Pain Reports最新文献

{"title":"Characterizing <i>OPRM1</i> DNA methylation in prescription opioid users with chronic musculoskeletal pain.","authors":"Sophia Sheikh,&nbsp;Carmen Smotherman,&nbsp;Monika Patel,&nbsp;Taimour Langaee,&nbsp;Danxin Wang,&nbsp;Edward Swaray,&nbsp;Esteban Velasquez,&nbsp;Siegfried O F Schmidt,&nbsp;Phyllis Hendry,&nbsp;Larisa H Cavallari,&nbsp;Roger B Fillingim","doi":"10.1097/PR9.0000000000001046","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001046","url":null,"abstract":"<p><strong>Introduction: </strong>Many patients with chronic pain use prescription opioids. Epigenetic modification of the μ-opioid receptor 1 (<i>OPRM1</i>) gene, which codes for the target protein of opioids, may influence vulnerability to opioid abuse and response to opioid pharmacotherapy, potentially affecting pain outcomes.</p><p><strong>Objective: </strong>Our objective was to investigate associations of clinical and sociodemographic factors with <i>OPRM1</i> DNA methylation in patients with chronic musculoskeletal pain on long-term prescription opioids.</p><p><strong>Methods: </strong>Sociodemographic variables, survey data (Rapid Estimate of Adult Health Literacy in Medicine-Short Form, Functional Comorbidity Index [FCI], PROMIS 43v2.1 Profile, Opioid Risk Tool, and PROMIS Prescription Pain Medication Misuse), and saliva samples were collected. The genomic DNA extracted from saliva samples were bisulfite converted, amplified by polymerase chain reaction, and processed for <i>OPRM1</i>-targeted DNA methylation analysis on a Pyrosequencing instrument (Qiagen Inc, Valencia, CA). General linear models were used to examine the relationships between the predictors and <i>OPRM1</i> DNA methylation.</p><p><strong>Results: </strong>Data from 112 patients were analyzed. The best-fitted multivariable model indicated, compared with their counterparts, patients with > eighth grade reading level, degenerative disk disease, substance abuse comorbidity, and opioid use < 1 year (compared with >5 years), had average methylation levels that were 7.7% (95% confidence interval [CI] 0.95%, 14.4%), 11.7% (95% CI 2.7%, 21.1%), 21.7% (95% CI 10.7%, 32.5%), and 16.1% (95% CI 3.3%, 28.8%) higher than the reference groups, respectively. Methylation levels were 2.2% (95% CI 0.64%, 3.7%) lower for every 1 unit increase in FCI and greater by 0.45% (95% CI 0.08%, 0.82%) for every fatigue T score unit increase.</p><p><strong>Conclusions: </strong><i>OPRM1</i> methylation levels varied by several patient factors. Further studies are warranted to replicate these findings and determine potential clinical utility.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/bd/99/painreports-7-e1046.PMC9699511.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10634896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electroencephalographic characteristics of children and adolescents with chronic musculoskeletal pain.","authors":"Don Daniel Ocay,&nbsp;Elizabeth F Teel,&nbsp;Owen D Luo,&nbsp;Chloé Savignac,&nbsp;Yacine Mahdid,&nbsp;Stefanie Blain-Moraes,&nbsp;Catherine E Ferland","doi":"10.1097/PR9.0000000000001054","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001054","url":null,"abstract":"<p><strong>Introduction: </strong>The pathophysiology of pediatric musculoskeletal (MSK) pain is unclear, contributing to persistent challenges to its management.</p><p><strong>Objectives: </strong>This study hypothesizes that children and adolescents with chronic MSK pain (CPs) will show differences in electroencephalography (EEG) features at rest and during thermal pain modalities when compared with age-matched controls.</p><p><strong>Methods: </strong>One hundred forty-two CP patients and 45 age-matched healthy controls (HCs) underwent a standardized thermal tonic heat and cold stimulations, while a 21-electrode headset collected EEG data. Cohorts were compared with respect to their EEG features of spectral power, peak frequency, permutation entropy, weight phase-lag index, directed phase-lag index, and node degree at 4 frequency bands, namely, delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz), at rest and during the thermal conditions.</p><p><strong>Results: </strong>At rest, CPs showed increased global delta (<i>P</i> = 0.0493) and beta (<i>P</i> = 0.0002) power in comparison with HCs. These findings provide further impetus for the investigation and prevention of long-lasting developmental sequalae of early life chronic pain processes. Although no cohort differences in pain intensity scores were found during the thermal pain modalities, CPs and HCs showed significant difference in changes in EEG spectral power, peak frequency, permutation entropy, and network functional connectivity at specific frequency bands (<i>P</i> < 0.05) during the tonic heat and cold stimulations.