An emotional component analysis of chronic pain

Role of psychology in pain management

Psychological factors are central to the experience of pain, the delivery of effective analgesia and for the specific treatment of chronic pain and disability. Improvement in pain management can often be brought about by very simple, if subtle, changes in clinical practice. Although simple, these changes can have significant effects in the experience of pain, distress and use of health-care resources. For the chronic pain patient, the presentation is much more complex and the treatment interdisciplinary and programmatic. The evidence for the effectiveness of cognitive behaviour therapy for adults with chronic pain is now well established. This treatment should be available as a core part of any chronic pain service.

Does failure hurt? The effects of failure feedback on pain report, pain tolerance and pain avoidance

In this study an experiment was conducted to examine whether failure experiences have an effect on pain report, pain tolerance and pain avoidance. Furthermore, it was investigated if negative affectivity (NA) affected the impact of failure feedback on pain report, either as a mediator, in the case of negative state affect, or as a moderator when NA as a personality trait was considered. Fifty-four healthy female volunteers were included and randomly assigned to one of three conditions: (1) failure feedback; (2) success feedback; (3) neutral control task. After the manipulation, subjects were given a cold pressor task in order to obtain pain measures. Regarding the effects of failure feedback on pain report, it was found that, in comparison with success feedback, failure feedback led to increased pain report. With regard to pain tolerance, pain was tolerated for longer when preceded by success feedback than when preceded by failure feedback. Differences between failure and control conditions did not reach significance. With regard to pain avoidance, no differences between the conditions were found. The hypothesized mediating role of negative state affect was not found. Though in the hypothesized direction, no significant effect was found for NA-trait moderating the influence of failure on pain. The discussion focuses on a number of research questions that remain to be answered, and the clinical relevance of the effects of failure and success experiences on pain report and pain tolerance.

Chronic spinal disorders and psychopathology. research findings and theoretical considerations

BACKGROUND CONTEXT

Numerous studies have documented a strong association between chronic spinal disorders and psychopathology. However, there have been methodological shortcomings associated with much of this.

PURPOSE

This article reviews the relevant research literature, including methodological refinements that have resulted in improved measurement of psychopathology, in order to provide the most updated conclusions concerning the links between spinal disorders and psychopathology.

STUDY DESIGN

A systematic review of all Medline referenced articles on this subject during the past three decades.

METHODS

Previous research has shown that chronic spinal disorders are most often associated with depressive disorders, somatoform disorders, anxiety disorders, substance use disorders, and personality disorders. In addition to reviewing this research, the relationship between chronic spinal disorders and depressive disorders is examined in more detail.

RESULTS

Although the relationship between spinal disorders and psychopathology is complex, a diathesis-stress model is emerging as the dominant overarching theoretical model. In this model, diatheses are conceptualized as pre-existing semidormant characteristics of the individual before the onset of chronic spinal disorders, which are then activated by the stress of this chronic condition, eventually resulting in a diagnosable depressive disorder.

CONCLUSIONS

In the present review, a diathesis-stress model was applied specifically to the relationship between chronic spinal disorders and depressive disorders. Such a model may also be applicable to the relationship between chronic spinal disorders and other types of psychopathology, such as anxiety and substance use disorders. However, conclusive empirical support will require a prospective research design, given that these diatheses could be validly assessed only before the onset of the chronic pain condition.

Catastrophizing, depression and expectancies for pain and emotional distress

The present research addressed the relation between catastrophizing, depression and response expectancies in anticipation of an experimental pain procedure. One hundred and twenty undergraduates (48 men, 72 women) participated in exchange for course credit. Prior to immersing one arm in a container of ice water, participants were asked to complete measures of catastrophizing and depression, and to estimate the degree of pain and emotional distress they expected to experience. After a 1-min immersion, participants rated their actual experience. Pain expectancies partially mediated the relation between catastrophizing and pain experience. Pain expectancies also mediated the relation between depression and pain experience. Catastrophizing, but not depression, was associated with a tendency to underestimate pain and emotional distress. The implications of these findings for the conceptual distinctiveness of catastrophizing and depression are discussed. Discussion also examines the potential implications of the present findings for pain management interventions.

