Central sensitivity in fibromyalgia: testing a model to explain the role of psychological factors on functioning and quality of life.

OBJECTIVES: Central sensitivity (CS) is defined as an increased responsiveness of nociceptive neurons in the central nervous system to normal or subthreshold inputs. CS has recently been linked to the psychological burden associated with chronic pain, such as fibromyalgia (FM). The primary objective of this study is to investigate the impact of specific psychological constructs on CS in patients with FM. In Study 1, we explore the influence of temperament, personality, childhood trauma, defence mechanisms, and mental pain on CS. In Study 2, our goal is to test the role of the best predictors of CS in influencing quality of life (QoL) and FM functioning through a path analysis model. METHODS: A total of 510 women with FM participated online, completing a self-administered protocol. Data collection took place between April and June of 2023. RESULTS: In Study 1, higher levels of low sensory threshold (ß=0.210), traumatic experiences of physical threat (ß=0.141), neurotic defences (ß=0.124), and mental pain (ß=0.241) emerged as the strongest predictors of increased CS. In Study 2, the presented model demonstrated a satisfactory fit (chi2=27.200; df=10; p=0.002; GFI=0.984; NFI=0.949; CFI=0.967; RMSEA=0.061 [95% CI 0.034-0.090]) with large and medium effect sizes on physical (-0.576) and psychological (-0.190) QoL. CONCLUSIONS: The study underscores the pivotal role of psychological dimensions in influencing CS levels and their relationships with QoL in patients with FM.

Quality of life, craniomandibular function, and psychosocial factors related to pain and movement in patients with head and neck cancer.

PURPOSE: To describe the characteristics of and the associations between health-related quality of life, pain, craniomandibular function, and psychosocial factors related to pain and fear of movement in patients with head and neck cancer. METHODS: Seventy-eight patients diagnosed with HNC were recruited. Measurements of the maximum mouth opening range and pressure pain thresholds on the masseter muscle and the distal phalanx of the thumb were conducted, as well as a battery of self-report questionnaires were administrated, including the QoL Questionnaire (EORT QLQ-H&N35), Numeric Rating Scale (NRS), Pain Catastrophizing Scale (PCS), the Spanish translation of the Tampa Scale for Kinesiophobia for Temporomandibular Disorders (TSK-TMD), and the short version of the Craniofacial Pain and Disability Inventory (CF-PDI-11). RESULTS: The study sample (66.7% men, mean age 60.12 [11.95] years) experienced a moderate impact on their QoL levels (57.68 [18.25] EORT QLQ-H&N35) and high kinesiophobia values (20.49 [9.11] TSK-TMD). Pain was present in 41% of the patients, but only 3.8% reported severe pain. 26.4% had a restricted mouth opening range, and 34.62% showed significant catastrophism levels. There were strong positive correlations between EORT QLQ-H&N35 and CF-PDI-11 (r = 0.81), between NRS and CF-PDI-11 (r = 0.74), and between PCS and CF-PDI-11 (r = 0.66). CONCLUSION: Patients with HNC experience negative effects in their QoL, related to their impairment in craniomandibular function. Fear of movement, pain intensity, and catastrophism are associated with poorer functionality; relationships that should be considered when attempting to improve health care.

Influence of genetic polymorphisms on mechanical pain sensitivity and endogenous pain modulation of trigeminal and spinal areas.

BACKGROUND: Previous evidence indicates significant association between genetic polymorphisms and phenotypes related to pain sensitivity in patients with temporomandibular disorders (TMD). Despite the important advances in cataloguing diverse factors such as sleep disorders, anxiety and depression, the interrelated mechanisms of painful TMD aetiopathogenesis still need investigation. OBJECTIVES: This case-control study aimed to evaluate the influence of genetic polymorphisms (rs6296, rs6295, rs1799971, rs4680, rs4633, rs4818) and psychosocial factors on the mechanical pain sensitivity and endogenous pain modulation in women with painful TMD and asymptomatic controls. METHODS: We evaluated six independent variables: anxiety levels, depression, stress, sleep quality, pain catastrophising and genetic polymorphisms, and four dependent variables: mechanical pain threshold (MPT), pressure pain threshold (PPT), wind-up ratio (WUR) and conditioned pain modulation (CPM) collected at masseter (trigeminal) and hand (spinal) areas in a sample of 95 painful TMD patients and 85 controls. A regression model was used to test the possible effect of the independent variables on dependent variables. RESULTS: The regression model was significant for MPT (F11,168  = 9.772; R2  = .390). Painful TMD diagnoses and sleep quality were associated with trigeminal MPT (B coefficient = -.499; and B coefficient = -.211, respectively). WUR was associated with rs6295 and rs6746030, respectively, for the spinal and the trigeminal area. CONCLUSION: Genetic polymorphisms had a slight contribution to endogenous pain modulation as indicated by the significant association with WUR but did not contribute to mechanical pain sensitivity. On the other hand, the presence of painful TMD and the sleep quality contributed significantly to mechanical pain sensitivity.

