Pain hypersensitivity in juvenile idiopathic arthritis: a quantitative sensory testing study

Development and validation of a home quantitative sensory testing tool-kit to assess changes in sensory and pain processing: a study in healthy young adults

ABSTRACT

Quantitative sensory testing (QST) is a set of methods for quantifying somatosensory functioning. Limitations of laboratory-based QST (LQST) include high cost, complexity in training, lack of portability, and time requirements for testing. Translating QST to a home setting could facilitate future research and clinical care. The objective of this study was to develop a home QST (HQST) tool-kit that is cost-effective, easy to use, and detects changes in sensory and pain processing. Thirty-two young healthy adults underwent sensory testing on their nondominant forearm using standard in-person LQST, followed by "simulated HQST" using video guidance in a separate room from the investigator before and after application of either a lidocaine or capsaicin cream. We observed good agreement between HQST and LQST scores, with significant correlations observed between the pinprick, pressure, cold and heat measures (|ρ| range = 0.36-0.54). The participants rated the HQST protocol as highly acceptable and safe but can be improved in future implementations. Home QST was able to detect hypoesthesia to vibration after lidocaine cream application ( P = 0.024, d = 0.502) and could detect hypoalgesia and hyperalgesia to pressure and heat pain sensitivity tests after application of lidocaine and capsaicin creams, respectively ( P -value range = <0.001-0.036, d -value range = 0.563-0.901). Despite limitations, HQST tool-kits may become a cost-effective, convenient, and scalable approach for improving sensory profiling in clinical care and clinical research.

Psychophysical and Functional Outcomes in Chemotherapy-induced Peripheral Neuropathy After Spinal Cord Stimulation: A Narrative Review and Case Series

OBJECTIVES

Chemotherapy-induced peripheral neuropathy (CIPN) is a complication that may occur after treatment with various anticancer drugs. In refractory CIPN cases, spinal cord stimulation (SCS) has garnered increased attention. The use of gait analysis and psychophysical quantitative sensory testing (QST) as an objective measurement of CIPN-related damage has burgeoned; however, these changes have not been reported for patients with CIPN after SCS implantation using either burst or tonic stimulation.

MATERIALS AND METHODS

This manuscript encompasses two parts: 1) a presentation of pain improvement in a series of patients who underwent tonic vs burst SCS for CIPN measured by gait and QST analysis and 2) a narrative review on gait and psychophysical QST outcomes between burst and tonic SCS stimulation pertaining to pain and the extrapolation to CIPN-related sequalae.

RESULTS

In these cases, gait scores improved in both patients. Touch thresholds were higher before SCS whereas skin temperatures were lower at the dorsal foot, subtalus, and posterior calf. Sharpness detection was drastically improved after SCS. In the review, the patients aligned with pain relief, suggesting good response to interventional outcomes with SCS. QST outcomes, particularly touch, sharpness, heat, and cold stimuli, however, were not fully corroborated. Similarly to other non-CIPN SCS gait studies, both tonic and burst studies provided positive outcomes on spatiotemporal gait parameters, gait form, and standardized gait scales.

CONCLUSION

We emphasize the use of different SCS waveforms as a therapy for CIPN management and the use of psychophysical testing as a measure for diagnosis and monitoring CIPN's progress in our case series and review.

Pain Interference in Juvenile Idiopathic Arthritis

OBJECTIVE

Despite treatment advances, pain remains a serious problem for many children with juvenile idiopathic arthritis (JIA). To better understand pain in children with JIA and identify potentially modifiable factors, this study evaluated Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Pain Interference (PI) and its relationships with other pain measures and demographic, clinical, psychosocial, and functional variables.

METHODS

This cross-sectional, observational, multicenter study used descriptive statistics and a mix of bivariate and multivariable analyses to describe PI and characterize relationships with other measures and variables.

RESULTS

Among 355 children with JIA, 27% reported moderate or severe PI and 13.3% reported daily pain. PI correlated with other pain measures. Increasing age, decreasing disease duration, and increasing number of active joints, as well as presence of active disease, steroid treatment, and biologic treatment, were associated with greater PI. All PROMIS psychosocial and functional measures were associated with PI in the expected direction except for PROMIS Pediatric Physical Activity, which showed no association. In multivariable analyses, only PROMIS Fatigue, PROMIS Mobility, and the exploratory interaction of PROMIS Anxiety and disease-modifying antirheumatic drug treatment were significant.

CONCLUSION

Moderate and severe PI was prevalent in this sample of children with JIA. PI increased with age and indicators of disease activity, but was more strongly associated with increasing fatigue and decreasing mobility. Findings support the use of PI as a short, easily administered multidimensional pain measure as part of routine clinical care. Fatigue, mobility, and disease activity should be assessed further when PI is high.

Pain catastrophizing in rheumatic diseases: prevalence, origin, and implications

Pain is a crucial factor in rheumatic disorders, and reducing it is a primary goal of successful treatment. Adaptive pain-coping strategies can enhance this improvement, but maladaptive approaches such as pain catastrophizing may worsen overall patient well-being. This narrative review aims to provide a concise overview of the existing knowledge on pain catastrophizing in the most prevalent specific rheumatic disorders. The objective of this study was to improve understanding of this phenomenon and its implications, as well as to pinpoint potential directions for future research. We conducted searches in the MEDLINE/PubMed, SCOPUS, and DOAJ bibliography databases to identify articles related to pain catastrophizing in rheumatoid arthritis, psoriatic arthritis, axial spondylarthritis, systemic sclerosis, systemic lupus erythematosus, Sjögren's syndrome, juvenile idiopathic arthritis, and osteoarthritis (non-surgical treatment). Data extraction was performed on November 1, 2023. The investigators screened the identified articles to determine their relevance and whether they met the inclusion criteria. Following a bibliography search, which was further expanded by screening of citations and references, we included 156 records in the current review. The full-text analysis centred on pain catastrophizing, encompassing its prevalence, pathogenesis, and impact. The review established the role of catastrophizing in amplifying pain and diminishing various aspects of general well-being. Also, potential treatment approaches were discussed and summarised across the examined disorders. Pain catastrophizing is as a significant factor in rheumatic disorders. Its impact warrants further exploration through prospective controlled trials to enhance global patient outcomes.

Determinants of physical activity level in children and adolescents with juvenile idiopathic arthritis

OBJECTIVE

One of the most frequently discussed physical parameters in juvenile idiopathic arthritis (JIA) is physical activity level. There is limited evidence about determinants of physical activity level in JIA. In this study, we aimed to investigate the determinants of physical activity level in children and adolescents with JIA.

MATERIALS AND METHODS

Thirty-two JIA patients and 18 age- and sex-matched healthy individuals were included in the study. The age range was 8-18 years. Sociodemographic and clinical data of the participants were recorded. In both groups, anthropometry, fatigue, pain, knee extension muscle strength, gait variables, functional exercise capacity assessed by six-minute walk test (6MWT), and arterial stiffness were evaluated. Physical activity level was assessed by an accelerometer.

RESULTS

The disease activity level of the patients was low. Pain and fatigue scores were significantly higher in the JIA group compared to healthy controls (p < 0.05). Walking speed, physical activity level, time spent in low-intensity physical activity, time spent in moderate-to-vigorous-intensity physical activity, and 6MWT distance were significantly lower than in healthy controls (p < 0.05). Quadriceps muscle strength and arterial stiffness assessment results were similar in both groups (p > 0.05). In the JIA group, there was a positive correlation between physical activity and age, height, fat-free body mass, quadriceps muscle strength, and 6MWT distance (p < 0.05). Also, there was a negative correlation between physical activity and pain, fatigue, and cadence. Physical activity level was independently associated with 6MWT distance (42.9% of the variability).

CONCLUSION

In mildly affected JIA patients, gait speed, functional exercise capacity, and physical activity level are affected. Functional exercise capacity is a determinant of physical activity level in JIA.

Impact of Musculoskeletal Pain on Functioning and Disability in Children with Juvenile Idiopathic Arthritis in Iceland

AIMS

1) to map questions of pain from a survey to the International Classification of Functioning, Disability and Health (ICF) 2) to compare the impact of musculoskeletal pain on functioning based on the different components of the ICF in children with juvenile idiopathic arthritis (JIA) and age-matched peers.