</p><p><strong>Conclusion: </strong>This suggests that EEG can characterize subtle differences in heat and cold pain sensitivity in CPs. The complementation of EEG and evoked pain in the clinical assessment of pediatric chronic MSK pain can better detect underlying pain mechanisms and changes in pain sensitivity.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788982/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10489755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distraction from pain depends on task demands and motivation.","authors":"Todd A Vogel,&nbsp;Carl F Falk,&nbsp;A Ross Otto,&nbsp;Mathieu Roy","doi":"10.1097/PR9.0000000000001041","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001041","url":null,"abstract":"<p><strong>Introduction: </strong>Pain captures attention automatically, yet we can inhibit pain when we are motivated to perform other tasks. Previous studies show that engaging in a cognitively demanding task reduces pain compared with a task that is minimally demanding, yet the effects of motivation on this pain-reducing effect remain largely unexplored.</p><p><strong>Objectives: </strong>In this study, we hypothesized that motivating people to engage in a task with high demands would lead to more cognitive resources directed toward the task, thereby amplifying its pain-reducing effects.</p><p><strong>Methods: </strong>On different trials, participants performed an easy (left-right arrow discrimination) or demanding (2-back) cognitive task while receiving nonpainful or painful heat stimuli. In half of the trials, monetary rewards were offered to motivate participants to engage and perform well in the task.</p><p><strong>Results: </strong>Results showed an interaction between task demands and rewards, whereby offering rewards strengthened the pain-reducing effect of a distracting task when demands were high. This effect was reinforced by increased 2-back performance when rewards were offered, indicating that both task demands and motivation are necessary to inhibit pain.</p><p><strong>Conclusions: </strong>When task demands are low, motivation to engage in the task will have little impact on pain because performance cannot further increase. When motivation is low, participants will spend minimal effort to perform well in the task, thus hindering the pain-reducing effects of higher task demands. These findings suggest that the pain-reducing properties of distraction can be optimized by carefully calibrating the demands and motivational value of the task.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9612955/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40439090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sex-related differences in experimental pain sensitivity in subjects with painful or painless neuropathy after surgical repair of traumatic nerve injuries","authors":"A. Miclescu, Panagiota Gkatziani, Pontus Granlund, Stephen Butler, T. Gordh","doi":"10.1097/PR9.0000000000001033","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001033","url":null,"abstract":"Higher pain intensities at all experimental stimuli but a tendency to faster recovery after cold conditioning stimuli were seen in women with neuropathy in comparison with men. Abstract Introduction: Sex-related influences represent a contributor to greater pain sensitivity and have a higher prevalence of many chronic pain conditions, including neuropathic pain (NP), among women. Objectives: The aim was to analyze how differences in ongoing pain, experimental pain intensity, and conditioned pain modulation (CPM) relate to sex in subjects with neuropathy after traumatic nerve injuries. Methods: Endogenous pain modulation was compared between male (n = 77) and female (n = 55) subjects and between subjects with NP (female = 31, male = 39) and pain-free subjects with posttraumatic neuropathy (female = 24, male = 38). Conditioned pain modulation was assessed by pain ratings to pressure stimuli before and after a noxious conditioning stimulus (CS) conducted with one arm submerged in cold water (4°C) for 1 minute. Time of recovery (Time off) of pain intensity from peak VASmaxc after CS was recorded and compared between male and female patients. Results: Greater ongoing pain intensity was found among female patients compared with male patients and more experimental pain after pressure and cold induced pain. Summing all groups together, women had 0.8 times higher odds (20%) of recovering sooner than men after CS (95% CI = 0.65–2.9). No differences in