Pain and quality of life in patients with critical limb ischaemia: results of a randomized controlled multicentre study on the effect of spinal cord stimulation. ESES study group

We carried out an assessment of pain and quality of life of patients with critical limb ischaemia during the follow-up of a multicentre randomized trial in more detail than previously reported. In a multicentre clinical trial 120 patients were randomized between medical treatment and medical treatment plus spinal cord stimulation. Patients were selected on the basis of clinical symptoms and macrocirculatory data as described in the European consensus document on critical limb ischaemia. Data were collected at intake and then 1, 3, 6, 12 and 18 months later. Primary outcome measures were limb salvage, pain relief and quality of life. Patient and limb survival was estimated with the Kaplan-Meier method. Pain was evaluated using the visual analogue scale (VAS), the McGill pain questionnaire, the pain score of the Nottingham Health Profile (NHP) and the use of analgesics. Quality of life was evaluated using the NHP, the EuroQol and mobility subscore of the Sickness Impact Profile. The 2-year limb survival was 52% for SCS treatment and 46% for standard treatment (p =0.47). Pain relief was considerable in both treatment strategies (p<0.005) with no significant differences between the strategies. The improvement occurred within the first few months and remained stable during further follow-up. Patients with SCS used fewer non-narcotic and narcotic drugs (p<0.001 at t=1 and t=3, p<0.002 at t=6). The overall scores of quality of life improved significantly (p<0.05), with no difference in score between treatments. The subscores of mobility and energy of the NHP in non-amputated patients was significantly better in the SCS group (p<0.005). Amputation had a negative effect on mobility, resulting in a difficult rehabilitation but relieved pain substantially (p<0. 05). In contrast to the existing literature, the randomized trial revealed no major difference in overall pain and quality of life assessment between treatment groups. The effect on energy and mobility was significantly better in patients treated with SCS, who also used substantially fewer analgesics.

Worrying about chronic pain: vigilance to threat and misdirected problem solving

Worry is reviewed to inform a cognitive-behavioural understanding of chronic pain. How worry comes to dominate is discussed as 'vigilance' and why worry comes to dominate is discussed as 'problem solving'. These two aspects are applied to worrying about chronic pain. Chronic pain is re-presented as chronic vigilance to threat that may lead to a perservation of attempts at solving the problem of achieving escape from pain. Attempts will be frustrated by the insolubility of the problem of chronic pain. The clinical and theoretical implications of this application are discussed.

Simple pain rating scales hide complex idiosyncratic meanings

Assumptions of reliability and consistency of self-report of pain by patients using visual analogue scales (VAS) and numerical rating scales (NRS) are based on narrow considerations of possible sources of error. This study examined patients' use of VASs and NRSs, by their own description, with particular attention to rating of multiple pains, of different dimensions of pain, and of interpretation and use of lower and upper endpoints and increments on the scales. These have implications for the approximation of the scales to psychometric requirements. An interview developed from a small pilot project was given to 78 volunteer chronic pain patients embarking on a pain management course, and consisted of both forced choice questions and free response. Data are described with reference to lack of concordance between patients and of consistency within patients; responses suggested that ratings incorporate multiple partially differentiated dimensions of pain, with particular importance placed on function or mobility. Labels assigned to scale endpoints by researchers, whether lexical or numerical, appeared to affect their use; however, covert relabelling of scale points was revealed in free response. The action of arriving at a rating is better conceptualised as an attempt to construct meaning, influenced by and with reference to a range of internal and external factors and private meanings, rather than as a task of matching a distance or number to a discrete internal stimulus.

A comparison of pain rating scales by sampling from clinical trial data

OBJECTIVE

The goals of this study were to examine agreement and estimate differences in sensitivity between pain assessment scales.

DESIGN

Multiple simultaneous pain assessments by patients in acute pain after oral surgery were used to compare a four-category verbal rating scale (VRS-4) and an 11-point numeric rating scale (NRS-11) with a 100-mm visual analog scale (VAS). The sensitivity of the scales (i.e., their ability [power] to detect differences between treatments) was compared in a simulation model by sampling from true pairs of observations using varying treatment differences of predetermined size.

RESULTS

There was considerable variability in VAS scores within each VRS-4 or NRS-11 category both between patients and for repeated measures from the same patient. Simulation experiments showed that the VAS was systematically more powerful than the VRS-4 in all simulations performed. The sensitivity of the VAS and NRS-11 was approximately equal.

CONCLUSIONS

In this acute pain model, the VRS-4 was less sensitive than the VAS. The simulation results demonstrated similar sensitivity of the NRS-11 and VAS when comparing acute postoperative pain intensity. The choice between the VAS and NRS-11 can thus be based on subjective preferences.

Validity of the pain anxiety symptoms scale (PASS): prediction of physical capacity variables

Anxious responses to pain may lead to avoidance of behavior expected to produce pain. McCracken et al. (1992) developed the Pain Anxiety Symptoms Scale (PASS) to assess anxiety related specifically to pain. Efforts to validate the scale, however, have been confined mostly to examining associations between the PASS and other self-report instruments. This study tested whether PASS scores were related to behavioral performance variables recorded by therapists during a physical capacity evaluation. Participants were 98 male patients with persistent pain referred to two industrial rehabilitation centers. PASS scores were correlated negatively with amount of weight lifted and carried, and results of hierarchical regressions showed that PASS scores accounted for additional variance in these variables when measures of trait anxiety, depression and pain severity were controlled. However, we did not replicate the findings of McCracken et al. (1992) that PASS scores accounted for variance in self-reported disability with trait anxiety, depression or pain severity controlled. Results extend the validity of the PASS and are consistent with models of fear of pain: patients with high PASS scores may avoid potentially painful physical exertion to reduce their fear.