METHOD

A cross-sectional case-control survey. A total of 28 children with JIA and 36 age-matched children participated. The survey included questions on the child's sex and age, about pain experienced, number of painful body areas, pain frequency and three short forms of Patient-Reported Outcome Measurement Information System (PROMIS) pain questionnaires. Sixteen children with JIA (57%) and 10 peers (28%) reported pain during past seven days. Their responses were used in the description of impact of pain.

RESULTS

After the mapping of the questions to ICF, a comparison between the two groups indicated that a higher number of children with JIA described effects of pain on mental function, mobility, general tasks and demands, than their peers. More children with JIA expressed to others that they had pain, non-verbally and verbally.

CONCLUSION

The findings provide important information about the impacts of pain on daily life in children with JIA and about their intervention needs.

An explorative study on proteomic analyses related to inflammation and pain in children with juvenile idiopathic arthritis

BACKGROUND

Our aim was attempting to find proteins involved in the pain process and correlating with pain but not degree of inflammation in children with juvenile idiopathic arthritis (JIA), using a proteomics panel.

METHODS

A total of 87 plasma samples were collected from 51 children with JIA (51 at diagnosis in a higher disease activity state, 18 at follow-up in a lower disease activity state) and 18 healthy controls. Relative levels of 92 proteins related to a wide range of biological processes in inflammation were obtained using a proximity extension assay panel. Comparisons between children with and without JIA, in different disease categories, by juvenile disease activity score (JADAS27) and degree of pain on a visual analogue scale (VAS), were performed using parametric and non-parametric statistical methods.

RESULTS

Nineteen proteins involved in arthritic inflammation, such as interleukin 6 (IL-6) and S100 protein A12, were higher in patients with JIA than controls, seven decreased significantly during treatment, and 18 correlated significantly with JADAS27. Three proteins correlated with pain VAS scores in unadjusted analyses: the glial cell line-derived neurotrophic factor (GDNF), transforming growth factor beta, and IL-18R1. Levels of GDNF correlated significantly with pain VAS scores but not with JADAS27.

CONCLUSIONS

Plasma levels of 18 of 92 tested proteins correlated with degree of disease activity. Levels of three proteins correlated with pain, and levels of one, GDNF, originating from neural cells, correlated with pain without correlating with inflammatory degree, suggesting that it may play a role in pain in JIA. Further studies in larger cohorts are warranted.

A systematic review of the psychosocial factors associated with pain in children with juvenile idiopathic arthritis

BACKGROUND

Pain is one of the most frequently reported experiences amongst children with Juvenile Idiopathic Arthritis (JIA); however, the management of JIA pain remains challenging. As pain is a multidimensional experience that is influenced by biological, psychological, and social factors, the key to effective pain management lies in understanding these complex relationships. The objective of this study is to systematically review the literature on psychosocial factors of children with JIA and their caregivers 1) associated with and 2) predictive of later JIA pain intensity, frequency, and sensitivity in children 0-17 years of age.

METHODS

The Joanna Briggs Institute methodology for etiology and risk and Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement guided the conduct and reporting of this review. Terms related to pain and JIA were searched in English without date restrictions across various databases (PubMed, CINAHL, PsycINFO, Embase, Scopus, and the Cochrane Central Register of Controlled Trials) in September 2021. Two independent reviewers identified, extracted data from, and critically appraised the included studies. Conflicts were resolved via consensus.

RESULTS

Of the 9,929 unique studies identified, 61 were included in this review and reported on 516 associations. Results were heterogeneous, likely due to methodological differences and moderate study quality. Results identified predominantly significant associations between pain and primary and secondary appraisals (e.g., more child pain beliefs, lower parent/child self-efficacy, lower child social functioning), parent/child internalizing symptoms, and lower child well-being and health-related quality of life. Prognostically, studies had 1-to-60-month follow-up periods. Fewer beliefs of harm, disability, and no control were associated with lower pain at follow-up, whereas internalizing symptoms and lower well-being were predictive of higher pain at follow-up (bidirectional relationships were also identified).

CONCLUSIONS

Despite the heterogeneous results, this review highlights important associations between psychosocial factors and JIA pain. Clinically, this information supports an interdisciplinary approach to pain management, informs the role of psychosocial supports, and provides information to better optimize JIA pain assessments and interventions. It also identifies a need for high quality studies with larger samples and more complex and longitudinal analyses to understand factors that impact the pain experience in children with JIA.

TRIAL REGISTRATION

PROSPERO CRD42021266716.

Quantitative Sensory Changes Following Posterior Spinal Fusion to Treat Adolescent Idiopathic Scoliosis

BACKGROUND

Sensory changes surrounding the incision frequently develop after posterior spinal fusion (PSF) to treat adolescent idiopathic scoliosis (AIS). Anecdotally, patients may experience sensory changes on the chest wall. Such postsurgical sensory changes are not well described quantitatively. This study aims to evaluate the presence, intensity, and duration of mechanical sensory changes in AIS patients postoperatively.

METHODS

A prospective cohort of AIS patients, 10 to 21 years old, was followed. Quantitative sensory testing (QST) included touch detection threshold [mechanical detection threshold (MDT)] and pain detection threshold (MPT), using VonFrey monofilaments and pinprick stimulators. QST was performed at 3 sites at T6: the right and left chest at the nipple line and adjacent to the incision below the inferior angle of the scapula. QST at the thenar eminence was the control. QST was collected at baseline, 3 days, 1, and 6 months postoperative.

RESULTS

Thirty-four patients (21% males; mean age: 14.9 years old; median preoperative curve: 58 degrees) completed all testing. Mean deformity correction was 64% (SD: 10.4). Adjacent to the incision site, MDT was significantly higher compared with baseline at 3 days and 1 month ( P < 0.001) but not at 6 months ( P = 0.19), whereas MPT was significantly higher at 3 days, ( P < 0.001), 1 month ( P < 0.001), and 6 months ( P = 0.001). For the chest wall in all patients, MPT was higher on the left chest at 3 days ( P = 0.04) and on the right chest at 3 days ( P = 0.022) and 1 month ( P = 0.05). For patients with right-sided curves, MDT ( P = 0.01) and MPT ( P = 0.015) overall were significantly higher on the concave side (left) chest postoperatively.

CONCLUSIONS

PSF is associated with sensory disturbances that are detectable within days, persist at 1 month, and improve at 6 months postoperatively adjacent to the incision and on the chest wall. We suspect that these sensory changes are transient. Describing postoperative sensory changes will help us better set postoperative expectations for patients undergoing PSF.

LEVEL OF EVIDENCE

Level I.

We need to talk: The urgent conversation on chronic pain, mental health, prescribing patterns and the opioid crisis

The opioid crisis’ pathways from first exposure onwards to eventual illnesses and fatalities are multiple, intertwined and difficult to dissect. Here, we offer a multidisciplinary appraisal of the relationships among mental health, chronic pain, prescribing patterns worldwide and the opioid crisis. Because the opioid crisis’ toll is especially harsh on young people, emphasis is given on data regarding the younger strata of the population. Because analgesic opioid prescription constitute a recognised entry point towards misuse, opioid use disorder, and ultimately overdose, prescribing patterns across different countries are examined as a modifiable hazard factor along these pathways of risk. Psychiatrists are called to play a more compelling role in this urgent conversation, as they are uniquely placed to provide synthesis and lead action among the different fields of knowledge and care that lie at the crossroads of the opioid crisis. Psychiatrists are also ideally positioned to gauge and disseminate the foundations for diagnosis and clinical management of mental conditions associated with chronic pain, including the identification of hazardous and protective factors. It is our hope to spark more interdisciplinary exchanges and encourage psychiatrists worldwide to become leaders in an urgent conversation with interlocutors from the clinical and basic sciences, policy makers and stakeholders including clients and their families.

