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Fear and anxiety: Divergent effects on human pain thresholds

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Abstract

Animal studies suggest that fear inhibits pain whereas anxiety enhances it; however it is unclear whether these effects generalize to humans. The present study examined the effects of experimentally induced fear and anxiety on radiant heat pain thresholds. Sixty male and female human subjects were randomly assigned to 1 of 3 emotion induction conditions: (1) fear, induced by exposure to three brief shocks; (2) anxiety, elicited by the threat of shock; (3) neutral, with no intervention. Pain thresholds were tested before and after emotion induction. Results suggest that findings from animal studies extend to humans: fear resulted in decreased pain reactivity, while anxiety led to increased reactivity. Pain rating data indicated that participants used consistent subjective criteria to indicate pain thresholds. Both subjective and physiological indicators (skin conductance level, heart rate) confirmed that the treatment conditions produced the targeted emotional states. These results support the view that emotional states modulate human pain reactivity.

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... 45 Psychiatric diagnoses have also been reported to predispose toward a paradoxically lower pain threshold in one study, whereas the relationship of anxiety to dental procedural pain is well established. [46][47][48] We noted an increase in PΔmax in patients with a pre-existing pain condition or who are currently prescribed an analgesic. Though chronic pain conditions vary considerably, there is extensive data in the pain literature describing decreased acute nociceptive thresholds in patients suffering from chronic pain in the form of temporomandibular joint dysfunction, migraines, tension headaches, and fibromyalgia. ...
... As was demonstrated in the study by Young et al., failed attempts were associated with increased pain scores and increased likelihood of failure of subsequent approaches, whereas anxiety can also contribute to increased pain. 21,47 Lastly, there was no statistical difference in PΔmax between unilateral and bilateral procedures. This finding was unanticipated. ...
Article
Objectives/Hypothesis Awake, unsedated in‐office upper airway procedures are performed frequently and have high completion rates, yet less is known about the patients' pain experience and potentially influencing factors. It is also unclear if patients' pain experiences become worse with repeated procedures. We identified procedure‐ and patient‐related factors that might influence procedural completion and pain scores. Study Design Retrospective chart review. Methods Pre‐, intra‐, and post‐procedure pain scores were collected prospectively for awake unsedated upper airway procedures performed at a single institution over a 5‐year period. Patient factors reviewed were demographics, body mass index, psychiatric and/or pain diagnosis, and related medications. Procedure factors reviewed were procedure type, route, side, and performance of the same procedure multiple times. Patients reported their pain level before, during, and after the procedure using a standard 0 to 10 scale. Maximum pain score change (PΔmax), or the difference between highest and lowest reported pain levels, was calculated. Descriptive and multivariate analyses were performed. Results Procedure completion was 98.7% for 609 first time patients and 99.0% in 60 patients undergoing 292 repeat procedures. PΔmax did not covary with age, gender, or BMI. PΔmax covaried with pain and psychiatric conditions and associated medications. PΔmax was highest for injection medialization and lowest for tracheoscopy. PΔmax decreased over time for those undergoing multiple identical procedures. Conclusions Procedures were performed with a very high completion rate and low pain scores. Age, sex, and BMI did not affect pain experience. A combination of pain and psychiatric conditions did. Injection medialization had the highest PΔmax and tracheoscopy the lowest. Level of Evidence 4 Laryngoscope, 2020
... In a state of "stress-induced hyperalgesia, " innocuous inputs may be perceived as painful (5,6). Both stress-induced analgesia and stress-induced hyperalgesia have been demonstrated in humans and can be seen outside of the artificial environment of the laboratory, for example after severe trauma (3,(7)(8)(9)(10). More broadly, there is abundant evidence that pain is influenced by cognitive and emotional factors, and that it can vary, subtly or dramatically, with context and behavioral state (11)(12)(13). ...
Article
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The sensory experience of pain depends not only on the transmission of noxious information (nociception), but on the state of the body in a biological, psychological, and social milieu. A brainstem pain-modulating system with its output node in the rostral ventromedial medulla (RVM) can regulate the threshold and gain for nociceptive transmission. This review considers the current understanding of how RVM pain-modulating neurons, namely ON-cells and OFF-cells, are engaged by “top-down” cognitive and emotional factors, as well as by “bottom-up” sensory inputs, to enhance or suppress pain.
... It is known that anxiety, worry and fear are directly associated with pain, and they raise the severity of each other [34]. In the study by Rhudy and Meagher (2000), it wa s stated that fear triggered by a sudden stimulus raised the pain tolerance, whereas anxiety felt from the threat of a sudden stimulus reduced the pain tolerance [35]. By af fecting the adrenal medulla, stress gives rise to vasoconstriction in veins through stimulation of the sympathetic system. ...
Article
Introduction Pain increases the patient's anxiety levels and prolongs examination and other medical processes. This study was conducted as a single-blind, randomized controlled study to determine the effects of acupressure applied on adult patients on their vital signs, acute pain, stress and satisfaction during venipuncture. Methods Patients who had a BMI of 18.5 to 30kg/m2, presence of an internal disease, coming to the clinic for a routine check-up, requested to have a blood sample, examined by the physician, had no sign of pain, hematoma, necrosis, scar, incision or infection on the skin around the venipuncture site and had taken no analgesic drug for the last six hours were included in the trial. Patients were randomly allocated into an acupressure group (n=100) and a no-intervention control group (n=100). Acupressure (LI 4, LI 11 and HT 7 points) was applied once by a certified researcher for 10 minutes prior to venipuncture. Pain, satisfaction, stress, heart rate and oxygen saturation levels of the patients in the acupressure and control groups were assessed 15 minutes before and immediately after the venipuncture procedure. The Visual Analog Scale for the Measurement of Pain Severity, the Visual Analog Patient Satisfaction Scale and the State-Trait Anxiety Inventory were used to collect the data. Results The acupressure group had a significantly lower mean pain score than the control group (respectively, 1.23±1.09 and 1.95±1.95, p<0.05). The acupressure group had a significantly higher mean satisfaction score than the control group (respectively, 9.13±1.31 and 8.51±1.86, p<0.05). The acupressure group had a significantly lower mean stress score than the control group (respectively, 34.66±7.99 and 41.91±9.21, p<0.05). Conclusion Acupressure reduced acute pain and stress and increased satisfaction levels in adult patients undergoing venipuncture.
... Anxiety is an emotion close to painful experience, as it can increase the perception of pain. This situation commonly observed among children has been also seen in adult studies where scores of anxiety and pain often have a positive correlation (1,2). ...
Article
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Objectives: Experience of hypnosis in gastrointestinal (GI) endoscopy is scarce in children. Our aims were to assess the rate of successful GI endoscopy performed using hypnosis alone or in combination with midazolam, with or without additional equimolar mixture of oxygen and nitrous oxide (EMONO), and to identify predictive factors of successful endoscopy in children. Methods: This prospective single-centre study included children older than 6 years requiring a diagnostic esophagogastroduodenoscopy (EGD) or rectosigmoidoscopy. Ericksonian hypnosis was performed alone or in combination with midazolam, with or without additional EMONO. Successful endoscopy was defined by a complete and well-tolerated procedure. Levels of satisfaction of the endoscopist, nurse, and patient were assessed. Results: One hundred forty children [70 boys, median age: 12 years (Q1–Q3: 9–14)] were included over a 14-month period. They underwent EGD in 51.4% ( n = 72) and rectosigmoidoscopy in 48.6% ( n = 68) of cases. EMONO and midazolam were combined with hypnosis in 136 cases (97.1%). Successful endoscopy rate reached 82.9%. The procedure was interrupted due to poor tolerance and was rescheduled under general anaesthesia in 11 patients (7.9%). Predictive factors for successful endoscopy were older age (13 vs. 8 years, OR: 1.34, CI 95% [1.10–1.62], p = 0.003) and type of endoscopy (EGD vs. rectosigmoidoscopy, OR: 16.34 [2.14–124.68], p = 0.007). A good cooperation of the patient was reported by the endoscopist and the nurse in 88.4 and 86.9% of cases, respectively. Ninety-two per cent of patients mentioned that the procedure went well. Conclusions: Our study suggests that hypnosis combined with EMONO and/or midazolam is of additional value to perform diagnostic EGD or rectosigmoidoscopy in children older than 6 years without systematic need for general anaesthesia.
... 16 Approximately 35% of neurons in the dorsal horn contain oxytocin receptors that act to inhibit pain-carrying Aδ-fibres and C-fibres 17-19 ; (2) oxytocin binds to opioid receptors, and results in analgesic effects when administered to the periaqueductal grey, and effect that can be blocked with an opioid antagonist. 20 21 Furthermore, analgesic effects of endogenous and exogenous oxytocin can be blocked by the opioid antagonist naloxone 22 ; and (3) oxytocin may decrease pain sensitivity by improving mood, reducing anxiety and buffering stress given that the induction of negative emotions are associated with heightened pain [23][24][25] and autonomic arousal. 24 In an informative controlled trial, intranasal administration of oxytocin in men resulted in greater calmness, less anxiety and a trend toward lower cortisol during the Trier Social Stress Test. ...
Article
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Introduction Current treatments for chronic pain (eg, opioids) can have adverse side effects and rarely result in resolution of pain. As such, there is a need for adjuvant analgesics that are non-addictive, have few adverse side effects and are effective for pain management across several chronic pain conditions. Oxytocin is a naturally occurring hormone that has gained attention for its potential analgesic properties. The objective of this trial is to evaluate the efficacy of intranasal oxytocin on pain and function among adults with chronic pain. Methods and analysis This is a placebo-controlled, triple-blind, sequential, within-subject crossover trial. Adults with chronic neuropathic, pelvic and musculoskeletal pain will be recruited from three Canadian provinces (British Columbia, Alberta and Newfoundland and Labrador, respectively). Enrolled patients will provide one saliva sample pretreatment to evaluate basal oxytocin levels and polymorphisms of the oxytocin receptor gene before being randomised to one of two trial arms. Patients will self-administer three different oxytocin nasal sprays twice daily for a period of 2 weeks (ie, 24 IU, 48 IU and placebo). Patients will complete daily diaries, including standardised measures on day 1, day 7 and day 14. Primary outcomes include pain and pain-related interference. Secondary outcomes include emotional function, sleep disturbance and global impression of change. Intention-to-treat analyses will be performed to evaluate whether improvement in pain and physical function will be observed posttreatment. Ethics and dissemination Trial protocols were approved by the Newfoundland and Labrador Health Research Ethics Board (HREB #20227), University of British Columbia Clinical Research Ethics Board (CREB #H20-00729), University of Calgary Conjoint Health Research Ethics Board (REB20 #0359) and Health Canada (Control # 252780). Results will be disseminated through publication in peer-reviewed journals and presentations at scientific conferences. Trial registration number NCT04903002 ; Pre-results.
... The BADP, typical of any assessment, imperfectly measures the constructs under study, but may be particularly inexact in distinguishing between anxiety and fear. Nevertheless, data on the differential impact of anxiety and fear on pain (Rhudy & Meagher, 2000) emphasize the importance of attempting to assess them both, but to do so independently. ...
Article
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Background The experience of pain is a complex interaction of somatic, behavioral, affective, and cognitive components. Negative psychological states (e.g., anxiety, fear, and depression) are intertwined with pain and contribute to poorer outcomes for individuals suffering from chronic and acute pain by exacerbating the overall experience of pain and leading to increased dysfunction, disability, and distress. A need exists for efficient assessment of aversive emotional states that are associated with pain. Methods A multi‐stage developmental process included expert judges, two undergraduate samples, and a chronic pain sample. The 4‐item Brief Assessment of Distress about Pain (BADP) scale was developed, assessing anxiety, fear, and depression related to pain, as well as an overall evaluation of distress about pain. Results Principal components analyses indicated that the BADP consisted of one factor; inter‐scale correlation coefficients revealed that the BADP was highly related to other measures that assess similar constructs, suggesting evidence for convergent validity. Intra‐scale correlation coefficients indicated that the items of the BADP were only moderately associated with each other. Findings also supported evidence for discriminative validity, test‐retest reliability, and internal consistency of the BADP. Conclusions The BADP has good psychometric properties as a measure of negative affectivity related to pain. The scale’s single negative affectivity item may be useful for screening. The BADP helps address a gap in the literature with regard to a brief measure assessing fear, anxiety, depression, and negative affect in relation to pain. Demonstrated utility in a patient sample indicates the measure is suitable for further clinical study.
... Both fear and anxiety are unpleasant emotional reactions to the presence (fear) or potential presence (anxiety) of a threat [14]; however, there is no empirical data on distinguishing expressions of anxiety vs. fear in dogs and cats (c.f. [15,16]). ...
