Structural MRI Analysis of Chronic Pain Patients Following Interdisciplinary Treatment Shows Changes in Brain Volume and Opiate-Dependent Reorganization of the Amygdala and Hippocampus.

OBJECTIVE: The present study examined pre- to post-treatment changes in volumes for brain structures known to be associated with pain processing (thalamus, caudate, putamen, pallidum, hippocampus, amygdala, and accumbens) following an interdisciplinary pain management program. DESIGN: Twenty-one patients participating in a four-week interdisciplinary pain management program completed the study. The program consisted of individual and group therapies with the following disciplines: physical therapy, occupational therapy, pain psychology, biofeedback/relaxation training, nursing lectures, and medical management. All patients underwent functional magnetic resonance imaging of the brain before the start and at completion of the program. They also completed standard outcome measures assessing pain, symptoms of central sensitization, disability, mood, coping, pain acceptance, and impressions of change. RESULTS: Our results showed a significant increase in total brain volume, as well as increased volumes in the thalamus, hippocampus, and amygdala. As expected, we also found significant improvements in our standard outcome measures. The majority of patients rated themselves as much or very much improved. The increase in volume in the hippocampus was significantly associated with patient perceptions of change. However, the correlations were in the unexpected direction, such that greater increases in hippocampal volume were associated with perceptions of less improvement. Further exploratory analyses comparing patients by their opioid use status (use vs no use) showed differential program effects on volume increases in the hippocampus and amygdala. CONCLUSIONS: These findings show that a four-week interdisciplinary pain management program resulted in changes in the brain, which adds objective findings further demonstrating program efficacy.

Psychometric Properties of the Multidimensional Impression of Change in a Cohort of Pediatric Patients With Pain.

OBJECTIVES: This study assessed the utility of the Multidimensional Patient Impression of Change (MPIC) questionnaire in a pediatric pain population after interdisciplinary treatment. DESIGN: Observational study with retrospective chart review. The observed treatment program included psychological counseling, relaxation training, physical therapy, occupational therapy, and physician management. SETTING: Outpatient pain management center affiliated with an academic rehabilitation hospital. PARTICIPANTS: A heterogeneous group of pediatric patients with chronic pain (N=202) who completed an interdisciplinary pain management program. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Measures assessing pain, mood, development, social functioning, physical functioning, and family functioning were administered pre- and posttreatment, and the MPIC was administered posttreatment. RESULTS: Statistically significant improvements were observed in all outcomes (P<.05). The majority of patients perceived themselves to be improved (minimally to very much) in all clinical domains of the MPIC, ranging from 60% (medication efficacy) to 96% (coping with pain). The MPIC ratings were significantly correlated with improvements in most of the outcome measures. The MPIC domains accounted for more than half of the unique variance in predictive models when added to the Patient Global Impression of Change, and most of the variance when added to the models first. CONCLUSIONS: The MPIC was found to be an effective screening tool for assessing patient perceived progress in a pediatric chronic pain population.

Impact of Symptom Reporting Agreement on Interdisciplinary Pain Program Participation.

OBJECTIVE: To investigate whether physician-patient agreement of potential patient problem areas impacts subsequent patient enrollment in an interdisciplinary pain management program. DESIGN: Retrospective chart review of 544 patients who underwent evaluation of their chronic pain. Physicians and their patients endorsed perceived patient problems during the evaluation. The potential problems included 7 clinical domains: pain, sleep, mood, physical functioning, ability to cope with pain, ability to manage pain flare-ups, and pain medication effectiveness. RESULTS: Results indicated statistically significant levels of agreement among the physicians and their patients (free-marginal kappa range, 0.19 to 0.94, P's < 0.001). The highest agreement occurred for pain and the lowest for pain medication effectiveness. Patients who enrolled in a recommended program did not differ from those who did not enroll based on either levels of agreement or average number of physician-patient agreements for the 7 clinical domains (P's > 0.05). Patients recommended for higher-intensity programs were perceived by their evaluating physician to have a significantly greater number of problematic clinical domains than those recommended for less intense pain programs. CONCLUSION: The level of physician-patient agreement regarding the patients' current difficulties did not appear to influence patients' decisions to participate in interdisciplinary pain management. Extraneous, nonclinical factors may have had a greater impact on participation in interdisciplinary pain management than physician-patient agreement. Future research should focus on identifying these factors and their impact. Also, studying the impact of physician-patient agreement beyond enrollment status (eg, on successful program completion) may be helpful in potentially enhancing patient outcomes.

