosen words (p < 0.001).

CONCLUSIONS

Patients with chronic orofacial pain suffer from negative psychological and personality changes.

Pain: psychiatric aspects of impairment and disability

Patients with chronic pain frequently experience a complex and convoluted journey through the health care system that often is unrewarding for all involved. As job satisfaction and financial security diminish during our economic recession, the impact of the disability epidemic becomes more profound. There often is no direct correlation between objective impairment and a patient's request for disability status. Injured workers maintained on workers' compensation may have an increased risk for developing chronic pain syndromes unresponsive to conventional treatments. These patients may have significant financial, psychosocial, and environmental reinforcement for maintenance of their disability and little incentive to return to work. Excessive pain behavior may lead to unnecessary diagnostic testing or invasive procedures and result in iatrogenic complications and prolonged disability. Patients with chronic pain syndrome who have not had psychosocial treatment may not be at maximum medical improvement. The purpose of this paper is to help the readership identify types of psychiatric, psychologic, and psychosocial issues that can coexist in patients with chronic pain who are applying for disability, and to help treating physicians avoid contributing to iatrogenic pain and disability by performing needless and potentially harmful procedures on patients who may be better served with an emphasis on psychiatric or psychologic care.

Salutogene Faktoren bei chronischen Rückenschmerzen:

Zusammenfassung. Theoretischer Hintergrund: In der Studie werden Rückenschmerzen in einer salutogenetischen Perspektive untersucht. Risikofaktoren chronischer Rückenschmerzen wie körperliche und psychosoziale Arbeitsbelastungen sind gut, während protektive Faktoren, die den Stress-Schmerz-Zusammenhang moderieren, bisher noch wenig untersucht sind. Fragestellung: Moderieren soziale Unterstützung, Arbeitszufriedenheit und sportliche Aktivität den Zusammenhang zwischen Arbeitsbelastungen und Rückenschmerzaktivität (RSA)? Methode: 1420 Beschäftigte aller Berufsgruppen eines Universitätsklinikums beantworteten einen standardisierten “Fragebogen zur Gesundheit“, der Stärke, Dauer und Häufigkeit von Rückenschmerzen, körperliche und psychosoziale Arbeitsbelastungen, sowie als potentielle Protektivfaktoren die generelle Arbeitszufriedenheit, die soziale Unterstützung und die Häufigkeit körperlicher Aktivität erfasste. Ergebnisse: Es zeigten sich Alters- Geschlechts- und Bildungseffekte auf die RSA sowie ein positiver Zusammenhang zwischen dem Ausmaß subjektiver Arbeitsbelastungen und der RSA. Die Protektivfaktoren moderieren diesen Belastungs-Schmerz-Zusammenhang in differentieller Weise in Form von “Puffer“- oder “Schutzschild“-Effekten. Schlußfolgerungen: Die Ergebnisse unterstützen eine salutogenetische Perspektive der RSA, und sie sprechen dafür, zukünftig theoretisch wie empirisch differentielle Modi protektiver Mechanismen zu differenzieren.

Pain management in the opioid-dependent patient

The opioid-dependent patient presents great challenges for pain management. These challenges are not limited to potential addictive behaviors. In contrast to the profound pain relieving effects of acute opioid intake, chronic opioid intake can promote a counterintuitive state of enhanced pain sensitivity. Multiple biologic mechanisms inducing opioid tolerance and hyperalgesia have recently been elucidated. The potential hyperalgesic state accompanying opioid dependence complicates pain management somewhat for acute pain and cancer pain, but it especially does so for chronic pain. Guidelines for treatment of opioid dependence in the pain patient are proposed. Treatment oriented toward the long term requires limit setting and psychologic support that go beyond simple medication management.

Chronic pain disorder following physical injury

Pain disorders that are primarily associated with psychological factors are of great clinical concern, but they are difficult to study because of the inability to make valid or reliable diagnoses by structured interview alone. The authors confront this difficulty by using an injured subject population that had extensive psychiatric and medical evaluations. Those who developed somatoform pain disorder (SPD) were compared with a control group who did not. The SPD group had distinctive associated factors: more sites of pain, spread of pain beyond area of original injury, and substantially more opiate and benzodiazepine use. Compensation/litigation influenced symptoms more in the SPD group. Psychotherapists often supported the patient's viewpoint that the pain was physical and to be endured.

Prediction of success from a multidisciplinary treatment program for chronic low back pain

STUDY DESIGN

The study included 90 disabled patients with chronic low back pain recruited from a pain clinic who were admitted to an 8-week program of functional restoration and behavioral support. Initial evaluations included a medical examination, rating of the physical impairment, a personal interview, a visual analogue scale to record pain intensity, an assessment of limitations for daily activities, a pain disability index, a depression and psychovegetative scale, and a scale to evaluate general living standards. The physical assessment included different flexibility measurements, measurement of power and endurance through standardized exercises, and measurements of isokinetic trunk and lifting strength and general endurance. The measurements were repeated at the end of the 8-week program and thereafter an intervals of 6 and 12 months. Final analyses were carried out on 82 patients.

