Variance In Pain Intensity Research Articles

Mechanical factors relate to pain in knee osteoarthritis

Background Pain experienced by people with knee osteoarthritis is related to psychosocial factors and damage to articular tissues and/or the pain pathway itself. Mechanical factors have been speculated to trigger this pain experience; yet mechanics have not been identified as a source of pain in this population. The purpose of this study was to identify whether mechanics could explain variance in pain intensity in people with knee osteoarthritis. Methods Data from 53 participants with physician-diagnosed knee osteoarthritis (mean age = 68.5 years; standard deviation = 8.6 years) were analyzed. Pain intensity was reported on the Western Ontario and McMaster Universities Osteoarthritis Index. Mechanical measures included weight-bearing varus–valgus alignment, body mass index and isokinetic quadriceps torque. Gait analysis captured the range of adduction–abduction angle, range of flexion–extension angle and external knee adduction moment during level walking. Findings Pain intensity was significantly related to the dynamic range of flexion–extension during gait and body mass index. A total of 29% of the variance in pain intensity was explained by mechanical variables. The range of flexion–extension explained 18% of variance in pain intensity. Body mass index added 11% to the model. The knee adduction moment was unrelated to pain intensity. Interpretation The findings support that mechanical factors are related to knee osteoarthritis pain. Because limitations in flexion–extension range of motion and body size are modifiable factors, future research could examine whether interventions targeting these mechanics would facilitate pain management.

Psychometric Properties of the Doloplus-2 Observational Pain Assessment Scale and Comparison to Self-assessment in Hospitalized Elderly

Self-report is the "gold standard" for pain assessment, however, observational pain scales, such as Doloplus-2 must be used for patients who cannot communicate. In this follow-up study, we report the psychometric properties of the observational Doloplus-2 scale using the visual analog scale (VAS) pain score as a gold standard and evaluate its performance. Prospective clinical study of 180 hospitalized older patients who demonstrated good comprehension and reliable use of the VAS: 131 participants with dementia and 49 without. All participants assessed their chronic pain using the VAS. Doloplus-2 was independently completed by the nursing team. Mean age of patients (133 women, 47 men) was 83.7+/-6.5. Median mini-mental state examination of patients with diagnosis of dementia was 18.0+/-7.7. Nearly half of the patients (49%) reported that they experienced pain in response to a direct question. The administration of Doloplus-2 was possible in all 180 patients. Doloplus-2 correlated moderately with self-assessment (Spearman coefficient: 0.46). In a multiple regression model, Doloplus-2 predicted 41% of the variability in pain intensity measured by VAS. The somatic dimension alone explained 36% of the variance, the psychosocial bloc 5% with no better contribution of the psychomotor bloc. To shorten Doloplus-2, we constructed a version with only the 5 items that were significantly associated with the VAS score in the multiple regression models. The observational Doloplus-2 scale correlates moderately with self-assessment pain score and has adequate internal consistency. Our data also suggest that Doloplus-2 could be substantially shortened as the brief version performed similarly to the complete Doloplus-2.

The relation between cognitive factors and levels of pain and disability in chronic low back pain patients presenting for physiotherapy

The aim of this study was to determine the extent to which a number of distinct cognitive factors were differentially related to the levels of pain and disability reported by 183 chronic low back pain (CLBP) patients presenting for physiotherapy. After adjusting for demographics, the cognitive factors accounted for an additional 30% of the variance in pain intensity, with functional self-efficacy ( β = −0.40; P < 0.001) and catastrophizing ( β = 0.21; P < 0.01) both uniquely contributing to the prediction of outcome. The cognitive factors also explained an additional 32% of the variance in disability after adjusting for demographics and pain intensity (total R 2 = 0.61). Higher levels of functional self-efficacy ( β = −0.43; P < 0.001) and lower levels of depression ( β = 0.23; P < 0.01) were uniquely related to lower levels of disability. Our findings clearly show that there is a strong association between cognitive factors and the levels of pain and disability reported by CLBP patients presenting for physiotherapy. Functional self-efficacy emerged as a particularly strong predictor of both pain intensity and disability. In view of our findings it would seem that targeting specific cognitive factors should be an integral facet of physiotherapy-based treatments for CLBP.