Multidimensional Patient Impression of Change Following Interdisciplinary Pain Management.

OBJECTIVES: To assess patient impression of change following interdisciplinary pain management utilizing a newly developed Multidimensional Patient Impression of Change (MPIC) questionnaire. METHODS: A heterogeneous group of chronic pain patients (N = 601) participated in an interdisciplinary treatment program. Programs included individual and group therapies (pain psychology, physical therapy, occupational therapy, relaxation training/biofeedback, aerobic conditioning, patient education and medical management). Patients completed measures of pain, mood, coping, physical functioning and pain acceptance both prior to and at completion of their treatment programs. The newly developed MPIC is an expansion to the Patient Global Impression of Change (PGIC) including seven additional domains (Pain, Mood, Sleep, Physical Functioning, Cope with Pain, Manage Pain Flare-ups, and Medication Effectiveness). The MPIC was administered to the patients post-treatment. RESULTS: There were statistically significant pre- to post-treatment improvements found on all outcome measures. The majority of these improvements were significantly correlated with all domains of the MPIC. The original PGIC item was significantly associated with all of the new MPIC domains and the MPIC domains were significantly associated with each other; but there were variations in the distribution of responses highlighting variation of perceived improvements among the domains. The MPIC accounted for greater amounts of variance among the program outcomes than did the PGIC. CONCLUSION: Our results support the use of the MPIC as a quick and easy post-treatment assessment screening tool. Future research is needed to examine relevant correlates to Medication Effectiveness.

Use of a medication quantification scale for comparison of pain medication usage in patients with complex regional pain syndrome (CRPS).

OBJECTIVE: To correlate the amount and types of pain medications prescribed to CRPS patients, using the Medication Quantification Scale, and patients' subjective pain levels. DESIGN: An international, multisite, retrospective review. SETTING: University medical centers in the United States, Israel, Germany, and the Netherlands. SUBJECTS/METHODS: A total of 89 subjects were enrolled from four different countries: 27 from the United States, 20 Germany, 18 Netherlands, and 24 Israel. The main outcome measures used were the Medication Quantification Scale III and numerical analog pain scale. RESULTS: There was no statistically significant correlation noted between the medication quantification scale and the visual analog scale for any site except for a moderate positive correlation at German sites. The medication quantification scale mean differences between the United States and Germany, the Netherlands, and Israel were 9.793 (P < 0.002), 10.389 (P < 0.001), and 4.984 (P = 0.303), respectively. CONCLUSIONS: There appears to be only a weak correlation between amount of pain medication prescribed and patients' reported subjective pain intensity within this limited patient population. The Medication Quantification Scale is a viable tool for the analysis of pharmaceutical treatment of CRPS patients and would be useful in further prospective studies of pain medication prescription practices in the CRPS population worldwide.

Short-Term Functional, Emotional, and Pain Outcomes of Patients with Complex Regional Pain Syndrome Treated in a Comprehensive Interdisciplinary Pain Management Program.

