Cognition and pain

Distinguishing pain profiles among individuals with long COVID

Background

For many people with long COVID (LC), new-onset pain is a debilitating consequence. This study examined the nature of new-onset pain and concomitant symptoms in patients with LC to infer mechanisms of pain from the relationships between pain and health-related factors.

Methods

Pain and other symptoms were evaluated in 153 individuals with LC using the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs, EuroQoL Visual Analog Scale, and Quality of Life in Neurological Disorders. The relationships between pain and patient factors were analyzed using Chi Square and independent t-tests.

Results

20.3% of individuals who reported new-onset pain had neuropathic pain, which was associated with lower quality of life and higher rates of cognitive dysfunction compared to those with non-neuropathic pain. Other symptoms were similar between groups, however heart-related symptoms were more prevalent in individuals with neuropathic pain and mood swings were more prevalent for individuals with non-neuropathic pain.

Conclusions

Characterizing the relationships between NP and quality of life in individuals with LC can aid in developing better clinical management strategies. Understanding the associations between NP and cognitive dysfunction provides the imperative foundation for future studies further examining the pathophysiological mechanisms underlying pain development in LC.

The effects of experimental pain on episodic memory and its top-down modulation: a preregistered pooled analysis

Introduction

Pain can automatically interfere with ongoing cognitive processes such as attention and memory. The extent of pain's negative effects on cognitive functioning seems to depend on a balance between top-down and bottom-up factors.

Objectives

In this large, preregistered, pooled reanalysis of 8 studies, we investigated the robustness of the detrimental effect of acute pain on recognition memory and whether top-down mechanisms such as pain-related expectations or cognitions (pain-related fear, pain catastrophizing) modulate this effect.

Methods

Two hundred forty-seven healthy participants underwent similar experimental paradigms, including a visual categorization task with images randomly paired with (or without) concomitant painful stimulation and a subsequent unannounced recognition task. Recognition memory (ie, d', recollection, and familiarity) and categorization performance (ie, reaction time, accuracy) served as proxies for the effect of pain on cognitive performance.

Results

Acute painful stimulation significantly impaired recognition performance (d', familiarity). However, recognition performance was not significantly modulated by participants' expectations regarding the effect of pain on task performance or pain-related cognitions in this sample of healthy participants.

Conclusion

Our results corroborate the negative effects of pain on (visual) memory encoding reported in previous studies and reports of "memory problems" from patients with chronic pain. To characterize the role of bottom-up and top-down factors for the detrimental effects of pain, large-scale studies with more nuanced study designs are necessary. Future studies in patient cohorts must unravel the interaction of maladaptive pain-related cognitions and the often-reported impaired cognitive performance in chronic pain patients.

Relationships Between Function, Pain Severity and Psychological and Cognitive Levels in People With Chronic Neck Pain: Cross-Sectional Study

OBJECTIVE

This study aimed to investigate the relationship between pain and functional levels with pain catastrophizing, rumination, decision-making, and critical thinking in people with chronic neck pain.

METHODS

The study included 62 patients with chronic neck pain who had presented to a physiotherapy center with pain complaints for at least 3 months. The visual analog scale for pain severity, the Neck Disability Index for functional level, the Pain Catastrophizing Scale, the Ruminative Thinking Scale, the Melbourne Decision-Making Scale I-II, and the Marmara Critical Thinking Inventory were used for assessments.

RESULTS

Activity pain, night pain, and disability were positively correlated with rumination (rho: 0.368, p = .003; rho: 0.423, p = <.001; rho = 0.334, p = .008). There was a positive correlation between night pain, disability, and pain catastrophizing (rho = 0.298, p = .019; rho = .434 p < .001). A negative correlation was observed between patients' pain severity and disability with critical thinking scores (rho = -0.393, p = .002; rho = -0.377 p = .003, rho = -0.428 p < .001, rho = -0.441 p < .001).

CONCLUSIONS

The study suggested that there were positive correlations between pain severity and disability with rumination and pain catastrophizing. Additionally, chronic neck pain was found to have negative correlations with critical thinking scores, indicating potential impacts on cognitive processes. These findings may provide insights into the complex interplay between chronic pain and psychological factors, which can inform the development of interventions to enhance chronic pain management.

How do the mindfulness and sensory-behavioural-emotional aspects influence the painful experience related to temporomandibular disorder?

BACKGROUND

Chronic pain is persistent or recurrent pain lasting longer than 3 months. The experience of temporomandibular disorder (TMD)-related pain is modulated by emotional and social factors, with mindfulness encapsulating these aspects.

OBJECTIVE

To investigate the association between cognitive-behavioural-emotional characteristics, mindfulness and the painful experience in women with chronic pain-related TMD.

METHODS

A cross-sectional study was conducted, including 90 women aged between 18 and 61 years old, diagnosed with chronic pain-related TMD according to the Diagnostic Criteria for Temporomandibular Disorder, considering both temporomandibular joint and muscle pain. Specific instruments were employed to assess cognitive-behavioural-emotional aspects. The Mindful Attention Awareness Scale and the Five Facets of Mindfulness Questionnaire scales evaluated the level and construct of mindfulness. The relationship between variables was analysed using bivariate association tests (.05 > p < .20), followed by multiple regression tests (p < .05).

RESULTS

The heightened experience of pain correlated with increasing age, a low level of education, the attribution of the locus of control by chance, and lower levels of mindfulness (p < .05). The heightened experience of pain was negatively influenced by mindfulness levels (p < .05). On the other hand, the painful experience was mainly influenced by facets describing negative formulation, distraction, non-reactivity and non-judgement (p < .05).

CONCLUSION

Demographic, cognitive-behavioural-emotional data and levels of mindfulness and its facets presented different influence weights on the painful experience. These findings provide support for future studies focusing on mindfulness strategies, education and pain management in women with chronic pain-related TMD.

Temporal summation of second pain is affected by cognitive load

This work attempted to clarify the interaction of cognition and pain sensitization during a paradigm of Temporal Summation of Second Pain (TSSP). We analyzed pain ratings and electroencephalographic (EEG) activity obtained from 21 healthy participants during the presentation of four experimental conditions that differed in the manipulation of attention to painful stimuli or working memory load (Attention to hand & TSSP; 0-back & TSSP (low cognitive load); 2-back & TSSP (high cognitive load); 2-back (without pain)). We found that the TSSP was reduced when the attention was diverted and the cognitive load increased, and this reduction was accompanied by higher midfrontal theta activity and lower posterior alpha and central beta activity. Although it is well established that TSSP is a phenomenon that occurs at the spinal level, here we show that it is also affected by supraspinal attentional mechanisms. Delivery of painful repeated stimuli did not affect the performance of the 2-back task but was associated with smaller amplitudes of attentional event-related potentials (ERPs) after standard stimuli (not the target). The study of brain activity during TSSP allowed to clarify the role of top-down attentional modulation in pain sensitization processes. Results contribute to a better understanding of cognitive dysfunction in pain conditions and reinforce the use of therapeutic strategies based on distracting attention away from pain.

The effect of experimental emotion induction on experimental pain: a systematic review and meta-analysis

ABSTRACT

The idea that emotions can influence pain is generally recognized. However, a synthesis of the numerous individual experimental studies on this subject is lacking. The aim of the present systematic review and meta-analysis was to synthesize the existing evidence on the effect of experimental emotion induction on experimental pain in nonclinical adults. PsycInfo and PubMed were searched up until April 10, 2023, for studies assessing differences in self-reported pain between emotion induction groups and/or control groups or between conditions within group. Risk of bias was assessed for the individual studies. The literature search yielded 78 relevant records of 71 independent studies. When compared with control conditions, the pooled results revealed a statistically significant pain-attenuating effect of positive emotion induction (between-group: Hedges g = -0.48, 95% CI: -0.72; -0.25, K = 9; within-group: g = -0.24, 95% CI: -0.32; -0.15, K = 40), and a statistically significant pain-exacerbating effect of negative emotion induction in within-group analyses but not between-group analyses (between-group: g = -0.29, 95% CI: -0.66; 0.07, K = 10; within-group: g = 0.14, 95% CI: 0.06; 0.23, K = 39). Bayesian meta-analysis provided strong support for an effect of positive emotion induction but weak support for an effect of negative emotion induction. Taken together, the findings indicate a pain-attenuating effect of positive emotion induction, while the findings for negative emotion induction are less clear. The findings are discussed with reference to theoretical work emphasizing the role of motivational systems and distraction for pain. Limitations include considerable heterogeneity across studies limiting the generalizability of the findings.

Cognition is selectively impaired in males with spinal pain: A retrospective analysis of data from the Longitudinal Study of Ageing Danish Twins

Cognitive decline and spinal pain (back pain [BP] and neck pain [NP]) represent a major public health challenge, yet the potential relationship between them remains elusive. A retrospective analysis of the Longitudinal Study of Ageing Danish Twins was performed to determine any potential relationships between BP/NP and cognitive function adjusting for age, sex, educational and socioeconomic status. A total of 4731 adults (2788 females/1943 males) aged 78 ± 6 (SD) years were included in the analysis. We observed a 1-month prevalence of 25% with BP, 21% with NP and 11% for combined BP/NP. While there were no differences in cognition scores for males and females reporting combined BP/NP, compared to those without combined BP/NP (34.38 points [95% confidence interval (CI) = 31.88, 36.88] vs. 35.72 points [95% CI = 35.19, 36.26]; P = 0.180; and 35.72 points [95% CI = 35.19, 36.26] vs. 35.85 points [95% CI = 35.39, 36.31]; P = 0.327; for male and females, respectively), an adjusted analysis revealed that males with combined BP/NP presented with lower cognitive scores compared to males without combined BP/NP (81.26 points [95% CI = 73.80, 88.72] vs. 79.48 points [95% CI = 70.31, 88.66]; P = 0.043). The findings of this hypothesis-generating study may highlight a potential sex-specific association between spinal pain and later-life neurodegeneration.