(970): Relationships among anxious symptomology, anxiety sensitivity and laboratory pain response in children

Anxiety sensitivity (AS) refers to the specific tendency to interpret arousal sensations (e.g., shortness of breath, rapid heart beat) as leading to harmful physical, psychological or social consequences. Previous work in adults has suggested that AS increases an individual’s propensity to experience pain-related anxiety which in turn enhances laboratory pain responsivity. Such relationships have not been examined in younger populations. Thus, the present study used structural equation modeling (SEM) to test a conceptual model in which AS would evidence an indirect relationship with pain intensity via its contribution to state-specific anticipatory anxiety in relation to a variety of laboratory pain tasks (cold pressor, thermal heat, and pressure pain) in 234 healthy children (116 girls; mean age= 12.6 years, range= 8-18 years). The model further hypothesized that existing anxious symptomology would demonstrate a direct relationship with pain intensity. The proposed conceptual model fit the data well (Satorra-Bentler Scaled chi-square (15, N=234)= 17.60, p=0.28, CFI= 0.97, NNFI=0.94, RMSEA=0.027). As expected, AS did not evidence a direct relationship with pain intensity but instead demonstrated a significant indirect effect on pain intensity through pain-related anticipatory anxiety. The total indirect effect of AS accounted for 29% of the variance in laboratory pain intensity via its effects on anticipatory anxiety. Anxious symptomology on the other hand, demonstrated a significant direct effect on pain intensity, accounting for 15% of variance. The combined effects of AS, anxiety symptoms, and anticipatory anxiety together explained 62% of the variance in pain intensity. These relationships did not differ for boys and girls indicating no moderating effect of sex in the conceptual model. The present results support the potential benefit of assessing both AS and anxiety symptoms in children prior to undergoing painful stimulation such as that induced by routine medical procedures.

Electronic Momentary Assessment in Chronic Pain I: Psychological Pain Responses as Predictors of Pain Intensity

Electronic momentary assessment was employed to substantiate the relevance of psychological functioning in chronic pain. More than 7,100 electronic diaries from 80 patients with varying IASP classified types of chronic pain served to investigate to what extent fear-avoidance, cognitive and spousal solicitous and punishing pain responses explained fluctuations in pain intensity and whether patients with pre-chronic, recently chronic and persistently chronic pain differed in this regard. Psychological pain responses explained 40% of the total variance in pain intensity: almost 24% concerned pain variance that occurred between the CPD patients and 16% pertained to pain variance due to momentary differences within these patients. Separately tested fear-avoidance and cognitive responses each explained about 28% of the total pain variance, while spousal responses explained 9%. Catastrophizing emerged as the strongest pain predictor, followed by pain-related fear and bodily vigilance. Results did not differ with the duration of chronicity. Exaggerated negative interpretations of pain, and fear that movement will induce or increase pain strongly predicted CPD pain intensity. Spousal responses-assessed only when the spouse was with the patient who at that moment was in actual pain-may more strongly affect immobility due to pain than pain intensity per se (see part II of the study). The findings substantiate the importance of catastrophizing, fear and vigilance identified primarily in low back pain and extend this to other forms of chronic pain. The compelling evidence of momentary within-patients differences underscores that these must be accounted for in chronic pain research and practice.

COPING STRATEGY USE: DOES IT PREDICT ADJUSTMENT TO CHRONIC BACK PAIN AFTER CONTROLLING FOR CATASTROPHIC THINKING AND SELF-EFFICACY FOR PAIN CONTROL?

To explore whether coping strategy use predicted levels of adjustment in chronic low back pain after controlling for the influence of catastrophic thinking and self-efficacy for pain control. Eighty-four patients with chronic low back pain completed the Coping Strategies Questionnaire, a pain VAS and the Roland Disability Questionnaire. To derive composite measures of coping, the Coping Strategies Questionnaire subscales, excluding the Catastrophizing subscale and 2 single-item scales, were entered into a principal components analysis. The extent to which scores on the coping measures predicted levels of adjustment after controlling for catastrophic thinking (Catastrophizing subscale) and self-efficacy for pain control (2 single-item scales) was explored using sequential multiple regression analysis. Two coping dimensions emerged from the principal components analysis, which were labelled Distraction and Praying or Hoping, and Denial of Pain and Persistence. Scores obtained on these coping measures explained an additional 5% and 13% of the variance in pain intensity and disability, respectively. Interestingly, however, the scores on the coping measures did not predict pain intensity or disability after controlling for the influence of catastrophic thinking and self-efficacy for pain control. Coping strategy use might only be related to levels of adjustment via the effect it has on catastrophic thinking and self-efficacy for pain control.