BACKGROUND: Complex regional pain syndrome (CRPS) is difficult to effectively treat with unimodal approaches. OBJECTIVE: To investigate whether CRPS can be effectively treated in a comprehensive interdisciplinary pain management program. DESIGN: Observational cohort study of 49 patients aged 18-89 who fulfilled 'Budapest Criteria' for CRPS and completed an interdisciplinary pain management program. Preprogram to postprogram changes in physical functioning, perceived disability, emotional functioning, acceptance, coping, and pain were assessed. The measures used included: Pain Disability Index, Six minute walk test, 2-minute sit-to-stand, Numerical Rating Scale, Center for Epidemiologic Studies Depression Scale, Pain Anxiety Symptoms Scale, Chronic Pain Acceptance Questionnaire, Coping Strategies Questionnaire-Revised, RIC- Multidimensional Patient Global Impression of Change (RIC-MPGIC), and Medication Quantification Scale. For worker's compensation patients, the rate of successful release to work at the end of the program was calculated. RESULTS: Results indicated significant improvements in physical functioning and perceived disability (P's<0.001). Patients reported increased usage of an adaptive coping strategy, distraction (P = 0.010), and decreased usage of maladaptive and passive strategies (P's < 0.001). Patients showed greater chronic pain acceptance (P's ≤ 0.010) and reductions in emotional distress (P's < 0.001). Medication usage at 1-month follow-up was significantly reduced compared to program start (P < 0.001) and discharge (P = 0.004). Patients reported "much improvement" in overall functioning, physical functioning, mood, and their ability to cope with pain and flare-ups (RIC-MPGIC). Patient report of pain was not significantly reduced at discharge (P =0.078). Fourteen (88%) of 16 total worker's compensation patients were successfully released to work at the end of the program. CONCLUSIONS: This study demonstrates short-term improvements in physical and emotional functioning, pain coping, and medication usage. These findings are consistent with the rehabilitation philosophy of improving functioning and sense of well-being as of equal value and relevance to pain reduction.

Ethnicity and interdisciplinary pain treatment.

OBJECTIVE: The purpose of this study was to identify ethnic differences in interdisciplinary pain treatment outcome and whether these differences occur while controlling for the effects of demographics, psychosocial, and secondary gain. METHODS: We assessed a sample of 116 (Caucasian, African American, and Latino/a) chronic pain patients who participated a 4-week interdisciplinary pain treatment program. Outcome measure included pretreatment, post-treatment, and change scores on the Multidimensional Pain Inventory, Pain Anxiety Symptom Scale 20, Chronic Pain Acceptance Questionnaire, Coping Strategies Questionnaire-revised, and the Center for Epidemiologic Studies Depression Scale-short form. RESULTS: Analysis of covariances revealed that after accounting for educational and sex differences, ethnic minorities differed from Caucasians on a number of treatment outcome measures at pre- and post-treatment [F's ≥ 5.38; P's < 0.01]. At pretreatment, Latino/a's endorsed greater levels of pain-related anxiety, pain severity, and pain catastrophizing than Caucasians. Both Latino/a's and African Americans reported greater use of prayer at pre- and post-treatment, with Caucasians showing the greatest decrease in the use of prayer in response to treatment. At post-treatment, African Americans had higher level of depression and lower levels of reported activity than Caucasians. CONCLUSIONS: Results support the notion that ethnic differences in pain treatment outcome exist. Further, ethnic minority groups appear to have greater levels of distress compared to Caucasians. However, African Americans, Latino/a's and Caucasians demonstrated similar improvements on all outcome measures, with exception of the use of prayer. Future studies should begin to explore the mechanisms to explain why ethnic group differences in pain treatment outcome occur.

Treatment outcomes for workers compensation patients in a U.S.-based interdisciplinary pain management program.