Article
Full-text available
A high proportion of dogs and cats are fearful during veterinary visits, which in some cases may escalate into aggression. Here, we discuss factors that contribute to negative emotions in a veteri-nary setting and how these can be addressed. We briefly summarise the available evidence for the interventions discussed. The set-up of the waiting area (e.g., spatial dividers; elevated places for cat carriers), tailoring the examination and the treatment to the individual, considerate handling (minimal restraint when possible, avoiding leaning over or cornering animals) and offering high-value food or toys throughout the visit can promote security and, ideally, positive associa-tions. Desensitisation and counterconditioning are highly recommended, both to prevent and ad-dress existing negative emotions. Short-term pain from injections can be minimised by using tactile and cognitive distractions and topical analgesics, which are also indicated for painful procedures such as ear cleanings. Recommendations for handling fearful animals to minimise aggressive re-sponses are discussed. However, anxiolytics or sedation should be used whenever there is a risk of traumatising an animal or for safety reasons. Stress-reducing measures can decrease fear and stress in patients and consequently their owners, thus strengthening the relationship with the cli-ents as well as increasing the professional satisfaction of veterinary staff.
... Deleterious changes in the central nervous system leads to high rates of comorbid neuropathic pain with psychological conditions, such as anxiety, depression, and sleep disorders (Descalzi et al., 2017;Guimarães et al., 2019). Negative emotions have been reported to exacerbate chronic pain, resulting in refractory diseases (Rhudy and Meagher, 2000;Ericsson et al., 2002). However, the neural circuit mechanisms underlying these symptoms remain unclear. ...
Article
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Neuropathic pain is a common cause of chronic pain and is often accompanied by negative emotions, making it complex and difficult to treat. However, the neural circuit mechanisms underlying these symptoms remain unclear. Herein, we present a novel pathway associated with comorbid chronic pain and anxiety. Using chemogenetic methods, we found that activation of glutamatergic projections from the rostral anterior cingulate cortex (rACC Glu ) to the ventrolateral periaqueductal gray (vlPAG) induced both hyperalgesia and anxiety-like behaviors in sham mice. Inhibition of the rACC Glu -vlPAG pathway reduced anxiety-like behaviors and hyperalgesia in the spared nerve injury (SNI) mice model; moreover, electroacupuncture (EA) effectively alleviated these symptoms. Investigation of the related mechanisms revealed that the chemogenetic activation of the rACC Glu -vlPAG circuit effectively blocked the analgesic effect of EA in the SNI mice model but did not affect the chronic pain-induced negative emotions. This study revealed a novel pathway, the rACC Glu -vlPAG pathway, that mediates neuropathic pain and pain-induced anxiety.
... On the other hand, it is well known that stress may affect pain sensation. So, intense acute stress reduces pain perception and suppresses pain behavior [9][10][11]. At variance, certain forms of chronic stress (immobilization, cold, etc.) exacerbate (hyperalgesia) or even generate (allodynia) pain [12,13]. ...
Article
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We have investigated whether the stress response mediated by the adrenal medulla in rats subjected to chronic constriction injury of the sciatic nerve (CCI) modulates their nocifensive behavior. Treatment with SK29661 (300 mg/kg; intraperitoneal (I.P.)), a selective inhibitor of phenylethanolamine N-methyltransferase (PNMT) that converts noradrenaline (NA) into adrenaline (A), fully reverted mechanical allodynia in the injured hind paw without affecting mechanical sensitivity in the contralateral paw. The effect was fast and reversible and was associated with a decrease in the A to NA ratio (A/NA) in the adrenal gland and circulating blood, an A/NA that was elevated by CCI. 1,2,3,4-tetrahydroisoquinoline-7-sulfonamide (SKF29661) did not affect exocytosis evoked by Ca2+ entry as well as major ionic conductances (voltage-gated Na+, Ca2+, and K+ channels, nicotinic acetylcholine receptors) involved in stimulus-secretion coupling in chromaffin cells, suggesting that it acted by changing the relative content of the two adrenal catecholamines. Denervation of the adrenal medulla by surgical splanchnectomy attenuated mechanical allodynia in neuropathic animals, hence confirming the involvement of the adrenal medulla in the pathophysiology of the CCI model. Inhibition of PNMT appears to be an effective and probably safe way to modulate adrenal medulla activity and, in turn, to alleviate pain secondary to the injury of a peripheral nerve.
... Both fear and anxiety are unpleasant emotional reactions to the presence (fear) or potential presence (anxiety) of a threat [14]; however, there is no empirical data on distinguishing expressions of anxiety vs. fear in dogs and cats (c.f. [15,16]). ...
Preprint
Full-text available
A high proportion of dogs and cats are fearful during veterinary visits, which in some cases may escalate into aggression. Here, we discuss factors that contribute to negative emotions in a veterinary setting and how these can be addressed. The set-up of the waiting area (e.g. spatial dividers; elevated places for cat carriers), tailoring the examination and the treatment to the individual, considerate handling (minimal restraint when possible, avoiding leaning over or cornering animals) and offering high-value food or toys throughout the visit can promote security and, ideally, positive associations. Desensitisation and counterconditioning are highly recommended both to prevent and address existing negative emotions. Some negative experiences such as short-term pain from injections can be minimised by using tactile and cognitive distractions. Preemptive analgesia is recommended for known painful procedures. Recommendations for handling fearful animals to minimise aggressive responses are discussed. However, anxiolytics or sedation should be used whenever there is a risk of traumatising an animal or for safety reasons. Stress-reducing measures can decrease stress and fear in patients and consequently their owners – thus strengthening the relationship with the clients as well as increasing the professional satisfaction of veterinary staff.
... This is coherent with the stressful condition experienced by HCWs and represented by the spread of the pandemic. While fear usually leads people to a fight or flight action in order to reduce the impact of the threat [49][50][51], within the context of the COVID-19 pandemic these reactions could not be fully expressed because the presence of COVID-19 did not represent a tangible threat to deal with; furthermore, lockdown restrictions reduced the possibility to actively contrast the danger. Therefore, despite fear scores being the highest observed in our sample, their associations with stress appeared limited. ...
Article
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The impact of the COVID-19 pandemic on global healthcare workers’ (HCWs) mental health has been well documented in the last two years; however, little is known regarding HCWs working in specific healthcare fields. During two subsequent periods of national lockdown in Italy (June–July 2020, T1, and November–December 2020, T2), a total sample of 47 HCWs working in a reproductive medicine hospital unit completed an ad hoc questionnaire for assessing emotional reactions to the pandemic, stress symptoms, and ways of coping. Moderate–high levels of anger and sadness were experienced by 65.9% and 68.1% of the HCWs, respectively, while moderate–high levels of anxiety and fear were experienced by 51.1% and 56.8%, respectively. Higher stress symptoms experienced by HCWs were hypervigilance, avoidance of thoughts and memories, and tiredness/low energy. At T2, levels of hypervigilance, irritability, intrusive thoughts, and detachment were higher than at T1, while avoidance of external triggers decreased. Moderate–high levels of anxiety resulted significantly associated with several symptoms of stress: irritability/fearfulness, depression/hopelessness, tiredness/low energy, problems with concentration, and intrusive thoughts. Regarding coping strategies, HCWs tended to adopt more problem-focused coping (e.g., contributing to improving a situation) and this tendency was higher at T2. Overall findings suggest a risk for the persistence of stress symptoms and, therefore, a risk for a chronic course, which might interfere with the global quality of mental health at work and the care provided to patients. Clinical implications highlight the relevance of implementing support programs for this category of HCWs focused on the elaboration of negative emotions and on fostering adaptive coping strategies.
... Anxiety is defined as a feeling of worry, nervousness, or unease, typically about an imminent event or something with an uncertain outcome. The separation of these two factors was inspired by research that suggested that fear inhibits pain whereas anxiety enhances it (Rhudy et al. 2000). This is important as this means personal anxieties about COVID-19 would grow over time whereas fear about the virus would decrease over time. ...
Research
On December 31, 2019, a previously unknown pneumonia was detected for the first time in Wuhan, China. This virus, later named COVID-19, would then completely change the world as we knew it. The relationship between knowledge and fear is one that has been contested with two prevalent schools of thought; is ignorance bliss, or is knowledge security. This project surveyed 109 people and utilized a Google Form. The form consisted of three parts, the first of which being a background question asking about location and age, the second part was a short seven question background knowledge questionnaire about the virus, and the third part was ranking questions for fear, anxiety, and impact. For this data set, the chi-squared test for association and the Spearman rank correlation coefficient were utilized to assess the data for statistically significant connections as levels of impact, anxiety and fear are ordinal data. There were highly statistically significant associations between: fear and anxiety; anxiety and accuracy; and fear and accuracy, and highly statistically significant negative correlations between: anxiety and accuracy; and fear and accuracy. This project suggests that knowledge is linked to lower anxiety and fear levels, contrary to the popular belief that ignorance is bliss.
... [35] We have numerous highly cited publications on well designed clinical trials and lab studies. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] Previously our team has a rich experience in working on various research projects across multiple disciplines. [51][52][53][54][55][56] Now the growing trend in this area motivated us to pursue this project. ...
Article
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Introduction: The aim of this study was to investigate the correlation between dental anxiety, salivary cortisol, and salivary Alpha Amylase (sAA) levels in chronic Endodontic pain. Furthermore, the aim was to look into individual differences such as age, race, gender, any existing pain, or traumatic dental experience and their effect on dental anxiety. Materials &Methods: This study followed a cross-sectional design and included a convenience sample of 46. Every patient was asked to complete the Dental Anxiety Scale (DAS) and a basic demographic/dental history questionnaire. A saliva sample, utilizing the spitting method, was then collected in sterile containers. Samples were analyzed for salivary cortisol and sAA levels by Salimetrics. Results: Significant associations were observed between DAS scores and presence of pain and history of traumatic dental experience. However, significant correlations were observed between DAS, cortisol, and sAA levels. Our study reconfirms that dental anxiety is associated with presence of pain and a history of traumatic dental experience. Conclusion: Based on the results of our study, we can conclude that presence of pain and any history of traumatic dental experience are associated with patients' dental anxiety level. Clinical Significance: Dentists need to be trained in anxiety management and communication techniques, this consideration will help in development of specialist postgraduates courses for dentists in management of dental anxiety. Such initiatives allow interested dentists to gain more confidence, more experience and skills in this specialized in the field of dentistry.
... To individuals who are fascinated with pain, the anticipation of pain might be perceived as pleasant because of its rather frightening nature. As shown by Rhudy and Meagher (2000), fear of an external stimulus can have an analgesic effect, Note: GP, general population sample (N = 355); SM, SM sample (N = 68); (-SSS-V), sensation seeking total score was partialed out of the respective GATPI subscale mean score. ...
Article
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Background: With regard to attitudes towards pain, many questionnaires have been developed. Although undoubtedly useful, they were specifically designed for the use in chronic pain and are less suitable for the assessment in the general population. The purpose of the present paper was to develop a measure for the assessment of general attitudes towards pain applicable in the general population, regardless of clinical condition, and to test its psychometric properties. Methods: We developed the General Attitudes Towards Pain Inventory and conducted two studies in order to provide psychometric data: In a general population sample (N = 362, study one), participants were asked to complete a questionnaire battery. To assess test-retest reliability, participants were contacted again after four weeks (retest sample: N = 101). For the evaluation of criterion validity (study two), a sample with sadomasochistic sexual preference (N = 68) was additionally recruited. Results: Statistical analyses revealed, overall, acceptable internal consistencies and test-retest reliabilities. A ten-factor model showed acceptable fit and was superior to alternative models. The inventory demonstrated convergent and divergent validity. In this context, we found pain sensitivity to be associated with pain attitudes. Finally, compared to the general population sample, individuals with sadomasochistic sexual preference showed significantly higher scores on fascination-pleasure and challenge subscales. Conclusions: In the present paper, we introduce a new and comprehensive instrument for pain research and provide evidence for its reliability and validity. In addition, we present new insights into how interindividual differences in pain sensitivity relate to pain attitudes.
