A randomized controlled trial on the impact of a specialized training program on anxiety and perceived pain in infertile women undergoing hysterosalpingography.

Hysterosalpingography (HSG) is a minimally invasive procedure that can be painful. This study aimed to examine the impact of a tailored training program on anxiety and perceived pain intensity in infertile women undergoing HSG. This research was a clinical trial involving 86 infertile women who were candidates for HSG and conducted at the radiology department of the Royan Infertility Center in Tehran, Iran, between November 22, 2021, to March 11, 2023.The participants were divided into two groups:43 women in the intervention group and 43 women in the control group. The randomization of the samples was carried out using a random number table. The women in the intervention group received two face-to-face group training sessions. Data were collected using valid questionnaires. Additionally, the heart rate and blood pressure of the participants were recorded. Data analysis showed the training intervention was significantly associated with reducing anxiety levels, perceived pain, systolic blood pressure, diastolic blood pressure, and heart rate in women undergoing HSG (p < 0.05). These findings support the use of structured training interventions to improve the overall experience and outcomes for patients undergoing HSG.Trial Registration Number: IRCT20150905023897N4.

Impact of virtual reality on the perception of procedural pain in paediatric oncology.

INTRODUCTION: Virtual reality is being used more and more in the healthcare field, particularly during treatment. In the context of pain management, the question arises as to the effectiveness of using virtual reality during care in reducing the perception of procedural pain. AIM: To study the impact of using virtual reality on the perception of procedural pain and on the course of care in pediatric oncology. METHODS: A quasi-experimental, matched-case-control study conducted at the pediatric oncology unit of the Tunis Children's Hospital over a three-month period. Each child had two nursing care : with and without the use of virtual reality. RESULTS: Thirty-two children were enrolled. The sex ratio was 0.88. The edia nage was 96 ± 49 months. The care provided was peripheral venous line insertion (53%), blood sampling (32%) and port-a-catheter puncture (15%). The use of virtual reality significantly reduced heart rate (p<0.0001), respiratory rate (p<0.0001) and pain perception (p<0.0001). Workload was reduced, as evidenced by a drop in the duration of nursing care (p<0.0001) and in the number of people needed to carry out care (p<0.0001). CONCLUSIONS: Virtual reality is a good non-pharmacological alternative for procedural pain control in a pediatric oncology unit.

Racial biases, facial trustworthiness, and resting heart rate variability: unravelling complexities in pain recognition.

The study explores whether racial identity and appearance-based trustworthiness judgments can affect recognition of pain in medical students differing in levels of resting heart rate variability (HRV), a measure of parasympathetic control of the heart. After undergoing HRV assessment, 68 medical students (37 females) participated in a dynamic pain recognition task, viewing video clips of White and Black faces, which differed in perceived trustworthiness based on facial appearance, transitioning from neutral to intense pain expressions. Response time, pain intensity attribution and treatment recommendations were analyzed. Pain was recognized slower and estimated as less intense in Black compared to White faces, leading to a lower likelihood of recommending therapy. Pain recognition was faster for untrustworthy-looking White faces compared to trustworthy ones, while perceived trustworthiness had a minimal impact on the speed of pain recognition in Black faces. However, untrustworthy-looking faces were estimated to express more pain, particularly for Black faces. Notably, these biases were more pronounced in individuals with low, rather than high, resting HRV. Considering that therapeutic decisions mirrored pain intensity attribution, it would be important to increase awareness of these biases during medical training in order to promote equity in future pain assessment and treatment.

The effect of colored masks used in pediatric emergency clinics on children's pain perception: Randomized controlled study.