OBJECTIVES: Assess the efficacy of an outpatient-based interdisciplinary pain rehabilitation program for patients with active workers compensation claims. PATIENTS: Data were available for 101 patients, primarily with chronic low back pain (75%), who participated in the program. METHODS: Treatment included a 4-week (Monday to Friday), 8-hours/day graded progressive program that included individual and group therapies (pain psychology, physical therapy, occupational therapy, relaxation training/biofeedback, aerobic conditioning, pool therapy, vocational counseling, patient education and medical management). Outcome measures included program completion status, release-to-work status, return-to-work status, total scores on the Beck depression inventory, state-trait anxiety inventory, pain catastrophizing scale, and the McGill pain questionnaire visual analogue scale (MPQ VAS). The majority of the patients (65%) graduated from the program. Pre-postoutcome data were available for those who graduated from the program. For noncompleters, last obtained MPQ VAS was compared with their initial MPQ VAS scores. RESULTS: Of those completing the program, most patients (91%)were released to return to work; with 80% released to full-time status and 11% released to gradual return. Approximately half (49%) of the program completers returned to work. Paired-samples t-tests showed that program completers had significant reductions in depression (P = 0.000), pain-related catastrophizing (P = 0.033), and pain intensity (P = 0.000), but not in anxiety (P = 0.098). Interestingly, the last obtained (at early discharge/withdrawal) pain intensity scores (M = 70.33) were higher than at baseline (M = 61.20) in the noncompleters. This difference was not statistically significant (P = 0.127) but may be clinically meaningful. DISCUSSION: Our results support the efficacy of an outpatient-based 4-week interdisciplinary pain rehabilitation program in decreasing emotional distress, reducing pain intensity, and improving return-to-work status in the majority of completers in this challenging population. Patients reporting increased pain at discharge or those discharged early may have been due to operant factors.

An Exploration of Physical Therapy Outcomes and Psychometric Properties of the Patient-Specific Functional Scale After an Interdisciplinary Pain Management Program.

OBJECTIVES: The Patient-Specific Functional Scale (PSFS) has been used to assess physical functioning in various chronic pain populations. There is a lack of evidence for its use with diverse pain populations who have high-impact chronic pain (HICP). The primary aim of this study was to assess the psychometric properties of the PSFS with a heterogeneous sample of patients with HICP. MATERIALS AND METHODS: A retrospective observational study of prospective functional outcomes collected before and after participation in an intensive pain management program: PSFS, Disabilities of the Arm, Shoulder, and Hand, Lower Extremity Functional Scale, Neck Disability Index, Oswestry Disability Index, multidimensional patient impression of change, pain intensity, pain limitation, and fear-avoidance from the charts of 509 intensive pain management program completers. The reliability, validity, and responsiveness of the PSFS were analyzed using Cronbach α, Pearson correlations, and receiver operating characteristics. RESULTS: Statistically significant improvements were found for all outcomes after program participation (all P < 0.0001). Correlations of the PSFS with similar outcomes (convergent validity) were lower than expected ( r = 0.16 to 0.33). A low correlation ( r = -0.12) with an unrelated measure, fear avoidance, supported divergent validity. PSFS change score correlations with similar outcome measures ranged from 0.46 to 0.53. The area under the curve values for the PSFS ranged from 0.801 to 0.857, suggesting a moderate ability for the PSFS to detect improvement. DISCUSSION: The psychometric properties of the PSFS showed mixed support for construct validity but good support for the responsiveness of the PSFS when used with a heterogeneous sample of patients with HICP.

Negligible analgesic tolerance seen with extended release oxymorphone: a post hoc analysis of open-label longitudinal data.

OBJECTIVE: To examine the development of analgesic tolerance in patients on oxymorphone extended-release (OxymER). DESIGN: Post hoc analysis of data from a previously conducted prospective 1 year multi-center open-label extension study in which patients were able to titrate as needed. PATIENTS: Sample of 153 hip and knee osteoarthritis (OA) subjects on OxymER. Primary analyses were limited to study completers (n = 62) due to the large amount of missing data for the noncompleters (n = 91). OUTCOME MEASURES: Main outcome measures included OxymER doses (pill counts) and pain intensity ratings using a visual analog scale at monthly visits. RESULTS: There were significant dose increases from weeks 1 to 2 and 2 to 6 (P < 0.05). Doses stabilized around week 6, suggesting the completion of what we defined as "titration." Both doses and pain ratings were stable when this titration phase was excluded from the analysis (P = 0.751; P = 0.056, respectively). Only 28% of the patients had any dose changes following this titration. While there was a significantly greater dose at week 52 compared with week 10 (P = 0.010), the increase in dose became insignificant after excluding four subjects who required two dose increases (P = 0.103). CONCLUSIONS: The results showed that most of the titration/dose stabilization changes occurred within the first 10 weeks. A minority (28%) of subjects required dosage increases after this (defined) titration period. Pain reports stabilized statistically after 2 weeks. The findings of this post hoc analysis suggest a lack of opioid tolerance in the majority (72%) of these OA patients who completed this study following a defined titration period on OxymER. SUMMARY: This post hoc analysis of oxymorphone ER consumption in osteoarthritis pain vs pain report showed that most dose changes occurred during an initial "titration period" as defined. Following this titration few subjects increased dose and analgesia remained stable. These findings suggest a lack of longitudinal opioid tolerance in the majority of those OA subjects who completed the trial.

