Quantitative Sensory Testing Measures Research Articles

Non-obese lipedema patients show a distinctly altered quantitative sensory testing profile with high diagnostic potential.

Lipedema is a widespread severe chronic disease affecting mostly women. Characterized by painful bilateral fat accumulation in extremities sparing hands and feet, objective measurement-based diagnosis is currently missing. We tested for characteristic psychometric and/or sensory alterations including pain and for their potential for medical routine diagnosis. Pain psychometry was assessed using the German Pain Questionnaire. Sensory sensitivity toward painful and nonpainful stimuli was characterized in non-obese lipedema patients and matched controls using the validated quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain. Lipedema patients showed no overt psychometric abnormalities. Pain was reported as somatic rather than psychosomatic aversive. All QST measurements were normal, but the z-score of pressure pain thresholds (PPT) was twofold reduced and the z-score of vibration detection thresholds (VDT) was two and a half times increased. Both thresholds were selectively altered at the affected thigh but not the unaffected hand. Receiver operating characteristic analysis of the combination of PPT and VDT of thigh vs hand into a PVTH score (PPT, VDT, thigh, hand-score) shows high sensitivity and specificity, categorizing correctly 95.8% of the participants as lipedema patients or healthy controls. Bayesian inference analysis corroborated the diagnostic potential of such a combined PVTH score. We propose to assess PPT and VDT at the painful thigh and the pain-free hand. Combination in a PVTH score may allow a convenient lipedema diagnosis early during disease development.

Assessing the effects of distinct biologic therapies on rheumatoid arthritis pain by nociceptive, neuropathic and nociplastic pain components: a randomised feasibility study

BackgroundPain management is a major unmet need in people with rheumatoid arthritis (RA). Although many patients are treated with disease modifying anti-rheumatic drugs (DMARDS), including biologic therapies, many people with RA continue to experience significant pain. We aimed to determine whether performing a comprehensive pain evaluation is feasible in people with active RA receiving conventional DMARDs and biologic therapies.MethodsThe BIORA-PAIN feasibility study was an open-label, randomised trial, which recruited participants suitable for treatment with biologic therapy. The primary feasibility outcomes were recruitment, randomisation and retention of eligible participants. All participants underwent pain assessment for nociceptive, neuropathic and nociplastic pain during the 12-month study period, with quarterly assessments for VAS (Visual Analogue Scale) pain, painDETECT and QST (quantitative sensory testing). This trial was registered in clinicaltrials.gov NCT04255134.ResultsDuring the study period, 93 participants were screened of whom 25 were eligible: 13 were randomised to adalimumab and 12 to abatacept. Participant recruitment was lower than expected due to the COVID-19 pandemic. Pain assessments were practical in the clinical trial setting. An improvement was observed for VAS pain from baseline over 12 months, with a mean (SEM) of 3.7 (0.82) in the abatacept group and 2.3 (1.1) in the adalimumab group. There was a reduction in painDETECT and improvement in QST measures in both treatment groups during the study. Participant feedback included that some of the questionnaire-based pain assessments were lengthy and overlapped in their content. Adverse events were similar in both groups. There was one death due to COVID-19.ConclusionsThis first-ever feasibility study of a randomised controlled trial assessing distinct modalities of pain in RA met its progression criteria. This study demonstrates that it is feasible to recruit and assess participants with active RA for specific modalities of pain, including nociceptive, neuropathic and nociplastic elements. Our data suggests that it is possible to stratify people for RA based on pain features. The differences in pain outcomes between abatacept and adalimumab treated groups warrant further investigation.Trial registrationNCT04255134, Registered on Feb 5, 2020.

The effects of neck exercise in comparison to passive or no intervention on quantitative sensory testing measurements in adults with chronic neck pain: A systematic review.

