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Biomedical subjects

Michael E Robinson

Publications and source records attributed to Michael E Robinson.

At least 55 records · Page 3Linked to original sources
PubMed2003

Ratings of experimental pain and pain-related negative affect predict clinical pain in patients with fibromyalgia syndrome.

Patients with fibromyalgia syndrome (FMS) report chronic pain related to abnormal sensitivity of muscles that is reflected by so-called tender points (TP). TP represent areas of abnormal mechanical pain thresholds that have only shown a minor correlation with clinical pain of FMS patients and seem to be better suited for predicting distress. Pain-related negative affect (PRNA), abnormal temporal summation of second pain (termed wind-up or WU), and abnormal WU decay are frequently present in FMS patients. WU and WU decay can provide measures of central sensitization, which may contribute to clinical FMS pain. We therefore investigated the role of WU, WU decay, TP count, and PRNA as predictors of clinical pain in FMS subjects.Fifty-five FMS subjects rated their clinical pain at entry into the study using a visual analogue scale (VAS). After a TP evaluation, all subjects received two trials of thermal WU and WU decay testing. Hierarchical regression analysis demonstrated that the combination of PRNA ratings, TP count, and WU decay ratings predicted 49.7% of the variance of clinical pain in FMS. This model demonstrates independent relationships of biological and psychological factors to clinical pain and underscores the important role of abnormal peripheral and central pain mechanisms for FMS. Therefore, the combination of PRNA, TP count, and WU decay may provide an excellent measure for future clinical studies of FMS patients.

Adult↗
PubMed2003

Reversal of visceral and cutaneous hyperalgesia by local rectal anesthesia in irritable bowel syndrome (IBS) patients.

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception. The aim of the study was to determine if local anesthetic blockade of peripheral visceral nociceptive input reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. Ten women with IBS (mean age 30+/-10 years) and ten control subjects (all women) (mean age 29+/-7 years) rated pain intensity and unpleasantness to distension of the rectum (35 mmHg) and thermal stimulation (47 degrees C) of the foot before and after rectal administration of either lidocaine jelly or saline jelly in a double blind crossover design. Intrarectal lidocaine (300 mg) reduced reported rectal and cutaneous pain in all of the IBS patients. The effects were statistically much greater than those of placebo and most of the effects were present within 5-15 min after the onset of the treatment. In the control subjects, rectal lidocaine did not decrease pain report from visceral and cutaneous stimuli. The results of this study support the hypothesis that local anesthetic blockade of peripheral impulse input from the rectum/colon reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. The results provide further evidence that visceral hyperalgesia and secondary cutaneous hyperalgesia in IBS reflects central sensitization mechanisms that are dynamically maintained by tonic impulse input from the rectum/colon. Rectal administration of lidocaine jelly may also be a safe and effective means of reducing pain symptoms in IBS patients.

Administration, Rectal↗
PubMed2003

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.

Adult↗
PubMed2003

Psychosocial factors and functional capacity evaluation among persons with chronic pain.

Psychosocial factors have been found to have a significant impact on functional activity, particularly among persons with chronic pain. While various systems have been developed to assess functional limitations through functional capacity evaluation (FCE), assessment of psychosocial factors that may impact function have been largely ignored. This paper examines the existing literature on psychosocial factors and FCE performance. Given that there are few studies that have directly addressed this issue, the paper also examines psychosocial factors that have been found to influence function in persons with pain. The results of the literature review indicate that few psychosocial factors have been found to be directly associated with FCE and functional measures, although many are related to various measures of disability. The strongest evidence that psychosocial factors are related to functional performance is based on the studies examining the association between functional activity and pain-related fear, self-efficacy, and illness behavior. Psychosocial factors have also been shown to influence measures of sincerity of effort often obtained during FCE. Proposals for modifying FCE assessment are given based on the available data, as well as suggestions for future research.

Anxiety↗
PubMed2003

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.