Botulinum toxin a in the treatment of chronic tension-type headache with cervical myofascial trigger points: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVE: To evaluate the efficacy of botulinum toxin A (BT-A) as a prophylactic treatment for chronic tension-type headache (CTTH) with myofascial trigger points (MTPs) producing referred head pain. BACKGROUND: Although BT-A has received mixed support for the treatment of TTH, deliberate injection directly into the cervical MTPs very often found in this population has not been formally evaluated. METHODS: Patients with CTTH and specific MTPs producing referred head pain were assigned randomly to receive intramuscular injections of BT-A or isotonic saline (placebo) in a double-blind design. Daily headache diaries, pill counts, trigger point pressure algometry, range of motion assessment, and responses to standardized pain and psychological questionnaires were used as outcome measures; patients returned for follow-up assessment at 2 weeks, 1 month, 2 months, and 3 months post injection. After 3 months, all patients were offered participation in an open-label extension of the study. Effect sizes were calculated to index treatment effects among the intent-to-treat population; individual time series models were computed for average pain intensity. RESULTS: The 23 participants reported experiencing headache on a near-daily basis (average of 27 days/month). Compared with placebo, patients in the BT-A group reported greater reductions in headache frequency during the first part of the study (P = .013), but these effects dissipated by week 12. Reductions in headache intensity over time did not differ significantly between groups (P = .80; maximum d = 0.13), although a larger proportion of BT-A patients showed evidence of statistically significant improvements in headache intensity in the time series analyses (62.5% for BT-A vs 30% for placebo). There were no differences between the groups on any of the secondary outcome measures. CONCLUSIONS: The evidence for BT-A in headache is mixed, and even more so in CTTH. However, the putative technique of injecting BT-A directly into the ubiquitous MTPs in CTTH is partially supported in this pilot study. Definitive trials with larger samples are needed to test this hypothesis further.

Interdisciplinary Pain Management Improves Pain and Function in Pediatric Patients with Chronic Pain Associated with Joint Hypermobility Syndrome.

BACKGROUND: The relation between chronic musculoskeletal pain and joint hypermobility in a small percentage of the pediatric population is well described. However, literature discussing the treatment of chronic pain associated with joint hypermobility in pediatrics is limited. The present study examines the impact of interdisciplinary treatment on chronic pain in pediatrics with joint hypermobility syndrome. OBJECTIVE: To determine if pediatric patients with chronic pain related to joint hypermobility can be effectively treated with an intensive, interdisciplinary pain management program, as measured by changes in pain, psychosocial and physical functioning, as well as parental coping. DESIGN: Retrospective cohort study. SETTING: Urban academic tertiary intensive outpatient interdisciplinary pain management clinic. PARTICIPANTS: The study involved 30 patients who met the criteria for a diagnosis of joint hypermobility and chronic pain and completed an interdisciplinary pain management program. INTERVENTION: All patients were treated in an intensive pediatric interdisciplinary pain management program for a duration of 6 to 8 weeks. The program provided physical therapy, occupational therapy, psychological counseling, and weekly pediatric rehabilitation medicine follow-up. MAIN OUTCOME MEASURES: Outcome measures included numeric rating scale pain scores, the Bath Adolescent Pain Questionnaire, and the Bath Adolescent Pain-Parent Impact Questionnaire. Changes from pre- to post-treatment were analyzed using paired-samples t tests. RESULTS: Patients endorsed pre- to post-treatment improvements in pain, depression, general anxiety, pain-related anxiety, social functioning, and physical functioning (P < .05). The patients' parents showed significant improvements in depression, anxiety, catastrophic thinking, self-blame and helplessness, leisure functioning, and parental behavior (P < .05). CONCLUSION: The present findings suggest that an intensive interdisciplinary rehabilitation pain management program yields short-term improvements in pain, emotional and physical function, and daily activity in a pediatric population diagnosed with joint hypermobility. Parents also experienced benefits from the program. A larger prospective study with longer-term follow-up is needed. LEVEL OF EVIDENCE: III.