Feasibility of quantitative sensory testing in juvenile idiopathic arthritis

OBJECTIVE

Juvenile Idiopathic Arthritis (JIA) is a childhood-rheumatic disease with pain as a major early complaint, and in 10-17% pain remains a major symptom. Very few data exist on sensory threshold changes at the knee in JIA, a location in which inflammation often manifests. We determined whether JIA is associated with sensory threshold changes at the knee by using Quantitative Sensory Testing (QST) and established reference values at the knee of children.

METHODS

Sixteen patients with JIA aged 9-18 years with one affected knee and a patient-reported pain by Visual Analog Scale (VAS) > 10 on a 0-100 scale, and 16 healthy controls completed the study and were included for the analysis. QST was assessed in compliance with the German Research Network on Neuropathic Pain (DFNS) standard. Disease severity was determined using Juvenile Disease Activity Score (JADAS. Perceived pain was assessed with a visual analogue scale(0-100). Feasibility of QST was tested in patients aged 6-9.

RESULTS

Under the age of 9, QST testing showed not to be feasible in 3 out of 5 JIA patients. Patients with JIA aged 9 and older reported an average VAS pain score of 54.3. QST identified a significant reduction in pressure pain threshold (PPT) and increase in cold detection threshold (CDT) compared to healthy controls. PPT is reduced in both the affected and the unaffected knee, CDT is reduced in the unaffected knee, not the affected knee.

CONCLUSION

In a Dutch cohort of Patients with JIA, QST is only feasible from 9 years and up. Also, sensory threshold changes at the knee are restricted to pressure pain and cold detection thresholds in Patients with JIA.

PERSPECTIVE

This article shows that in a Dutch population, the extensive QST protocol is only feasible in the age group from 9 years and older, and a reduced set of QST tests containing at least pressure pain thresholds and cold detection thresholds could prove to be better suited to the pediatric setting with arthritis.

Evidence of persistent glial cell dysfunction in the anterior cingulate cortex of juvenile idiopathic arthritis children: a proton MRS study

BACKGROUND

This study aims to investigate whether the neurometabolites of the anterior cingulate cortex (ACC) were distinct in patients with active and inactive juvenile idiopathic arthritis (JIA) using the proton magnetic resonance spectroscopy.

METHODS

We measured the levels of total N-acetylaspartate (tNAA), choline (Cho), myo-inositol (ml), glutamate (Glu) and the complex of glutamate and glutamine (Glx) relative to total creatine (tCr) in ACC of each participant.

RESULTS

Compared with the healthy controls, a significant decrease of total Cho/tCr and Glx/tCr ratio in ACC occurred in active and inactive JIA group. The tCho/Cr level was negatively associated with the serum level of ESR in active JIA patients. There was no difference in NAA/tCr ratio among the three groups, which may imply that no neuron and axonal losses occurred in either active or inactive JIA patients.

CONCLUSIONS

The abnormal neurometabolites in tCho/tCr and Glx/tCr in ACC may indicate that persistent dysfunction of glial cell, while neither neuron nor axonal losses occurred in active and inactive JIA patients.

Musculoskeletal pain and its effect on daily activity and behaviour in Icelandic children and youths with juvenile idiopathic arthritis: a cross-sectional case-control study

BACKGROUND

Juvenile idiopathic arthritis is characterised by recurring episodes of acute inflammation, with joint swelling in one or more joints, often accompanied by pain. These episodes can now be controlled better than in the past because of a new category of medications. However, despite more stable disease activity, pain may continue to cause problems in the children with juvenile idiopathic arthritis and can reduce their performance of routine physical activities and participation in social or school activities.

AIM

To evaluate the prevalence of pain, pain intensity, pain behaviour, and pain interference in Icelandic children with juvenile idiopathic arthritis compared with healthy peers.

METHODS

A cross-sectional, case-control study including 8-18 years old children; 28 with juvenile idiopathic arthritis and 36 in a control group. The children answered questions on pain experienced during the last 7 days, painful areas of the body and pain frequency. They completed short form versions of the Patient-Reported Outcome Measurement Information System (PROMIS) questionnaires on pain intensity, pain behaviour, and pain interference.

RESULTS

Significantly more children with juvenile idiopathic arthritis had pain compared with the control group (p = 0.02). Children with JIA also had a greater number of painful body areas (p = 0.03), more pain intensity (p = 0.009), and showed more pain behaviour (p = 0.006), and pain interference (p = 0.002). Children with juvenile idiopathic arthritis who had pain, experienced more pain interference (p = 0.023) than their peers who had pain. However, the groups did not differ in terms of pain intensity (p = 0.102) and pain behaviour (p = 0.058).

CONCLUSION

The research results indicate that pain experience was different between children with juvenile idiopathic arthritis and the control group. The results suggest that further research of the role of pain management on functional outcomes in children with juvenile idiopathic arthritis is needed.

Long-term alterations in somatosensory functioning in survivors of childhood cancer

ABSTRACT

Cancer and its treatment can have lasting consequences on somatosensation, including pain, which is often underrecognized and undertreated. Research characterizing the impact of cancer on pain and sensory processing in survivors of childhood cancer is scarce. This study aimed to quantify generalized differences in pain and sensory processing in survivors of childhood cancer compared with reference data using a standardized thermal and mechanical quantitative sensory testing (QST) protocol. The association between demographic, clinical (eg, leukemia vs other cancers and treatment exposures), and psychosocial (eg, anxiety and pain catastrophizing) variables and sensitivity to pain and sensory stimuli were also evaluated. Participants were 56 survivors of various types of childhood cancer (52% male, Mage = 13.5 years, SD = 3.2, range = 8-17 years). On average, children were 7 years (SD = 4.1, range = 1.2-16.5) post treatment. Almost all participants (86%) had at least 1 abnormal QST parameter compared with age- and sex-matched reference data; however, few participants self-reported the presence of sensory abnormalities. Generally, participants exhibited reduced sensitivity across the QST parameters examined (Ps < 0.05, ds = 0.40-3.45). A significant minority (45%) also exhibited pain sensitization (P <0.001, d = 0.42). Several risk factors for changes in sensory processing were identified, including current age, history of leukemia, certain treatment exposures (eg, vincristine cumulative dose, major surgery, and bone marrow or stem cell transplant), time off treatment, and higher anxiety and pain catastrophizing scores. Overall, this study demonstrated that somatosensory changes are prevalent in survivors of childhood cancer years after the completion of treatment. Future research is needed to understand long-term implications of altered somatosensation in this complex population.

Childhood maltreatment and its role in the development of pain and psychopathology

Childhood maltreatment represents a form of trauma capable of altering fundamental neurobiological properties and negatively impacting neurodevelopmental processes. An outcome of childhood maltreatment is the emergence of psychopathology, which might become evident during childhood or adolescence, but might also project into adulthood. In this Review, we propose a biobehavioural framework in which childhood maltreatment and the associated aberrant neurobiological mechanisms and behavioural processes additionally lead to the onset of altered pain processing and, ultimately, the existence of pain syndromes. Considering that subpopulations of maltreated children show preserved function and minimal psychiatric or pain symptoms, compensatory mechanisms-perhaps instilled by robust psychosocial support systems-are also discussed. We present validated tools and experimental methods that could facilitate better comprehension of the interactions between childhood maltreatment, psychopathology, and pain. Such tools and approaches can in parallel be implemented to monitor abnormal pain-related processes and potentially guide early intervention strategies in cases of childhood maltreatment.

Clinical use of Electroencephalography in the Assessment of Acute Thermal Pain: A Narrative Review Based on Articles From 2009 to 2019

Nowadays, no practical system has successfully been able to decode and predict pain in clinical settings. The inability of some patients to verbally express their pain creates the need for a tool that could objectively assess pain in these individuals. Neuroimaging techniques combined with machine learning are seen as possible candidates for the identification of pain biomarkers. This review aimed to address the potential use of electroencephalographic features as predictors of acute experimental pain. Twenty-six studies using only thermal stimulations were identified using a PubMed and Scopus search. Combinations of the following terms were used: "EEG," "Electroencephalography," "Acute," "Pain," "Tonic," "Noxious," "Thermal," "Stimulation," "Brain," "Activity," "Cold," "Subjective," and "Perception." Results revealed that contact-heat-evoked potentials have been widely recorded over central areas during noxious heat stimulations. Furthermore, a decrease in alpha power over central regions was revealed, as well as increased theta and gamma powers over frontal areas. Gamma and theta rhythms were associated with connectivity between sensory and affective regions involved in pain processing. A machine learning analysis revealed that the gamma band is a predominant predictor of acute thermal pain. This review also addressed the need of supplementing current spectral features with techniques that allow the investigation of network dynamics.