Outcome of unilateral and bilateral pallidotomy for Parkinson's disease: patient assessment

OBJECTIVE

Pallidotomy has recently regained acceptance as a safe and effective treatment for Parkinson's disease symptoms. The goal of this study was to obtain the patients' perspective on their results after undergoing this procedure. Special attention was focused on the potential complications and the respective advantages and risks of unilateral versus bilateral pallidotomy.

METHODS

Fifty-six patients were studied during a 2-year period; 44 completed the evaluation, with a median follow-up of 7 months. Of these patients, 22 underwent unilateral pallidotomy, and 17 had bilateral simultaneous pallidotomy. Five patients who underwent staged bilateral pallidotomy were excluded from the statistical analysis, because the number of patients was considered too small for analysis. The procedures were performed with magnetic resonance imaging determination of the target, combined with physiological confirmation, including microelectrode recording.

RESULTS

According to Visual Analog Scale scores, unilateral pallidotomy significantly improved dyskinesias (P < 0.05) but no other symptoms. Simultaneous bilateral pallidotomy improved slowness, rigidity, tremor, and dyskinesias (P < 0.05) but worsened speech function (P < 0.05). According to the patients' most frequently chosen answers to multiple-choice questions, unilateral pallidotomy improved night sleep, muscle pain, freezing, overall "on," overall "off," and the duration of "off periods," but it worsened the volume of the voice and articulation, increased drooling, and reduced concentration. Bilateral pallidotomy improved night sleep, muscle pain, freezing, overall "on," overall "off," duration of "off periods," and the amount of medication taken, but it increased drooling and worsened the volume of the voice, articulation, and writing. Subjective visual disturbance was noted in 36 and 41% of patients who underwent unilateral and simultaneous bilateral pallidotomy, respectively. Globally, the result of the procedure was rated "good" or "excellent" by 64% of the patients who underwent unilateral pallidotomy and by 76% of the patients who underwent bilateral pallidotomy. An age less than 70 years was a positive prognostic factor for the global outcome (P < 0.05), as were severe preoperative dyskinesias (P < 0.05).

CONCLUSION

This study confirms that, from a patient standpoint, unilateral and simultaneous bilateral pallidotomy can reduce all the key symptoms of Parkinson's disease (i.e., akinesia, tremor, and rigidity) and the side effects of L-dopa treatment (i.e., dyskinesias). Preoperative severe dyskinesias and younger age are positive prognostic factors for a successful outcome. Simultaneous bilateral pallidotomy was more effective than unilateral pallidotomy regarding tremor, rigidity, and dyskinesias, but it conferred a higher risk of postoperative speech deterioration.

Anger in chronic pain: investigations of anger targets and intensity

The study was designed to assess the frequency and intensity of patients' anger directed toward various potential targets and how intensity of anger toward different targets was related to the chronic pain experience. Ninety-six chronic pain patients who were referred for a comprehensive evaluation completed questionnaires to assess their levels of anger, pain, distress, and disability. Approximately 70% of the participants reported to have angry feelings. Most commonly, patients reported to be angry with themselves (74%) and health care professionals (62%). The relevance of anger to chronic pain experience seemed to vary across targets. Anger toward oneself was significantly associated with pain and depression, whereas only overall anger was significantly related to perceived disability. The results suggest that anger should be conceptualized as a multifactorial construct. In addition to presence, intensity, and expression of anger, targets of anger may be important to better understand psychological adaptation to chronic pain.

Transcutaneous electrical nerve stimulation: nonparallel antinociceptive effects on chronic clinical pain and acute experimental pain

OBJECTIVE

To investigate to what extent a single 60-minute session of transcutaneous electrical nerve stimulation (TENS) would modify chronic clinical pain, acute experimental pain, and the flexion reflex evoked in chronic low back pain patients.

STUDY DESIGN

Thirty young subjects with chronic low back pain were randomly allocated to two groups, receiving either TENS or placebo stimulation to the lumbosacral region for 60 minutes. The flexion reflex was elicited by an electrical stimulation applied to the subject's right sole and recorded electromyographically from the biceps femoris and the tibialis anterior muscles.

MAIN OUTCOME MEASURES

Subjective sensation of low back pain and the electrically induced pain were measured by two separate visual analog scales, termed VAS(LBP) and VAS(FR), respectively. Data obtained before, during, and 60 minutes after TENS and placebo stimulations were analyzed using repeated measures ANOVA.