Adolescent↗
PubMed2003

An examination of the relationships among recalled, expected, and actual intensity and unpleasantness of delayed onset muscle pain.

This investigation assessed the relationships among recalled, expected, and actual muscle pain intensity and unpleasantness during a period of 48 hours. We hypothesized that (1). specific expectations of pain after 24 hours would account for a significant amount of variance in actual pain, (2). recalled pain from the most recent episode of naturally occurring muscle pain would be significantly associated with expected pain, and (3). the accuracy of expectations (ie, the difference between expected and actual pain) would increase across time as the onset of muscle pain occurred. Ninety-five students completed 3 sessions. In Session 1, recalled muscle pain and expected muscle pain in the next 24 hours were collected before exercise. In Sessions 2 and 3, muscle pain during movement and expected pain in the next 24 hours were collected. Recalled muscle pain was associated with expectations at baseline, r values [equals].26 to.47, P [lt ].05. The accuracy of expected intensity increased during the study, t [equals] 3.20, P [lt ].01, and the accuracy of expected unpleasantness was associated with change in expected unpleasantness, r values [equals] [minus ].28, P [lt ].01. The amount of variance in actual intensity and unpleasantness accounted for by expectations increased up to 55% and 52%, respectively, during the study. Expected unpleasantness did not account for variance in actual intensity. Expected intensity accounted for 3% of the variance in actual unpleasantness, but only in the second 24-hour period. Thus, our hypotheses were generally supported, but unanticipated findings regarding changes across time in the relationships among recalled, expected, and actual muscle pain were also detected.

Adolescent↗
PubMed2003

Treatment of chronic constipation with colchicine: randomized, double-blind, placebo-controlled, crossover trial.

OBJECTIVE: Refractory constipation is a common GI complaint seen by physicians in all practice settings. We have previously shown that p.d. colchicine (0.6 mg t.i.d.) increases the number of spontaneous bowel movements, hastens GI transit, and improves GI symptoms in patients with chronic constipation during an 8-wk, open-label therapeutic trial. The aim of this study was to determine if p.d. colchicine will increase spontaneous bowel movements and accelerate colonic transit in patients with idiopathic chronic constipation in a randomized, placebo-controlled, crossover trial. METHODS: A total of 16 patients (15 women, one man) with a mean age of 47 yr (age range 25-89) with chronic idiopathic constipation who were refractory to standard medical therapy participated in the study. Patients randomly received either colchicine 0.6 mg p.o. t.i.d. or an identical placebo p.o. t.i.d. for a total of 4 wk in a double-blind, crossover fashion. Patients recorded their daily number of bowel movements and daily symptoms of daily nausea, abdominal pain, and bloating. Mean colonic transit was calculated at baseline, weeks 6 and 12. RESULTS: Colchicine increased the number of bowel movements and accelerated colonic transit compared with baseline and placebo conditions. There were no significant differences between conditions on ratings of nausea and bloating. During colchicine administration, mean abdominal pain was greater than the baseline or placebo conditions, however, the pain decreased significantly by the last week the patient was on colchicine. CONCLUSION: Colchicine increases the frequency of bowel movements and hastens colonic transit in patients with chronic constipation. Colchicine may be an effective agent available to practitioners to treat a subset of patients with chronic constipation who are refractory to standard medical therapy.

Adult↗
PubMed2002

Gender role expectations of pain: relationship to experimental pain perception.

The primary purpose of this study was to investigate the influence of an individual's Gender Role Expectations of Pain (GREP) on experimental pain report. One hundred and forty-eight subjects (87 females and 61 males) subjects underwent thermal testing and were asked to report pain threshold, pain tolerance, VAS ratings of pain intensity and unpleasantness, and a computerized visual analogue scales (VAS) rating of pain intensity during the procedure. Subjects completed the GREP questionnaire to assess sex-related stereotypic attributions of pain sensitivity, pain endurance, and willingness to report pain. Consistent with previous research, significant sex differences emerged for measures of pain threshold, pain tolerance, and pain unpleasantness. After statistically controlling for age, GREP scores were significant predictors of threshold, tolerance, and pain unpleasantness, accounting for an additional 7, 11, and 21% of the variance, respectively. Sex remained a significant predictor of pain tolerance in hierarchical regression analyses after controlling for GREP scores. Results provide support for two competing but not mutually exclusive hypotheses related to the sex differences in experimental pain. Both psychosocial factors and first-order, biological sex differences remain as viable explanations for differences in experimental pain report between the sexes. It appears that GREP do play a part in determining an individual's pain report and may be contributing to the sex differences in the laboratory setting.