Previous systematic reviews have identified the benefits of exercise for chronic neck pain on subjective reports of pain, but not with objective measures such as quantitative sensory testing (QST). A systematic review was conducted to identify the effects of neck specific exercise on QST measures in adults with chronic neck pain to synthesise existing literature and provide clinical recommendations. The study protocol was registered prospectively with PROSPERO (PROSPERO CRD42021297383). For both randomised and non-randomised trials, the following databases and trial registries were searched: AMED, CINAHL, Embase, Google Scholar, Medline, PEDro, PubMed, Scopus, SPORTDiscus, Science Citation Index and Social Science Citation Index from Web of Science Core Collection, clinicaltrials.gov, GreyOpen, and ISRCTN registry. These searches were conducted from inception to February 2022 and were updated until September 2023. Reference lists of eligible studies were screened. Study selection was performed independently by two reviewers, with data extraction and quality appraisal completed by one reviewer and independently ratified by a second reviewer. Due to high heterogeneity, narrative synthesis was performed with results grouped by exercise type. Three trials were included. Risk of bias was rated as moderate and the certainty of evidence as low or moderate for all studies. All exercise groups demonstrated statistically significant improvement at an intermediate-term follow-up, with progressive resistance training combined with graded physical training demonstrating the highest certainty of evidence. Fixed resistance training demonstrated statistically significant improvement in QST measures at a short-term assessment. Fixed resistance training is effective for short-term changes in pain sensitivity based on low-quality evidence, whilst moderate-quality evidence supports progressive resistance training combined with graded physical training for intermediate-term changes in pain sensitivity.

The Impact of Music Perception on Quantitative Sensory Testing (QST).

Objective: The impact of listening to music on pain perception has been evaluated using questionnaires and numeric/visual analogue scales. In this study, the impact of music perception on sensory pain functions was measured by means of quantitative sensory testing. Methods: We enrolled 10 female and 10 male healthy subjects (10 of them were professional musicians). All subjects underwent, in total, four quantitative sensory testing measures (first: baseline; second: after pleasant music [Johannes Brahms, 3rd symphony, 3rd movement]; third: after unpleasant music [Krzysztof Penderecki, Threnos]; fourth: after a longer break). The pleasantness of music was evaluated using the Ertel differential scale. Results: After the participants listened to pleasant music, an increased sensitivity to cold stimuli (both threshold and pain), to mechanical stimuli (only for threshold), and to repeated stimuli (wind-up reaction) was noted. Listening to unpleasant music was not associated with changes in sensitivity. We did not observe any significant differences between male and female subjects or between musicians and non-musicians. There was no significant correlation between the rating of the music as pleasant/unpleasant and the different quantitative sensory testing measures. Conclusions: Our data show that listening to music inducing a pleasant feeling can increase the sensitivity to stimuli applied during a quantitative sensory testing session. This should be considered when performing or interpreting quantitative sensory testing examinations. Interestingly, this finding is in contrast to the observation that listening to music can decrease pain perception during painful procedures.

Pain Catastrophizing Moderates the Relationship Between Pain Sensitivity and Clinical Pain in Adolescents With Functional Abdominal Pain

Pain catastrophizing has been linked to amplified pain sensitivity assessed using quantitative sensory testing (QST) in adults; pediatric data are limited, particularly in youth with functional abdominal pain (FAP). With increasing use of QST to evaluate somatosensory function and predict pain outcomes, we examined the associations between QST and clinical pain in adolescents with FAP and tested the moderating effects of pain catastrophizing. Seventy-seven adolescents (mean age 16.6 years, 85.7% female, 72.7% White, 90.8% non-Hispanic) who fulfilled diagnostic criteria for FAP completed QST assessment (pressure pain threshold and tolerance, heat pain threshold, conditioned pain modulation) and measures of abdominal pain intensity, pain interference, and pain catastrophizing. Adjusting for age and sex, only higher heat pain threshold was associated with higher abdominal pain intensity (Beta per 1-standard deviation = .54, P = .026). Contrary to hypothesis, for youth with higher pain catastrophizing, higher pressure pain tolerance was associated with greater abdominal pain intensity, but associations were not significant for youth with lower catastrophizing (P = .049). Similarly, for those with higher pain catastrophizing (in contrast to lower pain catastrophizing), higher pressure pain thresholds and tolerance were associated with higher pain interference (P = .039, .004, respectively). Results highlight the need to investigate the influence of pain catastrophizing on QST. PerspectiveThis study demonstrated unexpected findings of pain catastrophizing moderating the relationships between pressure pain threshold and tolerance, and clinical pain in adolescents with FAP. This raised questions regarding our understanding of psychological contributions to QST findings in pediatric populations with chronic pain.

