Exacerbation of pain by anxiety is associated with activity in a hippocampal network

Effect of dry needling on pain and central sensitization in women with chronic pelvic pain: A randomized parallel-group controlled clinical trial

Chronic pelvic pain (CPP) is a debilitating problem in women with clear evidence of myofascial dysfunction. It seems that Myofascial trigger points (MTrPs) contribute to the development of central sensitization (CS). This study aimed to investigate the effect of dry needling on pain and CS in women with CPP. Thirty-six women with CPP participated in this randomized controlled clinical trial and randomly assigned into three groups: dry needling group (DNG), placebo needling group (PNG) and control group (CG). The DNG received five sessions of DN using the "static needling", the PNG received non-penetrating method, and the CG did not receive any intervention. Assessment of outcomes including central sensitization inventory (CSI), short-form McGill pain questionnaire (SF-MPQ), electroencephalography (EEG), conditioned pain modulation (CPM), salivary cortisol concentration, 7-item general anxiety disorder scale (GAD-7), pain catastrophizing scale (PCS), and SF-36 questionnaire was performed pre-intervention, post-intervention, and three months post-intervention by a blind examiner. The result showed a significant group-by-time interaction for CSI, SF-MPQ, and PCS. There was a significant decrease in CSI score in post-intervention and three-months post-intervention compare to pre-intervention in the DNG and PNG. SF-MPQ-PPI score in DNG significantly decreased post-intervention. PCS-Total score decreased significantly post-intervention in DNG and PNG. No significant group-by-time interactions were observed for other variables. EEG results showed regional changes in the activity of frequency bands in both eye closed and eye open conditions. It seems that DN can affect central pain processing by removing the source of peripheral nociception. Trial registration: Iranian Registry of Clinical Trials (IRCT20211114053057N1, registered on: December 03, 2021. https://irct.behdasht.gov.ir/search/result?query=IRCT20211114053057N1).

Effectiveness of wearing glasses with green lenses on dental anxiety for third-molar surgery: A randomized clinical trial

BACKGROUND

Dental anxiety is a common problem for oral surgeries. This study investigated the effectiveness of wearing glasses with green lenses in reducing dental anxiety, blood pressure, heart rate, and intraoperative pain in patients undergoing first-time third-molar surgery.

METHODS

The authors planned this study as a randomized and parallel-group clinical trial. Patients' dental anxiety was measured with the use of a visual analog scale and a State-Trait Anxiety Inventory for baseline measurement purposes. At the same time, blood pressure, oxygen saturation, and heart rate values were recorded. Patients were given glasses with clear or green lenses, depending on their group. After 10 minutes, all parameters were measured again for preoperative measurement. Patients wore glasses with either green or clear lenses throughout the operation. After the operation, patients were asked to estimate the degree of intraoperative pain using the visual analog scale.

RESULTS

The study included 128 patients. On the basis of the change between baseline and preoperative measurements, the authors found a statistically significant difference in anxiety and heart rate. Intraoperative pain showed a significant difference between groups. No significant changes were found in blood pressure and oxygen saturation.

CONCLUSIONS

Patients with anxiety could wear low-cost, easy-to-use glasses with green lenses for 10 minutes before an operation to reduce anxiety and heart rate. In addition, wearing glasses during the surgical procedure can reduce intraoperative pain.

PRACTICAL IMPLICATIONS

By means of using glasses with green lenses throughout the procedure, existing anxiety and pain can be reduced. An operation can be performed more comfortably for both the patient and the dentist. This clinical trial was registered at ClinicalTrials.gov. The registration number is NCT05584696.

Deactivation of dorsal CA1 pyramidal neurons projecting to medial prefrontal cortex contributes to neuropathic pain and short-term memory impairment

ABSTRACT

Neuropathic pain after peripheral nerve injury is a multidimensional experience that includes sensory, affective, and cognitive components that interact with one another. Hypoexcitation of the medial prefrontal cortex (mPFC) was observed in mice with peripheral nerve injury, but the changes in neural inputs onto the mPFC have not been completely explored. Here, we report that the neural terminals from the dorsal hippocampus CA1 (dCA1) form excitatory connection with layer 5 pyramidal neurons in the prelimbic area (PrL) of the mPFC. Spared nerve injury (SNI) induced a reduction in the intrinsic excitability of dCA1 pyramidal neurons innervating the PrL and impairment in excitatory synaptic transmission onto dCA1 pyramidal cells. Specifically, activating the neural circuit from dCA1 to mPFC alleviated neuropathic pain behaviors and improved novel object recognition ability in SNI mice, whereas deactivating this pathway in naïve animals recapitulated tactile allodynia and memory deficits. These results indicated that hypoactivity in dCA1 pyramidal cells after SNI in turn deactivated layer 5 pyramidal neurons in PrL and ultimately caused pain hypersensitivity and memory deficits.

Mental health markers and protective factors in students with symptoms of physical pain across WEIRD and non-WEIRD samples - a network analysis

BACKGROUND

Studies conducted in Western societies have identified variables associated with chronic pain, but few have done so across cultures. Our study aimed to clarify the relationship between specific mental health markers (i.e., depression, anxiety, posttraumatic stress disorder [PTSD], perceived stress) as well as specific protective factors (i.e., social support and self-efficacy) related to physical pain among university students across non-WEIRD and WEIRD samples.

METHOD

A total of 188 university students (131 women and 57 men) were included in the study. We used network analysis to ascertain mental health markers especially central to the experience of physical pain.

RESULTS

No statistically significant difference was found between mental health markers (i.e., depression, anxiety, perceived stress, and PTSD) and protective factors (i.e., social support and self-efficacy) associated with physical pain symptoms for Swiss students versus Indian students (M = 0.325, p = .11). In addition, networks for Swiss versus Indian students did not differ in global strength (S = 0.29, p = .803). Anxiety was the most central mental health marker, and social support was the most important protective factor related to physical pain in both countries. However, for Swiss students, perceived stress, and for Indian students, PTSD symptoms were central mental health markers related to physical pain.

CONCLUSION

Our results identify factors that may serve as important treatment targets for pain interventions among students of both countries before it becomes chronic.