OBJECTIVES: This study was conducted in a randomized controlled manner to examine the effect of colored surgical masks used by nurses in pediatric emergency clinics on children's pain perception. METHODS: The study included 81 children aged 1-3 years who applied to the pediatric emergency clinic of a State Hospital located in a province in eastern Turkey. Data were collected using the 'Personal Information Form' and the 'Facial Expression, Leg Movement, Activity, Cry, Consolability (FLACC) Pain Assessment Tool' to measure the level of pain perception. During the vascular access procedure, colored surgical masks were used in the experimental group, while white surgical masks were used in the control group. Children's pain was assessed based on nurse observations. Independent samples t-test and ANOVA were employed to assess the data. The results were evaluated with a 95% confidence interval and a significance level of p<0.05. RESULTS: It was observed that in the white mask group, 35% of the children were 1 year old and 35% were 3 years old. In the colored mask group, 46.3% of the children were 2 years old. Furthermore, 52.5% of the children in the white mask group and 31.7% in the colored mask group were girls. The total mean score of the 'FLACC' scale was 8.92±1.526 in the white mask group and 4.73±2.721 in the colored mask group. CONCLUSION: The use of colored surgical masks by nurses during vascular access in children aged 1-3 years was found to be effective in reducing children's pain perception.

Modulating subjective pain perception with decoded Montreal Neurological Institute-space neurofeedback: a proof-of-concept study.

Pain is a complex emotional experience that still remains challenging to manage. Previous functional magnetic resonance imaging (fMRI) studies have associated pain with distributed patterns of brain activity (i.e. brain decoders), but it is still unclear whether these observations reflect causal mechanisms. To address this question, we devised a new neurofeedback approach using real-time decoding of fMRI data to test if modulating pain-related multivoxel fMRI patterns could lead to changes in subjective pain experience. We first showed that subjective pain ratings can indeed be accurately predicted using a real-time decoding approach based on the stimulus intensity independent pain signature (SIIPS) and the neurologic pain signature (NPS). Next, we trained participants (n = 16) in a double-blinded decoded fMRI neurofeedback experiment to up- or downregulate the SIIPS. Our results indicate that participants can learn to downregulate the expression of SIIPS independently from NPS expression. Importantly, the success of this neurofeedback training was associated with the perceived intensity of painful stimulation following the intervention. Taken together, these results indicate that closed-loop brain imaging can be efficiently conducted using a priori fMRI decoders of pain, potentially opening up a new range of applications for decoded neurofeedback, both for clinical and basic science purposes. This article is part of the theme issue 'Neurofeedback: new territories and neurocognitive mechanisms of endogenous neuromodulation'.

Use of Three Pre-Injection Procedures to Reduce Pain Perception of Intraoral Injections in Eight- to 12-Year-Old Children: Randomized Controlled Trial.

Purpose: To compare the efficacy of laser phototherapy, Buzzy®, and lignocaine gel in minimizing pain during intraoral injections. Methods: In this randomized controlled trial, the efficacy of standard lignocaine gel (Group A) was compared with Buzzy® (Group B) and laser phototherapy (Group C) as pre-anesthetic agents in 15 children aged eight to 12 years undergoing intraoral local anesthesia (LA). Pain perception during needle insertion was assessed objectively using the Face, Legs, Activity, Cry, Consolability (FLACC) scale and subjectively using the Visual Analogue Scale (VAS). Statistical analysis included chi-square and analysis of variance tests (P<0.05). Results: Objective assessment of pain perception using FLACC scores demonstrated that Buzzy® resulted in the highest comfort levels; 60 percent of the subjects treated with Buzzy®, 40 percent treated with laser phototherapy, and 6.7 percent treated with lignocaine topical anesthetic were judged to be relaxed and comfortable or exhibiting mild discomfort, respectively. Subjective pain assessment (self-reported using the VAS) was significantly lower in Buzzy® (0.67±0.82 standard deviation) followed by laser phototherapy (1.00±1.13) and Lignocaine gel group (2.13±1.51). Conclusions: The Buzzy® and laser phototherapy effectively reduced intraoral injection pain compared to the standard control, lignocaine gel. However, Buzzy® showed better efficacy.

Association Between Systemic Neuroinflammation, Pain Perception and Clinical Status in Fibromyalgia Patients: Cross-Sectional Study.