Biobehavioral Predictors of Pain Intensity, Pain Interference, and Chronic Pain Episodes: A Prospective Cohort Study of African-American Adults

Racial disparities in pain experiences are well-established, with African-American (AA) adults reporting higher rates of daily pain, increased pain severity, and greater pain-related interference compared to non-Hispanic Whites. However, the biobehavioral factors that predict the transition to chronic pain among AA adults are not well understood. This prospective cohort study provided a unique opportunity to evaluate predictors of chronic pain onset among 130 AA adults (81 women), ages 18 to 44, who did not report chronic pain at their baseline assessment and subsequently completed follow-up assessments at 6- and 12-months. Outcome measures included pain intensity, pain-related interference, and chronic pain status. Comprehensive assessments of sociodemographic and biobehavioral factors were used to evaluate demographics, socioeconomic status, stress exposure, psychosocial factors, prolonged hypothalamic-pituitary-adrenal secretion, and quantitative sensory testing responses. At baseline, 30 adults (23.1%) reported a history of prior chronic pain. Over the 12-month follow-up period, 13 adults (10.0%) developed a new chronic pain episode, and 18 adults (13.8%) developed a recurrent chronic pain episode. Whereas socioeconomic status measures (ie, annual income, education) predicted changes in pain intensity over the follow-up period, quantitative sensory testing measures (ie, pain threshold, temporal summation of pain) predicted changes in pain interference. A history of chronic pain and higher depressive symptoms at baseline independently predicted the onset of a new chronic pain episode. The present findings highlight distinct subsets of biobehavioral factors that are differentially associated with trajectories of pain intensity, pain-related interference, and onset of chronic pain episodes in AA adults. PerspectiveThis prospective study sought to advance understanding of biobehavioral factors that predicted pain outcomes over a 12-month follow-up period among AA adults without chronic pain at their initial assessment. Findings revealed distinct subsets of factors that were differentially associated with pain intensity, pain-related interference, and onset of chronic pain episodes.

The relationship of behavioral and psychological traits with pain sensitivity in females with patellofemoral pain: A cross-sectional study

ObjectiveThe purpose of this study was to describe the relationship between behavioral and psychological traits with indicators of central sensitization in female runners with patellofemoral pain (PFP), and to determine if behavioral and psychological traits improve with strength training. DesignCross-sectional study. SettingUniversity laboratory. ParticipantsTwenty-eight active females (mean age 32 ± 8.1 years) with PFP completed testing at baseline, 8 weeks (post intervention), and 12 weeks. Main outcome measuresBehavioral and psychological questionnaires included the General Anxiety Disorder-7, Patient Health Questionairre-9, Pain Catastrophizing Scale, Tampa Scale of Kinesiophobia-11, and Central Sensitization Inventory. Quantitative sensory testing (QST) measures were also collected. After baseline testing, subjects were instructed in a hip and knee strengthening intervention to be completed twice daily over 8 weeks. ResultsA statistically significant improvement was found at 12 weeks for anxiety (p = .015; ηp (Boling et al., 2010) = 0.099) and kinesiophobia (p = .041; ηp (Boling et al., 2010) = 0.076). There was no significant improvement for depression, catastrophizing, or subjective central sensitization. No significant correlations were found between any of the behavioral and psychological questionnaires with baseline QST variables. ConclusionsNo relationship was found for behavioral and psychological characteristics with QST measures in female runners with persistent PFP.

Sensory phenotypes in complex regional pain syndrome and chronic low back pain-indication of common underlying pathomechanisms.

First-line pain treatment is unsatisfactory in more than 50% of chronic pain patients, likely because of the heterogeneity of mechanisms underlying pain chronification. This cross-sectional study aimed to better understand pathomechanisms across different chronic pain cohorts, regardless of their diagnoses, by identifying distinct sensory phenotypes through a cluster analysis. We recruited 81 chronic pain patients and 63 age-matched and sex-matched healthy controls (HC). Two distinct chronic pain cohorts were recruited, ie, complex regional pain syndrome (N = 20) and low back pain (N = 61). Quantitative sensory testing (QST) was performed in the most painful body area to investigate somatosensory changes related to clinical pain. Furthermore, QST was conducted in a pain-free area to identify remote sensory alterations, indicating more widespread changes in somatosensory processing. Two clusters were identified based on the QST measures in the painful area, which did not represent the 2 distinct pain diagnoses but contained patients from both cohorts. Cluster 1 showed increased pain sensitivities in the painful and control area, indicating central sensitization as a potential pathomechanism. Cluster 2 showed a similar sensory profile as HC in both tested areas. Hence, either QST was not sensitive enough and more objective measures are needed to detect sensitization within the nociceptive neuraxis or cluster 2 may not have pain primarily because of sensitization, but other factors such as psychosocial ones are involved. These findings support the notion of shared pathomechanisms irrespective of the pain diagnosis. Conversely, different mechanisms might contribute to the pain of patients with the same diagnosis.