Integration of Prior Expectations and Suppression of Prediction Errors During Expectancy-Induced Pain Modulation: The Influence of Anxiety and Pleasantness

Pain perception arises from the integration of prior expectations with sensory information. Although recent work has demonstrated that treatment expectancy effects (e.g., placebo hypoalgesia) can be explained by a Bayesian integration framework incorporating the precision level of expectations and sensory inputs, the key factor modulating this integration in stimulus expectancy-induced pain modulation remains unclear. In a stimulus expectancy paradigm combining emotion regulation in healthy male and female adults, we found that participants' voluntary reduction in anticipatory anxiety and pleasantness monotonically reduced the magnitude of pain modulation by negative and positive expectations, respectively, indicating a role of emotion. For both types of expectations, Bayesian model comparisons confirmed that an integration model using the respective emotion of expectations and sensory inputs explained stimulus expectancy effects on pain better than using their respective precision. For negative expectations, the role of anxiety is further supported by our fMRI findings that (1) functional coupling within anxiety-processing brain regions (amygdala and anterior cingulate) reflected the integration of expectations with sensory inputs and (2) anxiety appeared to impair the updating of expectations via suppressed prediction error signals in the anterior cingulate, thus perpetuating negative expectancy effects. Regarding positive expectations, their integration with sensory inputs relied on the functional coupling within brain structures processing positive emotion and inhibiting threat responding (medial orbitofrontal cortex and hippocampus). In summary, different from treatment expectancy, pain modulation by stimulus expectancy emanates from emotion-modulated integration of beliefs with sensory evidence and inadequate belief updating.

The effect of weighted blankets on sleep and related disorders: a brief review

Background

Sleep disorders such as insomnia can lead to a range of health problems. The high risk of side effects and drug abuse of traditional pharmacotherapy calls for a safer non-pharmacotherapy.

Aims

To examine the use and efficacy of weighted blankets in improving sleep and related disorders in different populations and explore the possible mechanisms.

Methods

A literature search was conducted using PubMed, Embase, Web of Science, MEDLINE, Cochrane Library and CNKI databases. Eligible studies included an intervention with weighted blankets and outcomes covering sleep and/or related disorders (behavioral disturbance, negative emotions and daytime symptoms). Studies using other deep pressure, compression, or exercise-related interventions were excluded.

Conclusions

Most of the included studies showed that weighted blankets could effectively improve sleep quality and alleviate negative emotions and daytime symptoms in patients with sleep disorders, attention deficit hyperactivity disorder, autism spectrum disorder, and other related disorders, with a possible mechanism of deep pressure touch.

Recommendations

Weighted blankets might be a promising tool for sleep interventions among individuals with sleep disorders in clinical settings. More high-quality and large-scale randomized controlled trials are needed to further validate the safety and efficacy of weighted blankets and explore precise mechanisms.

A neural circuit associated with anxiety-like behaviors induced by chronic inflammatory pain and the anxiolytic effects of electroacupuncture

AIMS

Negative emotions induced by chronic pain are a serious clinical problem. Electroacupuncture (EA) is a clinically proven safe and effective method to manage pain-related negative emotions. However, the circuit mechanisms underlying the effect of EA treatment on negative emotions remain unclear.

METHODS

Plantar injection of complete Freund's adjuvant (CFA) was performed to establish a rat model of chronic inflammatory pain-induced anxiety-like behaviors. Adeno-associated virus (AAV) tracing was used to identify excitatory synaptic transmission from the rostral anterior cingulate cortex (rACC) to the dorsal raphe nucleus (DRN). Employing chemogenetic approaches, we examined the role of the rACC-DRN circuit in chronic pain-induced anxiety-like behaviors and investigated whether EA could reverse chronic pain-induced dysfunctions of the rACC-DRN circuit and anxiety-like behaviors.

RESULTS

We found that chemogenetic activation of the rACC-DRN circuit alleviated CFA-induced anxiety-like behaviors, while chemogenetic inhibition of the rACC-DRN circuit resulted in short-term CFA-induced anxiety-like behaviors. Further research revealed that the development of CFA-induced anxiety-like behaviors was attributed to the dysfunction of rACC CaMKII neurons projecting to DRN serotonergic neurons (rACCCaMKII-DRN5-HT neurons) but not rACC CaMKII neurons projecting to DRN GABAergic neurons (rACCCaMKII-DRNGABA neurons). This is supported by the findings that chemogenetic activation of the rACCCaMKII-DRN5-HT circuit alleviates anxiety-like behaviors in rats with chronic pain, whereas neither chemogenetic inhibition nor chemogenetic activation of the rACCCaMKII-DRNGABA circuit altered CFA chronic pain-evoked anxiety-like behaviors in rats. More importantly, we found that EA could reverse chronic pain-induced changes in the activity of rACC CaMKII neurons and DRN 5-HTergic neurons and that chemogenetic inhibition of the rACCCaMKII-DRN5-HT circuit blocked the therapeutic effects of EA on chronic pain-induced anxiety-like behaviors.

CONCLUSIONS

Our data suggest that the reversal of rACCCaMKII-DRN5-HT circuit dysfunction may be a mechanism underlying the therapeutic effect of EA on chronic pain-induced anxiety-like behaviors.

Is implicit memory associated with the hippocampus?

According to the traditional memory-systems view, the hippocampus is critical during explicit (conscious) long-term memory, whereas other brain regions support implicit (nonconscious) memory. In the last two decades, some fMRI studies have reported hippocampal activity during implicit memory tasks. The aim of the present discussion paper was to identify whether any implicit memory fMRI studies have provided convincing evidence that the hippocampus is associated with nonconscious processes without being confounded by conscious processes. Experimental protocol and analysis parameters included the stimulus type(s), task(s), measures of subjective awareness, explicit memory accuracy, the relevant fMRI contrast(s) or analysis, and confound(s). A systematic review was conducted to identify implicit memory studies that reported fMRI activity in the hippocampus. After applying exclusion criteria, 13 articles remained for analysis. We found that there were no implicit memory fMRI studies where subjective awareness was absent, explicit memory performance was at chance, and there were no confounds that could have driven the observed hippocampal activity. The confounds included explicit memory (including false memory), imbalanced attentional states between conditions (yielding activation of the default-mode network), imbalanced stimuli between conditions, and differential novelty. As such, not a single fMRI study provided convincing evidence that implicit memory was associated with the hippocampus. Neuropsychological evidence was also considered, and implicit memory deficits were caused by factors known to disrupt brain regions beyond the hippocampus, such that the behavioral effects could not be attributed to this region. The present results indicate that implicit memory is not associated with the hippocampus.