Association between pelvic pain bothersomeness and pain sensitivity: A community-based cross-sectional study of young adult females in the Raine Study.

OBJECTIVE: Pelvic pain has been associated with augmented nociceptive processing, but large studies controlling for multiple potential confounding factors are lacking. This study investigated the association between pelvic pain bothersomeness and pain sensitivity in young adult women, accounting for potential confounding factors. DESIGN: Cross-sectional study. SETTING: Community-dwelling sample. POPULATION: The Raine Study Gen2-22 year follow-up (n = 475). MAIN OUTCOME MEASURES: The experience of bothersomeness related to pelvic pain was determined from a question in the Urogenital Distress Inventory short form. Pain sensitivity was measured using pressure pain and cold pain thresholds. Potential confounding factors included ethnicity, marital status, highest level of education, income, waist-hip ratio, level of activity, sleep quality, smoking, comorbidity history, C-reactive protein level, musculoskeletal pain experience and psychological distress. RESULTS: Three hundred and sixty-two women (76.2%) reported no pelvic pain bothersomeness, 74 (15.6%) reported mild pelvic pain bothersomeness and 39 (8.2%) reported moderate-severe pelvic pain bothersomeness. After adjusting for marital status (and test site), moderate-severe pelvic pain bothersomeness was associated with a lower pressure pain threshold (i.e. greater pressure pain sensitivity) (coefficient -51.46, 95% CI -98.06 to -4.86, p = 0.030). After adjusting for smoking, moderate-severe pelvic pain bothersomeness was also associated with a higher cold pain threshold (i.e. greater cold pain sensitivity) (coefficient 4.35, 95% CI 0.90-7.79, p = 0.014). CONCLUSIONS: This study suggests augmented nociceptive processing as a contributing factor in pelvic pain bothersomeness for some women. Thorough assessment of women who present clinically with pelvic pain should consider pain sensitivity as a potential contributing factor to their presentation.

Relationships Between Psychological, Sleep, and Physical Activity Measures and Somatosensory Function in People With Peripheral Joint Pain: A Systematic Review and Meta-Analysis.

OBJECTIVE: Alteration in somatosensory function has been linked to pain experience in individuals with joint pain. In this systematic review we aimed to establish the level of evidence of associations between psychological, social, physical activity, and sleep measures and somatosensory function that were assessed via quantitative sensory testing (QST) among individuals with joint pain. METHODS: A comprehensive literature search was conducted in 6 electronic databases from their inception to July 2019. Two reviewers independently assessed the methodological quality using a modified Quality in Prognostic Studies (QUIPS) tool and supplemented with recommendations from the Critical Appraisal and Data Extraction for Systematic Review of Prediction Modelling Studies (CHARMS) checklist and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The level of evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) system. Data were pooled to evaluate the strength of the relationships of interest. RESULTS: Seventeen studies related to joint pain were included. Pain catastrophizing, depression, anxiety, and physical activity level have been shown to have a significant (small to fair) association with several QST measures. Pressure pain threshold (PPT) is the only measure that was found to be consistently correlated with all the domains. The overall quality of evidence for all factors ranged from very low to moderate. Subgroup analysis revealed a stronger association for depression and pain catastrophizing and PPT and temporal pain summation in individuals with shoulder pain. CONCLUSION: Psychological factors and physical activity levels are associated with somatosensory function in people with joint pain. These factors need to be adjusted when establishing predictive relationships between somatosensory function and pain outcomes in individuals with joint pain.

Associations Among Sleep Latency, Subjective Pain, and Thermal Pain Sensitivity in Gynecologic Cancer.