CPM, time off, and psychosocial variables were seen between female and male patients (P < 0.05). Conclusion: Our hypothesis for sex differences in endogenous pain modulation was only supported by a shorter after-sensation time after cold CS in female patients. No sex differences in the magnitude of CPM effect were identified. Increased pain intensity for experimental pain, in both neuropathic pain and neuropathy without pain, was found in female patients.","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46933484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of stimulation area and temperature rates on offset analgesia","authors":"T. Szikszay, Nina Melz, Barbara von Glasenapp, W. Adamczyk, K. Luedtke","doi":"10.1097/PR9.0000000000001043","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001043","url":null,"abstract":"Supplemental Digital Content is Available in the Text. Two consecutive experiments showed that not the temperature rates but the area of stimulation mediates offset analgesia. Abstract Introduction: Offset analgesia describes the effect of a slightly reduced nociceptive stimulus, resulting in a disproportionate large reduction in the pain perception. This effect may be associated with descending pain inhibition, but parameters influencing this phenomenon are poorly understood. Objectives: In this study, 2 separate experiments were conducted to investigate both, the spatial aspects of offset analgesia and the influence of different rates of temperature rise. Methods: In both experiments, 29 healthy participants received individualized and heat-based offset analgesia paradigms applied to the forearm, with continuous assessment of pain intensity. In experiment 1, offset analgesia paradigms with 3 different rates of temperature rise were applied, whereas in experiment 2, offset analgesia paradigms with 2 different heat application areas were used. Results: The results of experiment 1 showed that different temperature rates had no effect on the offset analgesia response (P > 0.05). Experiment 2, however, showed the influence of the size of a stimulated area on offset analgesia (P = 0.009), which can be explained mainly by the influence of spatial summation of pain and habituation processes. Conclusions: The study showed a lack of influence of different temperature rates on offset analgesia; however, spatial aspects of offset analgesia could be identified. These are most likely based on spatial summation of pain and altered adaptation to pain.","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45600174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relief of chronic pain associated with increase in midline frontal theta power.","authors":"Nabi Rustamov,&nbsp;Elizabeth A Wilson,&nbsp;Alexandra E Fogarty,&nbsp;Lara W Crock,&nbsp;Eric C Leuthardt,&nbsp;Simon Haroutounian","doi":"10.1097/PR9.0000000000001040","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001040","url":null,"abstract":"<p><strong>Introduction: </strong>There is a need to identify objective cortical electrophysiological correlates for pain relief that could potentially contribute to a better pain management. However, the field of developing brain biomarkers for pain relief is still largely underexplored.</p><p><strong>Objectives: </strong>The objective of this study was to investigate cortical electrophysiological correlates associated with relief from chronic pain. Those features of pain relief could serve as potential targets for novel therapeutic interventions to treat pain.</p><p><strong>Methods: </strong>In 12 patients with chronic pain in the upper or lower extremity undergoing a clinically indicated nerve block procedure, brain activity was recorded by means of electroencephalogram before and 30 minutes after the nerve block procedure. To determine the specific cortical electrophysiological correlates of relief from chronic pain, 12 healthy participants undergoing cold-pressor test to induce experimental acute pain were used as a control group. The data were analyzed to characterize power spectral density patterns of pain relief and identify their source generators at cortical level.</p><p><strong>Results: </strong>Chronic pain relief was associated with significant delta, theta, and alpha power increase at the frontal area. However, only midfrontal theta power increase showed significant positive correlation with magnitude of reduction in pain intensity. The sources of theta power rebound were located in the left dorsolateral prefrontal cortex (DLPFC) and midline frontal cortex. Furthermore, theta power increase in the midline frontal cortex was significantly higher with chronic vs acute pain relief.