RESULTS

The VAS(LBP) score was significantly reduced to 63.1% of the prestimulation value after TENS (p<.001), but the reduction was negligible after placebo stimulation (to 96.7%, p = .786). In contrast, no significant change was found in the VASFR score (p = .666) and the flexion reflex area (p = .062) during and after stimulation within each group and between the two groups (p = .133 for VASFR and p = .215 for flexion reflex area).

CONCLUSIONS

The same TENS protocol had different degrees of antinociceptive influence on chronic and acute pain in chronic low back pain patients.

Negative affect and pain in arthritis

The experience of pain in arthritis conditions has important affective dimensions. This article reviews evidence for a relatively strong association between negative affect (i.e., depression, anxiety, and anger) and arthritis-related pain. Possible physiologic and psychologic mechanisms of the relationship between negative affect and pain are examined, and issues relevant to future research, particularly the need for biopsychosocial theoretical models are discussed. Finally, the article highlights the importance of biopsychosocial treatment approaches in managing arthritis-related pain and negative affect.

Self-reported sleep and mood disturbance in chronic pain patients

OBJECTIVE

To evaluate the prevalence of self-reported sleep disturbance and its relationship to mood disturbance in chronic pain patients.

DESIGN AND SETTING

Survey of patients referred to a multidisciplinary outpatient pain clinic.

PATIENTS

The sample consisted of 105 consecutive patients (59 men and 46 women), with an average age of 41.5 (SD +/-13.4) years.

MEASURES

Self-report measures of sleep disturbance and visual analog scales of mood disturbance (anxiety and depression) and pain experience (intensity and unpleasantness).

RESULTS

Patients were grouped according to whether they considered themselves "poor" (n = 68) or "good" (n = 37) sleepers. Poor sleepers reported more difficulties initiating and maintaining sleep and greater pain intensity and pain unpleasantness than did good sleepers. The two groups did not differ on measures of depressive or anxious mood.

CONCLUSION

The results suggest that sleep disturbance is a prevalent complaint in chronic pain patients, but it is not always associated with an underlying mood disturbance.

Anger management style and the prediction of treatment outcome among male and female chronic pain patients

Anger is a prominent emotion experienced by chronic pain patients. Anecdotes suggest that anger predicts poor outcome following multidisciplinary pain programs, but no empirical evidence documents this link. We expected that patient anger expression or suppression would predict poor outcome following a pain program and that gender differences would emerge. Pre- to posttreatment measures of lifting capacity, walking endurance, depression, pain severity and activity level were collected from 101 chronic pain patients. An 'anger expression x gender' interaction was found such that anger expression among males was correlated negatively with lifting capacity improvements. 'Anger suppression x gender' interactions emerged such that anger suppression among males was correlated negatively with improvements in depression and general activities. These effects remained significant after controlling for trait anger. Thus, how anger is managed may exert unique influence on outcomes apart from the effects of mere anger proneness, at least among male pain patients.

Pain-related anxiety predicts non-specific physical complaints in persons with chronic pain

Persons with chronic pain often report a range of physical symptoms beyond their primary pain complaint itself. We predicted that non-specific physical symptom complaints would correlate more strongly with pain-related distress than with general measures of distress, and that they would contribute directly to disability. Results from 210 adults with chronic pain showed that collateral physical complaints are common in persons with chronic pain. Correlational analyses showed that greater reporting of physical complaints was associated with reports of higher pain severity, higher levels of depression, more cognitive, escape/avoidance, fearful appraisal, and physiological symptoms of pain-related anxiety and more physical and psychosocial disability. Regression analyses showed that, with pain-related anxiety variables entered either before or after depression, physiological symptoms of pain-related anxiety significantly predicted physical complaints. In comparison with cognitive and somatic depression symptoms physiological symptoms of pain-related anxiety were the stronger predictor.

Investigating the relationship between pain and discomfort and quality of life, using the WHOQOL

The aim of this study was to examine the impact of pain on quality of life and its components in a representative sample of 320 well people, and patients selected from all major categories of illness. Quality of life was assessed using a new, multidimensional, multilingual, generic profile designed for cross-cultural use in health care, i.e. the WHOQOL. Within the WHOQOL, pain and discomfort is one of 29 areas or facets of quality of life, grouped into six domains. It was found that pain and discomfort made a significant impact on perceptions of general quality of life related to health. Furthermore, the presence of pain affected perceptions of five of the six domains of quality of life; the domain of spirituality, religion and personal beliefs being the exception. When quality of life is assessed, negative feelings are most closely associated with reports of pain and discomfort than any other facet. But quality of life surrounding pain and discomfort is more fully explained by the inclusion of six additional facets; the availability of social care, mobility, activities of daily living, positive mood and to a lesser extent, sleep and dependence on medication. Together, these seven facets represent criteria against which the success of pain treatments may be evaluated. As predicted, those who were pain-free had significantly better quality of life than those in pain. A longer duration of pain is associated with increasingly poorer quality of life. Intense affective pain is particularly detrimental to a good quality of life. The psychometric properties of the pain and discomfort facet of the WHOQOL and WHOQOL-100 were assessed. Internal consistency (reliability), discriminant and criterion/concurrent validity were found to be good to excellent, justifying the use of this instrument with a range of chronic and acute pain patients.