A brief virtual reality intervention for pre-operative anxiety in adults

OBJECTIVE

Virtual reality (VR) is a promising non-pharmacologic tool for managing health care anxiety. We assessed the feasibility and acceptability of a pre-operative VR intervention by adult patients and medical staff and measured anxiety in adult patients pre- and post-VR intervention.

STUDY DESIGN

We recruited 30 patients scheduled to undergo oral surgery and 8 medical staff as participants. The patients completed a verbal demographic survey and rated their anxiety before the VR intervention and at 1 minute and 2 minutes post-intervention. We administered the Acceptability of Intervention Measure to the patients to measure their perceptions of the VR intervention and the Feasibility of Intervention Measure to the medical staff to assess their perception of VR implementation. We performed an analysis of variance to compare pre-operative anxiety over time and assess demographic differences.

RESULTS

The patients showed high and consistent acceptability of the pre-operative use of VR among patients, but acceptability varied among medical staff. The patients experienced a statistically significant reduction of pre-operative anxiety (P = .003).

CONCLUSION

A brief VR pre-intervention is highly accepted by and very beneficial for patients undergoing oral surgery, positively affecting anxiety reduction. The perception of VR by health care providers needs to be explored to increase acceptability.

Expectations underlie the effects of unpredictable pain: a behavioral and electroencephalogram study

ABSTRACT

Previous studies on the potential effects of unpredictability on pain perception and its neural correlates yielded divergent results. This study examined whether this may be explained by differences in acquired expectations. We presented 41 healthy volunteers with laser heat stimuli of different intensities. The stimuli were preceded either by predictable low, medium, or high cues or by unpredictable low-medium, medium-high, or low-high cues. We recorded self-reports of pain intensity and unpleasantness and laser-evoked potentials (LEPs). Furthermore, we investigated whether dynamic expectations that evolved throughout the experiment based on past trials were better predictors of pain ratings than fixed (nonevolving) expectations. Our results replicate previous findings that unpredictable pain is higher than predictable pain for low-intensity stimuli but lower for high-intensity stimuli. Moreover, we observed higher ratings for the medium-high unpredictable condition than the medium-low unpredictable condition, in line with an effect of expectation. We found significant interactions (N1, N2) for the LEP components between intensity and unpredictability. However, the few significant differences in LEP peak amplitudes between cue conditions did not survive correction for multiple testing. In line with predictive coding perspectives, pain ratings were best predicted by dynamic expectations. Surprisingly, expectations of reduced precision (increased variance) were associated with lower pain ratings. Our findings provide strong evidence that (dynamic) expectations contribute to the opposing effects of unpredictability on pain perception; therefore, we highlight the importance of controlling for them in pain unpredictability manipulations. We also suggest to conceptualize pain expectations more often as dynamic constructs incorporating previous experiences.

The effect of unpredictability on the perception of pain: a systematic review and meta-analysis

ABSTRACT

Despite being widely assumed, the worsening impact of unpredictability on pain perception remains unclear because of conflicting empirical evidence, and a lack of systematic integration of past research findings. To fill this gap, we conducted a systematic review and meta-analysis focusing on the effect of unpredictability on pain perception. We also conducted meta-regression analyses to examine the moderating effect of several moderators associated with pain and unpredictability: stimulus duration, calibrated stimulus pain intensity, pain intensity expectation, controllability, anticipation delay, state and trait negative affectivity, sex/gender and age of the participants, type of unpredictability (intensity, onset, duration, location), and method of pain induction (thermal, electrical, mechanical pressure, mechanical distention). We included 73 experimental studies with adult volunteers manipulating the (un)predictability of painful stimuli and measuring perceived pain intensity and pain unpleasantness in predictable and unpredictable contexts. Because there are insufficient studies with patients, we focused on healthy volunteers. Our results did not reveal any effect of unpredictability on pain perception. However, several significant moderators were found, ie, targeted stimulus pain intensity, expected pain intensity, and state negative affectivity. Trait negative affectivity and uncontrollability showed no significant effect, presumably because of the low number of included studies. Thus, further investigation is necessary to clearly determine their role in unpredictable pain perception.

CCL2 Potentiates Inflammation Pain and Related Anxiety-Like Behavior Through NMDA Signaling in Anterior Cingulate Cortex

Previous studies have shown that the C-C motif chemokine ligand 2 (CCL2) is widely expressed in the nervous system and involved in regulating the development of chronic pain and related anxiety-like behaviors, but its precise mechanism is still unclear. This paper provides an in-depth examination of the involvement of CCL2-CCR2 signaling in the anterior cingulate cortex (ACC) in intraplantar injection of complete Freund's adjuvant (CFA) leading to inflammatory pain and its concomitant anxiety-like behaviors by modulation of glutamatergic N-methyl-D-aspartate receptor (NMDAR). Our findings suggest that local bilateral injection of CCR2 antagonist in the ACC inhibits CFA-induced inflammatory pain and anxiety-like behavior. Meanwhile, the expression of CCR2 and CCL2 was significantly increased in ACC after 14 days of intraplantar injection of CFA, and CCR2 was mainly expressed in excitatory neurons. Whole-cell patch-clamp recordings showed that the CCR2 inhibitor RS504393 reduced the frequency of miniature excitatory postsynaptic currents (mEPSC) in ACC, and CCL2 was involved in the regulation of NMDAR-induced current in ACC neurons in the pathological state. In addition, local injection of the NR2B inhibitor of NMDAR subunits, Ro 25-6981, attenuated the effects of CCL2-induced hyperalgesia and anxiety-like behavior in the ACC. In summary, CCL2 acts on CCR2 in ACC excitatory neurons and participates in the regulation of CFA-induced pain and related anxiety-like behaviors through upregulation of NR2B. CCR2 in the ACC neuron may be a potential target for the treatment of chronic inflammatory pain and pain-related anxiety.

Mapping the associations of daily pain, sleep, and psychological distress in a U.S. sample

Chronic pain, sleep problems, and psychological distress (PD) can be disabling conditions and previous research has shown that they are associated. The nuances of the comorbid nature of these conditions may be important to understand for those who treat these conditions. This study examined the bidirectional associations of these health factors concurrently and over time in a sample of U.S. adults (N = 1,008, Mage = 57.68) from the Midlife in the United States (MIDUS) study. Participants reported on their daily pain, sleep quantity, and psychological distress over eight days. A modified Random Intercept Cross-lagged Panel Model was used to analyze the relations, starting with the whole sample and then a comparison of those with and without chronic pain. Results indicated that nightly variation in sleep quantity predicted next day psychological distress for both groups. Sleep quantity also predicted next-day pain, but only for individuals with chronic pain. Associations between pain and psychological distress were found both at the daily level and individual (between-person) level. This between-person association was stronger for those with chronic pain. The lagged associations between sleep, and both pain and psychological distress for the chronic pain group indicate that, increased quantity of sleep predicts decreased next-day pain and psychological distress. Providers could consider this unidirectional lagged relationship when prioritizing treatment for patients with these comorbid conditions. Future research may examine whether responsive, just-in-time treatments might intervene after participants wake from a poor night's sleep to counteract the negative effects of reduced sleep on PD and pain.