BACKGROUND: Fibromyalgia (FM) is characterized by chronic pain and a complex array of symptoms, with neuroinflammation implicated in its pathophysiology. METHODS: This study aimed to explore the association between neuroinflammation, measured through interleukin levels (IL-1, IL-6, IL-8), and clinical outcomes in FM patients. Using a cross-sectional study design, blood levels of these interleukins were correlated with pain severity and disability, assessed via the Fibromyalgia Impact Questionnaire (FIQ) and pain measures. RESULTS: Results indicated that IL-6 and IL-8 may particularly serve as biomarkers for pain severity and disability in FM patients, showing significant associations with worse clinical outcomes. Elevated IL-8 levels, for instance, correlated strongly with increased pain perception and higher disability scores. CONCLUSIONS: These findings suggest that specific interleukins are not only elevated in FM but are actively involved in the modulation of pain and disability, underscoring the role of systemic neuroinflammation in the clinical severity of FM. This study contributes to a deeper understanding of the inflammatory mechanisms in FM and underscores the potential of targeting interleukins in therapeutic strategies.

Evaluation of a novel blood collection set for venipuncture in oncology patients with difficult venous access: Impact on sample quality, phlebotomist satisfaction and patient pain perception.

PURPOSE: Difficult venous access (DVA), characterized by non-visible and non-palpable veins, is common in oncology patients. The objectives of this study were to compare the performances of two blood collection sets in an oncology phlebotomy setting: BD Vacutainer® UltraTouch™ Push Button (UT-PBBCS) and BD Vacutainer® Safety-Lok™ Blood Collection Set (SLBCS). The two sets were evaluated to assess whether use of a smaller gauge (G) needle (down-gauging) may reduce patient pain and improve peripheral venous access experience during phlebotomy in oncology patients. METHODS: Questionnaires were used to record patient data (age, gender), phlebotomy procedural observations (venipuncture site, number of collected tubes, blood flow, needle repositioning, underfilled tubes), patient pain perception and phlebotomist difficulty perception scores (0-10 points scale). Specimen quality was evaluated by hemolysis index (HI) on Roche Cobas® 6000. RESULTS: Subject groups showed no statistical difference. SLBCS (21/23G) or UT-PBBCS (23/25G) were used in 264 (45.8%) and 313 (54.2%) subjects respectively. Lower gauge was preferred for DVA (hand venipuncture), and DVA was associated with tube underfilling but no with type of blood collection set. For UT-PBBCS, pain perception, patients' anxiety level and phlebotomists' difficulty grade were lower when compared to SLBCS (p < 0.001). Blood samples collected with UT-PBBCS showed less hemolysis compared to samples collected with SLBCS (p < 0.001). CONCLUSION: Provision of a smaller gauge UT-PBBCS option during phlebotomy in oncology patients with DVA reduces procedural pain and anxiety and improved phlebotomist' experience during sample collection. Despite the down-gauging, hemolysis was lower for UT-PBBCS, keeping sample quality while improving DVA patient comfort.

Effect of Humour on Pain Perception among Young Healthy Indian Adults Using Cold Pressor Task.

Background Currently there is little research, especially in India, which has looked at the physiological effects of humour on pain perception. Objective To compare pain sensitivity across the three arms of intervention (control, neutral and funny videos). And to investigate the relationship between a) cardiovascular responses across and within each arm, b) pain sensitivity and resting blood pressure, pulse rate, c) humour trait with pain sensitivity. Method Subjects were exposed in random order to cold pressor task, during which they either watched a 'neutral video' or 'funny video' or did not watch any video. During the intervention, pain threshold and tolerance were recorded. Systolic and diastolic blood pressure, and pulse rate were measured before and after intervention. Pain unpleasantness was recorded post intervention. Result Neither humorous nor neutral videos had a significant effect on pain threshold, tolerance and unpleasantness and cardiovascular responses. There was significant difference between the pre and post values of cardiovascular measures within neutral and funny video arms. In the 'no video' arm, negative correlations were found between resting blood pressure and pain unpleasantness, and between delta diastolic blood pressure and pain threshold. Humour trait and subject's self-rating of pain tolerance had no effect on both pain sensitivity and cardiovascular responses to cold pain. Conclusion Humorous distraction had no effect on objective or subjective pain measures or cardiovascular responses to cold pain exposure. There was a significant difference in the pre-post values of cardiovascular measures within neutral and funny video arms.

Neural dynamics of pain modulation by emotional valence.

