Richard T. Gross

The pain anxiety symptoms scale: development and validation of a scale to measure fear of pain

&NA; Fear of pain has been implicated in the development and maintenance of chronic pain behavior. Consistent with conceptualizations of anxiety as occurring within three response modes, this paper introduces an instrument to measure fear of pain across cognitive, overt behavioral, and physiological domains. The Pain Anxiety Symptoms Scale (PASS) was administered to 104 consecutive referrals to a multidisciplinary pain clinic. The alpha coefficients were 0.94 for the total scale and ranged from 0.81 to 0.89 for the subscales. Validity was supported by significant correlations with measures of anxiety and disability. Regression analyses controlling for measures of emotional distress and pain showed that the PASS made a significant and unique contribution to the prediction of disability and interference due to pain. Evidence presented here supports the potential utility of the PASS in the continued study of fear of pain and its contribution to the development and maintenance of pain behaviors. Factor analysis and behavioral validation studies are in progress.

Effect of Iyengar yoga therapy for chronic low back pain

Low back pain is a significant public health problem and one of the most commonly reported reasons for the use of Complementary Alternative Medicine. A randomized control trial was conducted in subjects with non‐specific chronic low back pain comparing Iyengar yoga therapy to an educational control group. Both programs were 16 weeks long. Subjects were primarily self‐referred and screened by primary care physicians for study of inclusion/exclusion criteria. The primary outcome for the study was functional disability. Secondary outcomes including present pain intensity, pain medication usage, pain‐related attitudes and behaviors, and spinal range of motion were measured before and after the interventions. Subjects had low back pain for 11.2±1.54 years and 48% used pain medication. Overall, subjects presented with less pain and lower functional disability than subjects in other published intervention studies for chronic low back pain. Of the 60 subjects enrolled, 42 (70%) completed the study. Multivariate analyses of outcomes in the categories of medical, functional, psychological and behavioral factors indicated that significant differences between groups existed in functional and medical outcomes but not for the psychological or behavioral outcomes. Univariate analyses of medical and functional outcomes revealed significant reductions in pain intensity (64%), functional disability (77%) and pain medication usage (88%) in the yoga group at the post and 3‐month follow‐up assessments. These preliminary data indicate that the majority of self‐referred persons with mild chronic low back pain will comply to and report improvement on medical and functional pain‐related outcomes from Iyengar yoga therapy.

Prediction of pain in patients with chronic low back pain: effects of inaccurate prediction and pain-related anxiety

This study investigated predictions of pain intensity, reports of pain and anxiety, frequency of pain-related anxiety symptoms, and range of motion, in 43 patients exposed to pain during a physical examination. All patients had primary complaints of low back pain. The pain stimuli used for this study included back and/or leg pain produced by repeatedly raising the extended leg of the patient to the point of pain tolerance. Generally, findings demonstrated that (a) predictions of pain were a function of discrepancies between previous predictions and experiences of pain, (b) patients reporting greater pain-related anxiety showed a tendency to overpredict new pain events, but corrected their predictions readily, (c) patients reporting less pain-related anxiety displayed a persistent tendency to underpredict pain, and (d) higher predictions of pain, independent of pain reports, related to less range of motion during a procedure that involved painful movement. Discussion focuses on differences between these results and those of previous studies and the implications of inaccurate prediction for continued pain and disability.

Evaluation of the effectiveness and efficacy of Iyengar yoga therapy on chronic low back pain.

Study Design. The effectiveness and efficacy of Iyengar yoga for chronic low back pain (CLBP) were assessed with intention-to-treat and per-protocol analysis. Ninety subjects were randomized to a yoga (n = 43) or control group (n = 47) receiving standard medical care. Participants were followed 6 months after completion of the intervention. Objective. This study aimed to evaluate Iyengar yoga therapy on chronic low back pain. Yoga subjects were hypothesized to report greater reductions in functional disability, pain intensity, depression, and pain medication usage than controls. Summary of Background Data. CLBP is a musculoskeletal disorder with public health and economic impact. Pilot studies of yoga and back pain have reported significant changes in clinically important outcomes. Methods. Subjects were recruited through self-referral and health professional referrals according to explicit inclusion/exclusion criteria. Yoga subjects participated in 24 weeks of biweekly yoga classes designed for CLBP. Outcomes were assessed at 12 (midway), 24 (immediately after), and 48 weeks (6-month follow-up) after the start of the intervention using the Oswestry Disability Questionnaire, a Visual Analog Scale, the Beck Depression Inventory, and a pain medication-usage questionnaire. Results. Using intention-to-treat analysis with repeated measures ANOVA (group × time), significantly greater reductions in functional disability and pain intensity were observed in the yoga group when compared to the control group at 24 weeks. A significantly greater proportion of yoga subjects also reported clinical improvements at both 12 and 24 weeks. In addition, depression was significantly lower in yoga subjects. Furthermore, while a reduction in pain medication occurred, this was comparable in both groups. When results were analyzed using per-protocol analysis, improvements were observed for all outcomes in the yoga group, including agreater trend for reduced pain medication usage. Although slightly less than at 24 weeks, the yoga group had statistically significant reductions in functional disability, pain intensity, and depression compared to standard medical care 6-months postintervention. Conclusion. Yoga improves functional disability, pain intensity, and depression in adults with CLBP. There was also a clinically important trend for the yoga group to reduce their pain medication usage compared to the control group.

