Pain distribution, intensity, and duration in patients with chronic pain

Reliability of the Pen-on-Paper Pain Drawing Analysis Using Different Scanning Procedures

INTRODUCTION

Pen-on-paper pain drawing are an easily administered self-reported measure that enables patients to report the spatial distribution of their pain. The digitalization of pain drawings has facilitated the extraction of quantitative metrics, such as pain extent and location. This study aimed to assess the reliability of pen-on-paper pain drawing analysis conducted by an automated pain-spot recognition algorithm using various scanning procedures.

METHODS

One hundred pain drawings, completed by patients experiencing somatic pain, were repeatedly scanned using diverse technologies and devices. Seven datasets were created, enabling reliability assessments including inter-device, inter-scanner, inter-mobile, inter-software, intra- and inter-operator. Subsequently, the automated pain-spot recognition algorithm estimated pain extent and location values for each digitized pain drawing. The relative reliability of pain extent analysis was determined using the intraclass correlation coefficient, while absolute reliability was evaluated through the standard error of measurement and minimum detectable change. The reliability of pain location analysis was computed using the Jaccard similarity index.

RESULTS

The reliability analysis of pain extent consistently yielded intraclass correlation coefficient values above 0.90 for all scanning procedures, with standard error of measurement ranging from 0.03% to 0.13% and minimum detectable change from 0.08% to 0.38%. The mean Jaccard index scores across all dataset comparisons exceeded 0.90.

CONCLUSIONS

The analysis of pen-on-paper pain drawings demonstrated excellent reliability, suggesting that the automated pain-spot recognition algorithm is unaffected by scanning procedures. These findings support the algorithm's applicability in both research and clinical practice.

Chronic pain and COVID-19 hospitalisation and mortality: a UK Biobank cohort study

ABSTRACT

The risk of COVID-19 in those with chronic pain is unknown. We investigated whether self-reported chronic pain was associated with COVID-19 hospitalisation or mortality. UK Biobank recruited 502,624 participants aged 37 to 73 years between 2006 and 2010. Baseline exposure data, including chronic pain (>3 months, in at least 1 of 7 prespecified body sites) and chronic widespread pain (>3 months, all over body), were linked to COVID-19 hospitalisations or mortality. Univariable or multivariable Poisson regression analyses were performed on the association between chronic pain and COVID-19 hospitalisation and Cox regression analyses of the associations with COVID-19 mortality. Multivariable analyses adjusted incrementally for sociodemographic confounders, then lifestyle risk factors, and finally long-term condition count. Of 441,403 UK Biobank participants with complete data, 3180 (0.7%) were hospitalised for COVID-19 and 1040 (0.2%) died from COVID-19. Chronic pain was associated with hospital admission for COVID-19 even after adjustment for all covariates (incidence rate ratio 1.16; 95% confidence interval [CI] 1.08-1.24; P < 0.001), as was chronic widespread pain (incidence rate ratio 1.33; 95% CI 1.06-1.66; P = 0.012). There was clear evidence of a dose-response relationship with number of pain sites (fully adjusted global P -value < 0.001). After adjustment for all covariates, there was no association between chronic pain (HR 1.01; 95% CI 0.89-1.15; P = 0.834) but attenuated association with chronic widespread pain (HR 1.50, 95% CI 1.04-2.16, P -value = 0.032) and COVID-19 mortality. Chronic pain is associated with higher risk of hospitalisation for COVID-19, but the association with mortality is unclear. Future research is required to investigate these findings further and determine whether pain is associated with long COVID.

Spreading of Pain in Patients with Chronic Pain is Related to Pain Duration and Clinical Presentation and Weakly Associated with Outcomes of Interdisciplinary Pain Rehabilitation: A Cohort Study from the Swedish Quality Registry for Pain Rehabilitation (SQRP)

Introduction

The extent to which pain is distributed across the body (spreading of pain) differs largely among patients with chronic pain conditions and widespread pain has been linked to poor quality of life and work disability. A longer duration of pain is expected to be associated with more widespread pain, but studies are surprisingly scarce. Whether spreading of pain is associated with clinical presentation and treatment outcome in patients seen in interdisciplinary multimodal pain rehabilitation programs (IMMRPs) is unclear. The association between spreading of pain and (1) pain duration (2) clinical presentation (eg, pain intensity, pain-related cognitions, psychological distress, activity/participation aspects and quality of life) and (3) treatment outcome were examined.

Methods

Data from patients included in the Swedish Quality Registry for Pain Rehabilitation were used (n=39,916). A subset of patients that participated in IMMRPs (n=14,666) was used to examine whether spreading of pain at baseline predicted treatment outcome. Spreading of pain was registered using 36 predefined anatomical areas which were summarized and divided into four categories: 1–6 regions with pain (20.6% of patients), 7–12 regions (26.8%), 13–18 regions (22.0%) and 19–36 regions (30.6%).