Brain morphology predicts individual sensitivity to pain: a multicenter machine learning approach

ABSTRACT

Sensitivity to pain shows a remarkable interindividual variance that has been reported to both forecast and accompany various clinical pain conditions. Although pain thresholds have been reported to be associated to brain morphology, it is still unclear how well these findings replicate in independent data and whether they are powerful enough to provide reliable pain sensitivity predictions on the individual level. In this study, we constructed a predictive model of pain sensitivity (as measured with pain thresholds) using structural magnetic resonance imaging-based cortical thickness data from a multicentre data set (3 centres and 131 healthy participants). Cross-validated estimates revealed a statistically significant and clinically relevant predictive performance (Pearson r = 0.36, P < 0.0002, R2 = 0.13). The predictions were found to be specific to physical pain thresholds and not biased towards potential confounding effects (eg, anxiety, stress, depression, centre effects, and pain self-evaluation). Analysis of model coefficients suggests that the most robust cortical thickness predictors of pain sensitivity are the right rostral anterior cingulate gyrus, left parahippocampal gyrus, and left temporal pole. Cortical thickness in these regions was negatively correlated to pain sensitivity. Our results can be considered as a proof-of-concept for the capacity of brain morphology to predict pain sensitivity, paving the way towards future multimodal brain-based biomarkers of pain.

Anxiety, Disability, and Pain Predict Outcomes of Complex Regional Pain Syndrome: An 8-year Follow-up of a Prospective Cohort

Factors contributing to the varied outcomes of complex regional pain syndrome (CRPS) are not well known. This study aimed to determine whether baseline psychological factors, pain, and disability influence long-term CRPS outcomes. We conducted an 8-year follow-up from a previous prospective study of CRPS outcomes. Sixty-six people diagnosed with acute CRPS were previously assessed at baseline, 6 months, and 12 months and in the current study, 45 were followed up after 8 years. At each timepoint, we measured signs and symptoms of CRPS, pain, disability, and psychological factors. Mixed-model repeated measures were used to identify baseline predictors of CRPS severity, pain, and disability at 8 years. Predictors of greater CRPS severity at 8 years were female sex, greater baseline disability, and greater baseline pain. Predictors of greater pain at 8 years were greater baseline anxiety and disability. The only predictor of greater disability at 8 years was greater baseline pain. Findings suggest CRPS is best understood from a biopsychosocial perspective, and baseline anxiety, pain, and disability may influence the trajectory of CRPS outcomes as far as 8 years later. These variables could be used to identify those at risk of poor outcomes or form targets for early interventions. PERSPECTIVE: This paper presents the findings of the first study to prospectively investigate predictors of CRPS outcomes over 8 years. Baseline anxiety, pain, and disability predicted greater CRPS severity, pain, and disability over 8 years. These factors could identify those at risk of poor outcomes or form targets for early interventions.

Endometriosis-Related Chronic Pelvic Pain

Endometriosis, which is the presence of endometrial stroma and glands outside the uterus, is one of the most frequently diagnosed gynecologic diseases in reproductive women. Patients with endometriosis suffer from various pain symptoms such as dysmenorrhea, dyspareunia, and chronic pelvic pain. The pathophysiology for chronic pain in patients with endometriosis has not been fully understood. Altered inflammatory responses have been shown to contribute to pain symptoms. Increased secretion of cytokines, angiogenic factors, and nerve growth factors has been suggested to increase pain. Also, altered distribution of nerve fibers may also contribute to chronic pain. Aside from local contributing factors, sensitization of the nervous system is also important in understanding persistent pain in endometriosis. Peripheral sensitization as well as central sensitization have been identified in patients with endometriosis. These sensitizations of the nervous system can also explain increased incidence of comorbidities related to pain such as irritable bowel disease, bladder pain syndrome, and vulvodynia in patients with endometriosis. In conclusion, there are various possible mechanisms behind pain in patients with endometriosis, and understanding these mechanisms can help clinicians understand the nature of the pain symptoms and decide on treatments for endometriosis-related pain symptoms.

A narrative review of the literature on illness uncertainty in hypermobile ehlers-danlos syndrome: implications for research and clinical practice

BACKGROUND

Hypermobile Ehlers-Danlos syndrome (hEDS) is characterized by joint and skin laxity, and often accompanied by chronic pain, dysautonomia, increased distress and, functional limitations. The journey to accurate diagnosis is often prolonged due to unclear etiology of symptoms. This manuscript is a narrative review of the literature on illness uncertainty (IU) in hEDS, highlighting the unique facets of IU in this population, as compared to the broader chronic pain population (given symptom overlap between these two disease groups), that warrant additional investigation. Additionally, we considered the unique challenges associated with IU in the context of the developmental nuances of pediatric populations. Specifically, we aimed to (1) map the extant literature of the IU experience in chronic pain conditions broadly including the pediatric and adult research to identify key concepts related to IU and incorporate potential developmental considerations in IU; (2) delineate and describe the IU experience specifically in patients with hEDS, with the goal of identifying gaps in the literature based on aspects of presentation in hEDS that do and do not differ from the broader chronic pain population; and (3) elucidate the potential areas of adverse impact of IU in both general chronic pain populations, and those with hEDS specifically, to provide actionable areas for future research and clinical care of individuals with hEDS. Results of this review indicate that IU has been well-studied in chronic pain generally, but inadequately evaluated in hEDS specifically. Specific features of hEDS (complexity of the disorder, involvement of multiple bodily systems, contribution of organic pathology) may uniquely contribute to IU in this population. This review suggests that ambiguities surrounding the diagnosis of hEDS, symptom course, and treatment recommendations, along with misdiagnosis, perceived dismissal of symptoms, or attribution of symptoms to mental health concerns might increase risk for IU and related distress in patients.