Residual limbs of amputees are significantly cooler than contralateral intact limbs.

OBJECTIVE: To test the hypothesis that distal residual limbs (DRLs) have significant vasomotor abnormalities. DESIGN: Comparative surface temperature studies of DRLs using paired samples (DRL vs. similar site on intact contralateral limb). SUBJECTS/PATIENTS: Thirty-six volunteer subjects with unilateral, upper or lower limb amputations were recruited and evaluated at a pain research center in an urban academic rehabilitation facility. METHODS: Our main outcomes were subjects' residual limb temperature as measured by quantitative infrared telethermography (qIRT), temperature strips, and examiner's palpation, compared with the contralateral limb. RESULTS: The qIRT showed that the DRLs were significantly cooler than the corresponding area of the contralateral intact limbs (P < 0.01). The difference using temperature strips supported this finding (P < 0.05); while on physical examination, 39% of the residual limbs were perceived by the examiner as cooler than the corresponding unaffected limbs. CONCLUSIONS: DRLs as measured by qIRT were significantly cooler than the corresponding area of the contralateral intact limbs. A better understanding of these findings may be important in elucidating the pathophysiology of relevant clinical features such as a potential sympathetic component of postamputation pain.

Self-care behaviors for muscle pain.

UNLABELLED: This investigation examined self-care behaviors for muscle pain because of the prevalence of musculoskeletal pain and the substitution of self-care for formal medical care. In Study 1, university students (N = 187) completed a retrospective questionnaire about self-care for muscle pain. In Study 2, muscle pain was experimentally induced in university students (N = 79) with subsequent measurement of self-care. In both studies, stretching and massaging were the most frequently performed behaviors, and consuming medication was the least frequently performed. In Study 1, the perceived effectiveness of behaviors and level of pain required to perform self-care accounted for 12% to 32% of the variance in behavior frequency. In Study 2, pain ratings and pain during activities were higher among those who performed self-care (ds = .59 to 1.00). These studies indicated that self-care behaviors are performed for both naturally occurring and experimentally induced muscle pain. However, both studies determined that the performance of self-care behaviors did not always correspond with current evidence of treatment effectiveness for muscle injuries. Unique opportunities for future investigations of self-care behavior models and interventions are permitted by muscle pain induction. PERSPECTIVE: Self-care for pain reduction is an understudied behavior. This report describes 2 studies of self-care behaviors for naturally occurring and experimentally induced muscle pain. The most frequent types of self-care behaviors are similar for the types of pain, and the perceived effectiveness of behaviors and pain level influence performance of the behaviors.

Altering gender role expectations: effects on pain tolerance, pain threshold, and pain ratings.

The literature demonstrating sex differences in pain is sizable. Most explanations for these differences have focused on biologic mechanisms, and only a few studies have examined social learning. The purpose of this study was to examine the contribution of gender-role stereotypes to sex differences in pain. This study used experimental manipulation of gender-role expectations for men and women. One hundred twenty students participated in the cold pressor task. Before the pain task, participants were given 1 of 3 instructional sets: no expectation, 30-second performance expectation, or a 90-second performance expectation. Pain ratings, threshold, and tolerance were recorded. Significant sex differences in the "no expectation" condition for pain tolerance (t = 2.32, df = 38, P <.05) and post-cold pressor pain ratings (t = 2.6, df = 37, P <.05) were found. Women had briefer tolerance times and higher post-cold pressor ratings than men. When given gender-specific tolerance expectations, men and women did not differ in their pain tolerance, pain threshold, or pain ratings. This is the first empirical study to show that manipulation of expectations alters sex differences in laboratory pain.