Article
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Introduction: The present study investigates how preoperative anxiety and pain sensitivity affect the consumption of anesthetics, time elapsed until the desired sedation level is achieved, preoperative hemodynamics, postoperative recovery time, and postoperative pain. Methods: The present study includes 80 ASA 1-2 patients aged between 20 and 65 who were scheduled for endoscopic ultrasonography (EUS) under sedation. Patients were instructed to fill out the Spielberger State-Trait Anxiety Inventory (STAI) and Pain Sensitivity Questionnaire (PSQ) before the procedure. For sedation, 0.03 mg kg-1 intravenous midazolam, 1 mg kg-1 lidocaine, 1 µ kg-1 fentanyl, and then a bolus dose of 1 mg kg-1 propofol were infused over a period of 60 s. The time elapsed until the bispectral index (BIS) value reached 75 was recorded. For anesthesia maintenance, 2 mg kg-1 h-1 propofol infusion was administered. In the case of sedation failure, an additional dose of 0.1 mg kg-1 propofol (IV) was administered to ensure sedation depth with a BIS level of 65-75, and the propofol infusion was halted once the BIS value dropped below 65. Results: STAI-S and STAI-T scores were significantly positively correlated with PSQ minor pain and PSQ total scores. The time elapsed until reaching a BIS level of 75, propofol infusion dose used during sedation, and the need for additional doses of propofol, heart rate (HR), and duration of post-anesthesia care unit stay were significantly positively correlated with both preoperative anxiety and preoperative pain sensitivity. In terms of postoperative pain, the visual analog scale (VAS) at 1 h was more highly correlated with STAI-S and STAI-T than with PSQ. The VAS 2 h was only correlated with STAI-S and STAI-T. Conclusion: The significant linear correlation between preoperative anxiety and pain sensitivity and anesthesia need can facilitate better preoperative management by predicting individual anesthetic consumption. Trial registration: The study was registered with the number NCT03114735 on ClinicalTrials.gov.
Article
Native Americans (NAs) experience higher rates of chronic pain. To examine the mechanisms for this pain inequity, we have previously shown that NAs report higher levels of pain-related anxiety and pain catastrophizing, which are in turn related to pronociceptive (pain-promoting) processes. But, it is currently unclear why NAs would report greater pain-related anxiety and catastrophizing. Given that NAs are also more likely to experience adverse life events (ALEs) and associated psychological distress, it was hypothesized that higher anxiety/catastrophizing in NAs would be partially explained by higher rates of ALEs and psychological distress. Structural equation modeling was used to analyze these pathways (NA ethnicity ➔ ALEs ➔ psychological distress ➔ pain anxiety/catastrophizing) in 305 healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Pain-related anxiety and situational pain catastrophizing were assessed in response to a variety of painful tasks. The Life Events Checklist was used to assess cumulative exposure to ALEs that directly happened to each participant. A latent psychological distress variable was modeled from self-reported perceived stress and psychological symptoms. Results found that NAs experienced more ALEs and greater psychological distress which was associated with higher rates of pain-related anxiety and pain catastrophizing. Notably, NAs did not report greater psychological distress when controlling for ALE exposure. This suggests that a higher risk of chronic pain in NAs may be due, in part, to psychological distress, pain-related anxiety, and pain catastrophizing that are promoted by exposure to ALEs. These results highlight several targets for intervention to decrease NA pain risk.
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Background BDSM is an acronym describing bondage & discipline, dominance & submission and sadism & masochism. Afflicting or receiving pain is usually an important part of the BDSM interaction. Aim This research will focus on better understanding the aspect of pain within a BDSM interaction. Methods Submissive and dominant counterparts of 35 couples were recruited to participate in a BDSM interaction, of which 34 dominants and 33 submissives were included in analyses. A non-BDSM interested control group (n=27) was included to control for social interaction, of which 24 were included in analyses. Outcomes This research investigates the differences in 1) baseline pain thresholds, 2) the impact of a BDSM interaction on those thresholds and 3) threshold moderating factors like pain cognition between submissive and dominant BDSM participants and control individuals. Results BDSM practitioners have a higher pain threshold overall and a BSDM interaction will result in a temporary elevation of pain thresholds for submissives. Additionally, pain thresholds in dominants will be dependent upon their fear of pain and tendency to catastrophize pain and submissives will experience less fear of pain than the control group. Clinical Implications By further enhancing our understanding of the mechanisms behind a BDSM interaction in this way, we aspire to relieve the stigma these practitioners still endure. Strengths & Limitations This is one of the first studies of its kind with a large sample size compared to similar research, which makes it a significant contribution to the field. It must be mentioned that there is a possible selection bias because recruitment was only done through the Flemish BDSM community and specifically those who visit clubs. Additionally, pain threshold remains a subjective measurement, which must be taken into account. Conclusion This study helps shed further light on the biological processes behind a BDSM interaction through pain threshold measurements.
Article
Acoustic startle stimuli inhibit pain, but whether this is due to a cross‐modal inhibitory process or some other mechanism is uncertain. To investigate this, electrical stimulation of the sural nerve either preceded or followed an acoustic startle stimulus (by 200 ms) or was presented alone in 30 healthy participants. Five electrical stimuli, five acoustic startle stimuli, 10 startle + electrical stimuli, and 10 electrical + startle stimuli were presented in mixed order at intervals of 30–60 s. Effects of the startle stimulus on pain ratings, pupillary dilatation and nociceptive flexion reflexes to the electric shock were assessed. The acoustic startle stimulus inhibited electrically evoked pain to the ensuing electric shock (p < .001), and the electrical stimulus inhibited the perceived loudness of a subsequent acoustic startle stimulus (p < .05). However, the startle stimulus did not affect electrically evoked pain when presented 200 ms after the electric shock, and electrically evoked pain did not influence the perceived loudness of a prior startle stimulus. Furthermore, stimulus order did not influence the pupillary responses or nociceptive flexion reflexes. These findings suggest that acoustic startle stimuli transiently inhibit nociceptive processing and, conversely, that electrical stimuli inhibit subsequent auditory processing. These inhibitory effects do not seem to involve spinal gating as nociceptive flexion reflexes to the electric shock were unaffected by stimulus order. Thus, cross‐modal interactions at convergence points in the brainstem or higher centers may inhibit responses to the second stimulus in a two‐stimulus train.
Article
Threat-induced pain modulation can increase survival by amplifying physiological and behavioral reactions towards danger. Threat can also modulate spinal nociception, suggesting engagement of endogenous top-down circuitry. A unique method to assess spinal nociception is via reflex receptive fields (RRF) associated with the nociceptive withdrawal reflex (NWR, a protective spinally-mediated reflex). The size of nociceptive RRFs can be modulated by top-down circuitry with the enlargement of RRFs related to increased spinal nociception. Threat has been previously shown to enhance pain and spinal nociception, but the relationship between threat and RRFs has not been investigated. The present study investigated this issue in 25 healthy individuals. RRFs were determined from NWRs measured by electromyography (EMG) of the tibialis anterior following electrocutaneous stimulations. RRFs and pain were assessed during periods in which participants were under threat of unpredictable painful abdominal stimulations and when they were not under threat. Results indicated that threat periods led to significantly higher pain, larger nociceptive RRFs and NWR magnitudes. These findings imply that threat produces changes in protective reflexes related to spinal nociceptive sensitivity and increased pain perception. This is likely mediated by top-down circuitry that enhances dorsal horn nociceptive neurons by enlarging RRFs and amplifying ascending pain signals. Perspective This article presents the enlargement of reflex receptive fields (RRF) during periods of threat. The results from this study may help clarify the mechanism underlining emotional modulation of spinal nociception.
Article
Chronic neuropathic pain affects 7–10 % of the population and is often accompanied by comorbid emotional disorders, which greatly reduce the quality of life of the patients, impairing physical, cognitive, emotional, and social functioning. Despite the higher prevalence and severity of chronic pain in women, the number of publications using female animals remains scarce. While in the chronic constriction injury (CCI) model the development of mechanical/thermal hyperalgesia, allodynia and spontaneous pain has been shown in both sexes, little is known on CCI-induced emotional impairments and sciatic nerve histopathology in female rats, as well as on the contributions of ovarian hormones to peripheral nerve injury. In this work, young adult rats (Wistar Han) were assigned to one of five groups: gonadally intact females (SHAM/SHAM), ovariectomized females (SHAM/OVX), gonadally intact females with CCI (CCI/SHAM); ovariectomized females with CCI (CCI/OVX) and males with CCI (CCIM). In the postoperative period, CCI animals, both females and males, displayed visible gait abnormalities, limping and guarding the affected hind paw although locomotion was not affected. Neuropathic females developed sustained mechanical allodynia, with CCI/OVX animals displaying symptoms two weeks before CCI/SHAM females. Interestingly, regarding mechanical and cold allodynia, CCI males slowly recovered from week 3 onwards. While CCI induced neither anxiety- nor depressive-like behaviour in females, ovariectomy per se induced anhedonic-like behaviour, regardless of CCI surgery. Histopathological analysis of the sciatic nerve showed CCI induced nerve damage, fibrosis, myelin sheath degradation and inflammation. Single-cell electrophysiological data from the rostral ventromedial medulla (RVM) suggests this area is partly involved in descending facilitation associated with experimental neuropathic pain. Altogether, our findings demonstrate CCI females display distinct sensory, emotional, electrophysiological, and histopathological impairments from males, and that ovariectomy aggravates females’ responses to peripheral nerve injury.
Article
Background: The purpose of this study was to evaluate the use of a stress ball as a distraction technique on stress levels of patients undergoing a dental procedure. Material and methods: A randomized, split-mouth design was conducted using 20 adult subjects requiring scaling and root planing (Sc/RP) in all four quadrants. Each side of the mouth (maxillary/mandibular) received Sc/RP with local anesthetic with or without the use of a stress-ball distraction over two separate sessions. Subjects completed two pre-procedural questionnaires (Spielberger State-Trait Anxiety Inventory, STAI; Modified Dental Anxiety Scale, MDAS) before and after each treatment session. A Galvanic Skin Response (GSR) sensor (Neulog) was used throughout each session to measure skin conductance or sweat. Results: No significant difference in GSR scores was found during treatment with or without the use of the stress ball. Also, no significant differences in the change in STAI or MDAS scores were found with or without the use of a stress ball. Conclusions: The results of this study found that the use of a stress ball as a distraction technique did not result in any significant reduction in stress levels in subjects undergoing scaling and root planing with local anesthesia. Key words:Anxiety, distraction, stress ball.
Article
Objective: The aim of this study was to determine if young children with high preprocedural anxiety experience increased pain at venipuncture. Methods: This was secondary analysis of prospectively obtained data from a randomized controlled trial comparing vapocoolant spray with jet-injected lidocaine for venipuncture pain. Children aged 1 to 6 years were enrolled and videotaped. Videos were reviewed and scored for anxiety using the modified Yale Preoperative Anxiety Scale score for preprocedural anxiety (score range, 23-100). High anxiety was defined as greater than 40. Pain at the time of venipuncture was scored using the Face, Legs, Activity, Cry, and Consolability scale (score range 0-10). Moderate to severe pain was defined as greater than 3. Logistic regression assessed patient factors associated with high preprocedural anxiety and evaluated the relationship between preprocedural anxiety and pain during venipuncture. Results: Two hundred five patients were enrolled; 59.5% of patients were male, and 53.7% were White. Mean age was 3.2 years. Prior to the procedure, 67% of patients had high anxiety. Patient age, race, sex, and previous venipuncture were not associated with increased odds of high anxiety. Moderate to severe pain at venipuncture was observed in 65% of children. High preprocedural anxiety was associated with increased odds of moderate to severe pain at venipuncture when controlled for patient characteristics (adjusted odds ratio, 4.62; 95% confidence interval, 2.03-8.54). Conclusions: Most young children undergoing venipuncture experienced high preprocedural anxiety. Children with high preprocedural anxiety had increased odds of moderate to severe pain at venipuncture. Anxiety-reducing interventions should be explored to reduce pain experienced during venipuncture.
Article
Background: Cancer-related worry (CRW) is common among cancer survivors; however, little is known about factors associated with CRW or its impact on health behaviors in adult survivors of childhood cancer. Methods: Survivors in the St. Jude Lifetime Cohort Study (n = 3211; 51% male; mean age, 31.2 years [SD, 8.4 years]; mean time after diagnosis, 22.8 years [SD, 8.3 years]) underwent medical evaluations and completed ratings of CRW, psychological symptoms, and health behaviors. Multivariable modified Poisson regression models examined associations between CRW and treatment exposures, chronic health conditions, psychological symptoms, and health behaviors. Results: Sixty-four percent of survivors (95% confidence interval [CI], 62.6-65.9) reported worry about subsequent malignancy, 45% (95% CI, 43.5-46.9) reported worry about physical problems related to cancer, and 33% (95% CI, 31.2-34.4) reported worry about relapse. Multiple psychological symptoms, treatment exposures, and chronic conditions significantly increased the risk of CRW. Survivors reporting CRW were at increased risk for substance use, inadequate physical activity, and increased health care utilization after adjustments for chronic conditions. For example, with adjustments for chronic conditions, those who endorsed CRW were more likely to have ≥5 cancer-related physician visits, ≥5 physician visits related to cancer, and ≥5 calls to a physician's office in the previous 2 years in comparison with survivors who were not worried. CRW was also associated with an increased risk of current tobacco use, past marijuana use, and current marijuana use. Conclusions: A substantial proportion of adult survivors of childhood cancer reported CRW associated with increased health care utilization. CRW may serve as an intervention target to promote well-being and adaptive health behaviors.