Systems genetics analysis reveals the common genetic basis for pain sensitivity and cognitive function

BACKGROUND

There is growing evidence of a strong correlation between pain sensitivity and cognitive function under both physiological and pathological conditions. However, the detailed mechanisms remain largely unknown. In the current study, we sought to explore candidate genes and common molecular mechanisms underlying pain sensitivity and cognitive function with a transcriptome-wide association study using recombinant inbred mice from the BXD family.

METHODS

The pain sensitivity determined by Hargreaves' paw withdrawal test and cognition-related phenotypes were systematically analyzed in 60 strains of BXD mice and correlated with hippocampus transcriptomes, followed by quantitative trait locus (QTL) mapping and systems genetics analysis.

RESULTS

The pain sensitivity showed significant variability across the BXD strains and co-varies with cognitive traits. Pain sensitivity correlated hippocampual genes showed a significant involvement in cognition-related pathways, including glutamatergic synapse, and PI3K-Akt signaling pathway. Moreover, QTL mapping identified a genomic region on chromosome 4, potentially regulating the variation of pain sensitivity. Integrative analysis of expression QTL mapping, correlation analysis, and Bayesian network modeling identified Ring finger protein 20 (Rnf20) as the best candidate. Further pathway analysis indicated that Rnf20 may regulate the expression of pain sensitivity and cognitive function through the PI3K-Akt signaling pathway, particularly through interactions with genes Ppp2r2b, Ppp2r5c, Col9a3, Met, Rps6, Tnc, and Kras.

CONCLUSIONS

Our study demonstrated that pain sensitivity is associated with genetic background and Rnf20-mediated PI3K-Akt signaling may involve in the regulation of pain sensitivity and cognitive functions.

Pain-sensorimotor interactions: New perspectives and a new model

How pain and sensorimotor behavior interact has been the subject of research and debate for many decades. This article reviews theories bearing on pain-sensorimotor interactions and considers their strengths and limitations in the light of findings from experimental and clinical studies of pain-sensorimotor interactions in the spinal and craniofacial sensorimotor systems. A strength of recent theories is that they have incorporated concepts and features missing from earlier theories to account for the role of the sensory-discriminative, motivational-affective, and cognitive-evaluative dimensions of pain in pain-sensorimotor interactions. Findings acquired since the formulation of these recent theories indicate that additional features need to be considered to provide a more comprehensive conceptualization of pain-sensorimotor interactions. These features include biopsychosocial influences that range from biological factors such as genetics and epigenetics to psychological factors and social factors encompassing environmental and cultural influences. Also needing consideration is a mechanistic framework that includes other biological factors reflecting nociceptive processes and glioplastic and neuroplastic changes in sensorimotor and related brain and spinal cord circuits in acute or chronic pain conditions. The literature reviewed and the limitations of previous theories bearing on pain-sensorimotor interactions have led us to provide new perspectives on these interactions, and this has prompted our development of a new concept, the Theory of Pain-Sensorimotor Interactions (TOPSMI) that we suggest gives a more comprehensive framework to consider the interactions and their complexity. This theory states that pain is associated with plastic changes in the central nervous system (CNS) that lead to an activation pattern of motor units that contributes to the individual's adaptive sensorimotor behavior. This activation pattern takes account of the biological, psychological, and social influences on the musculoskeletal tissues involved in sensorimotor behavior and on the plastic changes and the experience of pain in that individual. The pattern is normally optimized in terms of biomechanical advantage and metabolic cost related to the features of the individual's musculoskeletal tissues and aims to minimize pain and any associated sensorimotor changes, and thereby maintain homeostasis. However, adverse biopsychosocial factors and their interactions may result in plastic CNS changes leading to less optimal, even maladaptive, sensorimotor changes producing motor unit activation patterns associated with the development of further pain. This more comprehensive theory points towards customized treatment strategies, in line with the management approaches to pain proposed in the biopsychosocial model of pain.

Does pain influence cognitive performance in patients with mild traumatic brain injury?

OBJECTIVES

Pain is still a neglected problem in mild traumatic brain injury (mTBI). In this cross-sectional study, we examined the frequency of musculoskeletal pain in a sample of adult patients with persistent cognitive symptoms after mTBI and whether pain level affected cognition.

METHODS

The participants were 23 adult patients aged 18-50 referred to brain injury rehabilitation clinics for neuropsychological assessment after having sustained an mTBI. A non-injured control group (n = 29) was recruited through advertisements. The patients were, on average, assessed 22 months after trauma. All participants completed a comprehensive neuropsychological test battery and completed the Örebro Musculoskeletal Pain Screening Questionnaire, The Rivermead Post-Concussion Symptoms Questionnaire, and the State-Trait Anxiety Inventory.

RESULTS

Patients reported high levels of current pain and significantly more frequent neck and shoulder pain than the non-injured controls. Patients also reported high post-concussive symptoms and anxiety levels and performed less well on several neuropsychological tests. Pain level was associated with slower processing speed among the controls but not related to performance in the mTBI group.

CONCLUSION

We conclude that musculoskeletal pain is frequent in mTBI patients referred to rehabilitation settings. Furthermore, the results indicate that the interaction between pain and cognitive functioning differs in mTBI compared to controls. Our results implicate that pain screening should be an integrated part of neuropsychological rehabilitation after mTBI to identify conditions that run the risk of becoming chronic. The study was approved by the Regional Ethical Board in Stockholm, Sweden (04-415/2).

Prokineticin System Is a Pharmacological Target to Counteract Pain and Its Comorbid Mood Alterations in an Osteoarthritis Murine Model

Osteoarthritis (OA) is the most prevalent joint disease associated with chronic pain. OA pain is often accompanied by mood disorders. We addressed the role of the Prokineticin (PK) system in pain and mood alterations in a mice OA model induced with monosodium iodoacetate (MIA). The effect of a PK antagonist (PC1) was compared to that of diclofenac. C57BL/6J male mice injected with MIA in the knee joint were characterized by allodynia, motor deficits, and fatigue. Twenty-eight days after MIA, in the knee joint, we measured high mRNA of PK2 and its receptor PKR1, pro-inflammatory cytokines, and MMP13. At the same time, in the sciatic nerve and spinal cord, we found increased levels of PK2, PKR1, IL-1β, and IL-6. These changes were in the presence of high GFAP and CD11b mRNA in the sciatic nerve and GFAP in the spinal cord. OA mice were also characterized by anxiety, depression, and neuroinflammation in the prefrontal cortex and hippocampus. In both stations, we found increased pro-inflammatory cytokines. In addition, PK upregulation and reactive astrogliosis in the hippocampus and microglia reactivity in the prefrontal cortex were detected. PC1 reduced joint inflammation and neuroinflammation in PNS and CNS and counteracted OA pain and emotional disturbances.

The role of the male rat infralimbic cortex in distraction analgesia

Cognitive interventions, including distraction, have been successfully utilized in the manipulation of experimental pain and the treatment of clinical pain. Attentional diversions can reduce the experience of pain, a phenomenon known as distraction analgesia (DA). Prior research has suggested that variations in stimulus intensity may influence the magnitude of DA. However, the neural substrates of DA remain largely unknown. Converging evidence suggests that the infralimbic cortex (IL) in the brains of rats may contribute to the phenomenon of DA. The function of the rat IL in DA has never been directly investigated, therefore, this study sought to identify the role of the IL at two levels of noxious stimulus intensity among brain-intact and IL lesioned male rats within an established rat model of DA. A distractor object reduced formalin-induced nociceptive behavior in brain-intact rats, and this DA effect was detectable during low- (0.5% formalin) and high-intensity (1% formalin) stimulation. IL lesion resulted in a near-complete elimination of the DA effect and an overall reduction in formalin pain. These results provide the first known evidence that (i) the IL is involved in processing DA in rats, (ii) the IL contributes to formalin-induced nociceptive behavior irrespective of distraction, and (iii) a high-intensity stimulation was generally more susceptible to DA than low-intensity stimulation. These findings may further inform the mechanisms and future development of non-pharmacological strategies to reduce pain.

The Role of Serotonergic and Noradrenergic Descending Pathways on Performance-Based Cognitive Functioning at Rest and in Response to Exercise in People with Chronic Whiplash-Associated Disorders: A Randomized Controlled Crossover Study

(1) Background: Dysregulation in serotonergic and noradrenergic systems may be implicated in the neurobiophysiological mechanisms underlying pain-related cognitive impairment in chronic whiplash-associated disorders (CWAD). This study aimed to unravel the role of serotonergic and noradrenergic descending pathways in cognitive functioning at rest and in response to exercise in people with CWAD. (2) Methods: 25 people with CWAD were included in this double-blind, randomized, controlled crossover study. Endogenous descending serotonergic and noradrenergic inhibitory mechanisms were modulated by using a single dose of a selective serotonin reuptake inhibitor (Citalopram) or a selective norepinephrine reuptake inhibitor (Atomoxetine). Cognitive performance was studied at rest and in response to exercise (1) without medication intake; (2) after intake of Citalopram; and (3) after intake of Atomoxetine. (3) Results: After Atomoxetine intake, selective attention improved compared with the no medication day (p < 0.05). In contrast, a single dose of Citalopram had no significant effect on cognitive functioning at rest. When performing pairwise comparisons, improvements in selective attention were found after exercise for the no medication condition (p < 0.05). In contrast, after intake of Citalopram or Atomoxetine, selective and sustained attention worsened after exercise. (4) Conclusions: A single dose of Atomoxetine improved selective attention only in one Stroop condition, and a single dose of Citalopram had no effect on cognitive functioning at rest in people with CWAD. Only without medication intake did selective attention improve in response to exercise, whereas both centrally acting medications worsened cognitive performance in response to a submaximal aerobic exercise bout in people with CWAD.