OBJECTIVE: Pain is common among women with gynecologic cancer and contributes to depressed mood, sleep disturbances, and likelihood of future chronic pain. Little is known about how psychosocial factors are associated with central sensitization of pain in gynecologic cancer. This study examined relations among depressive symptoms, sleep, subjective pain, and aftersensation pain (a proxy for central sensitization of pain) in gynecologic cancer. METHODS: Participants were 42 women (mean age [SD] = 59.60 [10.11] years) enrolled in a randomized clinical trial examining psychological intervention effects on sleep, pain, mood, and stress hormones/cytokines in gynecologic cancer. Six to eight weeks after surgery, participants completed an assessment of depressive symptoms, sleep, and subjective pain and a temporal summation of pain protocol via quantitative sensory testing (QST). RESULTS: Controlling for recent chemotherapy, history of chronic pain, and analgesic medication use, regression analyses revealed that longer sleep onset latency (SOL; B = 3.112, P = 0.039, bias-corrected and accelerated (BCa) 95% confidence interval [CI] = 0.371 to 6.014) and greater sensory pain (B = 0.695, P = 0.023, BCa 95% CI = 0.085 to 1.210) were associated with greater aftersensation pain at 15 seconds. Greater sensory pain scores were associated with greater aftersensation pain at 30 seconds (B = 0.286, P = 0.045, BCa 95% CI = 0.008 to 0.513). Depression was not associated with aftersensation pain. The overall models accounted for 44.5% and 40.4% of the variance in aftersensation pain at 15 and 30 seconds, respectively. Conclusions. Longer SOL and higher subjective sensory pain were related to greater aftersensation of experimentally induced pain in women postsurgery for gynecologic cancers. Interventions that improve sleep and subjective sensory pain during the perisurgical period may reduce risk for central sensitization of pain.

Transcutaneous Electrical Stimulation on the Submental Area: The Relations of Biopsychological Factors with Maximum Amplitude Tolerance and Perceived Discomfort Level.

Transcutaneous electrical stimulation (TES) is a frequently used adjunctive modality in dysphagia rehabilitation. Stimulating deeper swallowing muscles requires higher TES amplitude. However, TES amplitude is limited by maximum amplitude tolerance (MAT). Previous studies have reported high interindividual variability regarding MAT and perceived discomfort. This variability might be one of the potential reasons of conflicting outcomes in TES-based swallowing studies. MAT and perceived discomfort are influenced by a variety of biopsychological factors. The influence of these factors related to swallow applications is poorly understood. This study explored the relation of biopsychological factors with MAT and perceived discomfort related to TES in the submental area. A convenience sample of thirty community-dwelling older adults between 60 and 70 years of age provided data for this study. Gender, submental adipose tissue thickness, perceptual pain sensitivity, and pain-coping strategies were evaluated for each subject. Subsequently, MAT and perceived discomfort level were determined using TES on the submental area. Relation of different biopsychological variables with MAT and discomfort level was examined using Pearson and Spearman correlation, and Mann-Whitney U test. Results indicated that neither gender nor adipose thickness was related to MAT and perceived discomfort. Among studied pain-coping strategies, catastrophizing was significantly related to MAT(r = - 0.552, p < .002). Distraction was significantly related to perceived discomfort level (r = - 0.561, p < 0.002). Given the negative impact of pain catastrophizing on MAT and the positive impact of distraction on perceiving discomfort, these coping strategies should be considered as amplitude-limiting and discomfort-moderating factors in TES-based dysphagia rehabilitation.

Effects of Phase Polarity and Charge Balance Spinal Cord Stimulation on Behavior and Gene Expression in a Rat Model of Neuropathic Pain.