Quantitative somatosensory testing of the abdomen: establishing initial reference values across developmental age and biological sex.

Abdominal pain is a common symptom of several debilitating conditions (eg, inflammatory bowel disease, irritable bowel syndrome, and endometriosis) and affects individuals throughout their lifespan. Quantitative sensory testing (QST) reference values exist for many body sites but not the abdomen. Using a QST battery adapted from the German Research Network on Neuropathic Pain, we collected QST data on the upper and lower abdomen in 181 pain-free participants, ages 12 to 50 years, to establish reference values by age and biological sex. The normative values are presented as medians for each QST measure by sex (male, n = 63; female, n = 118) and across 3 age categories (adolescents: 12-19 years, n = 48; young adults: 20-30 years, n = 87; and adults: 31-50 years, n = 46). Evaluating the sensory functioning of the abdomen and characterizing ranges of QST measures is an essential first step in understanding and monitoring the clinical course of sensory abnormalities in patients with underlying diseases affecting the abdomen and pelvis. The impact of age and development on sensory functioning is necessary, given age-related changes in pain perception and modulation.

Age-, gender- and body site-specific reference values of thermal Quantitative Sensory Testing in the Italian population using the Q-sense device

BackgroundAge-, gender- and body site-specific values of thermal Quantitative Sensory Testing (QST) measures have not yet been reported using the novel and cheap device ‘Q-sense’. Here, we aimed to assess normative values of Q-sense-derived parameters in a representative Italian population.MethodsQST parameters were measured in 84 healthy participants (42 males; aged 20–76 years) equally distributed into three age groups (18–39, 40–59 and 60–80 years). We explored the Warm and the Cold Detection Thresholds (WDT and CDT, respectively) with the method of limits (MLI) and the method of levels (MLE), and the Heat Pain Threshold (HPT) with the MLI. We tested the trigeminal supraorbital region, the hand thenar, and the foot dorsum on the right body side.ResultsWe calculated non-parametric reference limits (2.5–97.5th) according to age, gender and tested site. All QST measures were affected by age, gender and tested site. In the extra-trigeminal body sites, females showed lower WDT and higher CDT, while males had higher HPT. Worse sensory discriminative abilities and increased HPT values were found in people aged over 40 on the foot. Age-related differences were more evident with the reaction time–dependent MLI vs. MLE paradigm.ConclusionsDemographic characteristics must be considered when QST is used in the clinical setting. The definition of reference limits for sensory testing with the Q-sense herein provided can pave the way towards a more widespread use of thermal QST for diagnosing small fiber neuropathy and for identifying patients’ profiles in different chronic pain syndromes.

Comprehensive quantitative sensory testing shows altered sensory function in women with chronic pelvic pain: results from the Translational Research in Pelvic Pain (TRiPP) Study.

Chronic pelvic pain (CPP), despite its high prevalence, is still relatively poorly understood mechanistically. This study, as part of the Translational Research in Pelvic Pain (TRiPP) project, has used a full quantitative sensory testing (QST) paradigm to profile n = 85 women with and without CPP (endometriosis or bladder pain specifically). We used the foot as a control site and abdomen as the test site. Across 5 diagnostically determined subgroups, we found features which are common across different aetiologies, eg, gain of function in pressure pain threshold (PPT) when assessing responses from the lower abdomen or pelvis (referred pain site). However, disease-specific phenotypes were also identified, eg, greater mechanical allodynia in endometriosis, despite there being large heterogeneities within diagnostic groups. The most common QST sensory phenotype was mechanical hyperalgesia (>50% across all the groups). A "healthy' sensory phenotype was seen in <7% of CPP participants. Specific QST measures correlated with sensory symptoms assessed by the painDETECT questionnaire (pressure-evoked pain [painDETECT] and PPT [QST] [ r = 0.47, P < 0.001]; mechanical hyperalgesia (painDETECT) and mechanical pain sensitivity [MPS from QST] [ r = 0.38, P = 0.009]). The data suggest that participants with CPP are sensitive to both deep tissue and cutaneous inputs, suggesting that central mechanisms may be important in this cohort. We also see phenotypes such as thermal hyperalgesia, which may be the result of peripheral mechanisms, such as irritable nociceptors. This highlights the importance of stratifying patients into clinically meaningful phenotypes, which may have implications for the development of better therapeutic strategies for CPP.

A randomized phase III clinical trial of acupuncture for chemotherapy-induced peripheral neuropathy in survivors of cancer.