Modified Sensory Testing in Non-verbal Patients Receiving Novel Intrathecal Therapies for Neurological Disorders

Several neurological disorders may be amenable to treatment with gene-targeting therapies such as antisense oligonucleotides (ASOs) or viral vector-based gene therapy. The US FDA has approved several of these treatments; many others are in clinical trials. Preclinical toxicity studies of ASO candidates have identified dose-dependent neurotoxicity patterns. These include degeneration of dorsal root ganglia, the cell bodies of peripheral sensory neurons. Quantitative sensory testing (QST) refers to a series of standardized mechanical and/or thermal measures that complement clinical neurologic examination in detecting sensory dysfunction. QST primarily relies on patient self-report or task performance (i.e., button-pushing). This brief report illustrates individualized pragmatic approaches to QST in non-verbal subjects receiving early phase investigational intrathecal drug therapies as a component of clinical trial safety protocols. Three children with neurodevelopmental disorders that include Neuronal Ceroid Lipofuscinosis Type 7, Ataxia-Telangiectasia, and Epilepsy of Infancy with Migrating Focal Seizures are presented. These case studies discuss individualized testing protocols, accounting for disease presentation, cognitive and motor function. We outline specific considerations for developing assessments for detecting changes in sensory processing in diverse patient groups and safety monitoring trials of early phase investigational intrathecal drug therapies. QST may complement information obtained from the standard neurologic examination, electrophysiologic studies, skin biopsies, and imaging. QST has limitations and challenges, especially in non-verbal subjects, as shown in the three cases discussed in this report. Future directions call for collaborative efforts to generate sensory datasets and share data registries in the pediatric neurology field.

Psychosocial and psychophysical assessment in pediatric patients and young adults with chronic back pain: a cluster analysis

Background

Identifying subgroups with different clinical profiles may inform tailored management and improve outcomes. The objective of this study was to identify psychosocial and psychophysical profiles of children and adolescents with chronic back pain.

Methods

One hundred and ninety‐eight patients with chronic back pain were recruited for the study. Pain assessment was mainly conducted in the form of an interview and with the use of validated pain‐related questionnaires assessing their psychosocial factors and disability. All patients underwent mechanical and thermal quantitative sensory tests assessing detection and pain thresholds, and conditioned pain modulation efficacy.

Results

Hierarchal clustering partitioned our patients into three clusters accounting for 34.73% of the total variation of the data. The adaptive cluster represented 45.5% of the patients and was characterized to display high thermal and pressure pain thresholds. The high somatic symptoms cluster, representing 19.2% of patients, was characterized to use more sensory, affective, evaluative and temporal descriptors of pain, more likely to report their pain as neuropathic of nature, report a more functional disability, report symptoms of anxiety and depression and report poor sleep quality. The pain‐sensitive cluster, representing 35.4% of the cohort, displayed deep tissue sensitivity and thermal hyperalgesia.

Conclusions

This study identified clinical profiles of children and adolescents experiencing chronic back pain based on specific psychophysical and psychosocial characteristics highlighting that chronic pain treatment should address underlying nociceptive and non‐nociceptive mechanisms.

Significance

To our current knowledge, this study is the first to conduct cluster analysis with youth experiencing chronic back pain and displays clinical profiles based on specific physical and psychosocial characteristics. This study highlights that in a clinical context, chronic pain assessment should include multiple elements contributing to pain which can be assessed in a clinical context and addressed when pathoanatomical symptoms are unidentifiable.

Assessment of pain associated with chronic pancreatitis: An international consensus guideline

Pain is the most common symptom in chronic pancreatitis (CP) with a major impact on quality of life. Few validated questionnaires to assess pain in CP exist, and the lack of consensus negatively impacts clinical management, research and meta-analysis. This guideline aims to review generic pain questionnaires for their usability in CP, to outline how pain assessment can be modified by confounding factors and pain types, to assess the value of additional measures such as quality of life, mental health and quantitative sensory testing, and finally to review pain assessment questionnaires used specifically in CP. A systematic review was done to answer 27 questions that followed the PICO (Population; Intervention; Comparator; Outcome) template. Quality of evidence of the statements was judged by Grades of Recommendation, Assessment, Development and Evaluation (GRADE) criteria. The manuscript was sent for review to 36 experts from various disciplines and continents in a multi-stage Delphi process, and finally reviewed by patient representatives. Main findings were that generic pain instruments are valid in most settings, but aspects of pain are specific for CP (including in children), and instruments have to account for the wide phenotypic variability and development of sensitization of the central nervous system. Side effects to treatment and placebo effects shall also be considered. Some multidimensional questionnaires are validated for CP and are recommended together with assessment of quality of life and psychiatric co-morbidities. This guideline will result in more homogeneous and comprehensive pain assessment to potentially improve management of painful CP.

A multidisciplinary assessment of pain in juvenile idiopathic arthritis

INTRODUCTION

Pain is prevalent in juvenile idiopathic arthritis (JIA). Unknowns regarding the biological drivers of pain complicate therapeutic targeting. We employed neuroimaging to define pain-related neurobiological features altered in JIA.

METHODS

16 male and female JIA patients (12.7 ± 2.8 years of age) on active treatment were enrolled, together with age- and sex-matched controls. Patients were assessed using physical examination, clinical questionnaires, musculoskeletal MRI, and structural neuroimaging. In addition, functional magnetic resonance imaging (fMRI) data were collected during the resting-state, hand-motor task performance, and cold stimulation of the hand and knee.

RESULTS

Patients with and without pain and with and without inflammation (joint and systemic) were evaluated.  Pain severity was associated with more physical stress and poorer cognitive function. Corrected for multiple comparisons, morphological analysis revealed decreased cortical thickness within the insula cortex and a negative correlation between caudate nucleus volume and pain severity. Functional neuroimaging findings suggested alteration within neurocircuitry structures regulating emotional pain processing (anterior insula) in addition to the default-mode and sensorimotor networks.

CONCLUSIONS

Patients with JIA may exhibit changes in neurobiological circuits related to pain. These preliminary findings suggest mechanisms by which pain could potentially become dissociated from detectable joint pathology and persist independently of inflammation or treatment status.

Left to themselves: Time to target chronic pain in childhood rare diseases

BACKGROUND

Chronic pain is prevalent among patients with rare diseases (RDs). However, little is understood about how biopsychosocial mechanisms may be integrated in the unique set of clinical features and therapeutic challenges inherent in their pain conditions.

METHODS

This review presents examples of major categories of RDs with particular pain conditions. In addition, we provide translational evidence on clinical and scientific rationale for psychosocially- and neurodevelopmentally-informed treatment of pain in RD patients.

RESULTS

Neurobiological and functional overlap between various RD syndromes and pain states suggests amalgamation and mutual modulation of the respective conditions. Emotional sequelae could be construed as an emotional homologue of physical pain mediated via overlapping brain circuitry. Given their clearly defined genetic and molecular etiologies, RDs may serve as heuristic models for unraveling pathophysiological processes inherent in chronic pain.

CONCLUSIONS

Systematic evaluation of chronic pain in patients with RD contributes to sophisticated insight into both pain and their psychosocial correlates, which could transform treatment.