Anger management style and hostility: predicting symptom-specific physiological reactivity among chronic low back pain patients

It was hypothesized that anger management style (anger-in or anger-out) and hostility affect the aggravation of chronic low back pain (CLBP) through symptom-specific (i.e., lower paraspinal muscle) reactivity during stress. Subjects were 102 CLBP patients who performed mental arithmetic and an Anger Recall Interview (ARI) while trapezius and lower paraspinal EMG, SBP, DBP, and HR were recorded. Results showed anger-in x hostility and anger-out x gender interactions for lower paraspinal but not trapezius reactivity, and only during the ARI. Further analyses revealed that (1) hostility was related positively to lower paraspinal reactivity among high anger suppressors, (2) hostility was related negatively to lower paraspinal reactivity among low anger suppressors, and (3) anger expression was related positively to lower paraspinal reactivity only among men. Anger management style and hostility may contribute to the exacerbation of CLBP by influencing stress reactivity only in muscles near the site of pain or injury.

Assessing the stages of pain processing: a multivariate analytical approach

A four-stage model of pain processing was proposed, consisting of pain sensation intensity, pain unpleasantness (stage 1 affect), suffering (stage 2 affect), and pain behavior. We studied 506 chronic pain patients (230 male and 276 female) using a multivariate statistical technique (LISREL) in order to demonstrate the structural relationship among multiple indicators of pain processing; and to characterize these stages in terms of their interactions. A strong relationship was revealed between the majority of the underlying indicators of each pain processing stage. A linear stage sequence best fitted the relationship between the four stages. Successive stages did not have recursive effects on earlier pain components. A confirmatory LISREL analysis was conducted with an additional sample of 502 chronic pain patients. In this replication analysis the structural equation model consisted of pain intensity, unpleasantness (stage 1 affect), emotional suffering (stage 2 affect), and pain behavior. This study extends the validation of these pain dimensions, as well as the validity of the measure(s) of each separate stage.

Managing chronic back pain: impact of an interdisciplinary team approach

OBJECTIVE

To evaluate the effectiveness of a six-week outpatient program in pain management for patients with chronic back pain.

DESIGN

Retrospective review.

SETTING

Rehabilitation Clinical Business Unit, Essendon campus of the Royal Melbourne Hospital.

SUBJECTS

138 consecutive patients who participated in the unit's Chronic Back Pain Programme between 1991 and 1993.

INTERVENTION

Multidisciplinary program that promoted pain management rather than "cure", with two six-hour group sessions per week for six weeks.

OUTCOME MEASURES

Patient assessments before the program and at program completion and at three months' follow-up, with the West Haven-Yale Multidimensional Pain Inventory (WHYMPI) and a four-minute walk test.

RESULTS

At program completion, the WHYMPI showed significant decreases in the amount pain interfered with life and significant increases in patient sense of control and activity level. However, severity of pain remained the same. All these effects were maintained three months later.

CONCLUSIONS

A brief outpatient program was effective in improving pain management in a group of chronic back pain sufferers. This seems a useful and relatively inexpensive option in managing this problematic group of patients.

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

OBJECTIVE

The present study employed causal modeling to examine the impact of somatic and cognitive symptoms of depression on the functioning of patients with chronic pain.

DESIGN

Path analyses were conducted to determine whether pain level is directly related to the psychosocial and physical dimensions of functional status or whether this relationship is mediated by depression.

SETTING

Subjects were recruited from a facial pain clinic at the University of Florida, an outpatient clinic associated with a tertiary-care health center.

PATIENTS

Subjects were 70 patients with chronic pain, 53 of whom had primary facial pain.

MAIN OUTCOME MEASURES

All subjects completed a packet of self-report questionnaires, including the Beck Depression Inventory, McGill Pain Questionnaire, and Sickness Impact Profile.

RESULTS

Results of path analyses indicated that both somatic and cognitive symptoms of depression significantly correlate with psychosocial functioning even after controlling for the effects of pain level, trait anxiety, and trait anger. Somatic symptoms of depression were significantly correlated with physical functioning after pain level, anxiety and anger were controlled.