Results

More widespread pain was associated with a longer pain duration and a more severe clinical picture at baseline with the strongest associations emerging in relation to health and pain aspects (pain intensity, pain interference and pain duration). Widespread pain was associated with a poorer overall treatment outcome following IMMRPs at both posttreatment and at a 12-month follow-up, but effect sizes were small.

Discussion

Spreading of pain is an indicator of the duration and severity of chronic pain and to a limited extent to outcomes of IMMRP. Longer pain duration in those with more widespread pain supports the concept of early intervention as clinically important and implies a need to develop and improve rehabilitation for patients with chronic widespread pain.

Patients with Concomitant Chronic Neck Pain and Myofascial Pain in Masticatory Muscles Have More Widespread Pain and Distal Hyperalgesia than Patients with Only Chronic Neck Pain

Objective

Insufficient evidence exists to compare widespread pain (WP), pain sensibility, and psychological factors that occur in patients presenting with chronic neck pain (CNP) or a combination of temporomandibular disorder (TMD) and other complaints. The present study compared the pain sensibility and psychological factors of subjects with CNP with those with TMD + CNP.

Design

Cross-sectional study.

Setting

Local community.

Subjects

A nonprobabilistic convenience sample of 86 persons with CNP or TMD was recruited into three groups: CNP, TMD with myofascial pain in masticatory muscles with cocomitant CNP (TMD + CNP), and asymptomatic control groups consisted of 27, 29, and 30 participants, respectively.

Methods

Participants underwent a clinical examination to evaluate WP with computerized assessment based on the pain drawing, pressure pain thresholds (PPT), and psychological factors, which were evaluated using the pain catastrophizing scale (PCS) and the state-trait anxiety inventory (STAI).

Results

Statistically significant differences were observed between participants with CNP and TMD + CNP for WP (t = -2.80, P  < 0.01, d = -1.06). Post hoc analyses only revealed significant differences between TMD + CNP participants and asymptomatic controls for PPT at extratrigeminal areas. Pearson correlation analyses showed a moderate positive association between symptomatic groups within the WP and STAI ( P  < 0.05) and a moderate negative association between PCS and PPT ( P  < 0.05) at the right tibialis muscle.

Conclusion

TMD + CNP participants had more areas of pain and also showed widespread pain hyperalgesia. Both groups of participants had psychological factors positively associated with STAI and WP; further, PCS and the PPT at the extratrigeminal region were negatively associated with each other in both groups, except for the left tibialis in the TMD + CNP group.

Widespread pain sensitization after partial infraorbital nerve transection in MRL/MPJ mice

Clinical studies show that chronic pain can spread to adjacent or even distant body regions in some patients. However, little is known about how this happens. In this study, we found that partial infraorbital nerve transection (p-IONX) in MRL/MPJ mice induced not only marked and long-lasting orofacial thermal hyperalgesia but also thermal hyperalgesia from day 3 postoperatively (PO) and tactile allodynia from day 7 PO in bilateral hind paws. Pain sensitization in the hind paw was negatively correlated with facial thermal hyperalgesia at early but not late stage after p-IONX. After a rapid activation of c-Fos, excitability and excitatory synaptic neurotransmission in lumbar dorsal horn neurons were elevated from day 3 and day 7 PO, respectively. In addition, microglial activation after p-IONX transmitted caudally from the Vc in the medulla to lumber dorsal horn in a time-dependent manner. Inhibition of microglial activation by minocycline at early but not late stage after p-IONX postponed and attenuated pain sensitization in the hind paw. These results indicate that neuropathic pain after p-IONX in MRL/MPJ mice spreads from the orofacial region to distant somatic regions and that a rostral-caudal transmission of central sensitization in the spinal cord is involved in the spreading process of pain hypersensitivity.

Multidisciplinary approaches to managing osteoarthritis in multiple joint sites: a systematic review

Background

The National Institute for Health and Care Excellence’s Osteoarthritis (OA) guidelines recommended that future research should consider the benefits of combination therapies in people with OA across multiple joint sites. However, the clinical effectiveness of such approaches to OA management is unknown. This systematic review therefore aimed to identify the clinical and cost effectiveness of multidisciplinary approaches targeting multiple joint sites for OA in primary care.

Methods

A systematic review of randomised controlled trials. Computerised bibliographic databases were searched (MEDLINE, EMBASE, CINAHL, PsychINFO, BNI, HBE, HMIC, AMED, Web of Science and Cochrane). Studies were included if they met the following criteria; a randomised controlled trial (RCT), a primary care population with OA across at least two different peripheral joint sites (multiple joint sites), and interventions undertaken by at least two different health disciplines (multidisciplinary). The Cochrane ‘Risk of Bias’ tool and PEDro were used for quality assessment of eligible studies. Clinical and cost effectiveness was determined by extracting and examining self-reported outcomes for pain, function, quality of life (QoL) and health care utilisation. The date range for the search was from database inception until August 2015.