Variability in pain intensity, physical and psychological function in non-acute, non-traumatic neck pain.

Variability in clinical presentation among patients with neck pain disorders, in relation to symptom severity and the effect of the disorder on their physical and psychological function, has not been well documented. The present study examined the variability in pain intensity, physical and emotional or cognitive function in patients with non-acute, non-traumatic neck pain, and the extent to which these factors are associated at the time of referral for physiotherapy treatment. The study utilized a survey of patients referred for physiotherapy treatment for non-acute, non-traumatic neck pain. Seventy-two patients (mean age 58 years; SD 15.5 years) with a symptom duration ranging from four weeks to 30 years were recruited. Each completed measures of pain intensity using a visual analogue scale, and neck-pain related disability by use of the 'Neck Pain and Disability' scale (NPAD). Frequency distributions were calculated to examine variability in pain intensity, the total NPAD score and the effect of the disorder on different aspects of physical and emotional or cognitive function. Relationships between pain intensity, and physical and psychological function, were also examined. Pain intensity was normally distributed with a mean score of 6.3 cm (SD 2.5 cm). NPAD scores were normally distributed (mean 54.8%; SD 18%). Similar variability was noted in each of the NPAD factor scores for neck function, pain intensity, emotional or cognitive function and activities of daily living. Pain intensity was significantly (p < 0.01) correlated with the total NPAD score (r = 0.55) and with each of the four effects of neck pain represented in the NPAD sub-domains (r = 0.42-0.63). Symptom duration was not significantly correlated with pain intensity, or with the severity of disability, as reflected in the total NPAD score. The results highlight the variability between patients with neck pain, in relation to pain intensity and the effect of the disorder on physical and psychological function. Identifying the specific effects of the neck pain disorder in individual cases is important when defining the treatment objectives and selecting measures of treatment response.

Adjustment to chronic low back pain—the relative influence of fear-avoidance beliefs, catastrophizing, and appraisals of control

The present study investigated the relative extent to which patients’ adjustment to chronic low back pain (CLBP) was influenced by their fear-avoidance beliefs, their tendency to catastrophize, and their appraisals of control. Eighty-three CLBP patients completed a series of self-report measures before participating in a physical therapist-led intervention. Hierarchical multiple regression analyses revealed that patients’ perceptions of their ability to decrease pain explained a small, but statistically significant, proportion of the variance in pain intensity. In addition, patients’ levels of catastrophizing, as well as their fear-avoidance beliefs about both work and physical activity, were independently associated with levels of disability. Interestingly, however, when exploring the relative predictive utility of these three psychological factors, it became evident that fear-avoidance beliefs about physical activity (FABs-PA) were the only significant predictor of patients’ disability. Specifically, those patients who exhibited higher levels of FABs-PA tended to report greater levels of disability, even after adjusting for age, sex and pain intensity.

Prognostic factors for perceived pain and function at one-year follow-up in primary care patients with neck pain.

To identify prognostic factors for perceived pain and function with focus at one-year follow-up in primary care patients treated for non-specific neck pain. A prospective study was performed including 193 neck pain patients. Before and after treatment period, and 12 months after the start date for treatment, patients completed a questionnaire including background data and aspects of pain, function and general health. Linear multiple regression analysis was used to identify prognostic factors with the dependent variables Oswestry score and pain intensity at 12-month follow-up. Response rate 81%. At 12-month follow-up, Oswestry score identified four prognostic factors: pain intensity; well-being; expectations of treatment; and duration of current episode. Adjusted R2 for the model was 0.32, and 20% of the patients had three of the four prognostic factors at entry, indicating risk of poor outcome. The dependent variable pain intensity revealed three prognostic factors: Oswestry score; duration of current episode; and similar problem during the previous five years. Adjusted R2 was 0.24, and 60% of the patients had two of the three prognostic factors at entry, indicating risk of poor outcome. Different prognostic factors (with the exception of duration of current episode) were identified by the two outcome variables. Thus the results suggest that it should be taken into account whether an impairment or disability outcome is used.