TPS12144 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating side effect in cancer survivors that can last long after completion of neurotoxic chemotherapy. Patients with CIPN often experience neuropathy symptoms such as pain, tingling, numbness, paresthesia, and dysesthesia, which can lead to significant functional decline and diminished quality of life. This outcome highlights the importance of developing effective CIPN treatments to improve quality of life for this population. Identifying nonpharmacological approaches to reduce CIPN symptoms and improve cancer survivors’ outcomes is urgently needed. Acupuncture is a widely used, minimally invasive Traditional Chinese Medicine technique that has shown promising evidence as an effective and safe treatment for CIPN. We hypothesize that acupuncture may reduce CIPN pain and improve overall CIPN symptoms in cancer survivors. Methods: We are conducting a two-arm, parallel randomized clinical trial comparing electroacupuncture (EA) versus sham acupuncture (SA) in cancer survivors. The EA arm includes ten sessions of EA over eight weeks using a standardized, semi-fixed protocol developed by our group. The SA arm includes a sham technique that uses a combination of non-acupuncture points and a non-insertion procedure in ten sessions over eight weeks. The primary outcome of this study is the Brief Pain Inventory-Short Form average pain item. The secondary outcomes are quantitative sensory testing measures and patient-reported outcomes that include the Neuropathic Pain Scale, Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity, CIPN-20, PROMIS Global Health Scale, and Patients' Global Impression of Change. The primary end point is week 12 and the secondary end point is week 24; treatment effects are assessed at baseline and at weeks 4, 8, 12, 18, and 24. The eligibility criteria includes: 1) Patients must be have no evidence of disease or have stable disease; 2) CIPN diagnosis with moderate-to-severe CIPN pain, defined by a score of 4 or greater on a scale 0-10 numerical scale rating; 3) completed neurotoxic chemotherapy at least three months prior; and 4) no changes in anti-neuropathy medications within three months of enrollment. As of February 2023, we have accrued 89 participants, with a total accrual target of 250 participants. Accrual completion is anticipated by December 2024. The demographic breakdown of our participants is as following: 71% white, 15% black or African American, 10% Asian, 3% more than one race, and 1% Native Hawaiian or Pacific Islander. 89% of the participants are non-Hispanic or Latino, 10% are Hispanic or Latino, and 1% are unknown. 71% of the participants are female and 29% are male. Clinical trial information: NCT04917796 .

PD34-03 PRE-OPERATIVE CENTRAL SENSITIZATION AND HYPERSENSITIVITY TO PAIN IS ASSOCIATED WITH URETERAL STENT PAIN: FINDINGS FROM THE URINARY STONE DISEASE RESEARCH NETWORK (USDRN)

You have accessJournal of UrologyCME1 Apr 2023PD34-03 PRE-OPERATIVE CENTRAL SENSITIZATION AND HYPERSENSITIVITY TO PAIN IS ASSOCIATED WITH URETERAL STENT PAIN: FINDINGS FROM THE URINARY STONE DISEASE RESEARCH NETWORK (USDRN) Henry Lai, Hongqiu Yang, Jonathan Harper, Alana Desai, Gregory Tasian, Rebecca McCune, Ziya Kirkali, Hussein Al-Khalidi, Charles Scales, and Michele Curatolo Henry LaiHenry Lai More articles by this author , Hongqiu YangHongqiu Yang More articles by this author , Jonathan HarperJonathan Harper More articles by this author , Alana DesaiAlana Desai More articles by this author , Gregory TasianGregory Tasian More articles by this author , Rebecca McCuneRebecca McCune More articles by this author , Ziya KirkaliZiya Kirkali More articles by this author , Hussein Al-KhalidiHussein Al-Khalidi More articles by this author , Charles ScalesCharles Scales More articles by this author , and Michele CuratoloMichele Curatolo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003327.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: To examine the relationship between pre-operative central sensitization and hypersensitivity to pain, and post-operative stent pain after ureteroscopy (URS) for stones. METHODS: Adult participants enrolled in the USDRN STudy to Enhance uNderstanding of sTent-associated Symptoms (STENTS) underwent quantitative sensory testing (QST) prior to URS and stent placement. Hypersensitivity to mechanical pain was assessed with pressure algometer. Participants rated their pain intensity (0-100) to 2 kg and 4 kg pressure applied to the flank and lower abdominal quadrant on the side of planned stent, and the contralateral forearm (control). Pressure pain thresholds (PPT) were also assessed. Central sensitization was assessed by applying a pinprick stimulator and calculating temporal summation (TS). Post-operative stent pain was assessed using PROMIS questionnaires for pain intensity and pain interference. Data were analyzed using repeated-measures mixed-effects models. RESULTS: Among the 412 participants with QST data, median age was 54 years, 46% were female. Higher pre-operative pain ratings to mechanical pressure to the ipsilateral flank and abdominal areas were associated with higher stent pain intensity on post-operative days 1, 3, 5, 7-9, and 30 days post-stent removal (p<0.05). Lower pre-operative PPT (i.e. higher mechanical hypersensitivity) was associated with higher post-operative pain intensity (p<0.05). Greater degree of central sensitization pre-operatively (higher TS) was associated with higher post-operative pain intensity (p<0.05). Significant correlations existed between pre-operative QST measures at the ipsilateral flank area and post-operative stent pain intensity (Table). Similar correlations were observed for ipsilateral abdominal area but not consistently for the forearm control site (data not shown). CONCLUSIONS: We have identified a physiological risk factor associated with stent pain. Preoperative central sensitization and hypersensitivity to pain were associated with post-operative stent pain. QST is a potential tool to identify patients likely to experience post-URS stent pain, which may facilitate early identification for mitigation, counseling, and management options. Source of Funding: NIH/NIDDK © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e920 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Henry Lai More articles by this author Hongqiu Yang More articles by this author Jonathan Harper More articles by this author Alana Desai More articles by this author Gregory Tasian More articles by this author Rebecca McCune More articles by this author Ziya Kirkali More articles by this author Hussein Al-Khalidi More articles by this author Charles Scales More articles by this author Michele Curatolo More articles by this author Expand All Advertisement PDF downloadLoading ...