OBJECTIVE: To investigate the effect of phase polarity and charge balance of spinal cord stimulation (SCS) waveforms on pain behavior and gene expression in a neuropathic pain rodent model. We hypothesized that differing waveforms will result in diverse behavioral and transcriptomics expression due to unique mechanisms of action. MATERIALS AND METHODS: Rats were implanted with a four-contact cylindrical mini-lead and randomly assigned to two control (no-pain and pain model) and five test groups featuring monophasic, as well as charge-unbalanced and charge-balanced biphasic SCS waveforms. Mechanical and cold allodynia were assessed to measure efficacy. The ipsilateral dorsal quadrant of spinal cord adjacent to the lead was harvested post-stimulation and processed to determine gene expression via real-time reverse-transcriptase polymerase chain reaction (RT-PCR). Gene expression, SCS intensity (mA), and behavioral score as percent of baseline (BSPB) were statistically analyzed and used to generate correlograms using R-Studio. Statistical analysis was performed using SPSS22.0, and p < 0.05 was considered significant. RESULTS: As expected, BSPB was significantly lower for the pain model group compared to the no-pain group. BSPB was significantly improved post-stim compared to pre-stim using cathodic, anodic, symmetric biphasic, or asymmetric biphasic 1:2 waveforms; however, BSPB was not restored to Sham levels. RT-PCR analysis showed that eight genes demonstrated a significant difference between the pain model and SCS waveforms and between waveforms. Correlograms reveal a linear correlation between regulation of expression of a given gene in relation to mA, BSPB, or other genes. CONCLUSIONS: Our results exhibit that specific SCS waveforms differentially modulate several key transcriptional pathways that are relevant in chronic pain conditions. These results have significant implications for SCS: whether to move beyond traditional paradigm of neuronal activation to focus also on modulating immune-driven processes.

The Association of Psychosocial Factors and Exercise-Induced Hypoalgesia in Healthy People and People With Musculoskeletal Pain: A Systematic Review.

BACKGROUND: Exercise, a cornerstone in current treatments for people with musculoskeletal pain, elicits a phenomenon called exercise-induced hypoalgesia (EIH), which may result in reduced pain intensity and/or increased pain thresholds. However, EIH can be impaired in patients with musculoskeletal pain, and psychosocial factors may play a mediating role in EIH. OBJECTIVE: The aim of this study was to systematically review the scientific literature regarding the association between psychosocial factors and EIH in healthy people and people with musculoskeletal pain. METHODS: An extensive search in databases including Medline Ovid, Embase, Web of Science, PsycINFO Ovid, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCOhost was carried out. Two reviewers independently carried out study selection, data extraction, and critical appraisal. Included studies analyzed the association or effect of psychosocial factors on EIH in adults with or without musculoskeletal pain. RESULTS: Nine cross-sectional studies were included, 6 involving healthy people and 4 involving people with musculoskeletal pain; 1 study included both. Overall risk of bias was high. Different types of exercise bouts, psychosocial factors, and/or outcome measures were used across studies. In healthy people and people with musculoskeletal pain, most studies did not find an association between psychosocial factors and EIH. However, 1 study involving musculoskeletal pain and 2 studies with healthy people did find a significant association. CONCLUSION: Due to poor quality and heterogeneity between studies, no conclusions can be drawn regarding whether psychosocial factors are associated with EIH or not. This review includes recommendations and directions for further research to investigate the role of psychosocial factors on EIH.

Does Social Exclusion Alter Sensory and Pain Thresholds in Children and Adolescents with Functional Abdominal Pain? - Results from a Preliminary Study.

OBJECTIVE: Functional abdominal pain (AP) is a prevalent issue in childhood and adolescence. The contribution of psychosocial factors in the development and maintenance of this health problem is rather unclear, and experimental studies about underlying mechanisms are lacking. This study investigates whether experimentally induced social exclusion decreases sensory and pain thresholds in children suffering from AP. SUBJECTS: Twenty children/adolescents with AP and 22 healthy controls. METHODS: Children/adolescents participated in the Cyberball paradigm, which affects an experience of social exclusion. Thermal sensory and pain thresholds were measured before and after Cyberball. RESULTS: Children/adolescents with AP showed a divergent reaction regarding their sensory threshold after social exclusion: The control group exhibited a tendency toward a decreased sensory threshold whereas the AP group remained stable. Concerning the pain threshold, no effect of social exclusion could be identified. The increase of both thresholds ("numbing") after Cyberball was positively correlated with symptoms of mental health issues. CONCLUSIONS: This is the first study to investigate changes in sensory and pain thresholds following painful social interactions in a sample of children/adolescents with a chronic pain condition. Results suggest that AP and control children differ in their reaction of sensory thresholds, which might indicate an altered processing of social exclusion. Replication and further methodological improvements are needed.

Prognostic Value of Pain Sensitization During Early Recovery After Distal Radius Fracture in Complex Regional Pain Syndrome.