Catastrophizing is associated with pain intensity, psychological distress, and pain-related disability among individuals with chronic pain after spinal cord injury

Little research has examined the role of patient cognitive and behavioral responses, including catastrophizing, in adjustment to chronic pain associated with spinal cord injury (SCI). The objective of this study was to examine the associations of catastrophizing and specific pain coping strategies with pain intensity, psychological distress, and pain-related disability among individuals with chronic pain and SCI, after controlling for important demographic and SCI-related variables that might affect outcomes. Participants in this study were 174 community residents with SCI and chronic pain who completed a mailed questionnaire that included the SF-36 Mental Health scale, Coping Strategies Questionnaire, and Graded Chronic Pain Scale. The pain coping and catastrophizing measures explained an additional 29% of the variance in pain intensity after adjusting for the demographic and SCI variables ( P<0.001). The coping and catastrophizing scales accounted for an additional 30% of the variance in psychological distress ( P<0.001) and 11% of the variance in pain-related disability ( P<0.001), after controlling for pain intensity and demographic and SCI variables. Catastrophizing, but not any other single pain coping strategy, was consistently strongly and independently associated with the outcome measures. Potentially, the assessment and treatment of catastrophizing may reduce psychological distress and pain-related disability among individuals with chronic pain and SCI.

Prognostic factors for perceived pain and function at one-year follow-up in primary care patients with neck pain

Purpose: To identify prognostic factors for perceived pain and function with focus at one-year follow-up in primary care patients treated for non-specific neck pain. Methods: A prospective study was performed including 193 neck pain patients. Before and after treatment period, and 12 months after the start date for treatment, patients completed a questionnaire including background data and aspects of pain, function and general health. Linear multiple regression analysis was used to identify prognostic factors with the dependent variables Oswestry score and pain intensity at 12-month follow-up. Response rate 81%. Results: At 12-month follow-up, Oswestry score identified four prognostic factors: pain intensity; well-being; expectations of treatment; and duration of current episode. Adjusted R2 for the model was 0.32, and 20% of the patients had three of the four prognostic factors at entry, indicating risk of poor outcome. The dependent variable pain intensity revealed three prognostic factors: Oswestry score; duration of current episode; and similar problem during the previous five years. Adjusted R2 was 0.24, and 60% of the patients had two of the three prognostic factors at entry, indicating risk of poor outcome. Conclusions: Different prognostic factors (with the exception of duration of current episode) were identified by the two outcome variables. Thus the results suggest that it should be taken into account whether an impairment or disability outcome is used.

Pain in young adults--III: Relationships of three pain-coping measures to pain and activity interference.

The study had two purposes: (a) to examine the relationships among coping strategies measured by the Coping Strategies Questionnaire (CSQ) (1), the Vanderbilt Pain Management Inventory (VPMI) (2), and the Ways of Coping Inventory (WOC) (3) and identify the higher-order composite factors representing these relationships; and (b) to determine the degree to which individual coping scale scores and composite coping factor scores could explain variability in the pain intensity and pain-related activity interference reported by young adults. Measures of pain coping were collected from 206 young adults using the CSQ, VPMI, and WOC, along with measures of pain intensity, pain location, and the extent to which pain interfered with daily activities. Results indicated considerable variability in the reported frequency of use of pain-coping strategies and in pain intensity, location, and activity interference. Principal components factor analysis identified three higher-order coping factors (Emotional and Other-Directed Coping, Active Cognitive Coping, and Self-Efficacy for Pain Control) that explained 87% of the variance in individual coping scale scores. The degree to which individual scale scores and composite factor scores explained variability in pain intensity and activity interference variables was determined through a series of multiple regression analyses. The results revealed that individual scale scores, particularly the CSQ scales of catastrophizing and praying or hoping, were best able to explain the variance in measures of pain and activity interference. Taken together, these findings provide further support for the importance of coping variables in explaining the experience of pain and adjustment in young adults.

Myofascial face pain: seasonal variability in pain intensity and demoralization

Seasonal variability has been detected in a variety of illnesses. The purpose of this study is to examine seasonal variability in pain intensity, demoralization and range of mandibular motion among patients suffering from myofascial face pain. Pain and demoralization for cases (n = 140) and demoralization for controls (n = 133) were measured in each of 10 monthly interviews. Range of motion was measured once only for cases. Their pain intensity ( P < 0.009) and demoralization ( P < 0.04) were significantly greater in the peak dark months than in the peak light months. There was a non-significant trend ( P < 0.07) toward elevated demoralization in the darker months for controls. Range of motion, assessed cross-sectionally, did not demonstrate a seasonal pattern. These data support our prior finding that myofascial face pain and depressed mood are co-morbid and may be maintained by common risk factors.