Chapter
Perineal, anal, and anorectal pain is a common clinical manifestation, affecting 6.6% of the population. An organic cause that might explain this kind of pain is found in 30% of examined patients. Hence, in two thirds of the cases, anorectal pain can be termed idiopathic. Pain is defined as chronic when the symptoms have lasted for at least 6 months. The somatic-visceral duality of perineal innervation complicates the diagnosis and results in a limited effectiveness of specific treatments. Chronic idiopathic anorectal pain disorders are a challenge for physicians, and their complexity requires a multidisciplinary approach for both diagnosis and treatment. A better understanding of how visceral innervation works, along with a prospective randomized assessment of known treatments, will greatly contribute to improving chronic idiopathic anorectal pain management.
Article
Objective To determine whether exogenously reduced psychological distress reduces reported low‐back pain (LBP) and is associated with reduced medical visits for LBP. Data Sources National Health Interview Survey, National Ambulatory Medical Care Survey, National Hospital Ambulatory Medical Care Survey, 1998‐2004. Study Design We estimate a fuzzy regression discontinuity model in which a discontinuity in the prevalence of psychological distress is identified by exogenous national events. We examine whether this discontinuity induced a corresponding discontinuity in the prevalence of LBP. We additionally estimate a regression discontinuity model to determine associated changes in medical visits with LBP as the primary complaint. Principal Findings The prevalence of LBP was discontinuously reduced by one‐fifth due to the exogenous national discontinuous reduction in psychological distress. This discontinuity in LBP cannot be explained by discontinuities in employment, insurance, injuries/poisoning, general health status, or other factors. We find an associated three‐fifth discontinuous reduction in medical visits with LBP as the primary complaint. Conclusions On a monthly basis, 2.1 million (P < .01) adults ceased to suffer LBP due to the national reduction in psychological distress, and associated medical visits with LBP as the primary complaint declined by 685 000 (P < .01).
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Treatment of severe chronic and acute pain in sickle cell disease (SCD) remains challenging due to the interdependence of pain and psychosocial modulation. We examined whether modulation of the descending pain pathway through an enriched diet and companionship could alleviate pain in transgenic sickle mice. Mechanical and thermal hyperalgesia were reduced significantly with enriched diet and/or companionship. Upon withdrawal of both conditions, analgesic effects observed prior to withdrawal were diminished. Serotonin (5-hydroxytryptamine, 5-HT) was found to be increased in the spinal cords of mice provided both treatments. Additionally, 5-HT production improved at the rostral ventromedial medulla and 5-HT accumulated at the dorsal horn of the spinal cord of sickle mice, suggesting the involvement of the descending pain pathway in the analgesic response. Modulation of 5-HT and its effect on hyperalgesia was also investigated through pharmaceutical approaches. Duloxetine, a serotonin-norepinephrine reuptake inhibitor, showed a similar anti-nociceptive effect as the combination of diet and companionship. Depletion of 5-HT through p-chlorophenylalanine attenuated the anti-hyperalgesic effect of enriched diet and companionship. More significantly, improved diet and companionship enhanced the efficacy of a sub-optimal dose of morphine for analgesia in sickle mice. These findings offer the potential to reduce opioid use without pharmacological interventions to develop effective pain management strategies.
Article
Pleasant sensation is an underexplored avenue for modulation of chronic pain. Deeper pressure is perceived as pleasant and calming, and can improve sleep. Although pressure can reduce acute pain, its effect on chronic pain is poorly characterized. The current remote, double-blind, randomized controlled trial tested the hypothesis that wearing a heavy weighted blanket – providing widespread pressure to the body – relative to a light weighted blanket would reduce ratings of chronic pain, mediated by improvements in anxiety and sleep. Ninety-four adults with chronic pain were randomized to wear a 15-lb. (heavy) or 5-lb. (light) weighted blanket during a brief trial and overnight for one week. Measures of anxiety and chronic pain were collected pre- and post-intervention, and ratings of pain intensity, anxiety, and sleep were collected daily. After controlling for expectations and trait anxiety, the heavy weighted blanket produced significantly greater reductions in broad perceptions of chronic pain than the light weighted blanket (Cohen's f = .19, CI [-1.97, -.91]). This effect was stronger in individuals with high trait anxiety (p = .02). However, weighted blankets did not alter pain intensity ratings. Pain reductions were not mediated by anxiety or sleep. Given that the heavy weighted blanket was associated with greater modulation of affective versus sensory aspects of chronic pain, we propose that the observed reductions are due to interoceptive and social/affective effects of deeper pressure. Overall, we demonstrate that widespread pressure from a weighted blanket can reduce the severity of chronic pain, offering an accessible, home-based tool for chronic. The study purpose, targeted condition, study design, and primary and secondary outcomes were pre-registered in ClinicalTrials.gov (NCT04447885: “Weighted Blankets and Chronic Pain”). Perspective: This randomized-controlled trial showed that a 15-lb weighted blanket produced significantly greater reductions in broad perceptions of chronic pain relative to a 5-lb weighted blanket, particularly in highly anxious individuals. These findings are relevant to patients and providers seeking home-based, nondrug therapies for chronic pain relief.
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Background Repetitive transcranial magnetic stimulation (rTMS) is an efficacious and well-tolerated intervention for treatment-resistant depression (TRD). A novel rTMS protocol, intermittent theta burst stimulation (iTBS) has been recently implemented in clinical practice, and it is essential to characterize the factors associated to pain and the trajectory of pain of iTBS compared to standard rTMS protocols. Objective We aimed to characterize the side effect profile and the pain trajectories of High-Frequency Left (HFL) and iTBS in TRD patients in the THREE-D trial. We also investigated factors associated to pain and the relationship between pain and clinical outcomes. Methods 414 patients were randomized to either HFL or iTBS. Severity of pain was measured after every treatment. General Estimating Equation was used to investigate factors associated with pain. Latent class linear mixed model was used to investigate latent classes of pain trajectories over the course of rTMS. Results Higher level of pain was associated with older age, higher stimulation intensity, higher anxiety, female, and non-response. The severity of pain significantly declined over the course of treatments with a steeper decrease early on in the course of the treatment in both protocols, and four latent pain trajectories were identified. The less favorable pain trajectories were associated with non-response and higher stimulation intensity. Conclusions HFL and iTBS were associated with similar factors and pain trajectories, although iTBS was more uncomfortable. Response to rTMS was associated with less pain and more favorable pain trajectories furthering the evince base of overlapping neurobiological underpinnings of mood and pain. We translated these results into patient-oriented information to aid in the decision-making process when considering rTMS.
Article
Somatosensory afferents are traditionally classified by soma size, myelination, and their response specificity to external and internal stimuli. Here, we propose the functional subdivision of the nociceptive somatosensory system into two branches. The exteroceptive branch detects external threats and drives reflexive-defensive reactions to prevent or limit injury. The interoceptive branch senses the disruption of body integrity, produces tonic pain with strong aversive emotional components, and drives self-caring responses toward to the injured region to reduce suffering. The central thesis behind this functional subdivision comes from a reflection on the dilemma faced by the pain research field, namely, the use of reflexive-defensive behaviors as surrogate assays for interoceptive tonic pain. The interpretation of these assays is now being challenged by the discovery of distinct but interwoven circuits that drive exteroceptive versus interoceptive types of behaviors, with the conflation of these two components contributing partially to the poor translation of therapies from preclinical studies.
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Background Changes in pain sensitivity are a commonly suggested mechanism for the clinical effect of spinal manipulative therapy (SMT). Most research has examined pressure pain thresholds (PPT) and has primarily been conducted in controlled experimental setups and on asymptomatic populations. Many important factors are likely to differ between research and clinical settings, which may affect PPT changes following SMT. Therefore, we planned to investigate PPT before and after clinical chiropractic care and investigate relationships with various potentially clinically-relevant factors. Methods We recruited participants from four Danish chiropractic clinics between May and August 2021. A total of 129 participants (72% of the invited) were included. We measured PPT at eight pre-determined test sites (six spinal and two extra-spinal) immediately before ( pre-session ) and immediately after ( post-session ) the chiropractic consultation. We used regression analyses to investigate PPT changes, including the following factors: (i) vertebral distance to the nearest SMT site, (ii) rapid clinical response, (iii) baseline PPT, (iv) number of SMTs performed, (v) at the region of clinical pain compared to other regions, and (vi) if other non-SMT treatment was provided. We also performed topographic mapping of pre-session PPTs. Results After the consultation, there was a non-significant mean increase in PPT of 0.14 kg (95% CIs = − 0.01 to 0.29 kg). No significant associations were found with the distance between the PPT test site and nearest SMT site, the clinical response of participants to treatment, the pre-session PPT, the total number of SMTs performed, or the region/s of clinical pain. A small increase was observed if myofascial treatment was also provided. Topographic mapping found greater pre-session PPTs in a caudal direction, not affected by the region/s of clinical pain. Conclusions This study of real-world chiropractic patients failed to demonstrate a substantial local or generalized increase in PPT following a clinical encounter that included SMT. This runs counter to prior laboratory research and questions the generalizability of highly experimental setups investigating the effect of SMT on PPT to clinical practice.
Article
The nociceptive withdrawal reflex (NWR) is a behavioral response to protect the body from noxious stimuli. The spatial characteristics of the stimulus modulate the reflex response to prevent damage to the affected tissue. Interneurons in the deep dorsal horn in the spinal cord encode the relationship between stimulus characteristics and the magnitude of the NWR and are also likely integrating spatial information of the nociceptive stimulus. The aim of this study was to use the NWR to investigate whether the spinal spatial integration of a simultaneous stimulus is modulated by shifting the attention of the participant towards (attention) or away from (distraction) the stimulus. We hypothesized that the descending activity shapes the receptive fields of the spinal neurons encoding spatial integration of nociception. Twenty healthy volunteers participated in the study. Single and simultaneous stimuli were delivered through two stimulating electrodes located in the arch and on the lateral side in the sole of the foot. The NWR was quantified by electromyography from the Tibialis Anterior and Biceps Femoris muscles during baseline and active tasks (attention and distraction). During the baseline task, spatial summation of the NWR was evoked during simultaneous stimulation. During the distraction task, the NWR was significantly larger compared to baseline, regardless of the sites being stimulated (single and simultaneous stimuli). In contrast, the NWR recorded during the attention task did not differ from baseline. These results further support that the spinal NWR pathway is under descending control which can be modulated by cognitive processes. The NWRs recorded over both proximal and distal muscles were similarly affected by the tasks, suggesting that the descending control affects the lower leg spinal system, with no discrimination between spinal segments.
Article
Exposure to aversive stimuli such as stress results in profound analgesia named stress-induced analgesia (SIA). We previously showed that D1- and D2-like dopamine receptors within the nucleus accumbens (NAc) mediated the SIA in chronic pain. Since the neurophysiological mechanisms responsible for the various pain conditions are different, the present study aimed to examine the role of dopamine receptors within the NAc in the forced swim stress (FSS)-induced analgesia in the tail-flick test as an animal model of acute pain. Ninety-six adult male Wistar rats weighing 200–230 g were unilaterally implanted with a cannula into the NAc. SCH23390 or Sulpiride (0.25, 1, and 4 μg/0.5 μl vehicle), as D1- and D2-like dopamine receptor antagonists, respectively, were microinjected into the NAc, 5 min before exposure to FSS. The vehicle groups received saline or DMSO instead of SCH23390 or Sulpiride, respectively. The tail-flick test was performed in time set intervals after animals were subjected to FSS. The results showed that FSS produces analgesia during the tail-flick test. However, intra-accumbal injection of SCH23390 or Sulpiride attenuated the FSS-induced analgesia. D1-and D2-like dopamine receptor antagonists contributed almost equally to attenuating the antinociceptive responses induced by FSS. It seems that the mesolimbic dopamine system might act as a potential endogenous pain control system in stress conditions. Besides, an improved understanding of this endogenous pain inhibitory system can develop pharmacological and psychological approaches to treat pain.