OBJECTIVE: To evaluate the influence of pain sensitization in the early recovery of distal radius fractures (DRFs) on the occurrence and prognosis of complex regional pain syndrome (CRPS) type I. METHODS: We enrolled 58 patients who were diagnosed with CRPS I based on Budapest criteria within six months after sustaining DRF; they were age- and gender-matched with 58 patients with DRF who did not have CRPS I. We commonly measured patients' pressure pain thresholds (PPTs) in the forearm and administered a Pain Sensitivity Questionnaire (PSQ) when patients complained of pain with numeric rating scale ≥4 at three-month follow-up. Participants were followed up three, six, and 12 months after injury, and the symptoms and sign of CRPS were evaluated at each follow-up. RESULTS: Patients with CRPS I were more likely to have sustained high-energy injuries, had severe fractures, and had significantly higher PSQ scores and lower PPTs than the age- and gender-matched controls. At 12 months after injury, CRPS symptoms improved in 52% (30/58) of patients who had been diagnosed with CRPS I at three months after injury. The initial degree of pain sensitization and high-energy injury were associated with persistence of CRPS symptoms up to 12 months after initial injury. CONCLUSIONS: Patients with CRPS I after DRF exhibited significantly higher pain sensitization in the early post-trauma period, and the degree of initial pain sensitization and high-energy injuries were associated with prolonged CRPS I signs and symptoms up to one year after initial injury.

Beneficial Effects of Regular Physical Activity on Exercise-Induced Analgesia in Adolescent Males.

PURPOSE: To evaluate exercise-induced analgesia (EIA) effectiveness in healthy adolescent males and to investigate possible associations between EIA and physiological/psychological variables. METHODS: Twenty-eight healthy adolescent males (14-17 y) participated in this study. EIA was evaluated by comparing perceptions of heat pain stimulations before and after an increasing maximal load test on a cycle ergometer (VO2max). RESULTS: Pain intensity for mild and strong heat pain stimulations significantly decreased following physical exercise (mild: EIA = 28.6%; 95% confidence interval, 0.9-1.9; P < .001 and strong: EIA = 11.3%; 95% confidence interval, 0.3-1.4; P = .002). The number of physical activity hours per week was positively correlated with the effectiveness of EIA for mild and strong pain intensity (r = .41, P = .03 and r = .43, P = .02, respectively). CONCLUSIONS: Intense physical exercise decreases perception of intensity of experimental heat pain in healthy adolescent males. The least physically active adolescents have reduced EIA effectiveness to experimental heat pain stimulations compared with physically active ones. Adolescents adopting an active lifestyle have more endogenous pain inhibition and could, therefore, potentially be less disposed to suffer from chronic pain later in life.

Widespread mechanical pain hypersensitivity in patients with chronic migraine and temporomandibular disorders: relationship and correlation between psychological and sensorimotor variables.

OBJECTIVE: This study aimed to assess mechanical hyperalgesia in the trigeminal and extra-trigeminal regions in patients with chronic migraine (CM) and temporomandibular disorders (TMD) in comparison to asymptomatic subjects and to determine the association between sensorimotor variables and psychological and disability variables and evaluate the prediction of a sensorimotor variables though psychological and disability variables in patients with CM and TMD. MATERIAL AND METHODS: A total of 52 subjects with concomitant CM and TMD and 30 asymptomatic subjects were included in the study. The pressure pain threshold (PPT), maximal mouth opening (MMO) and a series of self-reported factors were compared. RESULTS: There were 52 CM and TMD (92.3% women and 7.7% men; age = 46.2 ± 9.5) and 30 asymptomatic subjects (80% women and 20% men; age = 47.4 ± 10). Differences were found between patients with CM and TMD and asymptomatic participants (p < .01) when comparing the PPTs in the trigeminal and extra-trigeminal regions. The PPT for the trigeminal region was predicted by depressive symptoms (variance of 18%) as well as disability and craniofacial pain (variance of 20%). The extra-trigeminal region PPT was predicted by depressive symptoms (variance of 10%), and pain-free MMO was predicted by disability and craniofacial pain (variance of 24%). CONCLUSIONS: This study suggests that patients with CM and TMD present with generalized mechanical hyperalgesia. In addition, an association between sensorimotor, psychological and disability variables was observed.

Sensitivity to Physical Activity Predicts Daily Activity Among Pain-Free Older Adults.