Sex differences in common pain events: expectations and anchors.

This study examined (1) the effects of sex-related stereotypes in commonly experienced, potentially painful events and (2) differences in events representing the worst pain sensation imaginable for the typical woman and the typical man. Undergraduates (63 women and 54 men) completed the Situational Pain Questionnaire as the typical woman would and as the typical man would. The participants also answered 2 open-ended questions regarding the worst pain sensation imaginable for the typical woman and for the typical man. Our findings demonstrate that sex-related stereotypes extend to common pain events and that men and women expected that men would report less pain for common pain events than women. This suggests a gender-role related learning history that is relatively consistent for both sexes. The worst pain sensation imaginable was perceived to be different for typical men and women. Both sexes chose injury as the class of events men would find most painful and childbirth and menstrual pain as the class of events women would find most painful. Implications of this finding for common pain scaling approaches are discussed. The results of this study were obtained from a fairly uniform group of undergraduate men and women, which may limit the generalizability of our findings.

Sex differences in pain anchors revisited: further investigation of "most intense" and common pain events.

Recent research suggests that the interpretation of maximal endpoints of pain scales vary between sexes. The purposes of this study were to investigate sex differences in (a) maximal endpoints of pain scales and (b) bias, discrimination, and the "better than average effect" for ratings of common pain events. Study participants described and rated the intensity of events that were the "most intense pain imaginable" for the typical woman, typical man, and one's self. Study participants also described and rated the intensity of the "most painful" events they had experienced. Study participants completed the situational pain questionnaire (SPQ), which measured the amount of pain that the typical woman, typical man, or one's self would be expected to experience during thirty common painful events. One hundred and fifteen undergraduate psychology students completed this study. Men and women differed in the categories of events selected for most intense pain imaginable for one's self. There were no significant sex differences for the intensity of most intense self-imagined pain or most painful event experienced. However, women were more likely to report the intensity of their worst self-imagined pain event as 100/100. In addition, only women demonstrated a significant correlation between the intensity of most painful self-experienced event and intensity of most intense self-imagined event. Analyses of the SPQ discrimination scores revealed no sex or version differences. Analyses of the SPQ bias scores showed that both sexes indicated that the typical woman would rate the intensity of common pain events higher than would the typical man. Women rated the intensity of common pain events for themselves lower than for the typical woman, but higher than the typical man, and men rated also rated themselves as lower than the typical women, but the same as the typical man. Thus, there was inconsistent support for the "better than average effect". Future research is needed to determine the clinical relevance of sex differences in pain anchors and gender-related stereotypes for evaluating other people's pain.

The osteoarthritis knee model: psychophysical characteristics and putative outcomes.

UNLABELLED: The knee osteoarthritis (KOA) model is a convenient and coherent archetype that is frequently used in pharmaceutical trials of drugs with analgesic and/or anti-inflammatory properties; yet, little is known about its specific pathophysiology. The presumed chronic inflammatory etiology of osteoarthritis suggests that nociceptive processes and neurogenic inflammation predominate in this condition. However, most chronic pain conditions are associated with changes in peripheral and central processing. Recent data corroborate this as an important mechanism in KOA. We compared psychophysical characteristics (including thermal Quantitative Sensory Testing); thermal, mechanical, and functional wind-up; thermal and mechanical aftersensations; and pressure algometry of 37 subjects with KOA with 35 age- and sex-matched controls. A third of the KOA subjects demonstrated hypoesthesia to vibration and the 4.56 von Frey fiber, yet few showed allodynia in their worse knee. The majority of subjects had abnormalities to pinprick (41% were hyperalgesic and 27% were hypoesthetic). Compared to controls, the more painful knee was hypoesthetic to cold detection and had greater thermal wind-up, lower pressure-pain thresholds, thermal and mechanical aftersensations, and twice the pain ratings of controls after stair climb. Substantial intraindividual differences were found in KOA subjects and controls for mechanical wind-up and algometric thresholds. PERSPECTIVE: These results develop the KOA model and suggest mechanistic hypotheses. Certain of these tests may ultimately prove to be responsive, quasi-objective, and quantitative outcomes for research and lend empirical support to the notion of measurable sensitization in osteoarthritis.