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Background: Chronic pain and the accompanying level of disability is a healthcare crisis that reaches epidemic proportions and is now considered a world level crisis. Chronic non-specific low back pain (CNLBP) contributes a significant proportion to the chronic pain population. CNLBP occurs with overlapping psychosocial factors. This study was design to investigate specific psychosocial factors and their influence on reported disability in a population with CNLBP. Methods: The specific psychosocial factors examined included fear, catastrophizing, depression, and pain self-efficacy. This cross-sectional correlational study investigated the mediating role between pain self-efficacy, the specific psychosocial factors, and reported disability. The study recruited 61 female and 29 male participants from physical therapy clinics. The participants were between 20-to-60 years of age and diagnosed with CNLBP. All participants completed the Fear Avoidance Belief Questionnaire, The Pain Catastrophizing Scale, The Patient Health Questionnaire-9, The Pain Self-Efficacy Questionnaire, and The Lumbar Oswestry Disability Index. The battery of questionnaires measured fear of physical activity, pain catastrophizing, depression, pain self-efficacy, and reported disability. Multivariate regression and mediation analyses was used to analyse the data. Results: The principal finding was a strong inverse relationship between pain self-efficacy and reported disability with a p-value < 0.001. Further, pain self-efficacy was considered a statistical mediator with consistent p-value < 0.001 for the specific psychosocial factors investigated within this data set. Pain self-efficacy was considered to have a mediating role between reported fear of physical activity and disability, reported pain catastrophizing and disability, and reported depression and disability. Additionally, age and reported pain levels proved to be statistically significant. Adjustments for age and pain level did not alter the role of pain self-efficacy. Conclusion: The results identified a mediating role for pain self-efficacy between the specific psychosocial factors (fear, catastrophizing, and depression) and reported disability. Pain self-efficacy plays a more significant role in the relationships between these specific psychosocial factors and reported disability with CNLBP than previously considered.
Article
Menschen mit chronischen Schmerzen haben oft Angst vor bestimmten Bewegungen. Sie vermeiden entsprechende Aktivitäten, bauen körperlich ab und leiden schlimmstenfalls unter noch stärkeren Schmerzen und Depressionen. Die Expositionstherapie sowie das Graded-Activity-Konzept helfen, den Teufelskreis des Angst-Vermeidungs-Modells zu durchbrechen.
Article
Objectives Pain-related anxiety has been linked to avoidance behaviour, maintenance of pain and disability. A valid and reliable tool is required to evaluate pain-related anxiety among Persian speaking adults with chronic non-specific neck pain (CNSNP). This study aimed to evaluate psychometric properties of the Persian pain anxiety symptom scale-20 (PASS-20) according to the consensus-based standards for the selection of health measurement instruments (COSMIN) checklist in Iranian adults with CNSNP. Methods 198 individuals with CNSNP completed the PASS-20. The factorial structure (confirmatory factor analysis (CFA), exploratory factor analysis (EFA)), test-retest reliability (intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable change (MDC)), internal consistency (Cronbach’s alpha), and construct validity (convergent and known-group validity) were assessed. The correlation between PASS-20 with pain catastrophizing scale (PCS), Tampa Scale for Kinesiophobia (TSK), neck disability index (NDI), Beck Depression Inventory (BDI), visual analog scale (VAS) (Spearman’s rank correlation) were examined. Known-group validity of PASS-20 was evaluated by comparing the difference between the PASS-20 scores of the known groups based on level of disability, pain intensity and gender using non-parametric tests. Results The CFA showed almost the best fit with the original version. The subscales and total score demonstrated good internal consistency (Cronbach’s α : 0.70–0.92) and high test-retest reliability (ICC: 0.94–0.97). PASS-20 had significant moderate correlations with PCS, TSK, NDI, VAS and a significant low correlation with BDI. Regarding known-group validity, the total score of Persian PASS-20 was higher in CNSNP with higher levels of pain and disability and in the female gender. Conclusions The Persian PASS-20 has acceptable psychometric properties in adults with CNSNP. The results of the factor analysis supported the four-factor structure comparable to the original version. Ethical Committee number 921672004.
Chapter
Dentists who provide care to children often face patients who are uncooperative in the dental situation. This chapter reviews the most common causes for uncooperative behavior and dental fear (including classical conditioning, social learning theory, cognitive bases of dental fear, helplessness, and loss of control), as well as more recent understandings of how genetics, family stressors, parenting styles, and other parental factors are related to child fear and uncooperative behavior. The chapter also describes the most common ways of measuring dental fear and uncooperative behavior, the importance of pain in the etiology of dental fear, and the relationships between verbal and nonverbal aspects of dentist-patient communication and how these may help both to reduce dental fear and increase children’s cooperation. Attention is also paid to how dentists may best work with adolescents’ developmental needs for increased autonomy in the dental setting.
Article
Breathlessness and pain frequently co-occur in chronic conditions, and their unpredictability is often reported to amplify perception and negative affect (NA), however any common neural mechanisms remain largely unexplored. This study examined the effects of (unpredictable) bodily threat on perception and neural gating of respiratory and somatosensory stimuli. Healthy adults (N=51) experienced brief paired inspiratory occlusions and electrocutaneous stimuli, with their neural activity monitored via electroencephalography. Neural gating was measured as a ratio of the N1 response to the second relative to the first stimulus in a pair. In 4/6 blocks, threatening stimulation, in form of additional loaded breaths or electrocutaneous pulses, was presented predictably or unpredictably. Participants reported: perceived intensity and unpleasantness of all stimuli, fear, trait NA and intolerance of uncertainty (IU). Threatening stimulation increased perception, fear, and N1 amplitudes, without affecting neural gating. There was no group effect of unpredictability, though interactions were found with NA and IU. Cross-modal correlations revealed significant baseline relationships in neural gating and perception, though not in their modulation by threat. The present findings demonstrate that respiratory and somatosensory modalities relate in baseline perception and neural gating, and exhibit similar modulation effects by unpleasant stimulation, with significant changes in perception but not gating. Further research is encouraged to elucidate the underlying mechanisms of these relationships, and the potential interactions with stimulus unpredictability.
Article
Background: Chronic Whiplash Associated Disorders (CWAD) are characterized by long-lasting symptoms of neck pain occurring after an acceleration-deceleration injury. Central sensitization (CS) has been suggested as the possible underlying mechanism for these symptoms, and is characterized by changes in the central nervous system. Besides CS, psychological factors are believed to play an important role in the experience of (chronic) pain. Objective: Investigating the relationships between self-reported pain, disability, quality of life, psychological factors and symptoms of CS; and electrical-based quantitative sensory testing (QST) outcomes in CWAD patients. Secondly, to investigate the differences in QST between CWAD patients and healthy controls. Methods: 72 CWAD patients and 55 healthy controls underwent electrical stimuli-based QST. Detection and pain thresholds (EPT), temporal summation (TS) and conditioned pain modulation (CPM) were examined. Spearman correlation and linear mixed models analyses were performed to assess respectively the hypothesized associations and group differences in QST. Results: The Pain Catastrophizing magnification subscale correlated with the left wrist EPT (r=-0.332;P=0.004), and the Pain Anxiety Symptom Scale-20 with the left wrist (r=-0.325;P=0.005) and ankle (r=-0.330;P=0.005) EPT. TS at the ankle correlated with the CS Inventory (r=0.303;P=0.010), Short Form 36 pain subscale (r=-0.325;P=0.005), and Illness Perception Questionnaire revised consequences subscale (r=0.325;P=0.005). EPTs left (P=0.011) and right wrist (P=0.023) were lower in the CWAD group, but CPM and TS did not differ between groups. Conclusion: QST outcomes relate to psychological constructs, rather than to self-reported pain intensity and distribution. Local hyperalgesia was found in patients with CWAD, but no differences in endogenous pain facilitation nor inhibition.
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Background: Many studies have shown effects of anodal transcranial direct current stimulation (a-tDCS) and high-frequency transcranial random noise stimulation (tRNS) on elevating cortical excitability. Moreover, tRNS with direct current (DC)-offset is more likely to lead to increases in cortical excitability than solely tRNS. While a-tDCS over primary motor cortex (M1) has been shown to attenuate pain perception, tRNS with DC-offset may prove as an effective means for pain relief. Objective: This study aimed to examine effects of a-tDCS and high-frequency tRNS + DC-offset over M1 on pain expectation and perception, and assess whether these effects could be influenced by the certainty of pain expectation. Methods: Using a double-blinded and sham-controlled design, 150 healthy participants were recruited to receive a single-session a-tDCS, high-frequency tRNS + DC-offset, or sham stimulation over M1. The expectation and perception of electrical stimulation in certain and uncertain contexts were assessed at baseline, immediately after, and 30 min after stimulation. Results: Compared with sham stimulation, a-tDCS induced immediate analgesic effects that were greater when the stimulation outcome was expected with uncertainty; tRNS induced immediate and sustained analgesic effects that were mediated by decreasing pain expectation. Nevertheless, we found no strong evidence for tRNS being more effective for attenuating pain than a-tDCS. Conclusions: The analgesic effects of a-tDCS and tRNS showed different temporal courses, which could be related to the more sustained effectiveness of high-frequency tRNS + DC-offset in elevating cortical excitability. Moreover, expectations of pain intensity should be taken into consideration to maximize the benefits of neuromodulation.
Article
Several reports indicate either increased or decreased pain sensitivity associated with psychiatric disorders. Chronic pain is highly prevalent in many of these conditions. We reviewed the literature regarding experimental pain sensitivity in patients with major depression, bipolar disorder, posttraumatic stress disorder (PTSD), generalized anxiety disorder, panic disorder, obsessive-compulsive disorder and schizophrenia. Electronic searches were performed to identify studies comparing experimental pain in patients with these conditions and controls. Across 31 depression studies, reduced pain threshold was noted except for ischemic stimuli, where increased pain tolerance and elevated sensitivity to ischemic pain was observed. A more pervasive pattern of low pain sensitivity was found across 20 schizophrenia studies. The majority of PTSD studies (n = 20) showed no significant differences compared with controls. The limited number of bipolar disorder (n = 4) and anxiety (n = 9) studies precluded identification of clear trends. Wide data variability was observed. Awareness of psychiatric patients’ pain perception abnormalities is needed for active screening and addressing physical comorbidities, in order to enhance quality of life, life expectancy and mental health.
Article
Most gastrointestinal diseases and disorders (GIDD) are associated with depression, anxiety, and cognitive dysfunction. This suggests that shared features of GIDD, particularly chronic pain and inflammation, affect specific neural targets. The critical review of clinical and animal research presented here reveals that anterior cingulate cortex (ACC) is a primary target. It is particularly sensitive to neuroinflammation, and its function accounts for altered mental function emergent in GIDD. We propose that peripherally-triggered neuroinflammation normally signals injury/illness to ACC, which increases threat assessment and pain sensitivity to cope with increased vulnerability. Chronic peripheral inflammation over-drives this process, leading to long-term ACC structural remodeling, and excessive threat signaling. This evokes anxiodepressive phenotypes even without direct evidence of threats because ACC utilizes schemas to infer affective outcomes (e.g. pain) based on complex contextual information. This activates the autonomic nervous system, exacerbates immune dysfunction, and promotes further gut pathology. This theory provides a mechanistic account of bidirectional interactions among gastrointestinal, immunological, and neural systems in GIDD, and is likely applicable to other chronic inflammatory conditions.
Article
Objective: To investigate the relationship between anxiety and pain scores using the Glasgow Composite Measure Pain Scale-Short Form (CMPS-SF) in dogs. Study: Prospective observational study. Animals: A group of 18 dogs undergoing surgical management of stifle disease. Methods: Preoperatively dogs were scored using the CMPS-SF, the anxiety behaviour-based Reactivity Evaluation Form (REF), a Visual Analogue Scale (VAS) for anxiety and a sedation score. Assessments of pain, anxiety and sedation were repeated approximately 2-6 hours postoperatively. Dogs were divided into groups based on preoperative REF ('Low REF' and 'High REF'), and VAS scores ('Low VAS' and 'High VAS'). Scores (CMPS-SF, REF, VAS and sedation) were compared between groups using Mann-Whitney U tests. Preoperative and postoperative CMPS-SF, REF and VAS scores were compared using Wilcoxon signed-rank tests. Relationships between anxiety and CMPS-SF scores were assessed using a Spearman rank correlation coefficient. Scores are presented as median (range). A p value of < 0.05 was considered significant. Results: When divided based on REF, CMPS-SF scores did not differ between groups preoperatively [Low REF: 2 (0-3), High REF: 2 (1-3); p = 0.509] or postoperatively [Low REF: 3 (2-5), High REF: 3 (2-5); p = 0.624]. When divided based on VAS, CMPS-SF scores did not differ between groups preoperatively [Low VAS: 2 (0-2), High VAS: 2 (1-3); p = 0.215] or postoperatively [Low VAS: 3 (2-5), High VAS: 3 (2-5); p = 1]. Postoperative REF [pre: 4.5 (2-8), post: 5 (4-10); p = 0.0105] and CMPS-SF scores [pre: 2 (0-3), post: 3 (2-5); p = 0.0318] increased significantly compared with preoperative scores. Conclusions and clinical relevance: No apparent relationship exists between baseline anxiety levels and CMPS-SF scores. Understanding the influence of anxiety when using the CMPS-SF is important when assessing pain in dogs. Anxiety and pain may increase postoperatively in dogs undergoing orthopaedic surgery.