Definitions of human pain acknowledge at least two dimensions of pain, affective and sensory, described as separable and thus potentially differentially modifiable. Using electroencephalography, we investigated perceptual and neural changes of emotional pain modulation in healthy individuals. Painful electrical stimuli were applied after presentation of priming emotional pictures (negative, neutral, positive) and followed by pain intensity and unpleasantness ratings. We found that perceptual and neural event-related potential responses to painful stimulation were significantly modulated by emotional valence. Specifically, pain unpleasantness but not pain intensity ratings were increased when pain was preceded by negative compared to neutral or positive pictures. Amplitudes of N2 were higher when pain was preceded by neutral compared to negative and positive pictures, and P2 amplitudes were higher for negative compared to neutral and positive pictures. In addition, a hierarchical regression analysis revealed that P2 alone and not N2, predicted pain perception. Finally, source analysis showed the anterior cingulate cortex and the thalamus as main spatial clusters accounting for the neural changes in pain processing. These findings provide evidence for a separation of the sensory and affective dimensions of pain and open new perspectives for mechanisms of pain modulation.

A computational mechanism of cue-stimulus integration for pain in the brain.

The brain integrates information from pain-predictive cues and noxious inputs to construct the pain experience. Although previous studies have identified neural encodings of individual pain components, how they are integrated remains elusive. Here, using a cue-induced pain task, we examined temporal functional magnetic resonance imaging activities within the state space, where axes represent individual voxel activities. By analyzing the features of these activities at the large-scale network level, we demonstrated that overall brain networks preserve both cue and stimulus information in their respective subspaces within the state space. However, only higher-order brain networks, including limbic and default mode networks, could reconstruct the pattern of participants' reported pain by linear summation of subspace activities, providing evidence for the integration of cue and stimulus information. These results suggest a hierarchical organization of the brain for processing pain components and elucidate the mechanism for their integration underlying our pain perception.

Psychological characteristics and structural brain changes in women with endometriosis and endometriosis-independent chronic pelvic pain.

STUDY QUESTION: Are there neurobiological changes induced by endometriosis? SUMMARY ANSWER: Women with endometriosis demonstrate specific neurobiological changes distinct from those in patients with chronic pelvic pain (CPP) in the absence of endometriosis. WHAT IS KNOWN ALREADY: Endometriosis is a chronic disease affecting women of reproductive age that presents with pain and infertility often accompanied by comorbid mental disorders. Only one study with a number of limitations has investigated changes in gray matter volumes and functional connectivity in a small group of patients with endometriosis. STUDY DESIGN, SIZE, DURATION: This prospective study recruited 53 women undergoing a laparoscopy due to suspicion of symptomatic endometriosis and 25 healthy, pain-free women. Clinical and psychological characteristics, thermal pain perception, and voxel- and surface-based morphology were assessed in all study participants. Thereafter, the patients underwent a laparoscopy, where endometriosis was either histologically confirmed and removed, or ruled out. Correspondingly, patients were assigned into the group with endometriosis (n = 27) or with endometriosis-independent CPP (n = 26) and compared to the pain-free controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study groups were generally representative for the population of women with endometriosis. Sociodemographic, medical, clinical, and psychological characteristics were collected using various questionnaires and a structured clinical interview. Thermal pain perception and voxel- and surface-based morphometry were assessed using thermode and MRI, respectively. MAIN RESULTS AND THE ROLE OF CHANCE: Despite comparable pain intensity and burden of mental disorders, both patient groups demonstrated distinct neurobiological patterns. Women with endometriosis exhibited increased gray matter volume (GMV) in the left cerebellum, lingual gyrus and calcarine gyrus, compared to those with endometriosis-independent CPP. Patients with CPP had decreased GMV in the right cerebellum as compared to controls. Dysmenorrhoea severity correlated positively with GMV in the left inferior parietal lobule, whereas depressive symptoms were associated with decreased GMV in the right superior medial gyrus across patient groups. Dyspareunia correlated negatively with cortical thickness in the left inferior temporal gyrus and left middle temporal gyrus. LIMITATIONS, REASONS FOR CAUTION: The study groups differed in a few baseline-characteristics, including educational levels, smoking and BMI. While measuring pain perception thresholds, we did not attempt to mimic CPP by placement of the thermode on the abdominal wall. WIDER IMPLICATIONS OF THE FINDINGS: Changes in gray matter volume associated with endometriosis differ from those observed in women with endometriosis-independent CPP. Our results underline an involvement of the cerebellum in pain perception and the pathogenesis of pain associated with endometriosis. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by the START Program of the Faculty of Medicine, RWTH Aachen, Germany, and supported by the International Research Training Group (IRTG 2150) of the German Research Foundation (DFG)-269953372/GRK2150, Germany. S.T. was supported by postdoctoral fellowship of the Faculty of Medicine, RWTH Aachen, Germany. There are no conflicts of interest. TRIAL REGISTRATION NUMBER: DRKS00021236.