Association between prescribed opioid dose and risk of motor vehicle crashes

ABSTRACT

Opioid-involved motor vehicle traffic fatalities have increased over the past 2 decades. However, the extent to which prescribed opioids increase the risk of motor vehicle crashes remains uncertain. This study used real-world healthcare claims data to examine the association between prescription opioid dose and motor vehicle crash risk. Using nationwide US commercial insurance claims data for 2010 to 2018, we identified 772,404 adults who received incident, noncancer opioid therapy. We examined associations between daily prescription opioid dose, calculated in morphine milligram equivalents (MME) from filled prescription claims, and risk of motor vehicle crashes, assessed as diagnoses of motor vehicle injuries in claims for emergency visits, inpatient hospitalizations, and ambulance transportation. We estimated associations using a within-individual design, which ruled out all time-stable confounding. We complemented the design with time-varying statistical adjustment for other pharmacotherapies and a negative control pain pharmacotherapy analysis (with incident cyclic antidepressant prescriptions). During 2,150,009 person-years of follow-up, there were 12,123 motor vehicle crashes (5.64 crashes per 1000 person-years). In within-individual comparisons, crash risk was greater during opioid prescription periods involving doses ≤60 MME/day (odds ratio [OR], 3.86; 95% confidence interval [CI], 3.54, 4.21), >60 to 120 MME/day (OR, 5.46; 95% CI, 4.44, 6.73), and >120 MME/day (OR, 3.45; 95% CI, 2.31, 5.15) than during off-treatment periods. The negative control analysis supported the specificity of the results to opioids rather than to other processes associated with pharmacologic pain management. These findings suggest that the receipt of prescription opioids, even at doses ≤60 MME/day, is associated with an increased risk of motor vehicle crashes.

Reorganization of brain networks in patients with temporal lobe epilepsy and comorbid headache

OBJECTIVE

The white matter structural network changes remain poorly understood in patients with temporal lobe epilepsy and comorbid headache (PWH). This study aimed at exploring topological changes in the structural network.

METHODS

Twenty-five PWH, 32 patients with temporal lobe epilepsy without headache, and 22 healthy controls were recruited in this study. High-resolution structural MRI and diffusion tensor imaging data were acquired from these participants. A graph theory-based approach was employed to characterize the topological properties of the structural network. A network-based statistical analysis was employed to explore abnormal connectivity alterations in PWH.

RESULTS

Compared with healthy controls, PWH exhibited significantly decreased small-world index, shortest path length, increased clustering coefficient, global efficiency, and local efficiency. Patients with temporal lobe epilepsy and comorbid headache displayed a significantly reduced small-world index, shortest path length, and increased global efficiency when compared with patients with temporal lobe epilepsy without headache. In addition, PWH exhibited abnormal local network parameters, mainly located in the prefrontal, temporal, occipital, and parietal regions. Furthermore, network-based statistical analysis revealed that PWH had abnormal structural connections between the temporoparietal lobe, occipital lobe, insula, cingulate gyrus, and thalamus.

CONCLUSION

This study reveals the abnormal white matter structural network alterations in PWH, allowing a better insight into the neuroanatomical mechanisms that predispose epileptic patients to comorbid headaches from the network levels.

Testing the Reserve Capacity Model: Does Race Moderate the Relationship Between Negative Emotions and Neurocognition?

OBJECTIVE

To test whether race moderates the relationship between negative emotions and neurocognition by applying the reserve capacity model within a large sample that spans adulthood.

METHOD

The study sample (N = 1,020) consisted of community-dwelling adults between 18 and 84 years of age who were drawn from the Virginia Cognitive Aging Project. Demographic variables were used to match a sample of Black participants to a sample of White participants. Race was examined as a moderator of the relationship between negative emotions (i.e., depressive symptoms, trait anxiety, and the negative affect subscale from the Positive and Negative Affect Schedule) and neurocognitive variables (episodic memory, reasoning, spatial visualization, and processing speed) with multiple-group structural equation modeling.

RESULTS

After accounting for sociodemographic variables, depressive symptoms were negatively associated with processing speed in both groups, and with worse reasoning in the White subsample. Negative affect was associated with lower reasoning performance in both groups and with lower spatial visualization in the White subsample. Trait anxiety was not significantly associated with the neurocognitive constructs in either group. Multigroup structural equation models showed that the magnitudes of the associations were not different between the Black and White subsamples. Thus, race did not moderate the relationships between depressive symptoms, trait anxiety, and negative affect with neurocognition.

CONCLUSIONS

Negative emotions are associated with lower performance on different neurocognitive tasks, but race does not moderate these relationships. Future research should examine perceived discrimination or other psychosocial variables when examining the relationships among negative emotions and neurocognition.

Delirium-related psychiatric and neurocognitive impairment and the association with post-intensive care syndrome-A narrative review

INTRODUCTION

Delirium is common among patients admitted to the intensive care unit (ICU) and its impact on the neurocognitive and psychiatric state of survivors is of great interest. These new-onset or worsening conditions, together with physical alterations, are called post-intensive care syndrome (PICS). Our aim is to update on the latest screening and follow-up options for psychological and cognitive sequelae of PICS.

METHOD

This narrative review discusses the occurrence of delirium in ICU settings and the relatively new concept of PICS. Psychiatric and neurocognitive morbidities that may occur in survivors of critical illness following delirium are addressed. Future perspectives for practice and research are discussed.

RESULTS

There is no "gold standard" for diagnosing delirium in the ICU, but two extensively validated tools, the confusion assessment method for the ICU and the intensive care delirium screening checklist, are often used. PICS complaints are frequent in ICU survivors who have suffered delirium and have been recognized as an important public health and socio-economic problem worldwide. Depression, anxiety, post-traumatic stress disorder, and long-term cognitive impairment are recurrently exhibited. Screening tools for these deficits are discussed, as well as the suggestion of early assessment after discharge and at 3 and 12 months.

CONCLUSIONS

Delirium is a complex but common phenomenon in the ICU and a risk factor for PICS. Its diagnosis is challenging with potential long-term adverse outcomes, including psychiatric and cognitive difficulties. The implementation of screening and follow-up protocols for PICS sequelae is warranted to ensure early detection and appropriate management.

Pain and aging: A unique challenge in neuroinflammation and behavior

Chronic pain is one of the most common, costly, and potentially debilitating health issues facing older adults, with attributable costs exceeding $600 billion annually. The prevalence of pain in humans increases with advancing age. Yet, the contributions of sex differences, age-related chronic inflammation, and changes in neuroplasticity to the overall experience of pain are less clear, given that opposing processes in aging interact. This review article examines and summarizes pre-clinical research and clinical data on chronic pain among older adults to identify knowledge gaps and provide the base for future research and clinical practice. We provide evidence to suggest that neurodegenerative conditions engender a loss of neural plasticity involved in pain response, whereas low-grade inflammation in aging increases CNS sensitization but decreases PNS sensitivity. Insights from preclinical studies are needed to answer mechanistic questions. However, the selection of appropriate aging models presents a challenge that has resulted in conflicting data regarding pain processing and behavioral outcomes that are difficult to translate to humans.

Examining associations between concussion history, subjectively experienced memory problems, and general health factors in older men

OBJECTIVE

Examine associations between subjective memory complaints (SMCs), concussion history, and cognitive, psychological, and physical health in older men from the general population.

METHOD

Participants were 504 men aged 50-79 who were recruited using an online labor market. Participants completed a survey assessing demographics, medication history, concussion history, recent memory problems, and additional aspects of recent cognitive, mental, and physical health.

RESULTS

Men with a lifetime history of ≥3 concussions also reported a lifetime history of being prescribed medication for anxiety (46.8%), depression (43.5%), chronic pain (79.0%), and high blood pressure (66.1%). When asked about symptoms experienced over the past year and the past week, they endorsed higher rates of cognitive and mental health problems, migraines, and difficulties with sleep and fatigue. The multivariable logistic regression model for predicting mild or greater memory problems was significant, χ2(8) = 168.97, p < .001. In unadjusted analyses, significant predictors, in order of magnitude (strongest to weakest), were fatigue (odds ratio [OR] = 3.21), back or neck pain (OR = 2.28), migraines (OR = 2.11), anxiety (OR = 2.07), depression (OR = 2.04), difficulty sleeping (OR = 1.98), and concussion history (OR = 1.49). In the multivariable model, only back or neck pain (OR = 1.51, p = .004) and fatigue (OR = 1.99, p = .004) were significant predictors.

CONCLUSIONS

A personal history of multiple concussions was associated with perceived memory problems, but to a lesser degree than fatigue, back or neck pain, and migraines.

Inhibition of anandamide breakdown reduces pain and restores LTP and monoamine levels in the rat hippocampus via the CB1 receptor following osteoarthritis

Chronic pain is a persistent, complex condition that contributes to impaired mood, anxiety and emotional problems. Osteoarthritis (OA) is one of the major causes of chronic pain in adults and elderly people. A substantial body of evidence demonstrate that hippocampal neural circuits, especially monoamine dopamine and serotonin levels, contributes to negative affect and avoidance motivation experienced during pain. Current pharmacological strategies for OA patients are unsatisfying and the endocannabinoid system modulation might represent an alternative for the treatment of OA-related pain. In the present study, we used a rat model of osteoarthritis induced by intra-articular injection of sodium monoiodoacetate to assess, 28 days post-induction, the contribution of endocannabinoid system on the possible alteration in pain perception and affective behavior, in LTP and monoamine levels in the lateral entorhinal cortex-dentate gyrus pathway. The results show that OA-related chronic pain induces working memory impairment and depressive-like behavior appearance, diminishes LTP, decreases dopamine levels and increases serotonin levels in the rat dentate gyrus. URB597 administration (i.p., 1 mg/kg) reduces hyperalgesia and mechanical allodynia, improves recognition memory and depressive-live behavior, restores LTP and normalizes monoamine levels in the hippocampus. The effect was observed 60-120 min post-treatment and was blocked by AM251, which proves the action of URB597 via the CB₁ receptor. Therefore, our study confirms the role of anandamide in OA-related chronic pain management at the behavioral and hippocampal levels. This article is part of the Special Issue on 'Advances in mechanisms and therapeutic targets relevant to pain'.