Offset analgesia identifies impaired endogenous pain modulation in pediatric chronic pain disorders

Offset analgesia (OA), a psychophysical test of endogenous pain inhibition, is diminished in many adult chronic pain disorders but OA has not been investigated in youth with chronic pain disorders. This study assessed OA responses in 30 youth with chronic primary and secondary pain disorders and 32 healthy controls. The OA, control, and constant thermal tests were evoked with an individualized noxious heat stimulus of approximately 50/100 mm on a visual analogue scale followed by 1°C offset temperature. This study also examined the association of OA responses with 2 self-report measures of pain sensitivity, the Central Sensitization Inventory (CSI) and Pain Sensitivity Questionnaire. Patients exhibited diminished capacity to activate OA with a reduction in ΔeVASc of 53 ± 29% vs controls 74 ± 24% (P = 0.003) even after multivariate regression adjusting for age, sex, and body mass index. Patients also showed decreased ability to habituate to a constant noxious heat stimulus compared to controls (P = 0.021). Central Sensitization Inventory scores showed excellent predictive accuracy in differentiating patients from controls (area under the curve = 0.95; 95% CI: 0.91-0.99) and CSI score ≥30 was identified as an optimal cutoff value. Pain Sensitivity Questionnaire scores did not differentiate patients from controls nor correlate with OA. In this study, 60% of youth with chronic pain showed reduced capacity for endogenous pain inhibition.

Altered sensory innervation and pain hypersensitivity in a model of young painful arthritic joints: short- and long-term effects

BACKGROUND

Early life experience can cause long-term alterations in the nociceptive processes underlying chronic pain, but the consequences of early life arthritic joint inflammation upon the sensory innervation of the joint is not known. Here, we measure pain sensitivity and sensory innervation in a young, juvenile and adult rodent model of arthritic joints and test the consequences of joint inflammation in young animals upon adult arthritic pain and joint innervation.

METHODS

Unilateral ankle joint injections of complete Freund's adjuvant (CFA) (6-20 µl) were performed in young, postnatal day (P)8, adolescent (P21) and adult (P40) rats. A separate cohort of animals were injected at P8, and again at P40. Hindpaw mechanical sensitivity was assessed using von Frey monofilaments (vF) for 10 days. Nerve fibres were counted in sections through the ankle joint immunostained for calcitonin gene-related peptide (CGRP) and neurofilament 200 kDa (NF200).

RESULTS

Ankle joint CFA injection increased capsular width at all ages. Significant mechanical pain hypersensitivity and increased number of joint CGRP + ve sensory fibres occurred in adolescent and adult, but not young, rats. Despite the lack of acute reaction, joint inflammation at a young age resulted in significantly increased pain hypersensitivity and CGRP+ fibre counts when the rats were re-inflamed as adults.

CONCLUSIONS

Joint inflammation increases the sensory nociceptive innervation and induces acute pain hypersensitivity in juvenile and adult, but not in young rats. However, early life joint inflammation 'primes' the joint such that adult inflammatory pain behaviour and nociceptive nerve endings in the joint are significantly increased. Early life joint inflammation may be an important factor in the generation and maintenance of chronic arthritic pain.

Pain sensitivity in young adults with juvenile idiopathic arthritis: a quantitative sensory testing study

BACKGROUND

To study for the first-time, pain perception, pain sensitivity, and self-reported pain in young adults with long disease duration of juvenile idiopathic arthritis (JIA) compared with controls.

METHODS

Children from Central Norway diagnosed with JIA between 1997 and 2004 were included consecutively in a population-based prospective study. Children with onset 1997-2000 were part of the Nordic JIA cohort. Controls were age- and sex-matched. In 2015-2017, study visits with investigator-blinded quantitative sensory testing (QST) comprising cold and warm detection thresholds (CDT/WDT), cold and heat pain thresholds (CPT/HPT), pressure pain threshold (PPT), and a suprathreshold heat pain test were performed. We constructed separate multilevel models for each variable of detection and pain thresholds with interaction between groups and site adjusted for the effect of age and sex.

RESULTS

Among 96 young adults with JIA, 71% were female, median age was 22.7 years, disease duration was 16.1 years, and 47% had oligoarticular disease. Among 109 controls, 71% were female, and median age was 23.5 years. Participants with JIA had lower pressure pain thresholds (PPTs) (95% CI) compared to controls, upper limb 888 (846,930) versus 1029 (999,1059) kPa and lower limb 702 (670,734) versus 760 (726,794) kPa. Participants with inactive disease had the lowest PPTs and cold pain thresholds (CPTs), compared to those in remission off medication and those with active disease. Minor differences were found regarding CDT/WDT and CPT/HPT in JIA compared to controls. The median (IQR) temperature needed to evoke pain = 6 on a 0-10 numeric rating scale (NRS) in the suprathreshold heat pain tests were lower in JIA than in controls (46 °C (45-47 °C) versus 47 °C (46-48 °C)). We found no associations between self-reported pain and pain thresholds.

CONCLUSIONS

Our results indicate for the first time that young adults with long disease duration of JIA may have altered pain perception and sensitivity compared to controls. A clinical implication may be the importance of early treatment to quickly achieve pain-free remission and avoid long-term pain sensitization.

Commentary: Novel Use of Offset Analgesia to Assess Adolescents and Adults with Treatment Resistant Endometriosis-Associated Pain

Background and Objective

Endometriosis, affecting approximately 176 million adults and adolescents worldwide, is a debilitating condition in which uterine tissue grows outside the uterus. The condition costs the US economy approximately $78 billion annually in pain-related disability. By understanding the neural underpinnings of endometriosis-associated pain (EAP) and risk factors for chronification, translational research methods could lessen diagnostic delays and maximize successful pain remediation. This can be accomplished by the novel use of a known method, offset analgesia (OA), to better elucidate the neural mechanisms that may contribute to and maintain EAP. This commentary will provide justification and rationale for the use of OA in the study of EAP.

Conclusion

Utilizing an OA paradigm in patients with endometriosis, especially adolescents, may (1) provide insight into neural mechanisms contributing to pain maintenance, which could capture those at-risk for the transition to chronic pelvic pain, (2) provide a metric for the development of future centrally mediated treatment options for this population, and (3) elucidate the brain changes that result in resistance to treatment and pain chronification.

Spinal interleukin-6 contributes to central sensitisation and persistent pain hypersensitivity in a model of juvenile idiopathic arthritis

Pain is the most debilitating symptom in juvenile idiopathic arthritis. As pain correlates poorly to the extent of joint pathology, therapies that control joint inflammation are often inadequate as analgesics. We test the hypothesis that juvenile joint inflammation leads to sensitisation of nociceptive circuits in the central nervous system, which is maintained by cytokine expression in the spinal cord. Here, transient joint inflammation was induced in postnatal day (P)21 and P40 male Sprague-Dawley rats with a single intra-articular ankle injection of complete Freund's adjuvant. Hindpaw mechanical pain sensitivity was assessed using von Frey hair and weight bearing tests. Spinal neuron activity was measured using in vivo extracellular recording and immunohistochemistry. Joint and spinal dorsal horn TNFα, IL1β and IL6 protein expression was quantified using western blotting. We observed greater mechanical hyperalgesia following joint inflammation in P21 compared to P40 rats, despite comparable duration of swelling and joint inflammatory cytokine levels. This is mirrored by spinal neuron hypersensitivity, which also outlasted the duration of active joint inflammation. The cytokine profile in the spinal cord differed at the two ages: prolonged upregulation of spinal IL6 was observed in P21, but not P40 rats. Finally, spinal application of anti-IL-6 antibody (30 ng) reduced the mechanical hyperalgesia and neuronal activation. Our results indicate that persistent upregulation of pro-inflammatory cytokines in the spinal dorsal horn is associated with neuronal sensitisation and mechanical hyperalgesia in juvenile rats, beyond the progress of joint pathology. In addition, we provide proof of concept that spinal IL6 is a key target for treating persistent pain in JIA.

Consequences of Juvenile Idiopathic Arthritis on Single Leg Squat Performance in Youth

OBJECTIVE

Juvenile idiopathic arthritis (JIA) affects body structure and function outcomes that may increase the risk of acute joint injury. The purpose of this study was to examine single leg squat (SLS) biomechanics for youth with JIA and their healthy peers. The study design was a matched pair cohort study.

METHODS

Sixty-five youth (JIA n = 30; control n = 35) participated in this ethics-approved study. Participants performed 3 sets of 5 consecutive SLS tasks. Disease activity and functional status were assessed using the Juvenile Arthritis Disease Activity Score and Child Health Assessment Questionnaire. Indexed (most-affected leg [JIA]; dominant leg [control]) and contralateral extremity biomechanics were obtained using a 12-camera system. Outcomes included hip flexion/extension (FE), adduction/abduction (AA), and internal/external (IE) rotation range of motion (ROM). Data were analyzed using a multivariate random coefficient model in R (α⍺ = 0.05).