Objective: Prior research indicates that older adults with knee osteoarthritis have increased sensitivity to physical activity (SPA) and respond to physical activities of stable intensity with increases in pain. Whether SPA is present in healthy older adults without chronic pain and predicts functional outcomes remains relatively unexplored. The purpose of this study was to determine the degree of SPA in healthy older adults in response to a standardized walking task, and whether SPA was associated with temporal summation of pain, pain-related fear of movement, and functional outcomes. Methods: Fifty-two older adults without chronic pain completed self-reported measures of activity-related pain and physical function, completed the Six-Minute Walk Test (6MWT), underwent quantitative sensory testing to measure temporal summation of heat pain, and wore an accelerometer for one week to measure physical activity behavior. Subjects rated overall bodily discomfort (0-100 scale) prior to and during each minute of the 6MWT. An SPA index was created by subtracting the initial bodily discomfort ratings from the peak ratings. Results: Repeated-measures analysis of variance indicated that bodily discomfort significantly increased across the walking task, with approximately 60% of the sample experiencing SPA. Hierarchical regressions indicated that greater SPA was associated with fewer average steps per day and greater activity-related pain. Additionally, analyses revealed that temporal summation of pain and pain-related fear of movement significantly predicted the degree of SPA on the walking task. Conclusions: These findings shed light on potential mechanisms underlying SPA in older adults and suggest that SPA might be a risk factor for reduced physical activity.

Pain catastrophizing, activity engagement and pain willingness as predictors of the benefits of multidisciplinary cognitive behaviorally-based chronic pain treatment.

Pain catastrophizing and pain acceptance have been shown to be associated with improvements after participation in cognitive behaviorally-based treatment (CBT) for chronic pain. However, it is not yet clear how important each of these factors is relative to the other. Furthermore, it is also not clear if multidisciplinary pain treatment has the same impact on the two primary dimensions of pain acceptance (activity engagement and pain willingness), and whether their role in explaining treatment outcome differs as a function of the outcomes under study. The aim of this study was to examine the relative importance of changes in pain catastrophizing, activity engagement and pain willingness as predictors of the benefits of a multidisciplinary CBT for chronic pain. 186 adults with chronic pain participated. Pain catastrophizing and activity engagement, but not pain willingness, were significantly associated with treatment outcome. Moreover, each one evidenced different patterns of associations with outcomes. Specifically, while changes in both were associated with improvements in depressive symptoms, only catastrophizing was associated with improvements in pain intensity and only activity engagement was associated with improvements in pain-related disability.

Pressure pain thresholds over the cranio-cervical region in headache: a systematic review and meta-analysis.

BACKGROUND: Sensitivity of tissues can be measured by algometry. Decreased pressure pain thresholds over the cranio-cervical area are supposed to reflect signs of sensitization of the trigemino-cervical nucleus caudalis. A systematic review was conducted to assess the current scientific literature describing pressure pain threshold (PPT) values over the cranio-cervical region in patients with migraine, tension-type headache (TTH), and cervicogenic headache (CeH). A literature search was executed in three databases. The search strategy included the following keywords: migraine, TTH, CeH, PPT and algometry. A total of 624 papers was identified of which relevant papers were subsequently assessed for methodological quality. Twenty-two selected papers were assessed by two independent reviewers and the majority of studies scored low risk of bias on the selected items. Mean PPT values of several sites measured in the cranio-cervical region in patients with migraine, chronic TTH and CeH scored lower values compared to controls. The trapezius muscle (midpoint between vertebrae C7 and acromion) was the most frequently targeted site and showed significantly lower PPT values in adults with migraine (pooled standardized mean difference kPa: 1.26 [95%CI -1.71, -0.81]) and chronic TTH (pooled standardized mean difference kPa: -2.00 [95%CI -2.93, -1.08]). Most studies found no association between PPT values and headache characteristics such as frequency, duration or intensity. Further standardization of PPT measurement in the cranio-cervical region is recommended.

[Links between self-harm and suicidal behaviour in adolescents]. / Liens entre conduites automutilatoires et suicidaires chez les adolescents.

Nonsuicidal self-injury (NSSI) and suicidal behaviour (SB) are both important issues in adolescent health care. The fact that they frequently coexist means that it is important to consider the nature of the link between them and the ways they are understood. Suicide and self-injury share the same risk factors. Integrated models envisage NSSI as a gateway enabling teenagers to acquire a capability for suicide. The act short-circuits the thought process and the intention to die underlying the act appears difficult to assess.