OBJECTIVES

To determine whether objective or subjective signs most influence the outcome of rehabilitation.

SUMMARY OF BACKGROUND DATA

In recent years, several studies have shown that active and intensive multimodal treatment of chronic low back pain is successful. Until now there has been lack of information about which patients will respond to the therapy and what is the most effective part of treatment.

METHODS

Prognostic factors (return to work, pain intensity, self-assessment of treatment success by patients) were tested by studying variance and regression analyses for their ability to predict treatment outcome.

RESULTS

Certain factors were identified that had a significant impact on determining the probability of a patient's return to work and the reduction of pain intensity. These factors included self-evaluation for predicting a return to work, the length of absence from work, application for pension, and a decrease is disability after treatment. Overall satisfaction with treatment was best determined by the number of medical consultations before treatment, the extent of disability, previous measures taken for coping with the disease, and reduction of disability during treatment. Medical background, medical diagnosis, and physical impairment had no predictive value. Physical variables (i.e., mobility, strength, endurance, and physical performance) also demonstrated only limited predictive value.

CONCLUSION

This study has demonstrated that the most important variable in determining a successful treatment of chronic low back pain is the reduction of subjective feelings of disability in patients.

[Multidisciplinary treatment program for chronic low back pain, part 2. Somatic aspects]

PROBLEM

There is a great need to expand current knowledge of the various functional capacity measurements used in the rehabilitation of chronic low back pain (CLBP) patients. The literature on these patients reports that mobility, endurance, trunk strength and lifting capacity decrease during the process of chronicity. Chronically disabled patients appear to have lower functional capacity than asymptomatic persons.

METHODS

Our study group consisted of 90 disabled CLBP patients (44 female, 46 male; average age 42 years) who underwent a multidisciplinary 8-week daily treatment program of functional restoration with behavioral support (instruction, endurance training, strength exercises, behavioral and treatment to facilitate return to work therapy). Initially these patients where compared with 107 asymptomatic persons (44 female, 63 male, average age 41 years). The patients were investigated before and after treatment, and at intervals of 6 and 12 months. The reliability of the functional measurements was evaluated by interrater comparison. Physical assessment included a medical examination (mainly diagnosis of radicular or nonradicular pain), changes in the lumbar spine revealed by X-ray studies according to Herron and Turner, rating of physical impairment according to Waddell, flexibility, length of hamstrings muscles (SLR), test of power and endurance of trunk movement by standardized exercises according to the Swiss group of Spring and isokinetic measurements (LIDO Back), tests of lifting capacity (LIDO Lift), and (in part) of general endurance on a cycle ergometer (CASE 15 Marquette).

RESULTS

Physical findings showed that mobility was reduced substantially in patients suffering from back pain due to reduced SLR (shortened hamstrings) and decreased spinal mobility. Patients also demonstrated significant reductions in their ability to perform lifting tasks in comparison to healthy individuals. The results of trunk flexion showed no significant differences between patients and the control group, whereas the ability to perform trunk extension was much better in the control group. In principle we found the same results with isokinetic measurements as in the exercises without machines. Cardiovascular endurance was also much better in the control group than it was in the back pain patients. At the end of the treatment program all physical deficits were improved significantly. In many cases performance was comparable with that of the control group. With time, however, training effects gradually decreased. The success of treatment (return to work, absence from work, pain reduction, use of medical care) was independent of the functional status of the patients before and after treatment.

CONCLUSION

Study results showed that physical capacity in disabled patients with low back pain is substantially reduced in comparison to persons who do not suffer from back pain. The only exception was in trunk flexor strength and endurance, in which measurements did not differ between the patients and the control group. However, even CLBP- patients with long-term pain and severe physical illness can successfully improve their physical condition by participating in an active treatment program. Back extensor muscle training has to be included in physical therapy. Because of loss of condition during the time after treatment, regular monitoring of patients and their home training programs is necessary. Overall, treatment of CLBP has to include physical training and psychosocial treatment to achieve satisfactory results.

The reliability and validity of a measure of perceived functional capacity for work in chronic back pain

Psychosocial factors, including perceived disability and self-efficacy, are important determinants of outcome for individuals with chronic back pain. Consequently, there is a need for an evaluation and consideration of such factors in occupational rehabilitation. This study evaluated the reliability and validity of a tool, the Spinal Function Sort, as a measure of perceived capacity for work-related tasks with 42 rehabilitation clients with chronic back pain. Results provided support for the internal consistency (Cronbach's alpha of 0.97), test-rest reliability (ICC of 0.89) and construct validity of the Spinal Function Sort as a measure of perceived capacity for work-related tasks in persons with chronic back pain. Measures of similar constructs were significantly correlated with the Spinal Function Sort and were highly predictive of the Spinal Function Sort on multiple regression. Relationships between perceived work capacity and pain intensity and gender are discussed. The need for the consideration of perceived capacity in the evaluation and rehabilitation of persons with chronic back pain is highlighted.