Adolescent↗
PubMed2002

Enhanced temporal summation of second pain and its central modulation in fibromyalgia patients.

We have previously shown that fibromyalgia (FMS) patients have enhanced temporal summation (windup) and prolonged decay of heat-induced second pain in comparison to control subjects, consistent with central sensitization. It has been hypothesized that sensory abnormalities of FMS patients are related to deficient pain modulatory mechanisms. Therefore, we conducted several analyses to further characterize enhanced windup in FMS patients and to determine whether it can be centrally modulated by placebo, naloxone, or fentanyl. Pre-drug baseline ratings of FMS and normal control (NC) groups were compared with determine whether FMS had higher pain sensitivity in response to several types of thermal tests used to predominantly activate A-delta heat, C heat, or cold nociceptors. Our results confirmed and extended our earlier study in showing that FMS patients had larger magnitudes of heat tap as well as cold tap-induced windup when compared with age- and sex-matched NC subjects. The groups differed less in their ratings of sensory tests that rely predominantly on A-delta-nociceptive afferent input. Heat and cold-induced windup were attenuated by saline placebo injections and by fentanyl (0.75 and 1.5 microg/kg). However, naloxone injection had the same magnitudes of effect on first or second pain as that produced by placebo injection. Hypoalgesic effects of saline placebo and fentanyl on windup were at least as large in FMS as compared to NC subjects and therefore do not support the hypothesis that pain modulatory mechanisms are deficient in FMS. To the extent that temporal summation of second pain (windup) contributes to processes underlying hyperalgesia and persistent pain states, these results indirectly suggest that these processes can be centrally modulated in FMS patients by endogenous and exogenous analgesic manipulations.

Adult↗
PubMed2001

Hypersensitivity to visceral and cutaneous pain in the irritable bowel syndrome.

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception. Previous studies in IBS have failed to demonstrate altered somatic or cutaneous perception. The aims of the study were to determine whether IBS patients have visceral hypersensitivity and cutaneous heat-induced hyperalgesia restricted to lumbosacral dermatomes, consistent with a localized segmental mechanism. Twelve patients (ten women, two men) with IBS and 17 control subjects (13 women, four men) rated pain intensity and unpleasantness to distension of the rectum (35, 55 mmHg) and thermal stimulation (45, 47 degrees C) of the hand and foot. Patients with IBS demonstrated cutaneous allodynia/hyperalgesia to thermal pain applied to the hand and foot. The cutaneous hyperalgesia was pronounced in the lower extremity yet present in the upper extremity to a lesser extent. Psychological testing revealed the IBS patients report more state anxiety and a greater number of somatic symptoms that significantly correlated with most of the pain measures. However, they did not differ from controls on several personality trait measures. These results suggest that patients with IBS have visceral hyperalgesia and cutaneous hyperalgesia that is distributed over a considerable rostral-caudal distance yet optimally expressed in lumbosacral dermatomes. This distribution is consistent with patterns of spinal hyperexcitability observed in experimentally induced persistent pain conditions.

Adult↗
PubMed1999

A meta-analytic review of pain perception across the menstrual cycle.