THE RELATIONSHIP BETWEEN THERMAL PAIN SENSATION, FREE TESTOSTERONE, TRPV1, MOR LEVELS AND VARIOUS DEGREES OF HOSTILITY IN YOUNG HEALTHY MALES.

Large number of studies consider gonadal hormones as factors influencing pain perception by changing the activity of nociceptive and antinociceptive systems. Recent studies indicate that testosterone, along with some other gonadal hormones, plays a key role in the regulation of TRPV1 and MOR expression. In addition, some works focus on the relationship between pain sensation and hostility indices, as well as their interaction with gonadal hormones. The purpose of this study is to elucidate the relationship of thermal sensation and pain threshold with free testosterone, transient receptor potential cation channel subfamily V member 1(TRPV1) and µ-opioid receptor (MOR) protein levels as well as various degrees of hostility in young healthy males. Significant positive correlation is found between heat pain threshold, free testosterone and MOR levels. Each of these parameters significantly correlates positively with various degrees of assault and insignificantly with that of verbal and indirect hostility. They also significantly correlate negatively with various degrees of irritability, resentment, suspicion and guilt. Significant negative correlation is detected between heat pain threshold and TRPV1 level as well as free testosterone and TRPV1 level. The relationship among cold pain threshold, free testosterone, TRPV1, MOR levels and hostility indices is insignificant. Consequently, we consider it to the purpose to further studies in this direction including interaction among other forms of pain sensation and psychological indices.

[CORRELATION BETWEEN HEAT PAIN THRESHOLD DEGREE AND TRPV1 RECEPTOR PROTEIN LEVEL OVER VARIOUS PHASES OF THE OVARIAN-MENSTRUAL CYCLE].

Numerous scientific studies demonstrating differences in pain sensitivity over various phases of the ovarian-menstrual cycle (OMC) in healthy women have been published in recent decades, but the basis for these differences is however still poorly understood. The aim of the current study was to assess the correlation between the heat pain threshold degree and the dynamics of TRPV1 (Transient receptor potential channeling subfamily V member1) receptor protein level, as well as aggression degree in healthy women in the follicular and luteal phases of OMC. An increased TRPV1 receptor protein level and a decreased thermal pain threshold were found in the luteal phase of the OMC. The study revealed a correlation of the progesterone level in the luteal phase with a degree of increase of TRPV1 level, as well as with the degree of decrease of heat pain threshold. The relationship between the degree of pain threshold, as well as TRPV1 level with follicle stimulating (FSH), luteinizing (LH) hormones and prolactin levels was not found. Also, there was no correlation between TRPV1 or heat pain threshold levels and aggression degree.

Electrophysiological and psychophysical correlates of spatial summation to noxious heat: the possible role of A-delta fibers.

Although spatial summation of pain (SSP) is central to the processing of pain intensity and quality, its mechanism is not fully understood. We previously found greater heat SSP in hairy than in glabrous skin, suggesting that perhaps A-mechano-heat II (AMH-II) nociceptors are the dominant subserving system. In order to further explore the role of A-delta fibers in heat-induced SSP, we analyzed the electrophysiological correlates of SSP under conditions that minimize the influence of skin thicknesses. Among 17 subjects, fast rate of rise (70 °C/sec) heat stimuli that induced a pre-fixed, similar, SSP magnitude for hairy and glabrous skin were repeatedly administered using large and small probes, during which time the contact heat-evoked potentials (CHEPs) and pain ratings were recorded. Both N2 and P2 amplitudes were larger in hairy than in glabrous skin, but a differential effect of SSP was found on the CHEPs. Despite similar psychophysical SSP in hairy and glabrous skin, the electrophysiological SSP reflected in N2 but not P2 amplitude was larger in hairy skin. Nevertheless, regardless of skin type, SSP was manifested by an increase in P2 amplitudes. Considering the uniform psychophysical SSP for the two skin types, the fast stimulation rate and lower activity of AMH-II in glabrous skin, a greater electrophysiological SSP in hairy than in glabrous skin may suggest that SSP is mainly subserved by AMH nociceptors. The overall SSP effect, manifested in greater P2 amplitude, may reflect specific brain responses aimed to prepare the individual to an increased potential tissue damage.