Quantified pain drawing in subacute low back pain. Validation in a nonselected outpatient industrial sample

STUDY DESIGN

The criterion and construct validities of pain drawing, quantified by a simple total body area score of pain extent (area raw extent assessment score), were analyzed prospectively on consecutive patients (n = 103), drawn from a predefined blue collar worker population, all sick listed for 6 weeks as a result of low back pain.

OBJECTIVES

To evaluate the validity of pain drawing as a screening tool in the secondary prevention of subacute low back pain.

SUMMARY OF BACKGROUND DATA

Pain drawings have been used clinically for more than 40 years as a complement to a patient's verbal pain descriptions. The main objectives have been to differentiate functional pain from organic pain and to identify meaningful features in spatial-anatomic pain distribution. The ability of the pain drawing to delineate concurrent psychopathology correctly has been questioned. There is no consensus on which scoring method should be used.

METHODS

The area raw extent assessment score was analyzed concurrently against the penalty point system and predictively against return to work and absenteeism over a period of 2 years. Content and construct validity assessed the relative influence of medical, psychologic, and subjective disability as well as psychosocial factors.

RESULTS

Criterion validation of the area raw extent assessment score showed significant correlations, both concurrently against the penalty point score (r = 0.86, P < 0.001, with explained variance R2 = 0.75, P < 0.001) and predictively against occupational handicap (r = 0.48, P < 0.001). In construct validation, the highest explained variance was shown for medical (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.34, P < 0.001) and for subjective disability (R2 = 0.32, P < 0.001). Variance in the area raw extent assessment score also was explained by psychosocial factors (R2 = 0.19, P < 0.01).

CONCLUSIONS

Pain drawing quantification of the extent of pain shows high criterion and construct validity for the area raw extent assessment score. Content validity could be shown for significant clinical aspects of the disability experience--assets preferred for a screening tool in secondary prevention.

Pain behavior in industrial subacute low back pain. Part I. Reliability: concurrent and predictive validity of pain behavior assessments

The reproducibility of overt pain behavior ratings was shown to be reliable between independent observers. In the clinical evaluation of 103 blue collar workers with subacute low back pain (LBP), concurrent validity was high between Behavioural Signs (Waddell et al. 1980) and UAB Pain Behavior Rating scale (Richards et al. 1982). Correlations with pain rated on visual analogue scales (Scott and Huskisson 1976) were generally lower. Behavioural Signs correlated separately with covert pain behavior (general convictions concerning back strength and general health). It seems that subacute LBP patients do not behave as a homogenous group since pain behaviors predicted occupational handicap (absenteeism) in a non-linear fashion. Return to work was best predicted by UAB and covert pain behavior, absenteeism up to 2 years by covert pain behavior. The findings emphasize the potential social implications of overt pain behaviors and the importance of covert pain behavior in maintaining the sick role. The conclusion is that, in secondary prevention, where the main targets are to interfere with somatic deconditioning and sick-role development, a more diversified primary approach may be possible, based on supplementary use of relatively easy observational tests and quick self-reports.

Perceptions of disability and occupational stress as discriminators of work disability in patients with chronic pain

Pain-related work disability can be influenced by a number of medical, physical, and psychosocial factors. The present study investigated the role of perceived disability, occupational stress, pain, and distress in patients with chronic pain disorders who work despite pain and patients who are work disabled. A total of 165 patients referred to a multidisciplinary pain treatment center for chronic pain (> 6 months) were studied. The two groups were compared on age, gender, education, marital status, duration of pain problem, pain severity, psychological distress, perceived disability, and perception of the work environment. A discriminant function analysis was computed entering pain severity, distress, perceived disability (physical and psychosocial) and work environment variables. The two groups were equivalent on age, gender, education, marital status, and duration of pain problem. The groups differed on diagnosis and insurance coverage with the work-disabled group diagnosed with low back pain and receiving Workers Compensation coverage more frequently than working controls. Univariate analyses indicated that the work-disabled group reported higher pain severity, perceived physical and psychosocial disability, and job stress than their working cohorts. The discriminant function analysis indicated that the perception of physical disability, supervisor support, distress, and work pressure were capable of correctly classifying patients with chronic pain who continued to work from those who were work disabled. These findings indicate the importance of evaluating perceived disability and job stress, and if present, directing intervention effort at these factors in order to facilitate work re-entry.