</p><p><strong>Conclusion: </strong>These findings may provide basis for targeting chronic pain relief via modulation of the midline frontal theta oscillations.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9555895/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33515104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The power of integrating data: advancing pain research using meta-analysis.","authors":"Joel Fundaun, Elizabeth T Thomas, Annina B Schmid, Georgios Baskozos","doi":"10.1097/PR9.0000000000001038","DOIUrl":"10.1097/PR9.0000000000001038","url":null,"abstract":"<p><p>Publications related to pain research have increased significantly in recent years. The abundance of new evidence creates challenges staying up to date with the latest information. A comprehensive understanding of the literature is important for both clinicians and investigators involved in pain research. One commonly used method to combine and analyse data in health care research is meta-analysis. The primary aim of a meta-analysis is to quantitatively synthesise the results of multiple studies focused on the same research question. Meta-analysis is a powerful tool that can be used to advance pain research. However, there are inherent challenges when combining data from multiple sources. There are also numerous models and statistical considerations when undertaking a meta-analysis. This review aims to discuss the planning and preparation for completing a meta-analysis, review commonly used meta-analysis models, and evaluate the clinical implications of meta-analysis in pain research.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534369/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9477437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preliminary study: quantification of chronic pain from physiological data.","authors":"Zhuowei Cheng,&nbsp;Franklin Ly,&nbsp;Tyler Santander,&nbsp;Elyes Turki,&nbsp;Yun Zhao,&nbsp;Jamie Yoo,&nbsp;Kian Lonergan,&nbsp;Jordan Gray,&nbsp;Christopher H Li,&nbsp;Henry Yang,&nbsp;Michael Miller,&nbsp;Paul Hansma,&nbsp;Linda Petzold","doi":"10.1097/PR9.0000000000001039","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001039","url":null,"abstract":"<p><strong>Introduction: </strong>It is unknown if physiological changes associated with chronic pain could be measured with inexpensive physiological sensors. Recently, acute pain and laboratory-induced pain have been quantified with physiological sensors.</p><p><strong>Objectives: </strong>To investigate the extent to which chronic pain can be quantified with physiological sensors.</p><p><strong>Methods: </strong>Data were collected from chronic pain sufferers who subjectively rated their pain on a 0 to 10 visual analogue scale, using our recently developed pain meter. Physiological variables, including pulse, temperature, and motion signals, were measured at head, neck, wrist, and finger with multiple sensors. To quantify pain, features were first extracted from 10-second windows. Linear models with recursive feature elimination were fit for each subject. A random forest regression model was used for pain score prediction for the population-level model.</p><p><strong>Results: </strong>Predictive performance was assessed using leave-one-recording-out cross-validation and nonparametric permutation testing. For individual-level models, 5 of 12 subjects yielded intraclass correlation coefficients between actual and predicted pain scores of 0.46 to 0.75. For the population-level model, the random forest method yielded an intraclass correlation coefficient of 0.58. Bland-Altman analysis shows that our model tends to overestimate the lower end of the pain scores and underestimate the higher end.</p><p><strong>Conclusion: </strong>This is the first demonstration that physiological data can be correlated with chronic pain, both for individuals and populations. Further research and more extensive data will be required to assess whether this approach could be used as a \"chronic pain meter\" to assess the level of chronic pain in patients.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534370/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33496494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fibromyalgia in women: association of inflammatory plasma proteins, muscle blood flow, and metabolism with body mass index and pain characteristics.","authors":"Bijar Ghafouri,&nbsp;Emelie Edman,&nbsp;Marie Löf,&nbsp;Eva Lund,&nbsp;Olof Dahlqvist Leinhard,&nbsp;Peter Lundberg,&nbsp;Mikael Fredrik Forsgren,&nbsp;Björn Gerdle,&nbsp;Huan-Ji Dong","doi":"10.1097/PR9.0000000000001042","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001042","url":null,"abstract":"<p><strong>Introduction: </strong>Obesity is a common comorbidity in fibromyalgia (FM). Both FM and obesity have been connected to low-grade inflammation, although it is possible that previously reported inflammatory alterations in FM primarily may be linked to increased body mass index (BMI).