CONCLUSIONS

This study indicates that depression is directly related to both the physical and the psychosocial functioning of facial pain patients, while self-reported level of pain is not. A better understanding of the impact of depression on chronic pain and the relationship of these two disorders could lead to improved assessment and treatment of chronic pain disorders.

Anger management style, hostility and spouse responses: gender differences in predictors of adjustment among chronic pain patients

This study examined whether relationships between anger management style (anger suppression; anger expression) and adjustment variables for patients with chronic pain depend on patient hostility, and/or depend on a patient's gender. A 'spouse response model' was also evaluated to test whether patient expression of hostile anger is linked to infrequent positive and frequent negative responses from spouses, and hence to poor adjustment. The sample of 127 married chronic pain patients was assessed prior to entry into a multidisciplinary pain treatment program. Hierarchical multiple regressions revealed significant 'Anger Expression x Hostility x Gender' interactions for pain severity, activity interference and activity level: High Anger Expressor/Low Hostile women reported the lowest pain and highest activity; Low Anger Expressor/High Hostile men reported the highest pain and highest interference. Among men, support was also found for a spouse response model: pain severity and activity interference for High Anger Expressors was partly accounted for by negative spouse responses. Results suggest that discriminations among patients may be made based on anger management style in interaction with level of hostile attitude and the patient's gender, and that these distinctions may have implications for understanding mechanisms of pain and disability, and for designing appropriate treatment.

A psychoanalytic investigation to improve the success rate of spinal cord stimulation as a treatment for chronic failed back surgery syndrome

OBJECTIVE

The analysis of patient data concerning psychological structure and functioning produced an instrument to determine whether a neurostimulator ought to be implanted or not.

DESIGN

A questionnaire containing 24 items was developed by a psychologist and tested in 40 chronic failed back surgery patients for whom a spinal cord stimulation seemed to be the only therapeutic approach. This questionnaire was based upon some crucial psychological themes, on which the patient took a position. A predictive indication factor (I.F.; %) for implantation of the neurostimulator was obtained from the 24 items. Six months after the implantation of the neurostimulator, we correlated the evaluation factor (E.F.; %) with a six-point evaluation scale considering the pain reduction. The aim was to compare the I.F. and E.F. to verify the correlation between them. This comparison was intended to answer the question if psychological variables included in our scale improve the success rate of the therapy.

SETTING

Data were collected by a psychologist at the Pain Clinic of the University Hospital of Gent, Belgium.

RESULTS AND CONCLUSIONS

The correlation between the I.F. and the E.F. was calculated for the 40 patients by the Spearman correlation test. A coefficient value of 0.8083 (p = 0.000) was found, indicating the existence of a very close correlation between the predictive I.F. and the E.F. The indication scale appears to be a useful instrument for clinical psychologists to predict the success rate of a spinal cord stimulator in this group of patients.

The effect of age on A delta- and C-fibre thermal pain perception

It has been suggested that ageing may have a differential effect on C fibre-mediated protopathic/tonic pain versus epicritic/phasic pain perception mediated by A delta fibres. The present study attempted to independently assess age-related changes in the function of A delta- and C-nociceptive fibres by examining CO2 laser-induced thermal pain thresholds before, during and after a compression block of the superficial radial nerve in 15 young and 15 healthy elderly adult subjects. Nerve block efficacy was monitored via measures of cold, warm and mechanical threshold, and simple reaction time. During nerve compression block, reaction time and mechanical threshold increased, cold sensation became impaired while warm sensation remained unaffected throughout the test in both groups. With respect to pain sensitivity, young adults exhibited significant increases in thermal pain threshold during A-fibre block while pain threshold remained relatively stable across the 3 test periods in the elderly group. It would appear that elderly adults rely predominantly on C-fibre input when reporting pain whereas younger adults utilise additional input from A delta fibres. Subsequent analysis revealed that during pre- and post-block periods, older adults exhibited a significant elevation in thermal pain threshold; however, when A delta-fibre function was impaired and only C-fibre information was available, both groups responded similarly. These findings support the notion of a differential age-related change in A-fibre-mediated epicritic pain perception versus C-fibre-mediated protopathic pain.

Pain severity, negative affect, and microstressers as predictors of life interference in TMD patients

The purpose of this study was to examine the relationships among negative affect (depression, anxiety, and anger), microstressors (hassles), temporomandibular disorder (TMD) pain severity, and life interference, using structural equations modeling. One hundred four subjects were recruited from the Parker Mahan Facial Pain Clinic at the University of Florida. Significant positive direct effects were found for paths between pain severity and life interference; pain severity and negative affect; and negative affect and life interference. These results are consistent with a learning or behavioral model of suffering and suggest that negative affect is an important mediating variable in the relationship between pain and life interference. Microstressors were not a significant predictor and may not be a relevant issue in the TMD population. The results suggest that the impact of chronic pain conditions is influenced by both pain and negative affect, and assessment and treatment of chronic TMD disorders may better benefit from a multidisciplinary approach.