RESULTS

A total of 29 matched pairs were analyzed. Youth with JIA had low disease activity and performed the SLS with a more internally rotated hip (indexed leg P = 0.023, β = -1.9°). Female participants displayed greater hip FE (indexed leg P = 0.015, β = -4.3°; contralateral leg P = 0.005, β = -4.8°) and IE ROM (indexed leg P = 0.021, β = -2.1°) than male participants. Associations were observed for body mass index and hip IE ROM (contralateral leg P = 0.001, β = -0.4°), knee flexion angle, and hip FE ROM (indexed leg P = 0.001, β = 0.4°; contralateral leg P = 0.001, β = 0.5°) and AA (indexed leg P = 0.010, β = 0.1°; contralateral leg P = 0.002, β = 0.2°).

CONCLUSION

This study identified functional alterations for an SLS in youth with JIA. These findings support the use of physical therapy as part of a multidisciplinary management approach, to restore normal hip posture and movement.

The pain trajectory of juvenile idiopathic arthritis (JIA): translating from adolescent patient report to behavioural sensitivity in a juvenile animal model

BACKGROUND

While pain is a common symptom in JIA patients, it remains unclear why some JIA patients develop ongoing or persistent pain. Complex clinical and social settings confound analysis of individual factors that may contribute to this pain. To address this, we first undertook a retrospective analysis of pain reports in a JIA patient cohort with the aim of identifying potential factors contributing to persistent pain. We then carried out an experimental laboratory study, using joint inflammatory pain behaviour in rodents, to validate the role of these factors in the onset of persistent pain under controlled conditions.

METHODS

Patients: Retrospective analysis of anonymised pain visual analogue scale (VAS) scores and accompanying clinical scores from 97 JIA patients aged 13-19 (mean: 16.40 ± 1.21) collected over 50 weeks. Rats: Experimental study of pain behaviour following intra-articular microinjection of complete Freund's adjuvant (CFA) in adolescents (n = 25) and young adults (n = 43). Some animals (n = 21) had been previously exposed to joint inflammation in infancy or adolescence.

RESULTS

Patients: Cluster analysis of patient pain VAS scores revealed three trajectories over 50 weeks: consistently low pain (n = 45), variable pain (n = 30) and persistently high pain (n = 22). Number of actively inflamed joints did not differ in the three groups. High pain at a single visit correlated with greater physician global assessment of disease activity, while a high pain trajectory over 50 weeks was associated with more limited joints but fewer actively inflamed joints. Rats: Rodents administered ankle joint CFA also exhibit low, medium and high joint pain sensitivities, independent of joint inflammation. Prolonged inflammatory pain behaviour was associated with high background pain sensitivity, following joint inflammation at an earlier stage in life.

CONCLUSIONS

Both JIA patients and rodents differ in their individual pain sensitivity independent of the concurrent joint inflammation. Using experimental animal models allows us to isolate physiological factors underlying these differences, independently of social or clinical factors. The results suggest that a history of prior arthritic activity/joint inflammation may contribute to high pain sensitivity in adolescents with JIA.

Hyperexcitability of the Central Nervous System in Children with Chronic Pain: A Systematic Review

Objective

Hyperexcitability of the central nervous system plays an important role in the development and maintenance of chronic pain in adults. This knowledge has led to improved treatment strategies within this population. In children, however, research on the presence of central hyperexcitability is scarce. To further investigate this topic in children with chronic pain, there is a need for a clear literature overview.

Design

Systematic review.

Methods

The literature search was performed using the electronic databases PubMed and Web of Science. An article was considered eligible if it included children (age two to 12 years) diagnosed with chronic pain. Articles had to report original research outcomes related to central hyperexcitability, and a comparison with a healthy control group was necessary. Characteristics of the study sample, the assessment, and conclusions regarding central hyperexcitability were extracted from each included article.

Results

Twelve case-control studies were included with moderate to good methodological quality (510 children with chronic pain and 670 healthy controls). After summarizing the articles' results on indices of central hyperexcitability, we concluded that secondary hyperalgesia might be present in children with recurrent abdominal pain, juvenile fibromyalgia, and juvenile idiopathic arthritis. Preliminary evidence exists for altered cortical nociceptive processing in children with migraine and recurrent abdominal pain.

Conclusion

Based on the results of this review, central hyperexcitability might be present in in several pediatric chronic pain conditions. Further research on other manifestations of central hyperexcitability (e.g., bottom-up and top-down mechanisms and nociceptive brain changes) is necessary to provide firm evidence about its presence in children with chronic pain.

Physical activity and sedentary levels in children with juvenile idiopathic arthritis and inflammatory bowel disease. A systematic review and meta-analysis

BACKGROUND

Physical activity (PA) is essential for children throughout their growth and maturation. It improves physiological and psychological health and limits the risk of developing metabolic disorders. However, some chronic physiological and metabolic diseases may lead to decreased PA. The diversity of outcomes in the literature offers no consensus for physical activity and sedentary levels in children with juvenile idiopathic arthritis (JIA) or inflammatory bowel disease (IBD).

METHODS

A literature review and a meta-analysis were carried out with original studies from a Medline database search. Only high-quality studies (STROBE checklist) written in English comparing PA level or sedentary behavior (SB) between children with the disorders and their healthy peers were considered. The aim was to examine PA and SB in children with JIA or IBD compared to their healthy peers.

RESULTS

The literature review and meta-analysis identified decreased PA and increased time spent in SB in these populations, which may exacerbate both their lower physical fitness and the symptoms of their health disorders.

CONCLUSION

Results nevertheless show discrepancies due to the different materials and methods used and the variables measured. Further studies are needed to establish a gold standard method for assessing PA level in these populations.

Evaluating the psychometric properties of the Widespread Pain Index and the Symptom Severity scale in youth with painful conditions

Background

Assessing features of centralized pain may prove to be clinically meaningful in pediatric populations. However, we are currently limited by the lack of validated pediatric measures.

Aim

We examined the psychometric properties of the Widespread Pain Index (WPI) and Symptom Severity (SS) scale, to assess features of centralized pain, in youth with painful conditions from three clinical samples: (1) musculoskeletal surgery, (2) headache, and (3) chronic pain.

Methods

Participants were 240 youth aged 10-18 years (Mage=14.8, SD=1.9) who completed the WPI and SS scale. Subsets of participants also completed additional measures of pain region, pain intensity, quality of life, pain interference and physical function.

Results

Increased features of centralized pain by age were seen for the WPI (r=0.27, p<0.01) and SS scale (r=0.29, p<0.01). Expected differences in sex were seen for the WPI (sex:t₁₃₂=-3.62, p<0.01), but not the SS scale (sex:t₂₂₃=-1.73, p=0.09). Reliability for the SS scale was adequate (α=.70). Construct validity was demonstrated through relationships between the WPI and pain regions (r=.57, p<0.01), and between the SS scale and quality of life (r=-.59, p<0.01) and pain interference (r=.56, p<0.01). Criterion validity was demonstrated by differences on the WPI between the surgery sample and the headache and chronic pain samples (F_2,237=17.55, p<0.001). Comprehension of the SS scale items was problematic for some youth.

Conclusions

The WPI showed adequate psychometric properties in youth; however the SS scale may need to be modified. Our findings support the need to develop psychometrically sound instruments for comprehensive assessment of pain in pediatric samples.

Quantitative sensory testing in children with sickle cell disease: additional insights and future possibilities

Quantitative sensory testing (QST) is used in a variety of pain disorders to characterize pain and predict prognosis and response to specific therapies. In this study, we aimed to confirm results in the literature documenting altered QST thresholds in sickle cell disease (SCD) and assess the test-retest reliability of results over time. Fifty-seven SCD and 60 control subjects aged 8-20 years underwent heat and cold detection and pain threshold testing using a Medoc TSAII. Participants were tested at baseline and 3 months; SCD subjects were additionally tested at 6 months. An important facet of our study was the development and use of a novel QST modelling approach, allowing us to model all data together across modalities. We have not demonstrated significant differences in thermal thresholds between subjects with SCD and controls. Thermal thresholds were consistent over a 3- to 6-month period. Subjects on whom hydroxycarbamide (HC) was initiated shortly before or after baseline testing (new HC users) exhibited progressive decreases in thermal sensitivity from baseline to 6 months, suggesting that thermal testing may be sensitive to effective therapy to prevent vasoocclusive pain. These findings inform the use of QST as an endpoint in the evaluation of preventative pain therapies.