Differential synaptic mechanism underlying the neuronal modulation of prefrontal cortex, amygdala, and hippocampus in response to chronic postsurgical pain with or without cognitive deficits in rats

Chronic Postsurgical Pain (CPSP) is well recognized to impair cognition, particularly memory. Mounting evidence suggests anatomic and mechanistic overlap between pain and cognition on several levels. Interestingly, the drugs currently used for treating chronic pain, including opioids, gabapentin, and NMDAR (N-methyl-D-aspartate receptor) antagonists, are also known to impair cognition. So whether pain-related cognitive deficits have different synaptic mechanisms as those underlying pain remains to be elucidated. In this context, the synaptic transmission in the unsusceptible group (cognitively normal pain rats) was isolated from that in the susceptible group (cognitively compromised pain rats). It was revealed that nearly two-thirds of the CPSP rats suffered cognitive impairment. The whole-cell voltage-clamp recordings revealed that the neuronal excitability and synaptic transmission in the prefrontal cortex and amygdala neurons were enhanced in the unsusceptible group, while these parameters remained the same in the susceptible group. Moreover, the neuronal excitability and synaptic transmission in hippocampus neurons demonstrated the opposite trend. Correspondingly, the levels of synaptic transmission-related proteins demonstrated a tendency similar to that of the excitatory and inhibitory synaptic transmission. Furthermore, morphologically, the synapse ultrastructure varied in the postsynaptic density (PSD) between the CPSP rats with and without cognitive deficits. Together, these observations indicated that basal excitatory and inhibitory synaptic transmission changes were strikingly different between the CPSP rats with and without cognitive deficits.

SCFAs Ameliorate Chronic Postsurgical Pain-Related Cognition Dysfunction via the ACSS2-HDAC2 Axis in Rats

Patients with chronic postsurgical pain (CPSP) frequently exhibit comorbid cognitive deficits. Recent observations have emphasized the critical effects of gut microbial metabolites, like short-chain fatty acids (SCFAs), in regulating cognitive function. However, the underlying mechanisms and effective interventions remain unclear. According to hierarchical clustering and 16S rRNA analysis, over two-thirds of the CPSP rats had cognitive impairment, and the CPSP rats with cognitive impairment had an aberrant composition of gut SCFA-producing bacteria. Then, using feces microbiota transplantation, researchers identified a causal relationship between cognitive-behavioral and microbic changes. Similarly, the number of genera that generated SCFAs was decreased in the feces from recipients of cognitive impairment microbiota. Moreover, treatment with the SCFAs alleviated the cognitive-behavioral deficits in the cognitively compromised pain rats. Finally, we observed that SCFA supplementation improved histone acetylation and abnormal synaptic transmission in the medial prefrontal cortex (mPFC), hippocampal CA1, and central amygdala (CeA) area via the ACSS2 (acetyl-CoA synthetase2)-HDAC2 (histone deacetylase 2) axis. These findings link pain-related cognition dysfunction, gut microbiota, and short-chain fatty acids, shedding fresh insight into the pathogenesis and therapy of pain-associated cognition dysfunction.

Headache at the chronic stage of cerebral venous thrombosis

BACKGROUND

Headache is the most frequent symptom of cerebral venous thrombosis (CVT) but there is limited information about the frequency and phenotype of headache, weeks to months after cerebral venous thrombosis (post-cerebral venous thrombosis headache, post cerebral venous thrombosis headache).

OBJECTIVE

To assess the frequency, characteristics and predictors of PCH.

METHODS

In this cross-sectional study, the frequency and characteristics of PCH were assessed in cerebral venous thrombosis survivors. Patients were interviewed between six months and five years after the cerebral venous thrombosis diagnosis. Clinical and imaging characteristics at the time of cerebral venous thrombosis diagnosis, as well as history of headache prior to cerebral venous thrombosis were compared in subjects with (Group_PCH) and without PCH (Group_control).

RESULTS

Subjects (n = 100; 82% women) were assessed, on average, at 1.1 ± 1.6 years of follow-up. PCH was present in 59% of the patients, phenotypes of tension-type-like headache were present in 31/59 (52.6%) and of migraine-like headache in 16/59 (27.1%). History of primary headache prior to cerebral venous thrombosis was significantly more common (OR: 6.4; 95% CI: 1.7-36.3) in Group_PCH (33.9%) than in Group_control (7.3%).

CONCLUSION

Post cerebral venous thrombosis headache was present in more than half of the patients. History of prior headache may be a risk factor for post cerebral venous thrombosis headache. Prospective studies are required to confirm these findings and determine mechanisms, as well as interventions for prevention and treatment of post cerebral venous thrombosis headache.

Relationships Between Cognitive Screening Composite Scores and Pain Intensity and Pain Disability in Adults With/At Risk for Knee Osteoarthritis

OBJECTIVES

Chronic pain, cognitive deficits, and pain-related disability are interrelated. The prevalence of chronic pain and undiagnosed cognitive difficulties in middle age and older adults is increasing. Of the cognitive systems, executive function and episodic memory are most relevant to chronic pain. We examined the hypothesis that cognitive screening composite scores for executive function and memory would negatively associate with pain intensity and pain disability in a group of middle-aged and older adults with knee pain with or at risk for osteoarthritis.

METHODS

A total of 120 adults (44 men/76 women), an average age of 59 years, participated in the study. Demographic, health history, clinical pain, and cognitive measures were completed. Relationships between pain intensity, pain disability, and the Montreal Cognitive Assessment (MoCA) total and composite scores were examined with relevant covariates in the model.

RESULTS

MoCA raw scores ranged from 13 to 30 with a mean score of 23.9. Pain intensity was negatively associated with overall MoCA total and executive function and memory composite scores. Pain disability over the previous 6 months was negatively associated with executive function, while pain disability over the past 48 hours was not associated with executive function.

CONCLUSION

The results of the current study demonstrates associations between pain metrics and cognitive domain scores within a common cognitive screening tool.

Anxiety sensitivity and Pain Experience: a prospective investigation among World Trade Center Responders

Chronic pain is a significant public health problem and is exacerbated by stress. The World Trade Center (WTC) Disaster represents a unique stressor, and responders to the WTC disaster are at increased risk for pain and other health complaints. Therefore, there is a significant need to identify vulnerability factors for exacerbated pain experience among this high-risk population. Anxiety sensitivity (AS), defined as fear of anxiety-related sensations, is one such vulnerability factor associated with pain intensity and disability. Yet, no work has tested the predictive effects of AS on pain, limiting conclusions regarding the predictive utility and direction of associations. Therefore, the current study examined the prospective associations of AS, pain intensity, and pain interference among 452 (M_age = 55.22, SD = 8.73, 89.4% male) responders to the WTC disaster completing a 2-week daily diary study. Using multi-level modeling, AS total score was positively associated with both pain intensity and pain interference, and that AS cognitive concerns, but not social or physical concerns, were associated with increased pain. These results highlight the importance of AS as a predictor of pain complaints among WTC responders and provide initial empirical evidence to support AS as a clinical target for treating pain complaints among WTC responders.

Modulation of Trans-Synaptic Neurexin-Neuroligin Interaction in Pathological Pain

Synapses serve as the interface for the transmission of information between neurons in the central nervous system. The structural and functional characteristics of synapses are highly dynamic, exhibiting extensive plasticity that is shaped by neural activity and regulated primarily by trans-synaptic cell-adhesion molecules (CAMs). Prototypical trans-synaptic CAMs, such as neurexins (Nrxs) and neuroligins (Nlgs), directly regulate the assembly of presynaptic and postsynaptic molecules, including synaptic vesicles, active zone proteins, and receptors. Therefore, the trans-synaptic adhesion mechanisms mediated by Nrx-Nlg interaction can contribute to a range of synaptopathies in the context of pathological pain and other neurological disorders. The present review provides an overview of the current understanding of the roles of Nrx-Nlg interaction in the regulation of trans-synaptic connections, with a specific focus on Nrx and Nlg structures, the dynamic shaping of synaptic function, and the dysregulation of Nrx-Nlg in pathological pain. Additionally, we discuss a range of proteins capable of modulating Nrx-Nlg interactions at the synaptic cleft, with the objective of providing a foundation to guide the future development of novel therapeutic agents for managing pathological pain.

Cross-sectional relationship between pain intensity and subjective cognitive decline among middle-aged and older adults with arthritis or joint conditions: Results from a population-based study

Introduction

We investigated cross-sectional relationships between arthritis or joint-related pain intensity and subjective cognitive decline in middle-aged and older adults.

Methods

The sample consisted of 30,150 adults ⩾age 45 years with self-reported arthritis or joint conditions who completed key variables in the 2015 wave of the Behavioral Risk Factor Surveillance System.

Results

Using weighted data, 94.2% of the sample reported experiencing joint pain in the last month (35.9% reported moderate pain and 30.6% reported severe pain) and 17.3% reported subjective cognitive decline. In logistic regression models, pain intensity was associated with significantly higher odds of reporting subjective cognitive decline, after controlling for age, race/ethnicity, sex, education, household income, cardiovascular health, mental health, and history of stroke. Those with moderate pain were two times as likely to report subjective cognitive decline and those with severe pain were more than three times as likely to report subjective cognitive decline relative to those without pain, adjusting for covariates.

Conclusion

The results of this study highlight a significant relationship between pain intensity and subjective cognitive decline in middle-aged and older adults with arthritis or joint conditions typically associated with joint pain. Moderate and severe joint pain is significantly associated with higher risk of subjective cognitive decline, after controlling for personal and health characteristics. Future studies with more comprehensive assessments of pain and cognition are warranted to further elucidate these relationships and their underlying mechanisms.