ERD — Attentional and cognitive processes in the upper and lower alpha band

The identification of neurobiological markers that predict individual predisposition to pain are not only important for development of effective pain treatments, but would also yield a more complete understanding of how pain is implemented in the brain. In the current study using electroencephalography (EEG), we investigated the relationship between the peak frequency of alpha activity over sensorimotor cortex and pain intensity during capsaicin-heat pain (C-HP), a prolonged pain model known to induce spinal central sensitization in primates. We found that peak alpha frequency (PAF) recorded during a pain-free period preceding the induction of prolonged pain correlated with subsequent pain intensity reports: slower peak frequency at pain-free state was associated with higher pain during the prolonged pain condition. Moreover, the degree to which PAF decreased between pain-free and prolonged pain states was correlated with pain intensity. These two metrics were statistically uncorrelated and in combination were able to account for 50% of the variability in pain intensity. Altogether, our findings suggest that pain-free state PAF over relevant sensory systems could serve as a marker of individual predisposition to prolonged pain. Moreover, slowing of PAF in response to prolonged pain could represent an objective marker for subjective pain intensity. Our findings potentially lead the way for investigations in clinical populations in which alpha oscillations and the brain areas contributing to their generation are used in identifying and formulating treatment strategies for patients more likely to develop chronic pain.

Using Memory for Pain in Analgesic Research

To determine the validity of pain intensity recall at 24 and 48 hours as a substitute for hourly pain assessments in repeated-dose analgesic studies. Orthopedic unit of an acute care teaching hospital. Eighty-four patients undergoing arthroscopic reconstruction of the anterior cruciate ligament, using the patellar tendon, who were participating in a randomized, double-blind, parallel-group analgesic study. Patients rated their pain intensity every hour (while awake) for 48 hours and their recall of worst, least, and usual pain intensity at 24 and 48 hours using a visual analog scale (VAS). This study examined the relationship between recall of worst, least, and usual pain intensity at 24 and 48 hours and the experienced maximum, minimum, and mean pain intensity VAS scores obtained from hourly assessments over the 0-24- and 0-48-hour periods, respectively. The significance of differences between recalled and experienced pain intensity variables was assessed. Worst, least, and usual pain recall at 24 and 48 hours were highly correlated with experienced maximum, minimum, and mean pain from hourly reports, respectively, over the 0-24- and 0-48-hour periods (Pearson correlation coefficients, r = 0.80-0.89, p < 0.0001). Among the three pain recall variables, usual pain showed the highest correlation with hourly measurements. There were no significant differences between recalled pain and the corresponding measures of pain from the hourly VAS scores, except in the case of 48-hour recall of worst pain (Student's t-test, p = 0.001). The close agreement between actual pain experience and recall of pain provides support for the use of pain recall in assessing analgesic efficacy in clinical trials.

Clinical management of acute pain

The clinical management of acute pain has been impeded by traditions and misconceptions which have resulted in suboptimal application to the patient of the currently available methods of pain control. The search for new drugs and exotic ways to deliver them has further obscured many of the basic principles which should guide management. Standard regimens fail because of the wide, unpredictable variability in pain intensity, patient characteristics, and pharmacological responses. Treatment needs to be individualized for each patient. Unrelieved acute pain produces psychological, physiological and socioeconomic consequences. Pre-emptive analgesia may damp down the development of both immediate and long-term pain following surgery and adequate psychological preparation can improve coping abilities. The delivery of opioid analgesics can be improved using patient controlled analgesia or spinal administration in some cases. Regional analgesia, often using simple techniques, can produce excellent pain relief. Overall management and staff education should be delegated to an acute pain service.

Pain descriptions and surgical findings in patients with herniated lumbar intervertebral discs

The diagnostic value of pain mapping in patients with lumbago sciatica and herniated intervertebral discs is evaluated, somatosensory pain descriptions being compared with surgical findings. Information has been extracted from complex data sets using a multivariate data analysis program (FCVPC-87). Superficially experienced pain may represent pronounced nerve root affliction. Pain relief in particular body positions was related to extruded discs and additional osseous stenosis and rarely occurring relief to derangement of nerve root circulation. Neither somatosensory pain quality descriptions nor pain intensity variables were found to be of diagnostic value. Long duration of symptoms was found together with nerve root atrophy. Affliction of the L5 and S1 nerve roots showed differences with regard to pain localization and intensity and some surgical findings. Pain mapping may represent an indication of the patho-anatomical substratum in patients with herniated lumbar intervertebral discs.