Subclinical Peripheral Neuropathy in Patients with Head and Neck Cancer: A Quantitative Sensory Testing (QST) Study

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and chronic complication associated with cancer treatment. Prior investigations have demonstrated the presence of subclinical peripheral neuropathy in patients with colorectal cancer even before the patients had received chemotherapy.

OBJECTIVE

To investigate subclinical peripheral neuropathy of the upper limbs in patients with squamous cell carcinoma (SCC) of the head and neck which developed before their exposure to neurotoxic anticancer agents.

STUDY DESIGN

Retrospective analysis.

METHODS

With the use of our quantitative sensory testing (QST) data bank, we retrospectively assessed the afferent fiber function of 25 patients with SCC of the head and neck before they had received chemotherapy (the patient group) and compared our findings with those from 23 healthy control patients. Skin temperature, sensorimotor function, sharpness detection, thermal detection, and touch detection (using both von Frey monofilaments and the Bumps detection test) were measured.

RESULTS

Touch thresholds were statistically higher in the patient group than in the healthy volunteer group at the palm (mean [± SD], 0.54 g [± 0.07 g] and 0.27 g [± 0.05 g], respectively [P < 0.01]) and at the forearm (0.74 g [± 0.12 g] and 0.41 g [± 0.08 g] [P < 0.05]). There was also a clear deficit in touch sensation as indicated by a Bumps detection threshold in patients of 6.5 µm ± 0.8 µm and in controls of 3.7 µm ± 0.5 µm. This yields an elevation in threshold to 165% in the patients relative to that of the control volunteers. The grooved pegboard test showed delayed completion times for patients compared with controls, with differences of 18.65 seconds in the dominant hand and of 23.36 seconds in the nondominant hand. The sharpness detection thresholds did not differ between patients and volunteers.

LIMITATIONS

Inadequacies in the original data acquisition and documentation of the QST and the medical records could not be addressed due to the retrospective nature of the study. In addition, based on available information, we did not find an objective parameter able to correlate the QST findings with pre-pain levels.

CONCLUSION

Patients with SCC were found to have deficits in sensory function before undergoing treatment, suggesting that cancer itself alters peripheral nerve function and may contribute to the development of CIPN. These results confirm the sensitivity of the Bumps detection test and highlight its potential role in early detection of peripheral neuropathy, especially in cancer patients for whom chemotherapies associated with CIPN have been prescribed.

KEY WORDS

Peripheral neuropathy, head and neck cancer, quantitative sensory testing.

Patterns of pain over time among children with juvenile idiopathic arthritis

OBJECTIVES

Pain is a very common symptom of juvenile idiopathic arthritis (JIA). Disease activity alone cannot explain symptoms of pain in all children, suggesting other factors may be relevant. The objectives of this study were to describe the different patterns of pain experienced over time in children with JIA and to identify predictors of which children are likely to experience ongoing pain.

METHODS

This study used longitudinal-data from patients (aged 1-16 years) with new-onset JIA. Baseline and up to 5-year follow-up pain data from the Childhood Arthritis Prospective Study (CAPS) were used. A two-step approach was adopted. First, pain trajectories were modelled using a discrete mixture model. Second, multinomial logistic regression was used to determine the association between variables and trajectories.

RESULTS

Data from 851 individuals were included (4 years, median follow-up). A three-group trajectory model was identified: consistently low pain (n=453), improved pain (n=254) and consistently high pain (n=144). Children with improved pain or consistently high pain differed on average at baseline from consistently low pain. Older age at onset, poor function/disability and longer disease duration at baseline were associated with consistently high pain compared with consistently low pain. Early increases in pain and poor function/disability were also associated with consistently high pain compared with consistently low pain.

CONCLUSIONS

This study has identified routinely collected clinical factors, which may indicate those individuals with JIA at risk of poor pain outcomes earlier in disease. Identifying those at highest risk of poor pain outcomes at disease onset may enable targeted pain management strategies to be implemented early in disease thus reducing the risk of poor pain outcomes.

Development and feasibility testing of a Pain Neuroscience Education program for children with chronic pain: treatment protocol

BACKGROUND

Current treatment for adults with chronic pain often includes Pain Neuroscience Education (PNE) to make people understand the nature underlying their pain and thus provides a clear rational for a biopsychosocial approach. Despite recommendations to use Pain Neuroscience Education as well in children with chronic pain, a specific program, tailored to children aged 6-12 years is lacking.

OBJECTIVES

The aim of this study was to develop a Pain Neuroscience Education program for children with chronic pain and test its feasibility.

METHODS

First the internet and scientific literature was searched for sources (e.g., books, videos, etc.) that might be supportive in teaching children about the neurophysiology of pain. Based on this content, we developed a Pain Neuroscience Education program for children, 'PNE4Kids', which was tested for feasibility in three groups of healthy children (n=18; 9 girls and 9 boys) aged between 6 and 12 years old.

RESULTS AND CONCLUSIONS

This paper provides both scientists and clinicians with a specific program to explain the neurophysiology of pain to children with chronic pain, since it is past high time to use a modern neuroscience approach in this vulnerable population. Further research should examine the effectiveness of this developed PNE4Kids program on pain-related outcomes in children with chronic pain. Registration number: NCT02880332 (https://clinicaltrials.gov/ct2/show/NCT02880332).

Up-Down Reader: An Open Source Program for Efficiently Processing 50% von Frey Thresholds

Most pathological pain conditions in patients and rodent pain models result in marked alterations in mechanosensation and the gold standard way to measure this is by use of von Frey fibers. These graded monofilaments are used to gauge the level of stimulus-evoked sensitivity present in the affected dermal region. One of the most popular methods used to determine von Frey thresholds is the up–down testing paradigm introduced by Dixon for patients in 1980 and by Chapman and colleagues for rodents in 1994. Although the up–down method is very accurate, leading to its widespread use, defining the 50% threshold from primary data is complex and requires a relatively time-consuming analysis step. We developed a computer program, the Up–Down Reader (UDReader), that can locate and recognize handwritten von Frey assessments from a scanned PDF document and translate these measurements into 50% pain thresholds. Automating the process of obtaining the 50% threshold values negates the need for reference tables or Microsoft Excel formulae and eliminates the chance of a manual calculation error. Our simple and straightforward method is designed to save research time while improving data collection accuracy and is freely available at https://sourceforge.net/projects/updownreader/ or in supplementary files attached to this manuscript.

Small-fiber neuropathy and pain sensitization in survivors of pediatric acute lymphoblastic leukemia

BACKGROUND

Chemotherapy-induced Peripheral Neuropathy (CIPN) of large-fibers affects up to 20% of survivors of pediatric acute lymphoblastic leukemia (ALL). We aimed to describe small-fiber toxicity and pain sensitization in this group.

METHODS

In a cross-sectional, bicentric study we assessed 46 survivors of pediatric ALL (Mean age: 5.7 ± 3.5 years at diagnosis, median 2.5 years after therapy; males: 28).

INCLUSION CRITERIA

≥6 years of age, ≥3 months after last administration of Vincristine, and cumulative dose of Vincristine 12 mg/m². We used a reduced version of the Pediatric-modified Total Neuropathy Score (Ped-mTNS) as bedside test and Quantitative Sensory Testing (QST) for assessment of small- and large-fiber neuropathy as well as pain sensitization. We employed Nerve Conduction Studies (NCS) as the most accurate tool for detecting large-fiber neuropathy.