Vulnerable Dispositional Traits and Chronic Pain: Predisposing but not Predetermining

Dispositional traits can be protective or contribute to increased vulnerability in individuals with chronic pain. This study aims to evaluate the association between two dispositional trait measures, affect balance style and multi-domain trait groups, with psychosocial measures, clinical pain, functional pain, and experimental pain at two years in individuals with chronic knee pain. The study is a prospective analysis of 168 community dwelling individuals aged 45 to 85 years old with knee pain with or at risk for knee osteoarthritis. At baseline, affect balance style and multi-domain trait groups were associated with psychosocial measures, clinical pain, and functional status. At the two-year time point, the multi-domain trait groups were associated with the clinical pain measures. Interestingly, individuals with previously demonstrated vulnerable traits showed more variability in dispositional trait status at the two-year time point compared to those with dispositional traits previously demonstrated as more protective. Findings reiterate that dispositional traits are predisposing but are not predetermining regarding pain-related experiences. PERSPECTIVE: Vulnerable and protective dispositional traits are positively and negatively associated with clinical pain and functional limitations respectively. Although considered relatively stable, a 30-50% shift in dispositional traits was indicated over a two-year period. Findings highlight that dispositional trait are modifiable and thus, predisposing but not predetermining for persisting chronic pain.

The Association between Bodily Pain and Cognitive Impairment in Community-Dwelling Older Adults

BACKGROUND

Bodily pain is a common condition in older adults and interferes with individuals' cognitive functioning. We aimed to evaluate the association between bodily pain and related locations and cognitive impairment among community-dwelling older adults in Taiwan.

METHOD

In this retrospective, cross-sectional study, we enrolled 2022 participants aged 60‒70 years, from the Taiwan Biobank. Mini-Mental State Examination was performed to assess cognitive impairment. Further, logistic regression analyses were performed to identify the relationship between bodily pain and cognitive impairment.

RESULTS

Overall, 161 participants had cognitive impairment. Multivariable analysis showed that older adults who reported bodily pain were more likely than those who did not have cognitive impairment (odds ratio 1.68). Moreover, the occurrence of cognitive impairment correlated with the presence of two or more pain locations and self-reported low back and waist pain or sciatica.

CONCLUSION

Our study revealed that cognitive impairment was associated with bodily pain in community-dwelling older adults, particularly older adults with low back and waist pain or sciatica and those with two or more pain locations. To maintain the quality of older adults' life, pain and cognitive decline need to be simultaneously assessed with considerably more precise and objective markers.

Do Cognitively Impaired Elderly Patients with Cancer Respond Differently on Self-reported Symptom Scores? A 5-Year Retrospective Analysis

Objectives:

An increasing number of elderly subjects with cancer were admitted to the palliative care unit and they have suffered both distressing symptoms and cognitive impairment. We aim to identify the prevalence of cognitive impairment among elderly cancer patients receiving in-patient palliative care and to examine any difference between patients with cognitive impairment on self-reported symptoms.

Materials and Methods:

Subjects’ age ≥65 admitted to a palliative care unit from 01 September 2015 to 31 August 2020 was included in the study. Exclusion criteria were those with an impaired conscious state, severe cognitive impairment, or language problems that were non-communicable. Variables collected included baseline demographics, cancer diagnosis, cancer stage, mobility state using the modified Barthel index (mBI), and performance status as measured by the palliative performance scale. Cognitive impairment was defined by abbreviated mental test ≤6. Self-reported symptoms scales were measured by the Chinese version of MD Anderson Symptom Inventory and EORTC QLQ C-30 (European Organisation for Research and Treatment of Cancer, Quality of Life Core Questionnaire 30).

Results:

Nine hundred and ninety-one subjects with 1174 admissions were retrieved. Eight hundred and seventy-three admission episodes were included in this study. Three hundred and eight (35%) have cognitive impairment. Cognitively impaired subjects were older, showed worse physical function and performance status, and more often residing in old age homes. Independent predictors of cognitive impairment were age (OR 1.09), mBI (OR 0.96), chair/bed bound state (OR 1.79), and presence of brain metastasis (OR 2.63). They reported lower scores in pain (P < 0.001), distress (P < 0.001), sleep disturbance (P < 0.001) and nausea and vomiting (P = 0.012) in the self-reported symptoms scale.

Conclusion:

Elderly cancer patients with cognitive impairment were older with poorer performance status. They have reported a lower level of pain, distress, and sleep disturbance. Clinicians should be alerted to this phenomenon to tackle the unmet concomitant symptoms.

Tutorial: The Speech-Language Pathologist's Role in Return to Work for Adults With Traumatic Brain Injury

PURPOSE

Return to work (RTW) is a major life participation metric used for persons with a traumatic brain injury (TBI). Speech-language pathologists (SLPs) have clinical expertise in the cognitive-communication aspects of TBI. This clinical focus article aims to support the clinical practice of SLPs by summarizing key interprofessional vocational rehabilitation (VR) models and illustrating the role of the SLP throughout the RTW process with a case study.

METHOD

This clinical focus article was written by the Academy of Neurologic Communication Disorders and Sciences TBI Research Group along with a VR expert. Authors engaged in deliberative, agenda-based discussions beginning with a literature review based on previous systematic studies. Discussions explored relevant VR and SLP practices.

RESULTS

This clinical focus article presents key VR models in parallel with SLP assessment and treatment to illustrate best practice patterns in an RTW field with a dearth of SLP-specific literature. We summarize general VR approaches and four evidence-supported VR models for adults with TBI. We highlight how a model of interprofessional assessment can assist with planning and communication of important work-related concerns. We illustrate how the chronological model of work return can assist with developing goals and planning treatment.

CONCLUSIONS

SLPs play an important role in identifying, managing, and collaborating with an RTW team following TBI. A working knowledge of VR models can assist with improving the dialogue between SLPs and VR professionals and can inform practice when working with persons with TBI who have work return as a goal.

Modulation of nociception and pain-evoked neurobehavioral responses by levetiracetam in a craniotomy pain model

Traditional and novel analgesic modalities have been extensively tested for post-craniotomy pain management, yet the role of newer antiepileptic drugs in this area remains obscure. This study investigates the impact of levetiracetam (LEV) on pain modulation and neurobehavioral performance in a craniotomy model. Fifty-six Wistar rats were randomly assigned into seven groups: no intervention (CTRL), administration of placebo or LEV with no further intervention (PBO and LEV, respectively), and sham-operation or craniotomy in placebo (PBO-SHAM and PBO-CR, respectively) or LEV-treated rats (LEV-SHAM and LEV-CR, respectively). Pain was assessed by the rat grimace scale before, and at 8 and 24 h after craniotomy, following intraperitoneal injections of LEV (100 mg/kg twice daily) or normal saline two consecutive days before and on the craniotomy day. Elevated plus-maze and olfactory social memory tests were performed at 24- and 48 h post-craniotomy, respectively. Upon testing conclusion blood samples were collected for cytokines estimation. Levetiracetam administration enhanced antinociception in sham and craniotomy groups. In the elevated plus-maze test, LEV-CR rats spent more time in investigating open arms and performed more open arm entries than PBO-SHAM and PBO-CR animals. The olfactory test revealed no between-groups difference in acquisition time during first contact with a juvenile rat, while LEV-CR rats spent less time to recognize the same juvenile rat compared to PBO-SHAM and PBO-CR groups. Furthermore, LEV-treatment attenuated cortisol, interleukin-6 and TNF-a release, in sham and craniotomy animals. In conclusion, preemptive use of LEV decreases nociception, improves pain-evoked behavior and attenuates stress response in rats subjected to craniotomy.

Impact of inspiratory threshold loading on brain activity and cognitive performances in healthy humans

In healthy humans, inspiratory threshold loading deteriorates cognitive performances. This can result from motor-cognitive interference (activation of motor respiratory-related cortical networks vs. executive resources allocation), sensory-cognitive interference (dyspnea vs. shift in attentional focus), or both. We hypothesized that inspiratory loading would concomitantly induce dyspnea, activate motor respiratory-related cortical networks, and deteriorate cognitive performance. We reasoned that a concomitant activation of cortical networks and cognitive deterioration would be compatible with motor-cognitive interference, particularly in case of a predominant alteration of executive cognitive performances. Symmetrically, we reasoned that a predominant alteration of attention-depending performances would suggest sensory-cognitive interference. Twenty-five volunteers (12 men; 19.5-51.5 years) performed the Paced Auditory Serial Addition test (PASAT-A and B; calculation capacity, working memory, attention), the Trail Making Test (TMT-A, visuospatial exploration capacity; TMT-B, visuospatial exploration capacity and attention), and the Corsi block-tapping test (visuospatial memory, short-term and working memory) during unloaded breathing and inspiratory threshold loading in random order. Loading consistently induced dyspnea and respiratory-related brain activation. It was associated with deteriorations inPASAT A (52 [45.5;55.5] (median [interquartile range]) to 48 [41;54.5], p=0.01), PASAT B (55 [47.5;58] to 51 [44.5;57.5], p=0.01), and TMT B (44s [36;54.5] to 53s [42;64], p=0.01), but did not affect TMT-A and Corsi. The concomitance of cortical activation and cognitive performance deterioration is compatible with competition for cortical resources (motor-cognitive interference), while the profile of cognitive impairment (PASAT and TMT-B but not TMT-A and Corsi) is compatible with a contribution of attentional distraction (sensory-cognitive interference). Both mechanisms are therefore likely at play.