Peripheral sensory function in non-freezing cold injury patients and matched controls.

What is the central question of this study? Is peripheral sensory function impaired in the chronic phase of non-freezing cold injury (NFCI)? What is the main finding and its importance? Warm and mechanical detection thresholds are elevated and intraepidermal nerve fibre density is reduced in individuals with NFCI in their feet when compared to matched controls. This indicates impaired sensory function in individuals with NFCI. Interindividual variation was observed in all groups, and therefore a diagnostic cut-off for NFCI has yet to be established. Longitudinal studies are required to follow NFCI progression from formation to resolution ABSTRACT: The aim of this study was to compare peripheral sensory neural function of individuals with non-freezing cold injury (NFCI) with matched controls (without NFCI) with either similar (COLD) or minimal previous cold exposure (CON). Thirteen individuals with chronic NFCI in their feet were matched with the control groups for sex, age, race, fitness, body mass index and foot volume. All undertook quantitative sensory testing (QST) on the foot. Intraepidermal nerve fibre density (IENFD) was assessed 10cm above the lateral malleolus in nine NFCI and 12 COLD participants. Warm detection threshold was higher at the great toe in NFCI than COLD (NFCI 45.93 (4.71)°C vs. COLD 43.44 (2.72)°C, P=0.046), but was non-significantly different from CON (CON 43.92 (5.01)°C, P=0.295). Mechanical detection threshold on the dorsum of the foot was higher in NFCI (23.61 (33.59) mN) than in CON (3.83 (3.69) mN, P=0.003), but was non-significantly different from COLD (10.49 (5.76) mN, P>0.999). Remaining QST measures did not differ significantly between groups. IENFD was lower in NFCI than COLD (NFCI 8.47 (2.36) fibre/mm2 vs. COLD 11.93 (4.04) fibre/mm2 , P=0.020). Elevated warm and mechanical detection thresholds may indicate hyposensitivity to sensory stimuli in the injured foot for individuals with NFCI and may be due to reduced innervation given the reduction in IENFD. Longitudinal studies are required to identify the progression of sensory neuropathy from the formation of injury to its resolution, with appropriate control groups employed.

Signs of Nervous System Sensitization in Female Runners with Chronic Patellofemoral Pain.