Surgery for chronic pancreatitis: what quality of life ahead?

We attempted to evaluate the quality of life of patients with proved long-lasting chronic pancreatitis. We measured the clinical and psychological status of 60 patients who had undergone various surgical treatments for their disease. The presence and severity of depression and other symptoms of distress were assessed, as were disease-specific functional and physical problems. Few patients had serious conditions, such as pain, malnutrition, or psychoneurotic complaints. The relation between depression and the time of onset of symptoms and of surgery appeared doubtful, and no statistically significant correlations were found between severity of emotional disturbance and other functional characteristics. Insulin-dependent diabetes and correlated diseases had the most negative influence on everyday well-being. Postoperative follow-up and the need for recurrent medical control and care did not lead to negative feelings.

The scope and significance of anger in the experience of chronic pain

This paper is divided into 3 sections. The first provides the conceptual framework by introducing definitions of anger and related constructs and highlighting pertinent aspects of the concept of pain. The second section examines the evidence for anger as a feature of chronic pain. The available research indicates that chronic pain patients experience anger but this may be underestimated because of denial. In fact, anger stands out as one of the most salient emotional correlates of pain, even though past research has been largely confined to the study of depression and anxiety. the third section explores the significance of anger in chronic pain, in terms of its compounding effects on pain, depression and psychosocial functioning, as well as its consequences for physical health and health habits. The impact of anger among chronic pain patients for treatment outcome is discussed. Finally, the information from these sections is integrated into a model depicting the antecedents and consequences of anger as specifically associated with the chronic pain experience.

Personality characteristics before and after treatment of different head pain syndromes

In order to examine whether, in patients with different types of headache and craniofacial pain, MMPI and STAI scores are significantly different before and after treatment, 114 patients with tension-type headache (n = 34), atypical facial pain (n = 20), temporomandibular joint dysfunction (n = 36), migraine (n = 16), cluster headache (n = 4), chronic paroxysmal hemicrania (n = 2), trigeminal neuralgia (n = 2) were examined. A pain index was calculated (0-10) which quantified pattern, duration and frequency of pain. The Italian MMPI (356 item abbreviated version) and the STAI tests were administered before and after treatment. A paired t-test was used to assess pre- and post-treatment differences, and multiple regression analysis was employed to examine whether such differences correlated with the improvement in the pain index. In the total group after treatment, there was a significant reduction of certain MMPI scores (Hs, D, Hy, Pa, Pt, Sc, Si) and of STAI 1 and 2 scores. Separate analysis confirmed this among women but not among men. No relation was found between MMPI and STAI changes and the degree of improvement as assessed through the pain index. Clinical improvement leads to normalization of MMPI profiles and STAI scores in women. The psychometric data before treatment were not predictive for treatment outcome.

A comparison of pain measurement characteristics of mechanical visual analogue and simple numerical rating scales

Numerical rating scales and mechanical visual analogue scales (M-VAS) were compared for their capacity to provide ratio scale measures of experimental pain. Separate estimates of experimental pain sensation intensity and pain unpleasantness were obtained by each method, as were estimates of clinical pain. Orofacial pain patients made numerical scale and VAS ratings in response to noxious thermal stimuli (45-51 degrees C) applied for 5 sec to the forearm by a contact thermode. The derived stimulus-response function was well fit as a power function only in the case of sensory M-VAS. The power function derived from sensory M-VAS ratings predicted temperatures chosen as twice as intense as standard temperatures of 47 degrees C and 48 degrees C, thereby providing evidence for ratio scale characteristics of M-VAS. The stimulus-response function derived from sensory numerical ratings differed from that obtained with M-VAS and did not provide accurate predictions of temperatures perceived as twice intense at 47 degrees C or 48 degrees C. Both M-VAS and numerical rating scales produced reliably different stimulus response functions for pain sensation intensity as compared to pain unpleasantness and both provided consistent measures of experimental and clinical pain intensity. Finally, both mechanical and pencil-and-paper VAS produced very similar stimulus-response functions. The ratio scale properties of M-VAS combined with its ease of administration and scoring in clinical settings offer the possibility of a simple yet powerful pain measurement technology in both research and health care settings.

Failure hurts: the effects of stress due to difficult tasks and failure feedback on pain report

Two experiments were conducted to investigate the effects of task difficulty and perceived success/failure on pain report. The first experiment found that difficult reading comprehension problems led to an increase in pain report. The second experiment found that task difficulty per se may not have accounted for the effects, but that perceived failure of the more difficult task led to increased pain report. Social and theoretical implications are discussed. Failure may lead to negative affectivity, which can increase the report of painful stimuli.