Cognitive Reserve as a Protective Factor of Mental Health in Middle-Aged Adults Affected by Chronic Pain

Chronic pain is associated with worse mental health and cognitive impairment, which can be a cause or a consequence of brain structure and function alterations, e.g., maladaptive plasticity, antinociceptive system dysregulation. Cognitive reserve reflects the effectiveness of the internal connections of the brain and it has been shown to be a protective factor in brain damage, slowing cognitive aging or reducing the risk of mental health disorders. The current study explored the impact of chronic pain on psychosocial factors, mental health, and cognition. Furthermore, we aimed to examine the role of cognitive reserve in the relationship between mental health and chronic pain clinical characteristics in middle-aged adults. The study group consisted of 477 volunteers from the Barcelona Brain Health Initiative who completed online surveys on pain, mental health, cognitive reserve, and psychosocial factors (sleep and quality of life). We described the differences in sociodemographic data, psychosocial factors, mental health, and self-perceived cognitive impairment, and neuropsychological assessment, between participants reporting pain compared with those without pain, as well as the main characteristics of the chronic pain group. Finally, to study the role of cognitive reserve in the modulation of the relationship between chronic pain and mental health, we compared variables between subgroups of participants with high/low pain intensity and cognitive reserve. The results showed that chronic pain was reported by 45.5% of middle-aged adults. Our results revealed that participants with chronic pain were older and had worse health status than people without pain. The presence of chronic pain affected working memory, mental health, and daily life activities. Moreover, cognitive reserve moderated the influence of pain intensity on mental health, resulting in less mental health affection in people suffering from high pain intensity with high cognitive reserve. In conclusion, the construct of the cognitive reserve could explain differential susceptibility between chronic pain and its mental health association and be a powerful tool in chronic pain assessment and treatment, principally due to its modifiable nature.

Burning Fog: Cognitive Impairment in Burning Mouth Syndrome

Background: Due to its common association with chronic pain experience, cognitive impairment (CI) has never been evaluated in patients with burning mouth syndrome (BMS). The purpose of this study is to assess the prevalence of CI in patients with BMS and to evaluate its relationship with potential predictors such as pain, mood disorders, blood biomarkers, and white matter changes (WMCs).

Methods: A case-control study was conducted by enrolling 40 patients with BMS and an equal number of healthy controls matched for age, gender, and education. Neurocognitive assessment [Mini Mental State Examination (MMSE), Digit Cancellation Test (DCT), the Forward and Backward Digit Span task (FDS and BDS), Corsi Block-Tapping Test (CB-TT), Rey Auditory Verbal Learning Test (RAVLT), Copying Geometric Drawings (CGD), Frontal Assessment Battery (FAB), and Trail Making A and B (TMT-A and TMT-B)], psychological assessment [Hamilton Rating Scale for Depression and Anxiety (HAM-D and HAM-A), Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and 36-Item Short Form Health Survey (SF-36)], and pain assessment [Visual Analogic Scale (VAS), Total Pain Rating index (T-PRI), Brief Pain Inventory (BPI), and Pain DETECT Questionnaire (PD-Q)] were performed. In addition, blood biomarkers and MRI of the brain were recorded for the detection of Age-Related WMCs (ARWMCs). Descriptive statistics, the Mann-Whitney U-test, the Pearson Chi-Squared test and Spearman's correlation analysis were used.

Results: Patients with BMS had impairments in most cognitive domains compared with controls (p < 0.001^**) except in RAVLT and CGD. The HAM-D, HAM-A, PSQI, ESS, SF-36, VAS, T-PRI, BPI and PD-Q scores were statistically different between BMS patients and controls (p < 0.001^**) the WMCs frequency and ARWMC scores in the right temporal (RT) and left temporal (LT) lobe were higher in patients with BMS (p = 0.023^*).

Conclusions: Meanwhile, BMS is associated with a higher decline in cognitive functions, particularly attention, working memory, and executive functions, but other functions such as praxis-constructive skills and verbal memory are preserved. The early identification of CI and associated factors may help clinicians to identify patients at risk of developing time-based neurodegenerative disorders, such as Alzheimer's disease (AD) and vascular dementia (VD), for planning the early, comprehensive, and multidisciplinary assessment and treatment.

Factors mediating pain-related risk for opioid use disorder

Pain is a complex experience with far-reaching organismal influences ranging from biological factors to those that are psychological and social. Such influences can serve as pain-related risk factors that represent susceptibilities to opioid use disorder. This review evaluates various pain-related risk factors to form a consensus on those that facilitate opioid abuse. Epidemiological findings represent a high degree of co-occurrence between chronic pain and opioid use disorder that is, in part, driven by an increase in the availability of opioid analgesics and the diversion of their use in a non-medical context. Brain imaging studies in individuals with chronic pain that use/abuse opioids suggest abuse-related mechanisms that are rooted within mesocorticolimbic processing. Preclinical studies suggest that pain states have a limited impact on increasing the rewarding effects of opioids. Indeed, many findings indicate a reduction in the rewarding and reinforcing effects of opioids during pain states. An increase in opioid use may be facilitated by an increase in the availability of opioids and a decrease in access to non-opioid reinforcers that require mobility or social interaction. Moreover, chronic pain and substance abuse conditions are known to impair cognitive function, resulting in deficits in attention and decision making that may promote opioid abuse. A better understanding of pain-related risk factors can improve our knowledge in the development of OUD in persons with pain conditions and can help identify appropriate treatment strategies. This article is part of the special issue on 'Vulnerabilities to Substance Abuse.'.

Trigeminal neuralgia causes neurodegeneration in rats associated with upregulation of the CD95/CD95L pathway

Objectives

To explore the effects of trigeminal neuralgia on neurodegeneration in rats and the underlining mechanism.

Methods

Sixty adult male Sprague Dawley rats were divided randomly into Chronic Constriction Injury of the Rat’s Infraorbital Nerve (ION-CCI) group and sham group (n = 30). Right suborbital nerve was ligated in ION-CCI group to establish a trigeminal neuralgia model. In sham group, suborbital nerve was exposed without ligation. Pain thresholds were measured before surgery and 1, 7, 15, and 30 days after surgery (n = 10). Morris water maze tests (n = 10) were conducted at 1, 15, and 30 days after surgery to evaluate the changes in learning and memory ability of rats. At 5, 19, and 34 days after surgery, serum S100β protein concentration and hippocampal Aβ1-42 protein expression were detected by enzyme-linked immunosorbent assay; total tau protein expression was detected by Western blotting; changes of neurons in hippocampus were observed by Nissl staining; and the expression of ^ser404p-tau, cluster of differentiation (CD)95, CD95L, and cleaved caspase-3 proteins was detected by immunofluorescence and Western blotting.

Results

Hyperalgesia occurred in ION-CCI group, and mechanical pain threshold decreased significantly (P < 0.05). On the 15th and 30th days after surgery, ION-CCI group showed lower learning and memory ability than sham group (P < 0.05). Serum S100β protein concentration, hippocampal A β1-42, and ^ser404p-tau protein expression increased in the ION-CCI group 19 and 34 days after surgery (P < 0.05), hippocampal CD95 expression increased in the ION-CCI group after surgery (P < 0.05), hippocampal CD95L expression increased at 19 and 34 days after surgery (P < 0.05), and cleaved caspase-3 expression increased at 5 and 19 days after surgery (P < 0.05). Nissl bodies in ION-CCI group decreased significantly at 15 days after surgery. The expression of cleaved caspase-3 protein in ION-CCI group was positively correlated with the expression of CD95 and CD95L (P < 0.05).

Conclusions

Trigeminal neuralgia may lead to neuronal inflammation and neuronal apoptosis associated with upregulation of CD95/CD95L expression, thus causing neurodegeneration.

Cortical Modulation of Nociception

Nociception is the neuronal process of encoding noxious stimuli and could be modulated at peripheral, spinal, brainstem, and cortical levels. At cortical levels, several areas including the anterior cingulate cortex (ACC), prefrontal cortex (PFC), ventrolateral orbital cortex (VLO), insular cortex (IC), motor cortex (MC), and somatosensory cortices are involved in nociception modulation through two main mechanisms: (i) a descending modulatory effect at spinal level by direct corticospinal projections or mostly by activation of brainstem structures (i.e. periaqueductal grey matter (PAG), locus coeruleus (LC), the nucleus of raphe (RM) and rostroventral medulla (RVM)); and by (ii) cortico-cortical or cortico-subcortical interactions. This review summarizes evidence related to the participation of the aforementioned cortical areas in nociception modulation and different neurotransmitters or neuromodulators that have been studied in each area. Besides, we point out the importance of considering intracortical neuronal populations and receptors expression, as well as, nociception-induced cortical changes, both functional and connectional, to better understand this modulatory effect. Finally, we discuss the possible mechanisms that could potentiate the use of cortical stimulation as a promising procedure in pain alleviation.

Preoperative Acute Pain Is Associated with Postoperative Delirium

Background

Studies have provided some evidence that pain is a risk factor for postoperative delirium (POD). Therefore, we investigated the relationship between preoperative pain and POD after noncardiac surgery.

Methods

POD was assessed with the Montreal Cognitive Assessment, and preoperative cognition was assessed with the Mini-Mental State Examination. Plasma C-reactive protein (CRP) was detected by enzyme-linked immunosorbent assay before surgery. Preoperative pain was classified by its duration before surgery as chronic pain (lasting more than 1 month), acute pain (lasting less than 1 month), or no pain (no obvious pain). Multiple linear regression was used to adjust for confounding.

Results

From October 15, 2018, through August 12, 2019, a total of 67 patients were randomized; 7 were excluded because they were discharged before the seventh postoperative day. The prevalence of POD was significantly higher in the acute pain group (13 of 20; 65%) than in the chronic pain group (5 of 20; 25%) or the no pain group (6 of 20; 30%) (P = 0.019), indicating that delirium is associated with preoperative acute pain. The plasma level of preoperative CRP was also higher in the acute pain group than in the other two groups (mean [interquartile range]: 10.7 [3.3, 29.3] vs 1 [0.5, 3.8]mg/l; P &lt; 0.001), suggesting that elevated preoperative plasma levels of CRP were associated with delirium.

Conclusions

Preoperative acute pain was associated with POD, and increased plasma levels of CRP provide a marker. In addition, we found that illiteracy and advanced age were risk factors for POD.