CONCLUSION

Findings from the present review suggest that distinct features of hEDS yield a set of driving factors for IU that may be somewhat different than those faced by patients with chronic pain or other medical conditions. The development of a validated measure of IU to appropriately assess this construct in patients with hEDS is a research priority. In the clinical setting, providers should be attentive to the potentially aversive diagnostic and treatment experiences reported by patients and attempt to provide clear explanations based on the extant knowledge of hEDS, and implement best-practice recommendations for multidisciplinary treatment.

Effect of stress on contextual pain sensitivity in the preoperative period- A proof of concept study

Background and Aims

The importance of non-noxious contextual inputs in the interplay of pain with neurophysiologic and behavioral factors is gaining recognition. Stress of impending surgery can act as a negative context, leading to a decrease in pain threshold in patients. This study was conducted to assess the influence of stress conferred by the imminent and other contextual inputs such as anxiety, socioeconomic status, prior painful experience, and the effect of gender on modulation of pain perception in patients undergoing elective surgery.

Material and Methods

In total, 120 patients aged between 18 and 60 years of either gender posted for elective gastrointestinal surgery under general anesthesia were recruited. Data were collected on preoperative anxiety level, socioeconomic status, education, and any prior painful experience. A pressure algometer was used to measure the pressure pain thresholds and pain tolerance on the day before surgery and on the morning of surgery in the preoperative suite.

Results

There was a statistically significant decrease in both pain threshold (P < 0.0001) and pain tolerance in the immediate preoperative period in comparison to the baseline readings taken the day before surgery (P = 0.048). The magnitude of change in pain scalars was greater in females (P < 0.001), those with a high anxiety score, and a history of severe painful experience in the past.

Conclusion

Preoperative surgical stress lowers the pain threshold and pain tolerance. Contextual modulation of pain by factors such as anxiety and memory of prior painful experience, especially in the female gender, could influence postoperative patient outcomes and warrants further research.

Does addition of aromatherapy and music help to reduce pain and anxiety during shockwave lithotripsy compared to standard analgesia alone? A randomised controlled trial

PURPOSE

To assess the effect of aromatherapy with lavender oil alone, and in combination with music, on pain and anxiety during extracorporeal shockwave lithotripsy for kidney stones.

METHODS

This was a single-centre prospective, randomised controlled trial. The subjects were block randomised into 3 study groups, Group 1: Control; Group 2: Aromatherapy only; Group 3: Aromatherapy and music. All subjects were given patient-controlled intravenous alfentanil as standard analgesia. The primary outcome measures were pain and anxiety scores using visual analogue scale (VAS) and State-Trait Anxiety Inventory.

RESULTS

Ninety patients were recruited and randomised prospectively into Group 1 (n = 30), Group 2 (n = 30), and Group 3 (n = 30). For pain outcome, both Group 2 and Group 3 showed a trend towards lower mean VAS pain scores of 2.73 in both groups compared to the control with a mean VAS score of 3.50, but it was not statistically significant (p = 0.272). There was no significant difference in anxiety scores between groups post-treatment.

CONCLUSIONS

Our study was unable to show a significant improvement in pain relief and anxiety when aromatherapy with lavender oil was added to standard analgesia alone during shockwave lithotripsy. There was also no difference when aromatherapy was combined with music.

Effect of High-Definition Transcranial Direct Current Stimulation on Headache Severity and Central µ-Opioid Receptor Availability in Episodic Migraine

Objective

The current understanding of utilizing HD-tDCS as a targeted approach to improve headache attacks and modulate endogenous opioid systems in episodic migraine is relatively limited. This study aimed to determine whether high-definition transcranial direct current stimulation (HD-tDCS) over the primary motor cortex (M1) can improve clinical outcomes and endogenous µ-opioid receptor (µOR) availability for episodic migraineurs.

Methods

In a randomized, double-blind, and sham-controlled trial, 25 patients completed 10-daily 20-min M1 HD-tDCS, repeated Positron Emission Tomography (PET) scans with a selective agonist for µOR. Twelve age- and sex-matched healthy controls participated in the baseline PET/MRI scan without neuromodulation. The primary endpoints were moderate-to-severe (M/S) headache days and responder rate (≥50% reduction on M/S headache days from baseline), and secondary endpoints included the presence of M/S headache intensity and the use of rescue medication over 1-month after treatment.

Results

In a one-month follow-up, at initial analysis, both the active and sham groups exhibited no significant differences in their primary outcomes (M/S headache days and responder rates). Similarly, secondary outcomes (M/S headache intensity and the usage of rescue medication) also revealed no significant differences between the two groups. However, subsequent analyses showed that active M1 HD-tDCS, compared to sham, resulted in a more beneficial response predominantly in higher-frequency individuals (>3 attacks/month), as demonstrated by the interaction between treatment indicator and baseline frequency of migraine attacks on the primary outcomes. These favorable outcomes were also confirmed for the secondary endpoints in higher-frequency patients. Active treatment also resulted in increased µOR concentration compared to sham in the limbic and descending pain modulatory pathway. Our exploratory mediation analysis suggests that the observed clinical efficacy of HD-tDCS in patients with higher-frequency conditions might be potentially mediated through an increase in µOR availability.

Conclusion

The 10-daily M1 HD-tDCS can improve clinical outcomes in episodic migraineurs with a higher baseline frequency of migraine attacks (>3 attacks/month). This improvement may be, in part, facilitated by the increase in the endogenous µOR availability.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier - NCT02964741.

Botulinum toxin A decreases neural activity in pain-related brain regions in individuals with chronic ocular pain and photophobia

Introduction

To examine the effect of botulinum toxin A (BoNT-A) on neural mechanisms underlying pain and photophobia using functional magnetic resonance imaging (fMRI) in individuals with chronic ocular pain.

Methods

Twelve subjects with chronic ocular pain and light sensitivity were recruited from the Miami Veterans Affairs eye clinic. Inclusion criteria were: (1) chronic ocular pain; (2) presence of ocular pain over 1 week recall; and (3) presence of photophobia. All individuals underwent an ocular surface examination to capture tear parameters before and 4-6 weeks after BoNT-A injections. Using an event-related fMRI design, subjects were presented with light stimuli during two fMRI scans, once before and 4-6 weeks after BoNT-A injection. Light evoked unpleasantness ratings were reported by subjects after each scan. Whole brain blood oxygen level dependent (BOLD) responses to light stimuli were analyzed.