</p><p><strong>Objective: </strong>This study aimed to investigate whether the inflammatory plasma protein profile, muscle blood flow, and metabolism and pain characteristics (clinical parameters and patient-reported outcome measurements) differed between female patients with FM with and without obesity.</p><p><strong>Methods: </strong>Patients with FM underwent clinical examinations, physical tests, and answered questionnaires. They were dichotomized according to BMI (<30 kg/m² [n = 14]; ≥30 kg/m² [n = 13]). Blood samples were collected and analyzed using a panel of 71 inflammatory plasma proteins.</p><p><strong>Results: </strong>There were significant (<i>P</i> < 0.05) differences in blood pressure, pulse, max VO2, pain intensity, physical capacity, and Fibromyalgia Impact Questionnaire between the groups; the obese group had higher blood pressure, pulse, pain intensity, and Fibromyalgia Impact Questionnaire. There were 14 proteins that contributed to the group belonging. The 4 most important proteins for the group discrimination were MIP1β, MCP4, IL1RA, and IL6, which showed higher concentrations in obese patients with FM. Significantly decreased blood flow and increased concentration of pyruvate were detected in obese patients compared with nonobese patients. There was significant correlation between inflammatory proteins and sedentary behavior and health status in obese patients with FM.</p><p><strong>Conclusions: </strong>These findings suggest that metabolism and inflammation interact in female patients with FM with obesity and might cause chronic low-grade inflammation. Screening for obesity and monitoring of BMI changes should be considered in the treatment of patients with FM.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534367/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33496991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clusters of facilitatory and inhibitory conditioned pain modulation responses in a large sample of children, adolescents, and young adults with chronic pain.","authors":"Don Daniel Ocay,&nbsp;Diana-Luk Ye,&nbsp;Cynthia L Larche,&nbsp;Stéphane Potvin,&nbsp;Serge Marchand,&nbsp;Catherine E Ferland","doi":"10.1097/PR9.0000000000001032","DOIUrl":"https://doi.org/10.1097/PR9.0000000000001032","url":null,"abstract":"<p><strong>Introduction: </strong>When investigating the role of facilitatory and inhibitory pain mechanisms such as conditioned pain modulation (CPM) and temporal summation of pain (TSP), it is important to take both into consideration in a single experimental model to provide the most information on subgroups of patients. Therefore, the objective of this study was to identify subgroups in a large population of pediatric patients with chronic pain based on their facilitatory and inhibitory pain mechanisms and compare them with control subjects.</p><p><strong>Methods: </strong>Five hundred twenty-one female subjects and 147 male subjects between 8 and 21 years old underwent a CPM assessment using a 2-minute tonic noxious heat stimulation as the test stimulus and a 2-minute cold-pressor task (CPT) (12°C) as the conditioning stimulus.</p><p><strong>Results: </strong>The best partition of clusters of patients was 3 clusters accounting for 27.15% of the total variation in the data. Cluster 1 (n = 271) was best characterized by high pain intensity during the CPT, lack of TSP during the test stimuli, and efficient inhibitory CPM. Cluster 2 (n = 186) was best characterized by low pain intensity during the CPT, lack of TSP during the test stimuli, and efficient inhibitory CPM. Cluster 3 (n = 151) was best characterized by high pain intensity during the CPT, presence of TSP during the test stimuli, and inefficient inhibitory CPM.</p><p><strong>Discussion: </strong>A single thermal CPM experimental design can identify combinations of facilitatory and inhibitory pain modulation responses. Findings from the current study add to the literature by describing different clinical phenotypes of central pain mechanisms of youth with chronic pain.</p>","PeriodicalId":52189,"journal":{"name":"Pain Reports","volume":null,"pages":null},"PeriodicalIF":4.8,"publicationDate":"2022-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9534368/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33496492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}