Altered Intrinsic Brain Activity and Functional Connectivity Before and After Knee Arthroplasty in the Elderly: A Resting-State fMRI Study

Objective: This study aimed to investigate the brain functional alterations with resting-state functional magnetic resonance imaging (rs-fMRI) in older patients with knee osteoarthritis (KOA) before and after total knee arthroplasty (TKA) and to assess the causal relationship of the brain function and neuropsychological changes.

Methods: We performed rs-fMRI to investigate brain function of 23 patients aged ≥65 with KOA and 23 healthy matched controls. Of the KOA patients, 15 completed postoperative rs-fMRI examinations. Analyzes of the amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) were used to estimate differences in brain functional parameters between KOA patients, postoperative patients, and the controls. The relationship between changes of pre- and post-surgical status in ALFF and neuropsychological test results was analyzed.

Results: Compared with the controls, all patients with KOA exhibited decreased ALFF in the default mode network (bilateral angular gyrus, precuneus gyrus, medial superior frontal gyrus) and increased ALFF in the bilateral amygdala and cerebellum posterior lobe before surgery (P < 0.001). Altered ALFF persisted in the same brain regions 1 week postoperatively. The decreased ALFF in the left precuneus gyrus and middle temporal gyrus was found after surgery when compared with preoperative data (P < 0.01). Preoperatively, the KOA patients exhibited increased FC between the left precuneus gyrus and the right supplementary motor area compared to the controls (P < 0.001), but this connectivity became no significant difference after TKA. The left Cerebelum_9 was found to have decreased FC with the right precuneus gyrus postoperatively (P < 0.001) although this was not significantly different before surgery. The significantly altered ALFF values were not correlated with changes in cognitive assessment scores.

Conclusion: In older patients with end-stage KOA, functional alterations in important brain regions were detected with the persistence and further changes observed at an early stage after knee replacement. Our data further our understanding of brain functional abnormalities and cognitive impairment in older patients following knee replacement, which may provide therapeutic targets for preventive/treatment strategy to be developed.

Trial registration: Clinical Trial Registration: http://www.chictr.org.cn/index.aspx, ChiCTR1800016437; Registered June 1, 2018.

Patterns of change in physical functioning and posttraumatic stress disorder with cognitive processing therapy in a randomized controlled implementation trial

Background: Physical health concerns (e.g. chronic pain, fatigue) are common among clients with posttraumatic stress disorder (PTSD). Prior research has indicated that clients report improved physical functioning and fewer physical health symptoms after receiving Cognitive Processing Therapy (CPT) for PTSD. However, less is known about the impact of physical functioning on the clients' PTSD symptom improvement in CPT. Objective: The current study examined the patterns of change of and between physical functioning and PTSD symptoms over the course of CPT among a diverse military, veteran, and community sample. Method: We collected clients' (N = 188) physical functioning and PTSD symptom severity prior to and during CPT using the 12-Item Short Form Health Survey and the PTSD Checklist. We used multilevel modelling to 1) evaluate the impact of baseline physical functioning on the PTSD symptom trajectory, 2) examine the trajectory of physical functioning, and 3) assess the dynamics between physical functioning and PTSD symptoms over the course of CPT. Results: Our multilevel analyses indicated that 1) physical functioning significantly improved for those with low levels of functioning prior to treatment, 2) poorer baseline physical functioning predicted slower improvements in PTSD symptoms, and 3) poorer physical functioning in one session predicted less PTSD symptom improvement by the next session. Conclusions: Our findings demonstrate that while physical functioning can interfere with PTSD symptom improvement, physical functioning can also improve over the course of CPT. In light of the interconnected nature of physical health and PTSD symptoms, clinicians may need to attend to lower levels of physical functioning when providing CPT or other trauma-focused therapies. Future research to determine whether specific treatment adaptations may benefit such clients is needed.

TRP Channels Role in Pain Associated With Neurodegenerative Diseases

Transient receptor potential (TRP) are cation channels expressed in both non-excitable and excitable cells from diverse tissues, including heart, lung, and brain. The TRP channel family includes 28 isoforms activated by physical and chemical stimuli, such as temperature, pH, osmotic pressure, and noxious stimuli. Recently, it has been shown that TRP channels are also directly or indirectly activated by reactive oxygen species. Oxidative stress plays an essential role in neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases, and TRP channels are involved in the progression of those diseases by mechanisms involving changes in the crosstalk between Ca2+ regulation, oxidative stress, and production of inflammatory mediators. TRP channels involved in nociception include members of the TRPV, TRPM, TRPA, and TRPC subfamilies that transduce physical and chemical noxious stimuli. It has also been reported that pain is a complex issue in patients with Alzheimer's and Parkinson's diseases, and adequate management of pain in those conditions is still in discussion. TRPV1 has a role in neuroinflammation, a critical mechanism involved in neurodegeneration. Therefore, some studies have considered TRPV1 as a target for both pain treatment and neurodegenerative disorders. Thus, this review aimed to describe the TRP-dependent mechanism that can mediate pain sensation in neurodegenerative diseases and the therapeutic approach available to palliate pain and neurodegenerative symptoms throughout the regulation of these channels.

Probability of severe frailty development among operative and nonoperative adult spinal deformity patients: an actuarial survivorship analysis over a 3-year period

BACKGROUND

Little is known of how frailty, a dynamic measure of physiological age, progresses relative to age or disability status. Operative treatment of adult spinal deformity (ASD) may play a role in frailty remediation and maintenance.

PURPOSE

Compare frailty status, severe frailty development, and factors influencing severe frailty development among ASD patients undergoing operative or nonoperative treatment.

DESIGN

Retrospective review with maximum follow-up of 3 years.

SETTING

Prospective, multicenter, ASD database.

PARTICIPANTS

Patients were consecutively enrolled from 13 participating centers.

INCLUSION CRITERIA

≥18 years undergoing either operative or nonoperative treatment for ASD, exclusion criteria: spinal deformity of neuromuscular etiology, presence of active infection, or malignancy. The mean age of the participants analyzed were 54.9 for the operative cohort and 55.0 for the nonoperative cohort.

OUTCOMES MEASURES

Frailty status, severe frailty development, and factors influencing severe frailty development.

METHODS

ASD patients (coronal scoliosis ≥20°, sagittal vertical axis (SVA) ≥5 cm, Pelvic Tilt (PT) ≥25°, or thoracic kyphosis ≥60°) >18 y/o, with Base Line (BL) frailty scores were included. Frailty was scored from 0 to 1 (not frail: <0.3, frail 0.3-0.5, severe frailty >0.5) through the use of ASD-frailty index (FI) which has been validated using the International Spine Study Group (ISSG) ASD database, European Spine Study Group ASD database, and the Scoli-RISK-1 Patient Database. The ISSG is funded through research grants from DePuy Synthes and individual donations and supported the current work. Operative (Op) and Nonoperative (Non-Op) patients were propensity matched. T-tests compared frailty among treatment groups and BL, 1, 2, and ≥3 years. An actuarial Kaplan-Meier survivorship analysis with log-rank (Mantel-Cox) test, adjusting for patients lost to follow-up, determined probability of severe frailty development. Multivariate Cox Regressions gauged the effect of sagittal malalignment, patient and surgical details on severe frailty development.

RESULTS

The analysis includes 472 patients (236 Op, 236 Non-Op) selected by propensity score matching from a cohort of 1,172. Demographics and comorbidities were similar between groups (p>.05). Op exhibited decreased frailty at all follow-up intervals compared with BL (BL: 0.22 vs Y1: 0.18; Y2: 0.16; Y3: 0.15, all p<.001). Non-Op displayed similar frailty from BL to 2Y follow up, and increased frailty at 3Y follow up (0.23 vs 0.25, p=.014). Compared with Non-Op, Op had lower frailty at 1Y (0.18 vs 0.24), 2Y (0.16 vs 0.23), and 3Y (0.15 vs 0.25; all p<.001). Cumulative probability of maintaining nonsevere frailty was (Op: 97.7%, Non-Op: 94.5%) at 1Y, (Op: 95.1%, Non-Op: 90.4%) at 2Y, and (Op: 95.1%, Non-Op: 89.1%) at ≥3Y, (p=.018). Among all patients, baseline depression (hazard ratio: 2.688[1.172-6.167], p=.020), Numeric Rating Scale (NRS) back pain scores (HR: 1.247[1.012-1.537], p=.039), and nonoperative treatment (HR: 2.785[1.167-6.659], p=.021) predicted severe frailty development with having a HR>1.0 and p value<.05. Among operative patients, 6-week postoperative residual SVA malalignment (SRS-Schwab SVA+modifier) (HR: 15.034[1.922-116.940], p=.010) predicted severe frailty development indicated by having a HR>1.0 and p value <.05.

CONCLUSIONS

Non-Op patients were more likely to develop severe frailty, and at a quicker rate. Baseline depression, increased NRS back pain scores, nonoperative treatment, and postoperative sagittal malalignment at 6-week follow-up significantly predicted severe frailty development. Operative intervention and postoperative sagittal balance appear to play significant roles in frailty remediation and maintenance in ASD patients. Frailty is one factor, in a multifactorial conservation, that may be considered when determining operative or nonoperative values for ASD patients. Operating before the onset of severe frailty, may result in a lower complication risk and better long-term clinical outcomes.

The Effects of Opioids on Cognition in Older Adults With Cancer and Chronic Noncancer Pain: A Systematic Review

CONTEXT

Opioids are prescribed to manage moderate-to-severe pain and can be used with older adults; however, they may lead to several adverse effects, including cognitive impairment.

OBJECTIVES

To identify, appraise, and synthesize evidence on the impact of opioids on cognition in older adults with cancer/chronic noncancer pain, and screening tools/neuropsychological assessments used to detect opioid-induced cognitive impairment.