Pain perception during intravitreal injections is related to the timing of instilling anesthetic eyedrops.

PURPOSE: To evaluate the correlation between the timing of instilling anesthetic eyedrops prior to intravitreal injection and the patient's perception of pain associated with the injection. METHODS: A prospective observational study which included 192 eyes of 192 patients. Time interval between instillation of Oxybuprocaine-0.4% and Tetracaine-0.5% eyedrops upon checking-in and injection was measured and pain level was evaluated by the 101-point-Numeric Rating Scale. RESULTS: We found significant correlation between time interval from the first eyedrops to injection and injection related pain. The lowest pain score (11 ± 18) was found in the 11-15 min group, while the highest was found in the 0-6 min (26 ± 25) and in the > 35 min (31 ± 28) groups. The highest percentage of patients without pain was found in the 11-15 min (64%), followed by the 7-10 min (56%) and 16-20 min (47%) groups. 10% or 17% of the 0-6 min or > 35 min. groups, respectively, reported no pain. No patients in 11-15 min group reported severe pain versus 10% in the 0-6 min and 17% in the > 35 min groups. The highest percentage of patients with 'absent-to-mild' pain was in the 11-15 min (89%) and the 7-10 min (87%) compared to all other groups. CONCLUSIONS: Administration of first dose of anesthetic eyedrops within 11-15 min before intravitreal injection yields the lowest levels of injection-related pain, with 7-10 min being second best. Administration of eyedrops outside of this time-window results in higher pain levels avoidable with more attention to the timing issue.

An initial investigation into the use of virtual reality (VR) glasses on self-reported pain perception during mammography.

OBJECTIVE: Pain is one of the causes of refraining from mammography. This study aimed to investigate the use of virtual reality (VR) glasses for management of pain during mammography. METHODS: Fifty subjects who were referred to the radiology unit for mammography screening were invited to participate in the study. The study was approved by the hospital's ethics committee and participants provided written and oral informed consent. Craniocaudal (CC) and mediolateral oblique (MLO) views of the right breast were first acquired, followed by left CC and MLO mammographic views with the VR glasses on. After the examination, participants completed a questionnaire including a validated visual analog scale (VAS) scoring system to analyze pain scores. Data were analyzed using Spearman's rho and the Kruskal-Wallis test, as well as the Bland-Altman analysis to examine discrepancy. RESULTS: The association of the right breast pain score with the parameters of age, breast density, previous mammography, family history of breast cancer, educational attainment, and employment status was examined using a correlation test. All the parameters showed no significant correlation with the right breast pain score except age (p: 0.016, correlation coefficient: -.340). Apart from that this study demonstrated no significant correlation between the perceived pain experienced during mammography and the utilization of VR technology. CONCLUSION: The findings indicate an inverse correlation between participant's age and pain perception during mammography examinations. Moreover, the utilization of Virtual Reality (VR) did not demonstrate efficacy in reducing pain perception.

Non-invasive electroencephalography in awake cats: Feasibility and application to sensory processing in chronic pain.