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PurposeThis study aimed to determine degree of postoperative pain and the incidence of serious postoperative pain after glaucoma surgery and further to identify the associated risk factors.MethodsA total of 194 consecutive patients who were diagnosed with glaucoma and underwent glaucoma surgery were enrolled in this study. The intensity of postoperative pain was evaluated using numerical rating scale (NRS) within 24 h after surgery; NRS ≥ 5 was considered as clinically significant postoperative pain. Risk factors associated with the development of postoperative pain were analyzed by multivariate logistic regression analysis.ResultsClinically significant postoperative pain was experienced at any time after glaucoma surgery in 41.75% of the patients, which peak at 2 h. 27.8% of the patients requested analgesic medication within 24 h after surgery. According to multivariate logistic regression analysis, preoperative anxiety (OR = 4.13 [1.29–13.2], p = 0.017), cyclophotocoagulation (OR = 30.9 [3.47–375.1], p = 0.002), and phacotrabeculectomy combined with or without intraocular lens implantation (OR = 30.0 [2.69–335.6], p = 0.006) were associated with increased clinically significant postoperative pain. Interestingly, patients with diabetes and/or hypertension were associated with less postoperative pain after glaucoma surgery (OR = 0.23 [0.08–0.64], p = 0.005).Conclusion Patients undergoing glaucoma surgery tend to experience postoperative pain in the early postoperative period. Anxiety level and surgery types of cyclophotocoagulation and phacotrabeculectomy are risk factors for postoperative pain. Patients with diabetes and/or hypertension are less likely to develop postoperative pain.
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Background Postoperative complications occur frequently, despite progress in anesthetic pharmacology and surgical techniques. Although habits, such as alcohol and tobacco use, and mental health have been studied individually as modifying factors, few studies have examined the relationship between multiple lifestyle choices and postoperative complications in patients undergoing surgery. Hence, this study aimed to investigate the associations between unhealthy lifestyle choices and postoperative complications. Methods We included 730 patients who underwent surgery in our department between March 2015 and April 2016. Participants completed preoperative questionnaires, including the Alcohol Use Disorders Identification Test, Fagerström Test for Nicotine Dependence, and tests for psychological stress (6-item Kessler Psychological Distress Scale; Hospital Anxiety and Depression Scale). Multivariable logistic analysis was used to analyze the association of preoperative drug dependence and psychological stress with postoperative complications. Results Of the 721 cases analyzed, 461 (64%) were women. The median age of patients was 62 years (interquartile range: 48–71). At the time of surgical decision-making, 429 out of 710 respondents (60%) had a drinking habit, and 144 out of 693 respondents (21%) had a smoking habit during the preceding year. Seventy-nine patients had developed complications. Multivariable analysis revealed that old age (p = 0.020), psychological stress (p = 0.041), and longer anesthesia time (p < 0.001) were significantly associated with postoperative complications. Drinking or smoking variables were not associated with postoperative complications. Conclusions Preoperative psychological stress, as evaluated with the 6-item Kessler Psychological Distress Scale, is associated with the risk of postoperative complications.
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Pain associated with infections of the tooth pulp and periapical tissues is intense and often the most common reason for patients seeking emergency dental care. Effective management of acute dental pain requires a deep understanding of pain mechanisms, which enables accurate diagnosis and definitive treatment. While drugs are only used as an adjunct to definitive dental treatment, a thorough understanding of their mechanism of action and effectiveness enables clinicians to effectively control intra-operative and post-operative pain and prevent persistent pain. This review describes how pain is detected, processed, and perceived. It also provides information on evidence-based strategies on the use of different classes of drugs to effectively manage endodontic pain.
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A model of fear and pain is presented in which the two are assumed to activate totally different classes of behavior. Fear, produced by stimuli that are associated with painful events, results in defensive behavior and the inhibition of pain and pain-related behaviors. On the other hand, pain, produced by injurious stimulation, motivates recuperative behaviors that promote healing. In this model injurious stimulation, on the one hand, and the expectation of injurious stimulation, on the other hand, activate entirely different motivational systems which serve entirely different functions. The fear motivation system activates defensive behavior, such as freezing and flight from a frightening situation, and its function is to defend the animal against natural dangers, such as predation. A further effect of fear motivation is to organize the perception of environmental events so as to facilitate the perception of danger and safety. The pain motivation system activates recuperative behaviors, including resting and body-care responses, and its function is to promote the animal's recovery from injury. Pain motivation also selectively facilitates the perception of nociceptive stimulation. Since the two kinds of motivation serve different and competitive functions, it might be expected that they would interact through some kind of mutual inhibition. Recent research is described which indicates that this is the case. The most important connection is the inhibition of pain by fear; fear has the top priority. This inhibition appears to be mediated by an endogenous analgesic mechanism involving the endorphins. The model assumes that fear triggers the endorphin mechanism, thereby inhibiting pain motivation and recuperative behaviors that might compete with effective defensive behavior.
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This paper applies the behavior systems approach to fear and defensive behavior, examining the neural circuitry controlling fear and defensive behavior from this vantage point. The defensive behavior system is viewed as having three modes that are activated by different levels of fear. Low levels of fear promote pre-encounter defenses, such as meal-pattern reorganization. Moderate levels of fear activate post-encounter defenses. For the rat, freezing is the dominant post-encounter defensive response. Since this mode of defense is activated by learned fear, forebrain structures such as the amygdala play a critical role in its organization. Projections from the amygdala to the ventral periaqueductal gray activate freezing. Extremely high levels of fear, such as those provoked by physical contact, elicit the vigorous active defenses that compose the circa-strike mode. Midbrain structures such as the dorsolateral periaqueductal gray and the superior colliculus play a crucial role in organizing this mode of defense. Inhibitory interactions between the structures mediating circa-strike and post-encounter defense allow for the rapid switching between defensive modes as the threatening situation varies.
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Prior research suggests that afferent nociceptive information can directly activate the opioid and nonopioid brainstem antinociceptive systems. Grau (1987a) has hypothesized that direct activation occurs when an organism is exposed to severe aversive stimuli and that forebrain systems mediate the activation of the antinociception systems when mild aversive stimuli are used. The present experiments tested this hypothesis by examining the impact of spinalization and decerebration on the antinociception observed after mild (3 0.75-s 1.0-mA shocks) and vs. severe (3 25-s 1.0-mA shocks) tailshocks. It was found that spinal transection eliminated the antinociception observed after both shock schedules, whereas decerebration blocked mild shock-induced, but not severe shock-induced, antinociception. Surprisingly, decerebration potentiated severe shock-induced antinociception. The opioid antagonist naltrexone had no effect on the antinociception observed after severe shock in sham or decerebrate rats.
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We tested the hypothesis that exposure to a stimulus resembling the original traumatic event would induce naloxone-reversible analgesia in patients with posttraumatic stress disorder (PTSD). Eight medication-free Vietnam veterans with PTSD and eight veterans without PTSD, matched for age and combat severity, viewed a 15-minute videotape of dramatized combat under naloxone hydrochloride and placebo conditions in a randomized double-blind crossover design. In the placebo condition, the subjects with PTSD showed a 30% decrease in reported pain intensity ratings of standardized heat stimuli after the combat videotape. No decrease in pain ratings occurred in the subjects with PTSD in the naloxone condition. The subjects without PTSD did not show a decrease in pain ratings in either condition. The results are consistent with the induction of opioid-mediated stress-induced analgesia in the patients with PTSD.
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Previous research (Grau, 1987a, 1987b) suggests that forebrain systems play an essential role in the hypoalgesia observed after brief shock but not long shock. Additional research has shown that pentobarbital anesthesia and decerebration block the hypoalgesia observed after 3 brief (0.75-s) shocks but not the hypoalgesia observed after 3 long (25-s) shocks. This is a study of whether a specific forebrain lesion, a frontal cortex lesion, would have a similar impact on hypoalgesia induced by brief (0.75 s) and long (25-s) shocks. Frontal cortex lesions, like decerebration and pentobarbital anesthesia, eliminated the hypoalgesia observed after brief but not long shocks. Because other research suggests that the stress of surgery may influence whether the hypoalgesia elicited by shock is opioid or nonopioid, the 2nd experiment was to examine whether the sham operation per se alters the form of the hypoalgesia observed after brief shock. It does not; in the sham-treated subjects, brief shock induced the usual transient nonopioid hypoalgesia followed by prolonged opioid hypoalgesia. These data suggest that frontal cortex lesions block nonopioid and opioid hypoalgesia observed after brief shock.
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Exposure to an aversive event, such as shock, can elicit either an opioid or nonopioid analgesia in rats. We suggest that the central representation of an aversive event in working memory activates both forms of analgesia. We formalize this basic hypothesis by coupling it with a current model of animal learning and memory, SOP (Wagner, 1981). SOP is designed to capture the standard operating procedures that govern memory systems. Our application of SOP suggests that manipulations which disrupt the maintenance of information in working memory should alter the magnitude and time course of analgesia. Three experiments are reported that support our proposal. Experiment 1 showed that analgesia decays more rapidly if the representation of the aversive event is displaced from working memory by presenting a postshock distractor. Experiment 2 demonstrated that the postshock distractor alters the magnitude and time course of both the opioid and nonopioid forms of analgesia. Experiment 3 demonstrated that pharmacologically disrupting working memory, by administering a high dose of pentobarbital, prevents mild shock from inducing a strong change in pain reactivity. Implications of the results are discussed.
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Two theories about the relationship between anxiety and pain were compared: (1) the attribution theory that relevant but not irrelevant anxiety intensifies pain, and (2) the perceptual disruption theory that all anxiety influences pain. Three types of instructions were presented to randomly selected groups of male university students immediately before nociception: (1) a standard set of instructions, (2) the standard instructions plus a pain warning (relevant anxiety condition), and (3) the standard instructions plus a warning about a stressful interview (irrelevant anxiety condition). Pain and stress intensity ratings, heart rate, frontalis electromyographic activity, and facial expressions were recorded continuously, and pain threshold and pain tolerance were recorded once. The anxiety-evoking effects of the instructions were confirmed by analyses of the stress measures obtained during a waiting period. The results indicated that both relevant and irrelevant anxiety-evoking instructions increased pain ratings, stress intensity ratings, and heart rate compared to standard control instructions when painful pressure was applied to the skin. In addition, the relevant but not the irrelevant anxiety instructions increased electromyographic activity and facial grimaces during nociception. However, tolerance, threshold, and post-experimental ratings did not differ among groups. These results are interpreted as supporting the perceptual disruption theory.
Chapter
In this chapter we review 228 of modern scientific studies on acupuncture. As most research has focused on acupuncture analgesia (AA) this will be the major topic. Two main conclusions are drawn: first that AA is effective in treating chronic pain (working better than placebo), and second that the neurological mechanisms of AA are rapidly becoming apparent. We conclude that acupuncture activates small myelinated nerve fibres in the muscle, which send impulses to the spinal cord, and then activates three centres (spinal cord, midbrain and pituitary-hypothalamus) to cause analgesia. The spinal cord centre uses enkephalin and dynorphin to block incoming painful information. The midbrain centre uses enkephalin to activate the raphe descending system which inhibits spinal cord pain transmission using the monoamines (serotonin and norepinephrine). The third centre is the hypothalamus-pituitary, which releases beta endorphin into the blood and cerebrospinal fluid to cause analgesia at a distance. Thus all three endorphins (enkephalin, beta endorphin, and dynorphin) have a role in AA, and two monamines (serotonin and norepinephrine) are also involved. When high frequency low intensity stimulation is used a non-endorphin type of analgesia occurs. Unfortunately, much less research has been done into the other claims made in addition for acupuncture, and these will be given less coverage (Sects. 1.3 and 1.4). Finally, the specificity of acupuncture points will be discussed in Section 1.5.