Results

The search identified 1148 individual titles of which four were included in the review. A narrative review was conducted due to the heterogeneity of the included trials. Each of the four trials used either educational or exercise interventions facilitated by a range of different health disciplines. Moderate clinical benefits on pain, function and QoL were reported across the studies. The beneficial effects of exercise generally decreased over time within all studies. Two studies were able to show a reduction in healthcare utilisation due to a reduction in visits to a physiotherapist or a reduction in x-rays and orthopaedic referrals. The intervention that showed the most promise used educational interventions delivered by GPs with reinforcement by practice nurses.

Conclusions

There are currently very few studies that target multidisciplinary approaches suitable for OA across multiple joint sites, in primary care. A more consistent approach to outcome measurement in future studies of this nature should be considered to allow for better comparison.

Pain maps from facial pain patients indicate a broad pain geography

Two hundred consecutive female patients, who were referred to a university-based facial pain clinic, were asked to mark all painful sites on sketches showing the contours of a human body in the frontal and rear views. The drawings were analyzed with transparent templates containing 1875 (frontal view) and 1929 (rear view) square cells of equal size. The average patient scored 71.8 cells in the frontal and 99.7 cells in the rear view (corresponding to 3.8% and 5.2% of the maximum possible scores). In individual patient drawings, however, up to 42.7% and 44.9% of all cells were marked. Only 37 cases (18.5%) exhibited pain that was limited to the trigeminal system. An analysis of the pain distribution according to the arrangements of dermatomes revealed three distinct clusters of patients: (1) pain restricted to the region innervated by the trigeminal nerves (n = 37); (2) pain in the trigeminal dermatomes and any combination involving the spinal dermatomes C2, C3, and C4, but no other dermatomes (n = 32); and (3) pain sites involving dermatomes in addition to the ones listed above (n = 131). Mean ages in the three clusters were 38.7, 35.5, and 37.5 years, respectively (p = 0.62, n.s.). Widespread pain existed for longer durations (median, 48 months) than conditions involving local and regional pain (median, 24 months) (p = 0.02, s.). Our findings showed that among a great percentage of persistent facial pain patients the pain distribution is more widespread than commonly assumed, and that the persistence of pain in the regional and widespread pain presentations is significantly greater than in cases with pain limited to the trigeminal system.

Quantified pain drawing in subacute low back pain. Validation in a nonselected outpatient industrial sample

STUDY DESIGN

The criterion and construct validities of pain drawing, quantified by a simple total body area score of pain extent (area raw extent assessment score), were analyzed prospectively on consecutive patients (n = 103), drawn from a predefined blue collar worker population, all sick listed for 6 weeks as a result of low back pain.

OBJECTIVES

To evaluate the validity of pain drawing as a screening tool in the secondary prevention of subacute low back pain.

SUMMARY OF BACKGROUND DATA

Pain drawings have been used clinically for more than 40 years as a complement to a patient's verbal pain descriptions. The main objectives have been to differentiate functional pain from organic pain and to identify meaningful features in spatial-anatomic pain distribution. The ability of the pain drawing to delineate concurrent psychopathology correctly has been questioned. There is no consensus on which scoring method should be used.

METHODS

The area raw extent assessment score was analyzed concurrently against the penalty point system and predictively against return to work and absenteeism over a period of 2 years. Content and construct validity assessed the relative influence of medical, psychologic, and subjective disability as well as psychosocial factors.

RESULTS

Criterion validation of the area raw extent assessment score showed significant correlations, both concurrently against the penalty point score (r = 0.86, P < 0.001, with explained variance R2 = 0.75, P < 0.001) and predictively against occupational handicap (r = 0.48, P < 0.001). In construct validation, the highest explained variance was shown for medical (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.46, P < 0.001) and psychologic factors (R2 = 0.34, P < 0.001) and for subjective disability (R2 = 0.32, P < 0.001). Variance in the area raw extent assessment score also was explained by psychosocial factors (R2 = 0.19, P < 0.01).

CONCLUSIONS

Pain drawing quantification of the extent of pain shows high criterion and construct validity for the area raw extent assessment score. Content validity could be shown for significant clinical aspects of the disability experience--assets preferred for a screening tool in secondary prevention.