BACKGROUND: Feline osteoarthritis (OA) leads to chronic pain and somatosensory sensitisation. In humans, sensory exposure can modulate chronic pain. Recently, electroencephalography (EEG) revealed a specific brain signature to human OA. However, EEG pain characterisation or its modulation does not exist in OA cats, and all EEG were conducted in sedated cats, using intradermal electrodes, which could alter sensory (pain) perception. NEW METHOD: Cats (n=11) affected by OA were assessed using ten gold-plated surface electrodes. Sensory stimuli were presented in random orders: response to mechanical temporal summation, grapefruit scent and mono-chromatic wavelengths (500 nm-blue, 525 nm-green and 627 nm-red light). The recorded EEG was processed to identify event-related potentials (ERP) and to perform spectral analysis (z-score). RESULTS: The procedure was well-tolerated. The ERPs were reported for both mechanical (F3, C3, Cz, P3, Pz) and olfactory stimuli (Cz, Pz). The main limitation was motion artifacts. Spectral analysis revealed a significant interaction between the power of EEG frequency bands and light wavelengths (p<0.001). All wavelengths considered, alpha band proportion was higher than that of delta and gamma bands (p<0.044), while the latter was lower than the beta band (p<0.016). Compared to green and red, exposure to blue light elicited distinct changes in EEG power over time (p<0.001). COMPARISON WITH EXISTING METHOD: This is the first demonstration of EEG feasibility in conscious cats with surface electrodes recording brain activity while exposing them to sensory stimulations. CONCLUSION: The identification of ERPs and spectral patterns opens new avenues for investigating feline chronic pain and its potential modulation through sensory interventions.

Data-driven analysis of whole-brain intrinsic connectivity in patients with chronic low back pain undergoing osteopathic manipulative treatment.

BACKGROUND: Chronic Low Back Pain (cLBP) poses a significant health challenge, leading to functional disability and reduced quality of life. Osteopathic Manipulative Treatment (OMT) is emerging as a therapeutic option for cLBP, but the brain mechanisms underlying its analgesic effect remain unclear. MATERIALS AND METHODS: Thirty cLBP patients were randomly exposed to either four weekly sessions of OMT (N=16) or Sham treatment (N=14). Resting-state Magnetic Resonance Imaging (rs-MRI) scans and pain perception questionnaires were collected before and after treatment. A voxel-wise, rs-fMRI data-driven analysis was conducted to identify changes in the intrinsic functional connectivity across the whole brain that were associated with the OMT. Spearman's correlations were used to test for the association between changes in intrinsic connectivity and individual reports of pain perception. RESULTS: Compared to the Sham group, participants who received OMT showed significant alterations in the functional connectivity of several regions belonging to the pain matrix. Specifically, OMT was associated with decreased connectivity of a parietal cluster that includes the somatosensory cortex and an increase of connectivity of the right anterior insula and ventral and dorsal anterolateral prefrontal areas. Crucially, the change in connectivity strength observed in the ventral anterolateral prefrontal cortex, a putative region of the affective-reappraisive layer of the pain matrix, correlates with the reduction in pain perception caused by the OMT. CONCLUSIONS: This study offers insights into the brain mechanisms underlying the analgesic effect of OMT. Our findings support a link between OMT-driven functional cortical architecture alterations and improved clinical outcomes.

Disentangling the spinal mechanisms of illusory heat and burning sensations in the thermal grill illusion.

ABSTRACT: The thermal grill illusion (TGI), a phenomenon in which the juxtaposition of innocuous warm and cold temperatures on the skin elicits a burning sensation, offers a unique perspective to how pain occurs in response to harmless stimuli. We investigated the role of the spinal cord in the generation of the TGI across 2 experiments (total n = 80). We applied heat and cold stimuli to dermatomes, areas of skin innervated by a single spinal nerve, that mapped onto adjacent or nonadjacent spinal segments. Enhanced warm and burning ratings during the TGI were observed when cold and warm stimuli were confined within the same dermatome. Furthermore, we found the spatial organisation of warm and cold stimuli within and across dermatomes affected TGI perception. Perceived warmth and burning intensity increased when the cold stimulus projected to the segment more caudal to the warm stimulus, whereas perceived cold during the TGI decreased compared with the opposite spatial arrangement. This suggests that the perception of TGI is enhanced when cold afferents are projected to spinal segments positioned caudally in relation to those receiving warm afferents. Our results indicate distinct interaction of sensory pathways based on the segmental arrangement of afferent fibres and are consistent with current interpretations of the spread and integration of thermosensory information along the spinal cord.

Astrocytes in Pain Perception: A Systems Neuroscience Approach.