The purpose of this article is to review the sixteen published studies that examine associations between the perception of experimentally induced pain across menstrual cycle phases of healthy females. We also performed a meta-analysis to quantitatively analyze the data and attempt to draw conclusions. The results suggest that there are relatively consistent patterns in the sensitivity to painful stimulation. These patterns are similar across stimulus modality with the exception of electrical stimulation. The magnitude of the effect was approximately 0.40 across all stimulation. For pressure stimulation, cold pressor pain, thermal heat stimulation, and ischemic muscle pain, a clear pattern emerges with the follicular phase demonstrating higher thresholds than later phases. When the effect size was pooled across studies (excluding electrical) comparisons involving the follicular phase were small to moderate (periovulatory phase, d(thr) = 0.34; luteal phase, d(thr) = 0.37; premenstrual phase, d(thr) = 0.48). The pattern of effects was similar for tolerance measures. Electrical stimulation was different than the other stimulus modalities, showing the highest thresholds for the luteal phase. When the effect size was pooled across studies for electrical stimulation, effect sizes were small to moderate (menstrual (d(thr) = -0.37), follicular d(thr) = -0.30) periovulatory d(thr) = -0.61), and premenstrual d(thr) = 0.35) phases. This paper raises several important questions, which are yet to be answered. How much and in what way does this menstrual cycle effect bias studies of female subjects participating in clinical trials? Furthermore, how should studies of clinical pain samples control for menstrual related differences in pain ratings and do they exist in clinical pain syndromes? What this paper does suggest is that the menstrual cycle effect on human pain perception is too large to ignore.

Adult↗
PubMed1998

Sex differences in response to cutaneous anesthesia: a double blind randomized study.

The existing literature on experimentally induced pain indicates that there are sex differences, with females displaying greater sensitivity. In epidemiological studies, sex differences are also noted in the prevalence of a number of pain syndromes, with females reporting more severe pain, more frequent pain, and pain of longer duration. Complicating the interpretation of pain differences between men and women in clinical samples are reports of sex differences in response to pain-reducing medications. Studies in human subjects suggest that women respond better to certain opioid analgesics than men following third molar extraction, but few studies have assessed sex effects in effectiveness of topical anesthetics. The purpose of this study was to test for sex differences in response to a topical anesthetic, Lidocaine, using double blind, placebo controlled experimental methodology, in combination with a magnitude matching psychophysical protocol using a pressure algometer. The subjects were 21 female and 23 male adult volunteers. Twenty-four subjects (12 males and 12 females) were randomly assigned to the Lidocaine condition and 20 subjects were randomly assigned to the placebo control condition (9 males and 11 females). The effect size across sex for subjects in the Lidocaine treatment condition on the response bias variable was large indicating the males rated the stimuli as less painful than the females. Sex differences were not observed for discriminability in the Lidocaine treatment condition. This study did not show sex differences in the placebo condition. These results are particularly interesting in light of previous work that has shown similar pain stimuli (pressure pain) to be the stimulation most sensitive to sex differences. Results of this study suggest that the protocol employed (pressure pain stimulus with magnitude matching task) is sensitive to both anesthetic treatment and sex differences and represents an improvement in pain assessment methodology for use in experimental studies and in the clinic.

Adolescent↗
PubMed1994

Pain beliefs: assessment and utility.

When pain becomes persistent, patients may abandon previously held cultural or personal beliefs about pain to form new pain beliefs that are more consistent with their persistent pain experience. The Pain Beliefs and Perceptions Inventory (PBPI) is an instrument to assess these new beliefs. This paper presents 4 studies examining the utility of the PBPI. Two studies are factor analytic and support recent literature identifying 4 belief factors associated with this instrument. The third and fourth studies used a new scoring method for the PBPI creating 4 scales: Mystery, Self-blame, Pain Permanence, and Pain Constancy. These scales were then correlated with important pain indices such as measures of pain quality, psychological states (i.e., depression and anxiety), personality traits, physical functioning, and coping strategies. Each belief appears to have a unique association with the pain indices thus supporting the rescoring of this instrument with 4 scales. Belief in pain constancy is associated with greater pain self-report, permanence is associated with anxiety, mystery is associated with greatest overall distress, and self-blame is associated with depressive symptoms. An appendix is included that provides clinical norms for the use of the PBPI and a revised scoring key.