Results

At baseline, all subjects reported unpleasantness with light stimulation (average: 70.8 ± 32.0). Four to six weeks after BoNT-A injection, unpleasantness scores decreased (48.1 ± 33.6), but the change was not significant. On an individual level, 50% of subjects had decreased unpleasantness ratings in response to light stimulation compared to baseline ("responders," n = 6), while 50% had equivalent (n = 3) or increased (n = 3) unpleasantness ("non-responders"). At baseline, several differences were noted between responders and non-responders; responders had higher baseline unpleasantness ratings to light, higher symptoms of depression, and more frequent use of antidepressants and anxiolytics, compared to non-responders. Group analysis at baseline displayed light-evoked BOLD responses in bilateral primary somatosensory (S1), bilateral secondary somatosensory (S2), bilateral anterior insula, paracingulate gyrus, midcingulate cortex (MCC), bilateral frontal pole, bilateral cerebellar hemispheric lobule VI, vermis, bilateral cerebellar crus I and II, and visual cortices. BoNT-A injections significantly decreased light evoked BOLD responses in bilateral S1, S2 cortices, cerebellar hemispheric lobule VI, cerebellar crus I, and left cerebellar crus II. BoNT-A responders displayed activation of the spinal trigeminal nucleus at baseline where non-responders did not.

Discussion

BoNT-A injections modulate light-evoked activation of pain-related brain systems and photophobia symptoms in some individuals with chronic ocular pain. These effects are associated with decreased activation in areas responsible for processing the sensory-discriminative, affective, dimensions, and motor responses to pain.

Testosterone administration enhances the expectation and perception of painful and non-painful somatosensory stimuli

The influence of testosterone on pain perception remains inconsistent in the literature. This randomized, placebo-controlled, double-blind, crossover study investigated the effect of testosterone administration on perception and expectation of electrocutaneous stimulus. Thirty healthy male participants received a single dose of testosterone in one session and a placebo in the other session. For each session, they completed a pain-rating task in which a predictability cue was inserted before a painful or non-painful electocutaneous stimulus delivery, while neural activity was simultaneously recorded by a 64-channel electroencephalographic (EEG) system. Expected and perceived pain ratings, as well as event-related potentials (ERPs) to electocutaneous stimuli and prestimulus EEG oscillatory activities while expecting upcoming electocutaneous stimuli were comprehensively compared between testosterone and placebo sessions. Compared with the placebo session, participants in the testosterone session reported greater pain rating and exhibited greater amplitude of N1 component on ERPs when perceiving both painful and non-painful electrocutaneous stimuli. Mediation analysis revealed that testosterone enhanced the pain-intensity ratings via the N1 response to the electrocutaneous stimulus. Upon viewing the predictability cues after testosterone administration, expected pain intensity increased and spontaneous low-frequency α-oscillation power in the frontal region decreased. These results provide evidence that testosterone enhanced perception and expectation of somatosensory events, and that this was a general effect rather than pain-specific. A plausible explanation for these findings is that testosterone acts to increase vigilance and sustained attention levels, as evidenced by the decreased α-oscillation power. Thus, our findings support a causal role for testosterone in heightening the biological salience of incoming somatosensory information.

Pain and Disability Following Exercise-Induced Injury in Prognostic and Intervention Studies: The Why May Be More Important Than the How

OBJECTIVES

In preclinical prognostic studies, the description of expected outcomes during an informed consent process indicates that the extent of pain and disability experienced and recovery time is unknown. In intervention studies, the consent process suggests that pain and disability will definitely occur and a treatment provided. Our objective was to determine whether study design (prognosis or intervention) was associated with the severity of pain intensity and disability reports from a preclinical model.

MATERIALS AND METHODS

We pooled pain and disability outcomes from prognostic and intervention studies using an exercise-induced muscle injury model of pain. Pain intensity, disability, and fear of pain were collected by validated self-report measures. Pain and disability data were z-transformed for pooled analyses and compared across the study design.

RESULTS

Data from 310 people were included. The primary findings were that self-reported pain intensity and disability were: (1) higher in prognostic studies than in the intervention studies and (2) associated with fear of pain. A secondary finding was that fear of pain was lower in the intervention compared with the prognostic studies.

DISCUSSION

Although there are other possible explanations, we speculate that these results could be related to the uncertainty inherent to providing informed consent for a prognostic study. In light of these findings, we recommend that informed consent language be more carefully considered when pain is induced in a controlled manner. Incorporating informed consent language commonly used in prognostic studies could result in higher pain intensity and disability ratings in studies that use preclinical models to test the efficacy of pain interventions.

Activation of neuronal FLT3 promotes exaggerated sensorial and emotional pain-related behaviors facilitating the transition from acute to chronic pain

Acute pain has been associated with persistent pain sensitization of nociceptive pathways increasing the risk of transition from acute to chronic pain. We demonstrated the critical role of the FLT3- tyrosine kinase receptor, expressed in sensory neurons, in pain chronification after peripheral nerve injury. However, it is unclear whether injury-induced pain sensitization can also promote long-term mood disorders. Here, we evaluated the emotional and sensorial components of pain after a single (SI) or double paw incision (DI) and the implication of FLT3. DI mice showed an anxiodepressive-like phenotype associated with extended mechanical pain hypersensitivity and spontaneous pain when compared to SI mice. Behavioral exaggeration was associated with peripheral and spinal changes including increased microglia activation after DI versus SI. Intrathecal microglial inhibitors not only eliminated the exaggerated pain hypersensitivity produced by DI but also prevented anxiodepressive-related behaviors. Behavioral and cellular changes produced by DI were blocked in Flt3 knock-out animals and recapitulated by repeated intrathecal FL injections in naive animals. Finally, humanized antibodies against FLT3 reduced DI-induced behavioral and microglia changes. Altogether our results show that the repetition of peripheral lesions facilitate not only exaggerated nociceptive behaviors but also induced anxiodepressive disorders supported by spinal central changes that can be blocked by targeting peripheral FLT3.

Factors Associated With Low Procedural Pain Scores Among 1- to 5-Year-Old Patients Undergoing Facial Laceration Repair

OBJECTIVES

Our objectives were to quantify pain experienced by young children undergoing facial laceration repair and identify factors associated with low procedural pain scores.

METHODS

We conducted a prospective cohort study of children's distress among a convenience sample of children aged 1 to 5 years undergoing facial or scalp laceration repair in 2 pediatric emergency departments. We reviewed video recordings and documented pain scores at 15-second intervals using the Face, Leg, Activity, Cry, Consolability-Revised (FLACC-r) scale. We dichotomized FLACC-r into low/high scores (≤3 and >3) to evaluate practice variables.

