"My friend, the pain": does altered body awareness affect the valence of pain descriptors?

Nightmares, interoceptive sensibility and nociception: An exploratory study in a general population

OBJECTIVE

Nightmares are dysphoric dreams present in both clinical and non-clinical populations. Physiological activity underlies their emotional reactivity. Therefore, the objective of this study was to investigate the role of interoceptive processes (interoceptive sensibility and nociception) in nightmares in the general population.

METHOD

542 French participants were recruited from the general population to complete an online survey. Interoceptive sensibility, nociception, nightmare frequency and nightmare distress were assessed through online scales and questionnaires. Network analysis, regression and mediation analyses were conducted to assess the relationship between these variables.

RESULTS

The results showed the existence of associations between certain dimensions of interoceptive sensibility, nociception, nightmare frequency and nightmare distress. The regression analysis highlighted the involvement of interoceptive dimensions in predicting the nightmare distress score. Mediation analysis highlighted that nociception was a mediating variable in the relationship between nightmare frequency and nightmare distress.

CONCLUSION

This study provides initial evidence in favour of the involvement of interoceptive processes in the understanding of nightmares. These results offer a new window of understanding the etiology of nightmares but also present the interest to target interoceptive processes in the management of nightmares.

Words hurt: common and distinct neural substrates underlying nociceptive and semantic pain

Introduction

Recent studies have shown that processing semantic pain, such as words associated with physical pain, modulates pain perception and enhances activity in regions of the pain matrix. A direct comparison between activations due to noxious stimulation and processing of words conveying physical pain may clarify whether and to what extent the neural substrates of nociceptive pain are shared by semantic pain. Pain is triggered also by experiences of social exclusion, rejection or loss of significant others (the so-called social pain), therefore words expressing social pain may modulate pain perception similarly to what happens with words associated with physical pain. This event-related fMRI study aims to compare the brain activity related to perceiving nociceptive pain and that emerging from processing semantic pain, i.e., words related to either physical or social pain, in order to identify common and distinct neural substrates.

Methods

Thirty-four healthy women underwent two fMRI sessions each. In the Semantic session, participants were presented with positive words, negative pain-unrelated words, physical pain-related words, and social pain-related words. In the Nociceptive session, participants received cutaneous mechanical stimulations that could be either painful or not. During both sessions, participants were asked to rate the unpleasantness of each stimulus. Linguistic stimuli were also rated in terms of valence, arousal, pain relatedness, and pain intensity, immediately after the Semantic session.

Results

In the Nociceptive session, the 'nociceptive stimuli' vs. 'non-nociceptive stimuli' contrast revealed extensive activations in SI, SII, insula, cingulate cortex, thalamus, and dorsolateral prefrontal cortex. In the Semantic session, words associated with social pain, compared to negative pain-unrelated words, showed increased activity in most of the same areas, whereas words associated with physical pain, compared to negative pain-unrelated words, only activated the left supramarginal gyrus and partly the postcentral gyrus.

Discussion

Our results confirm that semantic pain partly shares the neural substrates of nociceptive pain. Specifically, social pain-related words activate a wide network of regions, mostly overlapping with those pertaining to the affective-motivational aspects of nociception, whereas physical pain-related words overlap with a small cluster including regions related to the sensory-discriminative aspects of nociception. However, most regions of overlap are differentially activated in different conditions.

Future Treatment of Neuropathic Pain in Spinal Cord Injury: The Challenges of Nanomedicine, Supplements or Opportunities?

Neuropathic pain (NP) is a common chronic condition that severely affects patients with spinal cord injuries (SCI). It impairs the overall quality of life and is considered difficult to treat. Currently, clinical management of NP is often limited to drug therapy, primarily with opioid analgesics that have limited therapeutic efficacy. The persistence and intractability of NP following SCI and the potential health risks associated with opioids necessitate improved treatment approaches. Nanomedicine has gained increasing attention in recent years for its potential to improve therapeutic efficacy while minimizing toxicity by providing sensitive and targeted treatments that overcome the limitations of conventional pain medications. The current perspective begins with a brief discussion of the pathophysiological mechanisms underlying NP and the current pain treatment for SCI. We discuss the most frequently used nanomaterials in pain diagnosis and treatment as well as recent and ongoing efforts to effectively treat pain by proactively mediating pain signals following SCI. Although nanomedicine is a rapidly growing field, its application to NP in SCI is still limited. Therefore, additional work is required to improve the current treatment of NP following SCI.