Effects of a cognitive intrusion manipulation on the sleep-onset latency of good sleepers

Thirty-eight female good sleepers were instructed to go to sleep as quickly as possible in a daytime nap session under one of three instructional sets designed to manipulate the likelihood of cognitive intrusions. Subjects informed that they would be required to present a speech after their sleep period and told the topic of the speech required significantly longer to fall asleep and obtained less sleep than subjects in two control conditions. Analysis of heart rate and skin conductance measures failed to support the mediational role of autonomic activity in retarding sleep-onset.

Work-related beliefs about injury and physical capability for work in individuals with chronic pain

&NA; According to a fear‐avoidance model of chronic pain, disability is largely determined by the erroneous belief that an increase in activity level is potentially harmful. Further, recent literature suggests that excessive fears regarding physical activities contribute to significant disability. However, the relation of changes in these fears to functional work capabilities has gone largely uninvestigated. The present study examined how changes in physical capability for work were related to changes in pain severity and fear‐avoidance beliefs for general physical and work‐specific activities, as well as investigating whether an interdisciplinary treatment program for chronic pain was associated with changes in these specific fears in 65 individuals with chronic pain. Results revealed that significant decreases in fear and pain levels occurred from pre‐ to post‐treatment, in addition to increases in physical capability for work. Further, changes in work‐specific fears were more important than changes in pain severity and fear of physical activity in predicting improved physical capability for work. These results expand previous research, which has found a relation between self‐reported disability and fear‐avoidance beliefs, by demonstrating the relation with fear of work to actual work‐related behaviors.

Predicting work status following interdisciplinary treatment for chronic pain

The effectiveness of interdisciplinary treatments for chronic pain is well established. In general, these treatments decrease psychosocial distress and increase physical abilities. Further, return to work rates following interdisciplinary treatment tend to be quite high. Previous studies have highlighted a number of factors that individually influence return to work rates; however, there is a need for more comprehensive and unified models that allow an evaluation of the inter‐relations among these factors. The present investigation examined how demographic and treatment outcome variables interacted to influence post‐treatment return to work rates in a sample of individuals with chronic pain following interdisciplinary treatment. Results indicated that patient age, lifting ability, pain duration, depression level, and reported disability were individually related to return to work; however, when these variables were evaluated relative to one another, level of depression and patient age had the best ability to predict post‐treatment work status. These results add to the literature by specifically highlighting post‐treatment factors that best discriminate patients who had returned to work from those that had not. Furthermore, they provide evidence that general emotional distress is perhaps the most important predictor of work status following treatment.

On the relationship between anxiety and pain: A methodological confounding

Abstract Anxiety and pain have been conceptualized as independent though interacting states. However, for both states, self-report data share common objective descriptors, physiological data reflect a general activation of sympathetic arousal, and overt-motor behaviors share common response characteristics. Likewise, the treatments for anxiety and pain are related for both medical and psychological interventions. For example, anti-anxiety agents have been suggested for the treatment of pain complaints and psychological procedures originally developed to treat anxiety have been successfully utilized in treating pain. The need for direct comparisons of anxiety and pain responding is emphasized, and preliminary data addressing self reported anxiety and pain symptoms are briefly reported. To further clarify the relationship between states, future research directions are suggested.

Pain-Related Anxiety in the Prediction of Chronic Low-Back Pain Distress

This study evaluated the relation of particular aspects of pain-related anxiety to characteristics of chronic pain distress in a sample of 76 individuals with low-back pain. Consistent with contemporary cognitive–behavioral models of chronic pain, the cognitive dimension of the Pain Anxiety Symptoms Scale (PASS; McCracken, Zayfert, and Gross, 1992, Pain 50: 67–73) was uniquely predictive of cognitive-affective aspects of chronic pain, including affective distress, perceived lack of control, and pain severity. In contrast, the escape and avoidance dimension of the PASS was more predictive of behavioral interference in life activities. Overall, the findings are discussed within the context of identifying particular pain-related anxiety mechanisms contributing to differential aspects of pain-related distress and clinical impairment.

Analysis of Breakthrough Pain in 50 Patients Treated with Intrathecal Morphine Infusion Therapy

Fifty patients with intractable benign pain were treated with intrathecal morphine (IT-MS) infusion therapy. Median follow-up was 39 months (range 5-70). Breakthrough pain was reported in 45 (90%) patients in 75 outpatient clinic events. A diagnostic algorithm was developed to evaluate and efficiently treat these patients. A programmed bolus (50% of daily dose) identified that 50 (67%) breakthrough events where due to partial tolerance to the IT-MS. Radiographic survey of the catheters identified malfunctions in 11 patients. Attempts to withdraw CSF from the side-port demonstrated obstruction in 7 due to kinking not seen on X-rays. Side-port myelography demonstrated scarring that obstructed the flow of morphine to the spinal cord in 2 patients. Benefits were regained after all surgical catheter corrections. In total, partial tolerance was seen in 23 patients (46%) during 50 (67%) breakthrough events, 15 patients (30%) required 22 catheter revisions during 27% of breakthrough events and 2 patients had progressive disease. True tolerance was encountered in only 5 patients (10%) during 5 (7%) breakthrough pain events.