Negative affect and the experience of chronic pain

Although it is clear from previous research that pain is associated with negative affect, the relative contribution of specific affective dimensions, e.g. depression, anxiety and anger, to the subjective experience of chronic pain is unclear. The literature is also mixed concerning the relative importance of state versus trait influences in the experience of chronic pain. The present study analyzed the ability of anxiety, anger, and depression (as measured by the State-Trait Personality Inventory, State-Trait Anger Expression Inventory, and the Beck Depression Inventory, respectively) to predict self-report of clinical pain as indicated by the McGill Pain Questionnaire (MPQ) in a sample of 60 chronic pain patients. The results of stepwise regression analyses consistently demonstrated that the state measures were more strongly related to MPQ pain ratings than trait measures. These data suggest support for the hypothesis that chronic pain adversely impacts mood rather than the opposing hypothesis that negative mood is a predisposing factor in the development of chronic pain. Furthermore, different aspects of the state emotional experience were found to be related to different components of pain report. The results of this study also suggest that attributional processes could be an important component of the relationship between negative mood and the experience of pain.

A canonical correlation analysis of the influence of neuroticism and extraversion on chronic pain, suffering, and pain behavior

The relationship between neuroticism and extraversion on the 4 major stages of pain processing, that of pain sensation intensity, pain unpleasantness, suffering, and pain behavior, were studied in 205 chronic pain patients (88 male and 117 female). Patients underwent psychological evaluation which included the Pain Experience visual analogue scales (VAS) (Price et al. 1983), NEO Personality Inventory (NEO-PI) (Costa and McCrae 1985), and the Psychosocial Pain Inventory (PPI) (Getto and Heaton 1980). Canonical correlation was used to control for pain sensation intensity in evaluating affective dimensions of pain and to control for neuroticism in assessing effects of extraversion on different stages and dimensions of pain. Neither neuroticism nor extraversion were related to pain sensation intensity. Only neuroticism was associated with pain unpleasantness. Personality factors had their greatest impact on stages 3 (suffering) and 4 (illness behavior) of pain processing. The results of multiple regression analyses indicated that life-long vulnerability to anxiety and depression is paramount in understanding the relationship between personality and suffering in chronic pain. These findings provide support for the idea that personality traits influence the ways in which people cognitively process the meanings that chronic pain holds for their life, and hence the extent to which they suffer.

Patterns of normal personality structure among chronic pain patients

Fifty-nine chronic pain patients satisfying one of four previously identified pain group classifications were evaluated using the NEO Personality Inventory (NEO-PI), a standardized measure of normal adult personality structure. Minnesota Multiphasic Personality Inventory (MMPI) pain subgroups differed with respect to level of NEO-PI Neuroticism. In particular, emotionally overwhelmed pain patients as defined by multiple MMPI scale elevations had higher NEO-PI Neuroticism scores. Post hoc analyses revealed higher levels of depression, anxiety, vulnerability, and hostility in emotionally overwhelmed subjects. None of the remaining groups differed from each other on NEO-PI Neuroticism. Additionally, none of the other NEO-PI domains discriminated pain subgroups. NEO-PI profiles for pain patients (except for Neuroticism in emotionally overwhelmed patients) yielded t scores in the average range, suggesting that chronic pain patients present with a relatively normal underlying personality structure.

Psychosocial factors in chronic spinal cord injury pain

Chronic pain is a problem among patients with spinal cord injuries, but the psychosocial factors associated with spinal cord injury (SCI) pain are not well understood. To understand SCI pain further, 54 patients (19 with quadriplegia and 35 with paraplegia) completed the Beck Depression Inventory, State-Trait Anxiety Inventory, Profile of Mood States, Acceptance of Disability Scale and SCI Interference Scale. Forty-two patients stated they had SCI pain and completed the Multidimensional Pain Inventory and the Pain Experience Scale. Results revealed that anger and negative cognitions were associated with greater pain severity. Patients who reported pain in response to a general prompt experienced more severe pain than patients who reported pain only when directly questioned about the presence of pain, but these different reporting groups did not differ on emotional variables. Those who were less accepting of their disability reported greater pain severity. Additionally, patients who perceived a significant other expressing punishing responses (e.g., expressing anger at the patients or ignoring the patients) to their pain behaviors reported more severe pain. Level of lesion, completeness of injury, surgical fusion and/or instrumentation and veteran status were not associated with pain severity. Finally, pain was associated with emotional distress over and above the distress associated with the SCI itself. Overall, psychosocial factors, not physiological factors, were most closely associated with the experience of pain. Multidimensional aspects of pain are used to explain these findings and suggest that treatment should be directed at the emotional and cognitive sequelae of chronic SCI pain.