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Offers explicit conceptual explanations of why and when distraction will be effective in coping with pain-produced distress and reviews research related to this conceptual scheme. A theoretical case for the effectiveness of distraction is drawn from assumptions about the importance of cognition in mediating the pain experience and the limited capacity available for focusing attention on different stimulus events. Combining these assumptions led to 4 principles that were examined with available data. Principle 1 holds that distractions will reduce stress as compared with uninstructed and placebo control conditions. Principle 2 maintains that distraction techniques that require more attentional capacity will be more effective. Principle 3 contends that distraction will have stronger effects on pain stimuli of low intensity. Principle 4 predicts that distraction will be more effective than sensation redefinition for mild pain stimuli, but the reverse will be true for intense pain stimuli. Data support these principles. Research is needed to compare distraction and expectancy control conditions, to test distraction for clinical as opposed to acute pain, to compare distraction strategies that vary in quantified attentional requirements, and to discover the features of pain stimuli. (89 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).
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Factors that determine whether naltrexone and pentobarbital anesthesia block the hypoalgesia produced by electric shock were investigated. The number of shocks delivered, the time since the last shock, and whether the subject is removed from the shock environment for testing were all found to be critical. One shock was followed by an initial hypoalgesia that was reversed by naltrexone but was not affected by pentobarbital. Moreover, this initial hypoalgesia was not eliminated by removing the subject from the shock apparatus. When testing was conducted in the shock context, this early hypoalgesia was followed by a hypoalgesia that was still reversed by naltrexone but differed from the early response in that it was eliminated by pentobarbital anesthesia. This second hypoalgesia did not occur when testing was conducted after removing the animal from the shock apparatus. Five shocks were also followed by two separable responses. Here the first response was also not reduced by pentobarbital, but it was not blocked by naltrexone. This initial response was also not prevented by removal from the shock context, but, again, the second response did not occur after removal. The pattern after 80 shocks was quite different. Here the hypoalgesic response did not appear to change in character across the 10 min of testing or with removal from the shock apparatus. The response persisted for 10 min in the shock context or after removal and was blocked by both naltrexone and pentobarbital throughout its entire duration. These results reconcile findings from different laboratories and bear on a number of theoretical models of stress-induced hypoalgesia.
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Prior research suggests that a coulometric relation (Intensity x Duration).determines whether an opioid or nonopioid hypoalgesic system is activated by afferent nociceptive information. Using a paradigm that generates a brainstem-mediated hypoalgesia on the tail-flick test, we found that a coulometric relation does not predict either the emergence or the form of shock-induced hypoalgesia in decerebrate rats. In fact, no evidence was obtained that the brainstem's opioid hypoalgesic system can be activated by ascending neurons. More severe shocks elicited hypoalgesia in spinalized rats. Although a coulometric relation did not predict the emergence of hypoalgesia in spinalized rats, shock severity did predict the form of the hypoalgesia; the least severe shocks elicited an opioid hypoalgesia, and the more severe shocks generated a nonopioid hypoalgesia. A similar pattern of data was observed in intact rats exposed to the least severe shock parameters.
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This study investigated the size of, and relationship between, different modulatory effects of aversive stimulation on the acoustic startle reflex. This reflex is potentiated by shock exposure and associative shock conditioning (in animals and human volunteers) and unpleasant pictures (tin human volunteers). In this study, dramatic sensitization of the probe-startle response was observed after shock exposure but not after a control task. Magnitude of sensitization was significantly larger than associative shock conditioning and picture modulation effects (also significant). Sensitization and conditioning scores showed modest, significant correlations with one another but not with picture modulation scores, consistent with animal data showing that partially overlapping brain mechanisms (i.e., amygdaloid-reticular projections) mediate these effects. The present results also indicate that sensitization of startle in human volunteers is a relatively more robust defensive response to aversive stimulation.
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• We tested the hypothesis that exposure to a stimulus resembling the original traumatic event would induce naloxone-reversible analgesia in patients with posttraumatic stress disorder (PTSD). Eight medication-free Vietnam veterans with PTSD and eight veterans without PTSD, matched for age and combat severity, viewed a 15-minute videotape of dramatized combat under naloxone hydrochloride and placebo conditions in a randomized double-blind crossover design. In the placebo condition, the subjects with PTSD showed a 30% decrease in reported pain intensity ratings of standardized heat stimuli after the combat videotape. No decrease in pain ratings occurred in the subjects with PTSD in the naloxone condition. The subjects without PTSD did not show a decrease in pain ratings in either condition. The results are consistent with the induction of opioid-mediated stress-induced analgesia in the patients with PTSD.
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Although it is a commonly accepted notion that anxiety and pain are positively related, it is unclear whether this relation holds regardless of the source of anxiety. The present research examined the relation between source of anxiety and pain responsivity by comparing the pain thresholds and pain tolerances of male and female undergraduates exposed to laboratory induced general anxiety, laboratory induced pain specific anxiety, non-veridical exaggerated descriptions of the sensations produced by a pain stimulator, and a control procedure. The results revealed that only pain specific anxiety enhanced pain responsivity for both males and females. The non-veridical instructions increased pain tolerance only for males but lowered both pain thresholds and pain tolerances for females. The results were interpreted as suggesting that anxiety enhances pain responsivity only if the source of anxiety is related to painful stimuli.
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The objective of this work was to simultaneously measure pain-related spinal and supraspinal physiological responses in humans. The sural nerve compound action potential (CAP), the spinal withdrawal reflex (RIII), the somatosensory evoked potential (SEP) and subjective magnitude ratings were elicited by electrical stimulation of the sural nerve in 10 healthy subjects. The sural nerve CAP was used to normalize the evoking stimulus current and to help identify the peripheral nerve afferent types contributing to the physiological and psychophysical responses.Normalizing stimulus current to a proportion of that which elicited a just maximal sural nerve CAP significantly reduced individual variability in magnitude ratings, the RIII and the SEP. Pain and RIII responses only occurred at stimulus levels that were greater than or equal to 1.5 × that which produced a just maximal sural nerve CAP and both responses were positively related to stimulus intensity above that level. Activity in the large diameter Aβ fibers will be saturated at stimulus levels near that which produced a just maximal CAP, which implies that both the pain and RIII responses can be attributed to recruitment of the smaller diameter Aδ fibers. Although the amplitudes of the P200 and P300 peaks of the SEP were significantly related to stimulation at noxious levels, both were also affected by stimulation at innocuous levels. This result implies that these peaks receive contributions from both noxious and innocuous somatosensory processes. Clearly, the non-pain-related components of these SEP peaks must be identified and isolated before their potential in measuring supraspinal nociceptive processes can be fully realized.
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Pain is better classified as an awareness of a need-state than as a sensation. It serves more to promote healing than to avoid injury. It has more in common with the phenomena of hunger and thirst than it has with seeing or hearing. The period after injury is divided into the immediate, acute and chronic stages. In each stage it is shown that pain has only a weak connection to injury but a strong connection to the body state.
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The CES-D scale is a short self-report scale designed to measure depressive symptomatology in the general population. The items of the scale are symptoms associated with depression which have been used in previously validated longer scales. The new scale was tested in household interview surveys and in psychiatric settings. It was found to have very high internal consistency and adequate test- retest repeatability. Validity was established by pat terns of correlations with other self-report measures, by correlations with clinical ratings of depression, and by relationships with other variables which support its construct validity. Reliability, validity, and factor structure were similar across a wide variety of demographic characteristics in the general population samples tested. The scale should be a useful tool for epidemiologic studies of de pression.
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fear and anxiety / neurochemistry of fear, anxiety and learned helplessness [anxiety and gamma-aminobutyric acid (GABA), learned helplessness and GABA, anxiety and 5-hydroxytryptamine (5-HT), learned helplessness and 5-HT] / the amygdala, dorsal raphe and periaqueductal gray / attention (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The present paper extends the coverage of the "Psychological Record" (1977) devoted to the topic of tonic immobility (also known as "animal hypnosis") by examining the applicability of the designation tonic immobility to special states of behavioral inhibition in humans, particularly the occurrence of rape-induced paralysis commonly reported by rape victims. Since fear, overtones of predation, contact, and restraint are common denominators to rape and the induction of tonic immobility, and because the reactions by rape victims are often isomorphic with behaviors shown by immobilized animals, it is concluded that tonic immobility and rape-induced paralysis represent the same phenomenon. The adaptive value of this reaction to rape is briefly discussed. (24 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
The time course of the facilitation of the acoustic startle reflex induced by anticipation of electric shocks was measured in 20 normal volunteers. Shocks could be administered during the last 10 s of 45-s threat conditions but not during 50-s no-threat conditions, each condition being signaled by a different light. Consistent with previous data, overall eyeblink startle levels were higher during the threat than during the no-threat conditions. However, the magnitude of this fear-potentiated startle effect became progressively larger in the threat condition the longer the light was on and then abruptly decreased with the onset of the light signaling the no-threat condition. These effects of the threat of shock on startle were interpreted in terms of anticipatory anxiety. Other interpretations, such as changes in selective or generalized attention, were also discussed. This paradigm provides a method to assess the time course of anticipatory anxiety in humans.
Article
New methodologies to assess analgesic response in humans are needed to better integrate preclinical and clinical data. In the present study we examined the test-retest stability of an innovative radiant heat methodology compared with an electrical stimulation methodology. For the radiant heat task, a modified rodent tail flick apparatus was used. The latency for finger withdrawal was recorded. For the electrical stimulation tasks, subjects placed two fingers on two electrodes from which they received a brief series of increasingly intense electrical stimulations. Maximum stimulus intensity (in milliamps) delivered was recorded. On each of 4 test days, the subjects received five test trials with a 10-min interval between trials. All the subjects were tested twice on each apparatus in a counterbalanced design. Finger withdrawal latencies for the radiant heat task did not differ significantly across test trials or test days. Finger withdrawal scores for electrical stimulation increased significantly across test trials as well as test days. These data show that the radiant heat method generates consistent latencies across trials and days, whereas shock produces trends over time. The radiant heat task, which is convenient to operate and inexpensive to build, appears promising as a reliable test of pain threshold in humans.
Article
Extensive evidence has indicated that distinct neural systems specifically designed to inhibit sensitivity to painful stimuli exist. Recent advances suggest that the endorphins, enkephalins and the opiate receptor interact with a descending serotonergic bulbospinal system to mediate the analgesic responses to opiates and electrical stimulation. In assessing the evolutionary and behavioral significance of this pain-inhibitory system, several laboratories discovered that acute exposure to a wide variety of stressful events results in a transient analgesia. Chronic exposure to a number of these stressors results in adaptation of the analgesic response. The purpose of this review is to identify and characterize the mechanisms by which these stressors activate pain-inhibition. The relationship of stress-induced analgesia to each of the following is reviewed: (a) the role of endorphins, enkephalins and the opiate receptor; (b) the role of the descending serotonergic bulbospinal system; (c) the role of the pituitary gland; and (d) the role of hypothalamic mechanisms. Data will be discussed in terms of “opiate” and “non-opiate” pain-inhibitory mechanisms, in which some stressors act through the former and other stressors act through the latter.
Article
In man, heterotopic painful thermal conditioning stimuli induce parallel decreases in the spinal nociceptive flexion (RIII) reflex and the concurrent sensation of pain elicited by electrical stimulation of the sural nerve at the ankle. Such phenomena may be related to the diffuse noxious inhibitory controls (DNIC) which were initially described in the rat and subsequently documented in humans. In 9 subjects in the present study, a 2 min application of a moderately noxious temperature (46°C) to the contralateral hand strongly depressed the RIII reflex elicited in the biceps femoris muscle by electrical stimulation of the sural nerve at 1.2 times the reflex threshold. These depressive effects were maximal during the second min of the conditioning period, showing a 80% inhibition of the RIII reflex which gradually recovered to its baseline value 7 min after the end of the conditioning period. Such inhibitory effects were completely blocked 15–26 min after administration of a low dose of morphine hydrochloride (0.05 mg/kg i.v.). The lifting of the inhibitions was compatible with an action at the opioid receptors since the inhibitions were re-observed 5–16 min after naloxone injection (0.006 mg/kg i.V.). During all the experimental sessions, heart and respiratoty rates remained stable at their control levels. Since it has been shown previously that such a dose of morphine could not have a direct effect within the spinal cord (Wilier 1985), it is concluded that this opiate blocks, in a naloxone-reversible fashion, those bulbo-spinal controls which are triggered by heterotopic nociceptive events. Possible implications for hypoalgesia based on the principles of counter-irritation are discussed.
Article
Proponents of the use of signal detection theory (SDT) in the assessment of pain modulation have generally looked for changes in d' to indicate a reduction of sensory function, and a change in criterion to indicate a modification of the subject's response bias or attitudinal predisposition. In the first experiment, both assumptions failed to receive empirical verification. Discrimination d' was eqivalent before and after two strong levels of electrical current was reduced. The criterion parameter appeared to shift in a more conservative direction after the stimulus diminution. These results are used to question the validity of both detection and discrimination indices in the measurement of pain. An alternative means for describing the experimental results revealed a striking adaptation-level effect with implications for the assessment of both experimentally induced and endogenous pain. The outcome of a second experiment reinforced the adaptation-level theory interpretation of the results and provided additional evidence concerning the difficultuies in evaluating SDT parameters in studies of potential analgesics.