Adaptation, Psychological↗
PubMed1994

Catastrophizing, depression and the sensory, affective and evaluative aspects of chronic pain.

Research has shown that catastrophizing is related to increased depression and chronic pain. However, some researchers have questioned the utility of catastrophizing as a separate construct, suggesting that it may just be a symptom of depression. The present investigation used path analysis to determine if catastrophizing was related to McGill Pain Questionnaire scores when controlling for depression as assessed by the Beck Depression Inventory in a group of 85 chronic pain patients. According to Fields' model of the relationship between pain and depression, we predicted that catastrophizing would mediate the the relationship between depression and the evaluative and affective aspects of pain, but not the sensory aspect. The resulting path coefficients appear to support these predictions. The results suggest that catastrophizing is a separate construct which may impact on pain perception and treatment. The data also provide some support for Field's neurobiological model of the relationship between depression and pain.

Adult↗
PubMed1989

The P-A-I-N MMPI classification system: a critical review.

The Costello et al. (Pain, 30 (1987) 199-209) literature-based MMPI clustering algorithm was compared to a standard clustering procedure of chronic pain patients' MMPI profiles. Results indicated that the Costello algorithm was too restrictive, failing to classify 69% of the MMPI profiles of the local sample. It was suggested that it may be premature to adopt a literature based clustering method until the validity of empirically derived clusters has been more thoroughly determined. The utility of a given set of clusters may best be determined by using locally derived clusters to predict treatment response. Once the predictive validity of the local clusters has been demonstrated, the Costello approach may prove more useful.

Adolescent↗
PubMedDate not supplied

Psychosocial contributions to sex-correlated differences in pain.

Sex-correlated differences in pain perception and behavior have been reported in several studies. Where such differences are found, they are most often in the direction of girls and women reporting more pain than is reported by boys and men. Although biologic, psychologic, and sociocultural factors act interdependently to influence pain responding, most efforts to explain sex-correlated differences in pain have focused on first-order biologic differences between the sexes. The current paper discusses empirical and theoretical literature addressing gender role socialization, cognitive factors, and affective factors associated with sex-correlated differences in pain. We affirm that there is convincing evidence that such psychosocial factors must be taken into account in research on sex-correlated differences in pain. We contend that the use of the dichotomous variable sex as a proxy for presumed biologic aspects of being female or male may obscure the contribution to sex-correlated differences that could be ascribed to the ways in which women and men are socialized with respect to pain perception and pain reporting.

Cognition↗
PubMedDate not supplied

Critical issues in the use of muscle testing for the determination of sincerity of effort.

Over the past 20 years, there have been numerous attempts to identify methodologies that are capable of the determination of sincerity of effort during muscle testing. The ensuing paper reviewed this literature and drew several conclusions. Injured patients and healthy volunteers do produce less force and more variable force while performing submaximal contractions than maximal contractions. However, submaximal efforts during strength testing can be reproduced and the use of force variability is not adequate to distinguish sincerity of effort. Visual examination of the shape of force output curves is also not adequate for distinguishing sincerity of effort. Furthermore, much of the research using strength ratios, difference scores, and an assortment of different parameters derived during strength testing has not established reliable and clinically useful methods of differentiating effort levels. Methods examining motion variability, radial/ulnar force output ratios, difference scores of eccentric-concentric ratios, and electromyography offer some promise, but numerous critical issues need to addressed. The use of the coefficient of variation, for example, is statistically untenable given the number of trials appropriate for clinical samples. Several studies have inadequate sample size to number of variable ratios. Many studies have questionable or at least unknown generalizability to patient samples and actual functional capacity. It is critical that other explanatory variables such as fear of injury, pain, medications, work satisfaction, and other motivational factors be considered. It is our opinion that there is not sufficient empirical evidence to support the clinical application of muscle testing to determine sincerity of effort.

Electromyography↗