METHODS

A systematic literature review following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (international prospective register of systematic reviews registration: CRD42018092943). MEDLINE, EMBASE, PsycINFO, CINAHL, Cochrane Library, and Web of Science were searched up to December 2018. Randomized controlled trials, quasi-experimental studies, and observational studies of adults aged 65 years and older with cancer/chronic noncancer pain taking opioids were included. A narrative synthesis was conducted.

RESULTS

From 4036 records, 10 met inclusion criteria. Five studies used one screening tool, and five studies used a range of neuropsychological assessments; assessing 14 cognitive domains. Most studies demonstrated no effect of opioid use on cognitive domains, whereas four studies showed mixed effects. In particular, attention, language, orientation, psychomotor function, and verbal working/delayed episodic memory were worsened. Changes to cognitive function were predominantly observed in studies with higher mean doses of opioids (120-190.7mg oral morphine equivalent daily dose).

CONCLUSION

Both improvements and impairments to cognition were observed in studies with higher mean opioid doses. In clinical practice, a brief screening tool assessing attention, language, orientation, psychomotor function, and verbal working/delayed episodic memory may be beneficial to detect worsening cognition in older adults with chronic pain using opioids.

The impact of aging on pressure pain thresholds: are men less sensitive than women also in older age?

PURPOSE

Men have generally demonstrated higher pressure pain thresholds (PPT) than women. However, the possible impact of aging on the gender differences in pain perception has not been fully evaluated. In this study, we aimed to investigate the gender differences in PPT over the life course, in young, middle-aged and older adults.

METHODS

This cross-sectional study involved 355 pain-free healthy individuals aged 19-95 years, divided into < 45, 45-64 and ≥ 65 years age groups. PPT were measured using Fisher's algometer. Data on anthropometry, formal education and occupation were collected for each participant, and a multidimensional geriatric assessment was performed in older individuals.

RESULTS

Lower PPT values were observed in old vs young adults (21.8 ± 8.7 N/cm² vs 59.5 ± 31.6, p < 0.0001) and in women vs men (16.3 ± 6.1 vs 42.8 ± 19.6 N/cm², p = 0.0003). A significant interaction emerged between age and sex in influencing PPT (p_interaction = 0.03). Although women had lower mean PPT values than men in all age groups, such gender difference diminished with aging, from 42.8 ± 19.6 vs 59.5 ± 31.6 N/cm² (p = 0.001) to 16.3 ± 6.1 vs 21.8 ± 8.7 vs N/cm² (p = 0.003) in younger and older women vs men, respectively.

CONCLUSIONS

Female gender and older age are associated with lower PPT, but such gender difference seems to decrease with aging.

An Electrophysiological Study of Cognitive and Emotion Processing in Type I Chiari Malformation

Type I Chiari malformation (CMI) is a neurological condition in which the cerebellar tonsils descend into the cervical spinal subarachnoid space resulting in cervico-medullary compression. Early case-control investigations have indicated cognitive deficits in the areas of attention, memory, processing speed, and visuospatial function. The present study further examined cognitive and emotional processing deficits associated with CMI using a dual-task paradigm. Nineteen CMI patients were recruited during pre-surgical consultation and 19 matched control participants identified emotional expressions in separate single and asynchronous dual-task designs. To extend earlier behavioral studies of cognitive effects in CMI, we recorded event-related potentials (ERPs) in the dual-task design. Though response times were slower for CMI patients across the two tasks, behavioral and ERP analyses indicated that patients did not differ from matched controls in the ability to allocate attentional resources between the two tasks. P1 ERP component analyses provided no indication of an emotional arousal deficit in our CMI sample while P3 ERP component analyses suggested a CMI-related deficit in emotional regulation. P3 analysis also yielded evidence for a frontalization of neurophysiological activity in CMI patients. Pain and related depression and anxiety factors accounted for CMI deficits in single-task, but not dual-task, response times. Results are consistent with a dysfunctional fronto-parietal attentional network resulting from either the indirect effects of chronic pain or the direct effects of CMI pathophysiology stemming from cervico-medullary compression.

Translation, cultural adaptation, and psychometric testing of the Yoruba version of Fear-Avoidance Beliefs Questionnaire in patients with low-back pain

PURPOSE

To translate, culturally adapt, and validate the Fear-Avoidance Beliefs Questionnaire into Yoruba language.

MATERIALS AND METHODS

Translation and cultural adaptation of the Yoruba version of the Fear-Avoidance Beliefs Questionnaire was carried out following the Guillemin criteria. One hundred and thirty-one individuals with chronic low-back pain participated in the psychometric evaluation of the Yoruba language translation. Cronbach's alpha (α), principal component analysis, intra-class correlation, Bland-Altman analysis, Spearman rank correlation coefficient, and minimal detectable difference were used for the analysis. Alpha level was set at p < 0.05.

RESULTS AND CONCLUSION

The mean age of the respondents was 53.6 ± 11.6 years. The internal consistency of the Yoruba language version of the Fear Avoidance Beliefs Questionnaire yielded a Cronbach's alpha of 0.9. Principal component analysis yielded a three-factor structure including the "work", "beliefs related to work", and "physical activity" which accounted for 61.6% of variance in the Yoruba translation. Test-retest reliability of the Yoruba translation yielded an Intra class correlation coefficient 0.97 (0.95-0.98). The Yoruba Fear Avoidance Beliefs Questionnaire was poorly correlated with the Visual Analog Scale (r = 0.01) and Roland-Morris Disability Questionnaire (r = 0.3). The minimal detectable difference of the Yoruba translation was 7.0. The Yoruba Fear Avoidance Beliefs Questionnaire demonstrated excellent psychometric properties similar to existing versions and is appropriate for clinical use among Yoruba-speaking patients.IMPLICATIONS FOR REHABILITATIONThe Fear-Avoidance Beliefs Questionnaire is a culturally sensitive psychosocial outcome measure, necessitating its existence, and adaptation into different languages.The instrument was translated and culturally adapted into the Yoruba language following the Guillemin criteria.The Yoruba translation demonstrated excellent internal consistency, test-retest reliability and weak correlations with the Visual analog scale and Roland-Morris Disability Scale.The Yoruba version of the Fear-Avoidance Beliefs Questionnaire can be used to assess fear-avoidance beliefs among Yoruba speaking patients with low-back pain.

Blockade of the Sigma-1 Receptor Relieves Cognitive and Emotional Impairments Associated to Chronic Osteoarthritis Pain

Osteoarthritis is the most common musculoskeletal disease worldwide, often characterized by degradation of the articular cartilage, chronic joint pain and disability. Cognitive dysfunction, anxiety and depression are common comorbidities that impact the quality of life of these patients. In this study, we evaluated the involvement of sigma-1 receptor (σ1R) on the nociceptive, cognitive and emotional alterations associated with chronic osteoarthritis pain. Monosodium iodoacetate (MIA) was injected into the knee of Swiss-albino CD1 mice to induce osteoarthritis pain, which then received a repeated treatment with the σ1R antagonist E-52862 or its vehicle. Nociceptive responses and motor performance were assessed with the von Frey and the Catwalk gait tests. Cognitive alterations were evaluated using the novel object recognition task, anxiety-like behavior with the elevated plus maze and the zero-maze tests, whereas depressive-like responses were determined using the forced swimming test. We also studied the local effect of the σ1R antagonist on cartilage degradation, and its central effects on microglial reactivity in the medial prefrontal cortex. MIA induced mechanical allodynia and gait abnormalities that were prevented by the chronic treatment with the σ1R antagonist. E-52862 also reduced the memory impairment and the depressive-like behavior associated to osteoarthritis pain. Interestingly, the effect of E-52862 on depressive-like behavior was not accompanied by a modification of anxiety-like behavior. The pain-relieving effects of the σ1R antagonist were not due to a local effect on the articular cartilage, since E-52862 treatment did not modify the histological alterations of the knee joints. However, E-52862 induced central effects revealed by a reduction of the cortical microgliosis observed in mice with osteoarthritis pain. These findings show that σ1R antagonism inhibits mechanical hypersensitivity, cognitive deficits and depressive-like states associated with osteoarthritis pain in mice. These effects are associated with central modulation of glial activity but are unrelated to changes in cartilage degradation. Therefore, targeting the σ1R with E-52862 represents a promising pharmacological approach with effects on multiple aspects of chronic osteoarthritis pain that may go beyond the strict inhibition of nociception.

Profiles of Subjective Well-being in Patients with Chronic Back Pain: Contrasting Subjective and Objective Correlates

OBJECTIVE

The detrimental impact of nonspecific chronic low back pain (CLBP) on quality of life is well known. However, patients with CLBP represent a remarkably heterogeneous group, and not all of them report compromised well-being.

METHODS

In this study, we investigated this heterogeneity by identifying profiles (or clusters) of well-being and their correlates in 239 CLBP patients. To take the multidimensionality of subjective well-being into account, we included multiple well-being indicators (depression, anxiety, affective distress, perceived control over life). For an in-depth characterization of the well-being profiles, we assessed 1) sociodemographic indicators (age, gender, education, marital status, occupational status), 2) pain-related measures (pain intensity, subjective and objective pain disability, number of pain locations), 3) psychosocial resources (mental health, resilience, perceived support), 4) biographical factors (trauma), and 5) somatosensory profiles based on quantitative sensory testing.

RESULTS

Based on two-step cluster analysis, we identified three distinct well-being profiles, characterized by either generally high well-being (cluster 1, n = 51), moderate well-being (cluster 2, n = 104), or consistently low well-being (cluster 3, n = 77), respectively. Most differences between the derived well-being profiles regarding sociodemographic, psychosocial, and biographical measures were of weak to moderate effect size. Larger effect sizes were observed for differences in pain intensity and subjective, but not objective, pain disability. Finally, the largest effects were found for differences in psychosocial resources.

CONCLUSIONS

Our findings suggest that not only in nonclinical samples, but also in patients with chronic pain, well-being is more closely associated with psychological resources and subjective evaluations than with objective parameters.