RESULTS

We included 11,474 FLACC-r observations from 258 procedures in the analysis. Two-thirds of 3- to 5-year-olds completed their laceration repair without the use of restraint, sedation, or anxiolytics. Mean distress scores were low (≤2.5 out of 10) across all procedure phases for 2- to 5-year-old patients. One-year-old patients experienced significantly more distress than their older counterparts (mean ≤4.2 out of 10). Odds of having low FLACC scores (≤3) were greater for patients with an expert clinician (adjusted odds ratio [aOR]: 1.72; 95% confidence interval [CI], 1.05-2.84). Wound infiltration (aOR, 0.35; 95% CI, 0.13-0.93), patient observation of a needle (aOR, 0.21; 95% CI, 0.14-0.33), and restraint (aOR, 0.04; 95% CI, 0.02-0.06) were negatively associated with low FLACC score.

CONCLUSION

The majority of 3- to 5-year-old patients were able to undergo facial laceration repair without restraint, sedation, or anxiolytics and with low mean distress scores. Our findings suggest that children's risk of experiencing moderate and severe distress during facial and scalp laceration repair may be reduced by prioritizing wound closure by expert-level clinicians, ensuring effective lidocaine-epinephrine-tetracaine application, avoiding restraint, and concealing needles from patient view.

Lateral septum-lateral hypothalamus circuit dysfunction in comorbid pain and anxiety

Pain and anxiety comorbidities are a common health problem, but the neural mechanisms underlying comorbidity remain unclear. We propose that comorbidity implies that similar brain regions and neural circuits, with the lateral septum (LS) as a major candidate, process pain and anxiety. From results of behavioral and neurophysiological experiments combined with selective LS manipulation in mice, we find that LS GABAergic neurons were critical for both pain and anxiety. Selective activation of LS GABAergic neurons induced hyperalgesia and anxiety-like behaviors. In contrast, selective inhibition of LS GABAergic neurons reduced nocifensive withdrawal responses and anxiety-like behaviors. This was found in two mouse models, one for chronic inflammatory pain (induced by complete Freund's adjuvant) and one for anxiety (induced by chronic restraint stress). Additionally, using TetTag chemogenetics to functionally mark LS neurons, we found that activation of LS neurons by acute pain stimulation could induce anxiety-like behaviors and vice versa. Furthermore, we show that LS GABAergic projection to the lateral hypothalamus (LH) plays an important role in the regulation of pain and anxiety comorbidities. Our study revealed that LS GABAergic neurons, and especially the LS^GABAergic-LH circuit, are a critical to the modulation of pain and anxiety comorbidities.

Neuroplasticity of pain processing and motor control in CAI patients: A UK Biobank study with clinical validation

Background

Pain plays an important role in chronic ankle instability (CAI), and prolonged pain may be associated with ankle dysfunction and abnormal neuroplasticity.

Purpose

To investigate the differences in resting-state functional connectivity among the pain-related brain regions and the ankle motor-related brain regions between healthy controls and patients with CAI, and explore the relationship between patients' motor function and pain.

Study design

A cross-database, cross-sectional study.

Methods

This study included a UK Biobank dataset of 28 patients with ankle pain and 109 healthy controls and a validation dataset of 15 patients with CAI and 15 healthy controls. All participants underwent resting-state functional magnetic resonance imaging scanning, and the functional connectivity (FC) among the pain-related brain regions and the ankle motor-related brain regions were calculated and compared between groups. The correlations between the potentially different functional connectivity and the clinical questionnaires were also explored in patients with CAI.

Results

The functional connection between the cingulate motor area and insula significantly differed between groups in both the UK Biobank (p = 0.005) and clinical validation dataset (p = 0.049), which was also significantly correlated with Tegner scores (r = 0.532, p = 0.041) in patients with CAI.

Conclusion

A reduced functional connection between the cingulate motor area and the insula was present in patients with CAI, which was also directly correlated with reduction in the level of patient physical activity.

The neurobiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is the most prevalent disorder of brain-gut interactions that affects between 5 and 10% of the general population worldwide. The current symptom criteria restrict the diagnosis to recurrent abdominal pain associated with altered bowel habits, but the majority of patients also report non-painful abdominal discomfort, associated psychiatric conditions (anxiety and depression), as well as other visceral and somatic pain-related symptoms. For decades, IBS was considered an intestinal motility disorder, and more recently a gut disorder. However, based on an extensive body of reported information about central, peripheral mechanisms and genetic factors involved in the pathophysiology of IBS symptoms, a comprehensive disease model of brain-gut-microbiome interactions has emerged, which can explain altered bowel habits, chronic abdominal pain, and psychiatric comorbidities. In this review, we will first describe novel insights into several key components of brain-gut microbiome interactions, starting with reported alterations in the gut connectome and enteric nervous system, and a list of distinct functional and structural brain signatures, and comparing them to the proposed brain alterations in anxiety disorders. We will then point out the emerging correlations between the brain networks with the genomic, gastrointestinal, immune, and gut microbiome-related parameters. We will incorporate this new information into a systems-based disease model of IBS. Finally, we will discuss the implications of such a model for the improved understanding of the disorder and the development of more effective treatment approaches in the future.

Theoretical and methodological approaches in designing, developing, and delivering interventions for oral health behaviour change

Oral health behaviour change interventions are gaining momentum on a global scale. After lagging behind other disciplines, oral health behaviour change is becoming an area of fast and important development. Theories used in medicine and healthcare more generally are now being applied to oral health behaviour change with varying results. Despite the importance of using theories when designing and developing interventions, the variety and variation of theories available to choose from create a series of dilemmas and potential hazards. Some theories, like the COM-B (Capability, Opportunity, Motivation-Behaviour) model, and frameworks, like the Behaviour Change Wheel might represent areas of opportunity for oral health behaviour change interventions with careful consideration vital. Different methodological approaches to intervention development are actively utilized in oral health with a wide host of potential opportunities. The issue of co-designing and co-developing interventions with intended users and stakeholders from the start is an important component for successful and effective interventions, one that oral health behaviour change interventions need to consistently implement. Oral health behaviour change interventions are utilizing technology-based approaches as a major vehicle for intervention delivery and, innovative solutions are implemented across a wide host of oral health behaviour change interventions. With multiple options for designing, developing, and delivering interventions, careful selection of appropriate, user-inclusive, and adaptable approaches is essential. With a lot of available information and evidence from other disciplines, oral health behaviour change interventions need to reflect on lessons learned in other fields whilst also maximizing the potential of the wide variety of theories, frameworks, methodologies, and techniques available at present.