Patellofemoral pain (PFP) is a common overuse injury among runners, affecting females at a higher rate than males. PFP can often become chronic, with evidence suggesting it may be linked to both peripheral and central sensitization of the nervous system. Sensitization of the nervous system can be identified through quantitative sensory testing (QST). The primary objective of this pilot study was to quantify and compare pain sensitivity as identified through QST measures, in active female runners with and without PFP. Cohort Study. Twenty healthy female runners and 17 female runners with chronic PFP symptoms were enrolled. Subjects completed the Knee injury and Osteoarthritis Outcome Score for Patellofemoral Pain (KOOS-PF), University of Wisconsin Running Injury and Recovery Index (UWRI), and the Brief Pain Inventory (BPI). QST consisted of pressure pain threshold testing to three local and three distant sites to the knee, heat temporal summation, heat pain threshold, and conditioned pain modulation. Data was analyzed utilizing independent t-tests for comparison of between-group data, effect sizes for QST measures (Pearson's r), and Pearson's correlation coefficient between pressure pain threshold values at the knee and functional testing. The PFP group exhibited significantly lower scores on the KOOS-PF (p<0.001), BPI Pain Severity and Interference Scores (p<0.001), and UWRI (p<0.001). Primary hyperalgesia, identified through decreased pressure pain threshold at the knee, was detected in the PFP group at the central patella (p<0.001), lateral patellar retinaculum (p=0.003), and patellar tendon (p=0.006). Secondary hyperalgesia, a sign of central sensitization, was observed via differences in pressure pain threshold testing for the PFP group at the uninvolved knee (p=0.012 to p=0.042), involved extremity remote sites (p=0.001 to p=0.006), and uninvolved extremity remote sites (p=0.013 to p=0.021). Compared to healthy controls, female runners with chronic PFP symptoms exhibit signs of both peripheral sensitization. Despite actively participating in running, nervous system sensitization may contribute to continued pain in these individuals. For female runners with chronic PFP, physical therapy management may need to include interventions which address signs of central and peripheral sensitization. Level 3.

Mechanistic and thermal characterization of acupuncture for chemotherapy-induced peripheral neuropathy as measured by quantitative sensory testing.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating side effect of chemotherapy. Acupuncture is a promising non-pharmacological intervention for CIPN. However, the physiological effects of acupuncture treatment remain poorly understood. We examined the effects of acupuncture on CIPN using semi-objective quantitative sensory testing (QST). We conducted a randomized controlled trial of real acupuncture (RA) and sham acupuncture (SA) compared to usual care (UC) in cancer survivors with moderate-to-severe CIPN. Treatment response was assessed with QST measures of tactile and vibration detection thresholds in hands and feet, thermal detection, and pain thresholds at weeks 0, 8, and 12. Constrained linear mixed model (cLMM) regression was used for statistical analysis. 63 patients completed QST testing. At week 8, vibrational detection thresholds in feet were significantly lower in RA and SA (p = 0.019 and p = 0.046) than in UC, with no difference between RA and SA (p = 0.637). Both RA and SA also showed significantly higher cool thermal detection than UC (p = 0.008 and p = 0.013, respectively), with no difference between RA and SA (p = 0.790). No differences in tactile detection, vibrational detection in hands, warm thermal detection, and thermal pain thresholds were detected among the three arms at weeks 8 and 12. QST demonstrated different patterns in RA, SA, and UC. After eight weeks of RA, we observed significant improvements in the vibrational detection threshold in feet and cool thermal detection threshold in hands compared to UC. No significant differences were seen when compared to SA. ClinicalTrials.gov (NCT03183037); June 9, 2017.

Pain Sensitization as a Potential Mediator of the Relationship Between Sleep Disturbance and Subsequent Pain in Rheumatoid Arthritis.

Many patients with rheumatoid arthritis (RA) experience sleep disturbances, commonly attributed to joint pain. Sleep disturbances could also influence pain. One mechanism may be through dysregulated pain processing, manifested by enhanced pain sensitivity. The present study was undertaken to examine the role of pain sensitization, measured by quantitative sensory testing (QST), as a mediator in the pathway of sleep disturbance leading to subsequent pain. We used longitudinal data from 221 patients with active RA who were followed for 12 weeks after initiating a disease-modifying antirheumatic drug. Baseline QST included pressure pain thresholds at articular (wrists, knees) and nonarticular (trapezius, thumbnails) sites, temporal summation (TS) at the wrist and forearm, and conditioned pain modulation (CPM). Baseline sleep disturbance and subsequent pain intensity were assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS). We evaluated correlations between sleep disturbance, QSTs, and subsequent pain intensity. Mediation analyses separately assessed each QST as a mediator, adjusting for baseline confounding factors. Sleep disturbance was correlated with all QST measures except wrist TS and CPM. Sleep disturbance significantly predicted subsequent pain (coefficient for a meaningful increase of 5 units in sleep disturbance=0.32 (95% confidence interval 0.11, 0.50) in multiple regression. QST mediated 10-19% of this effect. Pain sensitization may be one mechanism through which sleep disturbance contributes to pain. The small magnitude of association indicates that unmeasured pathways may contribute to this relationship. Intervention studies are needed to establish causality and determine whether improving sleep can improve pain in patients with RA.