RESULTS

Fifteen survivors (33%) had abnormal rPed-mTNS values (≥4 points) and 5 survivors (11%) reported pain. In QST, the survivor group showed significant (p < 0.001) inferior large-fiber function and pain sensitization when compared to healthy matched peers. We identified deficits of vibration in 33 (72%) and tactile hypoesthesia in 29 (63%), hyperalgesia to blunt pressure in 19 (41%), increased mechanical pain sensitivity in 12 (26%) and allodynia in 16 (35%) of 46 survivors. Only 7 survivors (15%) had pathologic NCS.

CONCLUSION

QST is a sensitive tool that revealed signs of large-fiber neuropathy in two thirds, small-fiber neuropathy and pain sensitization in one third of survivors. Prospective studies using QST in pediatric oncology may help to elucidate the pathophysiology of small-fiber neuropathy and pain sensitization as well as their relevance for quality of survival.

Pressure Pain Threshold and Anxiety in Adolescent Females With and Without Juvenile Fibromyalgia: A Pilot Study

OBJECTIVES

Reduced pain thresholds have been documented in adult fibromyalgia, but there are no quantitative studies of altered pain sensitivity in adolescents with juvenile fibromyalgia (JFM). The current study examined differences in pressure pain sensitivity between adolescent females with JFM and healthy controls. The relationship between levels of anxiety and pain were also examined.

METHODS

A total of 34 JFM (15.4±1.4 y old) and 31 controls (14.5±1.3 y old) completed self-report measures of pain and anxiety. Pressure pain threshold was assessed (palm and forehead sites) with a hand-held algometer. Participants indicated the first sensation of pain and then rated the intensity of pain on a Numerical Rating Scale.

RESULTS

Adolescents with JFM exhibited greater sensitivity to pressure pain compared with controls. While the difference between JFM and controls was only observed at the forehead, the intensity of pain produced by the pressure algometry at both sites was significantly higher in the JFM participants compared with controls. Correlations between clinical pain and anxiety were significant for the JFM group only. No relationships were observed between anxiety and pressure pain for either group.

DISCUSSION

This study is a first step toward investigating mechanisms of altered pain processing in adolescents with JFM. Adolescents with JFM were found be more sensitive to pressure pain than their healthy peers, which suggests a propensity for sensitization of peripheral and/or central nociceptive information often reported in adult fibromyalgia, and which does not appear to be affected by anxiety.

Chronic Pain Assessments in Children and Adolescents: A Systematic Literature Review of the Selection, Administration, Interpretation, and Reporting of Unidimensional Pain Intensity Scales

BACKGROUND

Advances in pain assessment approaches now indicate which measures should be used to capture chronic pain experiences in children and adolescents. However, there is little guidance on how these tools should best be administered and reported, such as which time frames to use or how pain scores are categorised as mild, moderate, or severe.

OBJECTIVE

To synthesise current evidence on unidimensional, single-item pain intensity scale selection, administration, interpretation, and reporting.

METHODS

Databases were searched (inception: 18 January 2016) for studies in which unidimensional pain intensity assessments were used with children and adolescents with chronic pain. Ten quality criteria were developed by modifying existing recommendations to evaluate the quality of administration of pain scales most commonly used with children.

RESULTS

Forty-six studies met the inclusion criteria. The highest score achieved was 7 out of a possible 10 (median: 5; IQR: 4-6). Usage of scales varied markedly in administrator/completer, highest anchors, number of successive assessments, and time referent periods used.

CONCLUSIONS

Findings suggest these scales are selected, administered, and interpreted inconsistently, even in studies of the same type. Furthermore, methods of administration are rarely reported or justified making it impossible to compare findings across studies. This article concludes by recommending criteria for the future reporting of paediatric chronic pain assessments in studies.

Modern pain neuroscience in clinical practice: applied to post-cancer, paediatric and sports-related pain

•

Generalized hypersensitivity in post-cancer, sports-related and pediatric pain.

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Rationale for pain education, stress management and cognition targeted exercises.

•

Need to change from a biomedical or psychosocial to an integrated approach.

In the last decade, evidence regarding chronic pain has developed exponentially. Numerous studies show that many chronic pain populations show specific neuroplastic changes in the peripheral and central nervous system. These changes are reflected in clinical manifestations, like a generalized hypersensitivity of the somatosensory system. Besides a hypersensitivity of bottom-up nociceptive transmission, there is also evidence for top-down facilitation of pain due to malfunctioning of the endogenous descending nociceptive modulatory systems. These and other aspects of modern pain neuroscience are starting to be applied within daily clinical practice. However, currently the application of this knowledge is mostly limited to the general adult population with musculoskeletal problems, while evidence is getting stronger that also in other chronic pain populations these neuroplastic processes may contribute to the occurrence and persistence of the pain problem. Therefore, this masterclass article aims at giving an overview of the current modern pain neuroscience knowledge and its potential application in post-cancer, paediatric and sports-related pain problems.

[Chronic primary pain disorders in children and adolescents]

AIM

Chronic and debilitating pediatric pain has a prevalence of 5% and as such constitutes a considerable health problem. The aim of this article is to provide an overview of current research activities on pediatric pain, available health care for children with chronic pain and education and training programs for health professionals.

METHOD

This overview is based on the authors' personal experience, information available from medical, research and professional associations, as well as a PubMed literature search for the time period 2012-2015 using "children";"pain" and "Germany" as search terms.

RESULTS

There are numerous research activities in Germany focusing on the epidemiology, the underlying psychobiological mechanisms and on the multimodal treatment of chronic pediatric pain. This research is internationally widely acknowledged and makes a significant contribution to current developments in pediatric pain research. By contrast, health services and basic science research is clearly lacking in Germany. Moreover, specialized health care for youth with chronic pain is far less institutionalized when compared to adults suffering from chronic pain. Indeed, primary and secondary care services have rarely been studied or even evaluated.

CONCLUSION

Similar to international trends, research on chronic pediatric pain has also grown and advanced in Germany. Indeed, not only the amount of research has increased but also its scope. Nonetheless, there is clearly a need for more research efforts with regard to the understanding of (pediatric) pain mechanisms, clinical studies and, especially, investigations on health care services. It is particularly important to focus on the implementation, improvement and systematic evaluation of specialized health care services which would be available and accessible for children and adolescents with chronic pain and not be restricted to tertiary care.

A population-based study of quantitative sensory testing in adolescents with and without chronic pain

Quantitative sensory testing (QST) has been used to characterize pain sensitivity in individuals with and without pain conditions. Research remains limited in pediatric populations, hindering the ability to expand the utility of QST toward its potential application in clinical settings and clinical predictive value. The aims of this study were to examine pain sensitivity using QST in adolescents with chronic pain compared to adolescents without chronic pain and identify predictors of pain sensitivity. A population-based study conducted from 2010 to 2011 provided data on 941 adolescents, 197 were classified as having chronic pain and 744 were classified without chronic pain. Self-reported data on pain characteristics, psychological functioning, and QST responses were examined. The findings revealed lower pressure pain threshold and tolerance on the trapezius (P's = 0.03) in adolescents with chronic pain compared to adolescents without chronic pain, but no differences on heat or cold-pressor pain tasks. Female sex (P's = 0.02) and poorer psychological functioning (P's = 0.02) emerged as significant predictors of greater pain sensitivity across all pain modalities. Exploratory analyses revealed several associations between clinical pain characteristics and QST responses within the chronic pain cohort. Findings from this large pediatric sample provide comprehensive data that could serve as normative data on QST responses in adolescents with and without chronic pain. These findings lay the groundwork toward developing future QST research and study protocols in pediatric populations, taking into consideration sex and psychological distress.

Quantitative sensory testing in pain management

Quantitative sensory testing (QST), a set of noninvasive methods used to assess sensory and pain perception, has been used for three decades. The precision of the instruments and the uninvasiveness encouraged many QST-based trials. The developments made have benefited multiple disciplines. QST relies on analysis of an individual's response to external stimuli, reflecting the integrity of the PNS and the sensory pathway. The sensory pathway cannot be assessed in isolation from the affective and cognitive characteristics of patients or testers. Many variables potentially affect the reliability and reproducibility of QST, which after all, is designed for the testing of individuals by other individuals. Several decades of QST research have yielded exciting contributions, but the future of QST cannot be fully known.