Pain catastrophizing, pain sensitivity and fear of pain are associated with early life environmental unpredictability: a path model approach

Background

Socioeconomic disadvantages in the childhood environment might strongly influence beliefs and behavior characterizing the adult years. When children experience unpredictable and adverse situations, they develop an unpredictability schema with the core belief that situations are unpredictable.

Methods

In two studies, we examined the association of childhood socioeconomic disadvantages with self-reported pain sensitivity, pain catastrophizing, and pain-related fear. Multidimensional survey measures were used to assess environmental conditions experienced in childhood. In addition, participants completed the Pain Catastrophizing Scale, Pain Sensitivity Questionnaire, Body Awareness Questionnaire, Unpredictability Schema Questionnaire, and Fear of Pain Questionnaire. In Study 1 (N = 252), in separate models, we examined pain sensitivity and pain catastrophizing of a community sample of pain-free young individuals in association with their childhood experiences. In Study 2 (N = 293), in a new sample, but with a wider age range, we examined the association of early life socioeconomic disadvantages with pain-related fear. In both studies, the predictions were tested with Structural Equation Modeling. Our models constituted a path from childhood socioeconomic status and household unpredictability to pain variables via the factors of family resources, unpredictability schemas, and body awareness.

Results and conclusions

The findings converged on the conclusion that individuals experiencing disadvantageous early life conditions tended to have an elevated level of pain catastrophizing, higher perceived sensitivity to pain, and higher level of pain-related fear. These associations were mediated by an unpredictability schema and body awareness.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-022-00800-0.

The characteristics and prognostic role of acute abdominal on-admission pain in acute pancreatitis: A prospective cohort analysis of 1432 cases

INTRODUCTION

Pain is the most common symptom in acute pancreatitis (AP) and is among the diagnostic criteria. Therefore, we aimed to characterize acute abdominal pain in AP.

METHODS

The Hungarian Pancreatic Study Group prospectively collected multicentre clinical data on 1435 adult AP patients between 2012 and 2017. Pain was characterized by its intensity (mild or intense), duration prior to admission (hours), localization (nine regions of the abdomen) and type (sharp, dull or cramping).

RESULTS

97.3% of patients (n = 1394) had pain on admission. Of the initial population with acute abdominal pain, 727 patients answered questions about pain intensity, 1148 about pain type, 1134 about pain localization and 1202 about pain duration. Pain was mostly intense (70%, n = 511/727), characterized by cramping (61%, n = 705/1148), mostly starting less than 24 h prior to admission (56.7%, n = 682/1202). Interestingly, 50.9% of the patients (n = 577/1134) had atypical pain, which means pain other than epigastric or belt-like upper abdominal pain. We observed a higher proportion of peripancreatic fluid collection (19.5% vs. 11.0%; p = 0.009) and oedematous pancreas (8.4% vs. 3.1%; p = 0.016) with intense pain. Sharp pain was associated with AP severity (OR = 2.481 95% CI: 1.550-3.969) and increased mortality (OR = 2.263, 95% CI: 1.199-4.059) compared to other types. Longstanding pain (>72 h) on admission was not associated with outcomes. Pain characteristics showed little association with the patient's baseline characteristics.

CONCLUSION

A comprehensive patient interview should include questions about pain characteristics, including pain type. Patients with sharp and intense pain might need special monitoring and tailored pain management.

SIGNIFICANCE

Acute abdominal pain is the leading presenting symptom in acute pancreatitis; however, we currently lack specific guidelines for pain assessment and management. In our cohort analysis, intense and sharp pain on admission was associated with higher odds for severe AP and several systemic and local complications. Therefore, a comprehensive patient interview should include questions about pain characteristics and patients with intense and sharp pain might need closer monitoring.

A Therapeutic Matrix: Virtual Reality as a Clinical Tool for Spinal Cord Injury-Induced Neuropathic Pain

Neuropathic pain (NP) is a chronic, debilitating, and resistant form of pain. The onset rate of NP following spinal cord injuries (SCI) is high and may reduce the quality of life more than the sensorimotor loss itself. The long-term ineffectiveness of current treatments in managing symptoms and counteracting maladaptive plasticity highlights the need to find alternative therapeutic approaches. Virtual reality (VR) is possibly the best way to administer the specific illusory or reality-like experience and promote behavioral responses that may be effective in mitigating the effects of long-established NP. This approach aims to promote a more systematic adoption of VR-related techniques in pain research and management procedures, highlighting the encouraging preliminary results in SCI. We suggest that the multisensory modulation of the sense of agency and ownership by residual body signals may produce positive responses in cases of brain-body disconnection. First, we focus on the transversal role embodiment and how multisensory and environmental or artificial stimuli modulate illusory sensations of bodily presence and ownership. Then, we present a brief overview of the use of VR in healthcare and pain management. Finally, we discus research experiences which used VR in patients with SCI to treating NP, including the most recent combinations of VR with further stimulation techniques.