Article
Used the procedures prescribed by the theory of signal detection (TSD) to investigate the effects of trait anxiety and experimental instructions, designed to manipulate the consequences of pain reports, on the focal pressure pain thresholds of 96 undergraduates who were chosen from a larger pool on the basis of their high and low scores on the Taylor Manifest Anxiety Scale. The results indicate that both anxiety and instruction affected pain thresholds. The TSD analysis, however, revealed that these findings were due to differences in response bias. No differences in sensitivity were found. (32 ref)
Article
The results of two experiments suggest that sensory and affective verbal descriptors provide a valid scaling method which discriminates between the sensory intensity and the affect, or unpleasantness, of electrocutaneous stimuli. Twenty-four subjects judged the sensory intensity and affect of noxious electrocutaneous stimuli by choosing verbal descriptors from randomized lists and by cross-modality matching to time duration and to handgrip force. The psychophysical functions for sensory intensity generated by the descriptor and the cross-modality functions for sensory intensity generated by the descriptor and the cross-modality methods are the same. Psychophysical functions for affect generated by thedescriptor and the cross-modality methods are different. However, only the descriptor method produces psychophysical functions for affect that are significantly different from all the sensory functions. This result suggest that only the descriptor method distinguishes between sensory intensity and affect. The discriminative power of the descriptor method is demonstrated further in an experiment in which 32 subjects rated either the sensory intensity or the affect of the electrocutaneous stimuli immediately before and after an i.v. administration of 5 mg diazepam. This common minor tranquilizer significantly lowered affective descriptor responses (P less than 0.005) without altering sensory descriptor and sensory and affective handgrip responses. These experiments indicate that sensory and affective verbal pain descriptors may be used as a valid and sensitive tool for the evaluation of pain and pain control methods.
Article
The coping behavior of rape victims can be analyzed in three distinct phases--the threat of attack, the attack itself, and the period immediately thereafter. The authors analyzed the reported coping behavior of 92 women diagnosed as having rape trauma. Most of the women used verbal, physical, or cognitive strategies when threatened, although 34 were physically or psychologically paralyzed. The actual rape prompted coping behaviors in all but 1 victim. Escaping the situation or the assailant is the primary task immediately after the attack. In counseling the rape victim, it is important to understand her individual style of coping, to be supportive of it, and to suggest alternatives for future stressful situations.
Article
So far, the association between anxiety and pain has not been studied with measures tapping a physiological dimension of anxiety. Therefore, during a blood extraction procedure, we recorded subjective anxiety, electrodermal activity, heart rate, and intensity of pain. Subjects were 15 patients with panic disorder and 24 healthy subjects. Positive associations between subjective anxiety and pain were found in each group. The physiological activity preceding the venipuncture, however, was not significantly related to the intensity of the pain.
Article
It was hypothesized that anxiety which is relevant to the source of pain exacerbates pain, whereas anxiety which is irrelevant to the source of pain reduces the experience of pain. Female subjects were given either high or low anxiety provoking information about a cold pressor task (relevant anxiety) or high or low anxiety provoking information about a potential shock (irrelevant anxiety). Subjects were then exposed to the cold pressor. The results demonstrated that subjects who were highly anxious about the cold pressor reported experiencing the most pain. Subjects who were highly anxious about the shock reported the least pain and reported significantly less pain than subjects who were highly anxious about the cold pressor. These findings clearly demonstrate that the relationship between anxiety and pain is not always positive or unidirectional.
Article
Four hypotheses about the influences of anxiety and attention on pain impact were tested in a critical experiment: (1) anxiety increases pain; (2) anxiety decreases pain; (3) attention to pain increases pain; (4) only the combination of anxiety and attention to pain increases pain (interaction hypothesis). In a 2 x 2 design, anxiety (low vs high) and attention (attention vs distraction from the pain) were experimentally manipulated. Subjects received 20 electrically produced painful stimuli. Subjective pain experiences, skin conductance responses and heart rate responses gave no support for a pain impact increasing effect of anxiety. The anxiety-attention interaction hypothesis did not receive any support either. There was some support, only from the heart rate responses, that anxiety reduces pain impact. The critical factor appeared to be attention. Attention to the pain stimulus was related to a stronger pain impact (indicated by all measures) and to less subjective habituation, compared to distraction.
Article
Previous research has demonstrated that exposure to a cat produces a naltrexone-reversible antinociception as assessed in the formalin test in rats. Because different neurochemical mechanisms inhibit different forms of nociception, the present study examined whether presentation of a cat would also produce a naltrexone-reversible antinociception in the tail-flick response to radiant heat and electric shock. Exposure to the cat produced antinociception in both tail-flick paradigms. Naltrexone blocked the inhibition of the thermally evoked tail-flick response, but had no effect in the electric shock tail-flick paradigm. These results indicate that opioid mediation of stress-induced analgesia is determined, in part, by the nociceptive test employed.
Article
Factors that determine whether naltrexone and pentobarbital anesthesia block the hypoalgesia produced by electric shock were investigated. The number of shocks delivered, the time since the last shock, and whether the subject is removed from the shock environment for testing were all found to be critical. One shock was followed by an initial hypoalgesia that was reversed by naltrexone but was not affected by pentobarbital. Moreover, this initial hypoalgesia was not eliminated by removing the subject from the shock apparatus. When testing was conducted in the shock context, this early hypoalgesia was followed by a hypoalgesia that was still reversed by naltrexone but differed from the early response in that it was eliminated by pentobarbital anesthesia. This second hypoalgesia did not occur when testing was conducted after removing the animal from the shock apparatus. Five shocks were also followed by two separable responses. Here the first response was also not reduced by pentobarbital, but it was not blocked by naltrexone. This initial response was also not prevented by removal from the shock context, but, again, the second response did not occur after removal. The pattern after 80 shocks was quite different. Here the hypoalgesic response did not appear to change in character across the 10 min of testing or with removal from the shock apparatus. The response persisted for 10 min in the shock context or after removal and was blocked by both naltrexone and pentobarbital throughout its entire duration. These results reconcile findings from different laboratories and bear on a number of theoretical models of stress-induced hypoalgesia.
Article
This chapter presents the electrophysiological evidence for the activation of descending inhibitory controls by nociceptive afferent pathways. The three routes of administration of morphine used for alleviating pain in man—systemic, intrathecal, intracerebroventricular (ICV)—can be correlated with a reduction of diffuse noxious inhibitory controls (DNIC). The two opposite manipulations, the activation of DNIC by counter irritation procedures and its blocking by morphine, lead in therapeutic terms to the same end point—that is, hypoalgesia. This anomaly reflects the complexity of the spinal systems and provides an insight into the role of the convergent neurons in the encoding of nociceptive and non-nociceptive sensory information. The existence within a neuronal population, of gradients of activity, at least for convergent cells in the rat, should be taken into consideration in pharmacological and biochemical studies concerning nociceptive transmission toward higher centers. The future trends of the research lie in determining the supraspinal circuitry that subserves DNIC.
Article
This experiment tested the hypothesis that perceived self-inefficacy in exercising control over cognitive stressors activates endogenous opioid systems. Subjects performed mathematical operations under conditions in which they could exercise full control over the cognitive task demands or in which the cognitive demands strained or exceeded their cognitive capabilities. Subjects with induced high perceived self-efficacy exhibited little stress, whereas those with induced low perceived self-efficacy experienced a high level of stress and autonomic arousal. Subjects were then administered either an inert saline solution or naloxone, an opiate antagonist that blocks the analgesic effects of endogenous opiates, whereupon their level of pain tolerance was measured. The self-efficacious nonstressed subjects gave no evidence of opioid activation. The self-inefficacious stressed subjects were able to withstand increasing amounts of pain stimulation under saline conditions. However, when endogenous opioid mechanisms that control pain were blocked by naloxone, the subjects were unable to bear much pain stimulation. This pattern of changes suggests that the stress-induced analgesia found under the saline condition was mediated by endogenous opioid mechanisms and counteracted by the opiate antagonist.
Article
The present study examines the inhibitory effect of segmentally applied TENS on the nociceptive component of the flexion reflex elicited in various lower limb muscles, in an attempt to gain some insight into the underlying mechanism. The flexion reflex from 11 normal subjects was recorded electromyographically from the biceps femoris (BF), the tibialis anterior (TA), and in 2 subjects, the hip flexor (HF), in the manner described in a previous paper [9]. Amplitude and area values of the flexion reflex of each muscle were computerized prior to, during, and 50 min after the application of placebo or low intensity TENS at 100 Hz, for 30 min to the low back, at levels of segmental innervation (L4-S1) similar to those of the muscles under study. In the majority of subjects, we found that: Low intensity TENS caused a significant inhibition of the flexion reflex in proximal limb flexors. Thus, the BF measured 64% and 52%, and the HF 45% and 51%, of their respective mean control amplitude and area values at the time of maximum inhibition during TENS. Moreover, less reduction of the mean values of the flexion reflex was observed in the TA, a distal limb (ankle) flexor. It is noteworthy that in both the BF and HF, the time to peak maximum inhibitory effect took 30 and 20 min respectively after the onset of TENS, and the flexion reflex often did not return to control values even at 40-50 min after TENS. In contrast, placebo TENS application resulted in no significant change of the flexion reflex in all the muscles examined. These findings showed that prolonged stimulation of large diameter fibers by conventional TENS application to the lumbosacral level, exerts a progressive and long latency inhibitory influence on a number of lower limb flexor motoneurons. In keeping with functional demand, this effect was found to be more prominent on the proximal than distal limb muscles. Furthermore, a gradual onset and offset of this inhibitory action is consistent with the results of some investigators demonstrating the possible involvement of endogenous opioids.
Article
Relations between anxiety and pain were assessed in inpatient male drug abusers characterized by high, moderate, and low anxiety levels. A tonic pain stimulus was used for enhanced similarity to clinical pain, and sensory decision theory methodology was applied to measure discriminative and decisional aspects of pain response. Compared with minimally and moderately anxious subjects, highly anxious men demonstrated decreased pain response latencies, reduced abilities to discriminate noxious stimuli, and increased bias to report pain. These findings have relevance for understanding pain perception, self-perceived anxiety, and more general emotional distress in clinical samples. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Using the thermal sense as a model for nociception, the effects of conventional and acupuncture-like transcutaneous nerve stimulation (TNS) were tested on thresholds for warm and cold sensation in 8 healthy subjects. Photic stimulation did not change the thermically neutral zone (the warm-cold difference limen) from that seen under baseline conditions. However, the thermal difference limen usually increased with both types of TNS. The effect was ipsi- as well as contralateral, implying that a central inhibitory mechanism is activated by conventional and acupuncture-like TNS.
Article
Three experiments were carried out to examine the effects of 10 mg of orally administered diazepam on the human pain experience. The first two studies focused on the tolerance of tourniquet pain and the changes in transitory anxiety associated with continuing pain. The third study was concerned with the effect of the drug on the perception of brief and precisely controlled radiant heat pain stimuli. Subjects who ingested diazepam tolerated the presence of the painful tourniquet longer than those who ingested a placebo or aspirin. Diazepam significantly reduced the anxiety associated with the most intense tourniquet pain in contrast to the placebo, but not in contrast to aspirin, but it had no effects on sensory sensitivity to radiant heat pain nor on the willingness of subjects to label noxious experience as pain. The results suggest that the drug affects the emotional motivational component of the pain experience, but not the sensory discriminative component or the central control of pain.
Article
The present study was designed to investigate some of the cognitive functions which may aid an individual in coping with physical pain. Four instructional tapes— relaxation, “anxiety”, cogitive rehearsal, and control—were tested for their ability to increase pain tolerance in a laboratory situation. Eigthy student nurses received one of four training procedures prior to the presentation of two pain stimulators. Pain tolerance was measured by the radiant heat method and the pressure algometer method. Half of the subjects in each group were tested by a male experimenter and the other half were tested by a female experimenter.The results showed that relaxation, “anxiety”, and cognitive rehearsal each was effective in increasing the subject's pain tolerance scores. Relaxation was the most effective method. With the male experimenter, relaxation, “anxiety” and cognitive rehearsal were all significantly better than the control group. With the female experimenter, only the relaxation group showed greater pain tolerance score than the control group.Experimental clinical implications of these results were discussed and suggestions for further research presented.