Does botulinum toxin type A decrease pain and lessen disability in hemiplegic survivors of stroke with shoulder pain and spasticity?: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: The aim of this study was to assess the efficacy of botulinum toxin type A injections in reducing pain, impairment, and disability in patients who have had a stroke with shoulder pain and spasticity. DESIGN: In this prospective randomized, double-blind, placebo-controlled trial, adults (n = 37) with post-stroke shoulder spasticity were screened for preinjection spasticity, rated 3 or 4 on the Modified Ashworth Scale for the shoulder adductors/internal rotators and shoulder pain. After the baseline screening, 21 subjects were randomized to receive either onabotulinumtoxinA (Botox; 140-200 units), into the pectoralis major with or without injections to the teres major, or placebo (saline) injections. Daily pain ratings using visual analog scales of best and worst pain and Disability Assessment Scale for dressing, hygiene, pain, and cosmesis; McGill Pain Questionnaire-Short Form; Fugl-Meyer Scale; upper limb range of motion; and Modified Ashworth Scale scores were assessed at baseline and 2, 4, and 12 wks after injection. Primary outcomes were assessed at week 4. RESULTS: The subject groups were well matched at baseline. Both the botulinum toxin type A and placebo groups showed decreased pain scores at 4 wks (P's < 0.05), with no significant differences between the groups found for any of the daily pain ratings (P's > 0.05). Significant improvement (P < 0.05) in change scores for hygiene on the Disability Assessment Scale was found in the botulinum toxin type A group compared with the placebo group at week 4, and there was a similar trend toward significance for improvement on the Disability Assessment Scale dressing scale (P = 0.061). CONCLUSIONS: Although botulinum toxin type A shoulder muscle injections in patients who have had a stroke with spasticity and shoulder pain resulted in improvement in selected disability measures, the observed pain reduction was not greater than that found for placebo.

Hypoesthesia in the distal residual limb of amputees.

OBJECTIVE: To test the emerging hypothesis that there is polymodal fiber degeneration/loss in distal residual limbs (DRL) of amputees. DESIGN: Prospective qualitative and quantitative psychophysical testing. SETTING: A pain research center at an urban academic rehabilitation hospital. PARTICIPANTS: Forty-four amputees (32 with pain, 12 without pain) with a single (upper or lower) limb amputation. Subjects are a clinical "convenience" sample derived from our amputee or prosthetic clinics. METHODS: Interventions were prospectively acquired psychophysical tests. The primary quantitative test was thermal Quantitative Sensory Testing (tQST) using a Peltier type thermal testing device, assessing sites on the DRL compared with anatomically similar regions on the contralateral "unaffected" extremity. RESULTS: Perceptual responses for several qualitative psychophysical stimuli and perceptual thresholds for tQST cold sensation were significantly reduced in the DRL (t(43)=-2.613, P=.012). There were no significant tQST differences in thresholds for warm perception, cold pain, or hot pain (P>.05). CONCLUSION: These results show a point prevalence of differential hypoesthesia in distal residual limbs. There was a selective loss of cold, but not warm perception or threshold for hot or cold pain by tQST. There are several possible explanations for this polymodal and selective hypoesthesia; specifically, these data may be indicative of a differential "dying back" peripheral neuropathy of the DRL, which may be operational in such clinical features as postamputation pain.