A method for scoring the pain map of the McGill Pain Questionnaire for use in epidemiologic studies

Identifying and quantifying the location of pain may be important for understanding specific functional impairments in elderly populations. The purpose of the present analysis was two-fold: first, to describe the reliability of a scoring method for the McGill Pain Map (MPM), and second, to validate the method of scoring the MPM as a tool for assessing areas of body pain in an epidemiologic study. In interviews performed at the subjects' homes, 411 community dwelling Mexican-American and non-Hispanic white subjects aged 65-74 from the San Antonio Longitudinal Study of Aging (SALSA) were asked to describe the location of their pain on the map of the human body included in the McGill Pain Questionnaire. The location of pain was scored by overlaying the survey figures with a MPM template divided into 36 anatomical areas. Inter- and intra-rater agreement among three raters was measured by calculating a kappa statistic for each of the body areas, and an intraclass correlation coefficient for the total number of painful areas (NPA). Internal validity was measured by Spearman's rho between the NPA and the Present Pain Index (PPI) and Pain Rating Index (PRI) of the McGill Pain Questionnaire, and external validity by correlation between NPA and the Perceived Health (PH), Amount of Bodily Pain (APB), and Pain Interference with Work (PIW) items of the Medical Outcomes Study, and the Perceived Physical Health (PPH) question of the San Antonio Heart Study. Average inter-rater agreement for individual MPM areas was 0.92 +/- 0.01, and average agreement for NPA was 0.96 +/- 0.01. Intra-rater agreement for individual areas averaged 0.94 +/- 0.01, and for NPA = 0.99 +/- 0.001. Pain in one or more areas was present in 47.7% of the subjects. For the whole sample, correlations between NPA and the validation indices were: PPI (0.91), PRI (0.89), PH (0.25), ABP (0.64), PIW (0.49), and PPH (0.20). Among the 196 subjects with pain, correlations were: PPI (0.34), PRI (0.34), PH (0.19), ABP (0.21), PIW (0.38), and PPH (0.19)-p < 0.01 for all correlations. In conclusion, we have developed a reliable method of scoring the MPM and have shown evidence of its validity in a community-based sample of elderly subjects. Patterns of painful body areas may be associated with specific diseases and functional impairments.

Extent measurement in localised low-back pain: a comparison of four methods

Seventeen drawings of localised low-back pain were analysed by two assessors using 4 systems. Three were grid-based systems and one was by computer. The mean area or 'extent' was calculated to be 7.7%, 4.7%, 3.6% and 2.3% of the body outline using 45, 200, 560 and 61,102 section analyses, respectively. The computer-assisted method provided a significantly lower estimate of pain extent than the grid-based assessments as expected. Analysis of variance showed that the method of analysis provided greater source of variation than raters (P < 0.0001). Inter-rater reliability was high using all 4 systems calculated using intraclass correlation and the kappa statistic. Correlation coefficients of extent between the systems varied from 0.46 to 0.94. Correlation was highest between systems of adjacent magnitude of sections. It is concluded that grid-based assessment of small areas overestimates the actual area of pain and this may account for the lack of sensitivity to change in clinical status.

Assessment and measurement of pain

This paper provides an overview of issues relating to pain assessment and management. Areas to be covered include the problems involved in assessing pain as a subjective phenomenon, the constraints of assessment within the clinical field, factors that affect pain, and pain assessment tools and questionnaires. The aim of the reference list is to provide back-up reading to assist in exploring the options available when considering the possibility of compiling a pain assessment protocol for individual clinical areas.

Automated 'pain drawing' analysis by computer-controlled, patient-interactive neurological stimulation system

We have developed a new method for the collection and analysis of pain drawings, as part of a computer-controlled, patient-interactive system for use with implanted neurological stimulators. The system has been tested in 44 patients with permanently implanted spinal cord stimulators for the relief of chronic, intractable pain. Patients interact directly with the system, using a graphics tablet, to enter pain drawings and corresponding outlines of their perceptions of stimulation paresthesias, for different stimulating pulse parameters and electrode geometries. Image analysis software has been developed to examine these data quantitatively. This precludes the inter-rater inconsistencies reported for manual pain drawing scoring techniques. A highly significant correlation has been observed between patients' analog ratings of the overlap of pain by paresthesias and the results of our automated analysis of graphic data. This in turn has been found to correlate with clinical observations of pain relief. The contemporary implantable stimulation devices supported by our system permit non-invasive selection of stimulating anodes and cathodes from a linear array of 4 electrodes. The 50 possible electrode combinations have certain geometric features, which we have entered into a multivariate statistical analysis, to determine their relationship with the overlap of pain by paresthesias. One particular configuration (cathode(s) flanked by anode(s) above and below) is significantly better, by this measure, than all the alternatives. This is consistent with prior clinical observations that this configuration is favored by patients whose systems have been adjusted by conventional, manual methods. Pain drawing' entry and analysis by a computerized, patient-interactive system has been useful in this specialized setting and may have broader applications.