Astrocytes play an active role in the function of the brain integrating neuronal activity and regulating back neuronal dynamic. They have recently emerged as active contributors of brain's emergent properties such as perceptions. Here, we analyzed the role of astrocytes in pain perception from the lens of systems neuroscience, and we do this by analyzing how astrocytes encode nociceptive information within brain processing areas and how they are key regulators of the internal state that determines pain perception. Specifically, we discuss the dynamic interactions between astrocytes and neuromodulators, such as noradrenaline, highlighting their role in shaping the level of activation of the neuronal ensemble, thereby influencing the experience of pain. Also, we will discuss the possible implications of an "Astro-NeuroMatrix" in the integration of pain across sensory, affective, and cognitive dimensions of pain perception.

An approach to the detection of pain from autonomic and cortical correlates.

OBJECTIVE: To assess the value of combining brain and autonomic measures to discriminate the subjective perception of pain from other sensory-cognitive activations. METHODS: 20 healthy individuals received 2 types of tonic painful stimulation delivered to the hand: electrical stimuli and immersion in 10 Celsius degree (°C) water, which were contrasted with non-painful immersion in 15 °C water, and stressful cognitive testing. High-density electroencephalography (EEG) and autonomic measures (pupillary, electrodermal and cardiovascular) were continuously recorded, and the accuracy of pain detection based on combinations of electrophysiological features was assessed using machine learning procedures. RESULTS: Painful stimuli induced a significant decrease in contralateral EEG alpha power. Cardiac, electrodermal and pupillary reactivities occurred in both painful and stressful conditions. Classification models, trained on leave-one-out cross-validation folds, showed low accuracy (61-73%) of cortical and autonomic features taken independently, while their combination significantly improved accuracy to 93% in individual reports. CONCLUSIONS: Changes in cortical oscillations reflecting somatosensory salience and autonomic changes reflecting arousal can be triggered by many activating signals other than pain; conversely, the simultaneous occurrence of somatosensory activation plus strong autonomic arousal has great probability of reflecting pain uniquely. SIGNIFICANCE: Combining changes in cortical and autonomic reactivities appears critical to derive accurate indexes of acute pain perception.

Identifying pain profiles in employees including work-related factors and pain perceptions: a cross-sectional study in Belgian companies.

OBJECTIVES: Studies usually investigate a limited number or a predefined combinations of risk factors for sickness absence in employees with pain. We examined frequently occurring combinations across a wide range of work-related factors and pain perceptions. DESIGN: Cross-sectional study. SETTING: Belgian companies that are under supervision of IDEWE, an external service for prevention and protection at work. PARTICIPANTS: In total, 249 employees experiencing pain for at least 6 weeks were included and filled out an online survey. OUTCOMES: Latent profile analysis was used to differentiate profiles of work-related factors (physical demands, workload, social support and autonomy) and pain perceptions (catastrophising, fear-avoidance beliefs and pain acceptance). Subsequently, profiles were compared on sociodemographics (age, gender, level of education, work arrangement, duration of complaints, multisite pain and sickness absence in the previous year) and predictors of sickness absence (behavioural intention and perceived behavioural control). RESULTS: Four profiles were identified. Profile 1 (38.2%) had favourable scores and profile 4 (14.9%) unfavourable scores across all indicators. Profile 2 (33.3%) had relatively high physical demands, moderate autonomy levels and favourable scores on the other indicators. Profile 3 (13.7%) showed relatively low physical demands, moderate autonomy levels, but unfavourable scores on the other indicators. Predictors of profiles were age (OR 0.93 and 95% CI (0.89 to 0.98)), level of education (OR 0.28 and 95% CI (0.1 to 0.79)) and duration of sickness absence in the previous year (OR 2.29 and 95% CI (0.89 to 5.88)). Significant differences were observed in behavioural intention (χ2=8.92, p=0.030) and perceived behavioural control (χ2=12.37, p=0.006) across the four profiles. CONCLUSION: This study highlights the significance of considering the interplay between work-related factors and pain perceptions in employees. Unfavourable scores on a single work factor might not translate into maladaptive pain perceptions or subsequent sickness absence, if mitigating factors are in place. Special attention must be devoted to employees dealing with unfavourable working conditions along with maladaptive pain perceptions. In this context, social support emerges as an important factor influencing sickness absence.