Rebuilding Body-Brain Interaction from the Vagal Network in Spinal Cord Injuries

Spinal cord injuries (SCIs) exert devastating effects on body awareness, leading to the disruption of the transmission of sensory and motor inputs. Researchers have attempted to improve perceived body awareness post-SCI by intervening at the multisensory level, with the integration of somatic sensory and motor signals. However, the contributions of interoceptive-visceral inputs, particularly the potential interaction of motor and interoceptive signals, remain largely unaddressed. The present perspective aims to shed light on the use of interoceptive signals as a significant resource for patients with SCI to experience a complete sense of body awareness. First, we describe interoceptive signals as a significant obstacle preventing such patients from experiencing body awareness. Second, we discuss the multi-level mechanisms associated with the homeostatic stability of the body, which creates a unified, coherent experience of one's self and one's body, including real-time updates. Body awareness can be enhanced by targeting the vagus nerve function by, for example, applying transcutaneous vagus nerve stimulation. This perspective offers a potentially useful insight for researchers and healthcare professionals, allowing them to be better equipped in SCI therapy. This will lead to improved sensory motor and interoceptive signals, a decreased likelihood of developing deafferentation pain, and the successful implementation of modern robotic technologies.

Different semantic and affective meaning of the words associated to physical and social pain in cancer patients on early palliative/supportive care and in healthy, pain-free individuals

Early palliative/supportive care (ePSC) is a medical intervention focused on patient's needs, that integrates standard oncological treatment, shortly after a diagnosis of advanced/metastatic cancer. ePSC improves the appropriate management of cancer pain. Understanding the semantic and emotional impact of the words used by patients to describe their pain may further improve its assessment in the ePSC setting. Psycholinguistics assumes that the semantic and affective properties of words affect the ease by which they are processed and comprehended. Therefore, in this cross-sectional survey study we collected normative data about the semantic and affective properties of words associated to physical and social pain, in order to investigate how patients with cancer pain on ePSC process them compared to healthy, pain-free individuals. One hundred ninety patients and 124 matched controls rated the Familiarity, Valence, Arousal, Pain-relatedness, Intensity, and Unpleasantness of 94 words expressing physical and social pain. Descriptive and inferential statistics were performed on ratings in order to unveil patients' semantic and affective representation of pain and compare it with those from controls. Possible effects of variables associated to the illness experience were also tested. Both groups perceived the words conveying social pain as more negative and pain-related than those expressing physical pain, confirming previous evidence of social pain described as worse than physical pain. Patients rated pain words as less negative, less pain-related, and conveying a lower intense and unpleasant pain than controls, suggesting either an adaptation to the pain experience or the role played by ePSC in improving patients' ability to cope with it. This exploratory study suggests that a chronic pain experience as the one experienced by cancer patients on ePSC affects the semantic and affective representation of pain words.

Disconnected Body Representation: Neuroplasticity Following Spinal Cord Injury

Neuroplastic changes in somatotopic organization within the motor and somatosensory systems have long been observed. The interruption of afferent and efferent brain–body pathways promotes extensive cortical reorganization. Changes are majorly related to the typical homuncular organization of sensorimotor areas and specific “somatotopic interferences”. Recent findings revealed a relevant peripheral contribution to the plasticity of body representation in addition to the role of sensorimotor cortices. Here, we review the ways in which structures and brain mechanisms react to missing or critically altered sensory and motor peripheral signals. We suggest that these plastic events are: (i) variably affected across multiple timescales, (ii) age-dependent, (iii) strongly related to altered perceptual sensations during and after remapping of the deafferented peripheral area, and (iv) may contribute to the appearance of secondary pathological conditions, such as allodynia, hyperalgesia, and neuropathic pain. Understanding the considerable complexity of plastic reorganization processes will be a fundamental step in the formulation of theoretical and clinical models useful for maximizing rehabilitation programs and resulting recovery.