Altered central pain processing assessed by quantitative sensory testing in patients with failed back surgery syndrome

ObjectiveTo investigate the presence of altered central pain processing in patients with failed back surgery syndrome (FBSS) using quantitative sensory testing (QST). MethodsThis study included 34 patients with FBSS, 102 patients post-lumbar surgery without low back pain (LBP), and 102 healthy subjects. All subjects underwent both pressure pain threshold (PPT) and conditioned pain modulation (CPM) in both local and remote pain-free areas, as well as temporal summation (TS) in a remote pain-free area. All patient subjects were assessed using the Pain Catastrophizing Scale (PCS), Beck Anxiety Inventory (BAI), Beck Depression Index (BDI), Numeric rating pain scale (NRS) and Oswestry Disability Index (ODI). ResultsCompared with both control groups, FBSS patients showed a reduction in both PPT and CPM in both tested areas, along with increased TS in a pain-free area (P < 0.05). Furthermore, the patients with FBSS had a significantly higher prevalence of anxiety, depression and pain catastrophizing thoughts than the patient controls (P < 0.05). In the FBSS patients, there was a significant correlation between LBP at rest and both CPM and TS in the pain-free areas, and QST measurements were also associated with the ODI, PCS and BAI (P < 0.05). ConclusionThese findings support the existence of augmented central pain processing in patients with FBSS, which may be caused by dysfunction of endogenous pain facilitation and inhibition. This central amplification of pain may contribute to both LBP intensity and disability in FBSS patients. Therefore, treatment efforts should take into account functional alterations in the central nervous system of FBSS patients.

Efficacy of Home-Based Transcranial Direct Current Stimulation on Experimental Pain Sensitivity in Older Adults with Knee Osteoarthritis: A Randomized, Sham-Controlled Clinical Trial.

Although transcranial direct current stimulation (tDCS) is encouraging regarding clinical pain intensity for individuals with knee osteoarthritis, very few studies have explored its impact on experimental pain sensitivity, which may hinder our understanding of underlying therapeutic mechanisms. The purpose of this study was to assess the efficacy of 15 home-based tDCS sessions on experimental pain sensitivity and explore its relationships with clinical pain intensity. We randomly assigned 120 participants to active tDCS (n = 60) and sham tDCS (n = 60). Quantitative sensory testing (QST) was used, including heat pain threshold and tolerance, pressure pain threshold, and conditioned pain modulation. Patients in the active tDCS group exhibited reduced experimental pain sensitivity as reflected by all QST measures at the end of treatment. Furthermore, correlations were observed between changes in clinical pain intensity and experimental pain sensitivity. These findings warrant further studies on tDCS and experimental pain sensitivity in patients with knee osteoarthritis and exploring the magnitude and sustainability of effects on a longer term.

A simple, bed-side tool to assess evoked pressure pain intensity.

Existing equipment for quantitative sensory testing is generally expensive and not easily applicable inaclinical setting thus simple bed-side devices are warranted. Pressure hyperalgesia is a common finding in patients withmusculoskeletal pain and an experimental model is delayed-onset muscle soreness (DOMS). DOMS ischaracterised by muscle hyperalgesia and some studies report facilitation of temporal summation of pain. This study aimed to detect DOMS induced muscle hyperalgesia and temporal summation of pain using a newly developed bed-side quantitative sensory testing device to deliver standardised pressure. Twenty-two healthy participants participated in two sessions with the second session approximately 48h after baseline. Pressure pain intensities were assessed from the gastrocnemius muscle with four probes calibrated to apply 2, 4, 6 and 8kg, respectively. Temporal summation of pain (10 stimuli delivered at 0.5Hz using the 6kg probe) intensities were assessed from the same location. DOMS was evoked in the gastrocnemius muscle by an eccentric exercise. Sleepiness and physical activity were measured with the Epworth Sleepiness Scale and the Global Physical Activity Questionnaire to investigate if they were associated with the quantitative sensory testing measures. Pressure pain intensity was significantly increased 48h after induction of DOMS when compared to baseline for all four probes (p<0.05). Temporal summation of pain was not statistically significant affected by DOMS and sleep quality and physical activity did not associate with any of the measures. This study introduces a simple, bed-side assessment tool for the assessment of pressure pain intensity and hence hyperalgesia and temporal summation of pain.