Clinical Neuroimaging of Photophobia in Individuals With Chronic Ocular Surface Pain

PURPOSE

To examine neural mechanisms underlying photophobia in individuals with chronic ocular surface pain by using functional magnetic resonance imaging (fMRI).

DESIGN

Cross-sectional case/control analysis.

METHODS

A total of 16 individuals from the Miami Veterans Affairs eye clinic underwent comprehensive ocular surface evaluations and were surveyed for ocular surface symptoms. Case patients included patients who reported chronic ocular surface pain symptoms and light sensitivity at least most of the time over 1 week. Controls included persons without chronic ocular surface pain who reported no or minimal light sensitivity. All patients viewed light stimuli during 2 fMRI scans, one before and one after topical anesthetic instillation, and rated their level of pain intensity to the stimulus at the end of each scan. Areas of brain activation in response to light stimuli presentation were correlated with pain responses and examined post- vs pre-anesthesia.

RESULTS

Case patients (n = 8) reported higher pain intensity ratings than controls (n = 8) in response to light stimuli during fMRI. Case patient ratings correlated more with light-evoked activation in pain-related areas within the trigeminal brainstem, primary somatosensory cortex (S1), anterior mid-cingulate cortex (aMCC), and insula than in controls. Topical anesthesia led to varying responses in pain ratings among case patients as well as decreased light-evoked activation in S1 and aMCC.

CONCLUSIONS

The trigeminal nociceptive system may contribute to photophobia in individuals with chronic ocular surface pain. We demonstrate modulation of cortical structures in this pathway with topically applied anesthetic to the eyes. Further understanding of modulatory interactions that govern ocular surface pain and photophobia is critical for developing effective, precision-based therapies.

Relationship between the affective dimension of pain and site of the disorder: A cross-sectional study

BACKGROUND

Pain is a complex experience with both sensory and affective dimensions, and the affective dimension can increase the risks of chronic pain development. It is thus critical to identify factors influencing the affective dimension of pain.

OBJECTIVE

This study aimed to identify the relationship between the affective dimension of pain and disorder site (primary pain source).

METHODS

Study participants were recruited from patients referred for physical therapy at an orthopedic outpatient clinic. Pain quality including the affective dimension, disorder site from descriptive medical diagnosis, pain intensity, duration from pain onset, and demographic data, was collected. A multivariable logistic regression model was constructed to analyze the relationship between the affective dimension of pain and the disorder site.

RESULTS

A total of 282 participants were included. Cervical and lumbar spine disorders were significantly associated with an affective dimension of pain compared to limbs disorders when adjusted for age, sex, pain intensity, and duration from the onset in the regression model.

CONCLUSIONS

Regardless of duration from the onset and other confounding factors, disorder site is correlated with the affective dimension of pain. Multidimensional pain assessment is crucial when clinicians evaluate patients with cervical and lumbar spine disorders, even in the acute phase.

Pain in Pets: Beyond Physiology

Animals do not speak a language humans understand, making it easy to believe that they do not experience pain the way humans do. Despite data affirming that companion animals can and do experience pain much as do humans, there remains a gap between companion animal acute pain management knowledge and its execution. Companion animal pain is not simply a physiological issue. Veterinary clinicians can and should embrace the foundational principles of clinical bioethics-respect for autonomy, nonmaleficence, beneficence, and justice-translated from human medicine for the benefit of their patients. By reframing companion animal pain as a bioethical issue, as described in this paper, veterinarians affirm their commitment to closing the gap between what is known and what is done for painful companion animals. This takes pet pain beyond physiology.

A web app-based music intervention reduces experimental thermal pain: A randomized trial on preferred versus least-liked music style

Digital technologies are increasingly being used to strengthen national health systems. Music is used as a management technique for pain. The objective of this study is to demonstrate the effects of a web app-based music intervention on pain. The participants were healthy adults and underwent three conditions: Conditioned Pain Modulation (CPM), Most-Liked Music (MLM) and Least-Liked Music (LLM). The music used is MUSIC CARE©, a web app-based personalized musical intervention ("U" Sequence based on a musical composition algorithm). Thermal pain was measured before starting the 20-min music intervention and after three time points for each music condition: 2.20, 11.30, and 20 min. Mean pain perceptions were significantly reduced under both LLM and MLM conditions. Pain decrease was more important under MLM condition than LLM condition at 2.20 min with a mean difference between both conditions of 9.7 (±3.9) (p = 0.0195) and at 11.30 min [9.2 (±3.3), p = 0.0099]. LLM is correlated with CPM but not MLM, suggesting different mechanisms between LLM and MLM. Musical intervention, a simple method of application, fits perfectly into a multidisciplinary global approach and helps to treat the pain and anxiety disorders of participants. Clinical trial registration: [https://clinicaltrials.gov/ct2/show/NCT04862832], ClinicalTrials.gov [NCT04862832].

The role of catastrophizing in chronic cyclical pelvic pain: A systematic review and meta-analysis

BACKGROUND

Dysmenorrhea (painful menstrual cramps) is one of the most common gynecological complaints in women and girls. Dysmenorrhea may be a condition itself or a result of another medical condition, including endometriosis and chronic pelvic pain. Research examining the relationship between menstrual pain ratings and catastrophizing has produced mixed results.

OBJECTIVE

To review and meta-analyze the relationship between catastrophizing and pain ratings of chronic cyclical pelvic pain.

DESIGN

Cross-sectional, longitudinal, and intervention studies that reported the relationship between menstrual/pelvic pain and catastrophizing were included. Study populations had to include healthy menstruating persons or persons with a condition associated with cyclical pelvic pain including primary dysmenorrhea, endometriosis, and/or chronic pelvic pain.

DATA SOURCES AND METHODS

A systematic search of articles published since 2012 on PubMed, PsychInfo, CINHAL, and Medline was conducted in January and rerun in November of 2022. Search terms included cyclical pelvic pain, dysmenorrhea, endometriosis, pelvic pain, and catastrophizing. Data extraction was completed independently by two extractors and cross-checked for errors. A random-effects meta-regression was used to synthesize the data using restricted maximum likelihood.

RESULTS

Twenty-five studies examining 4,540 participants were included. A random effects model found a meta-correlation between catastrophizing and pain of r = .31 (95% confidence interval: .23-.40) p < .001. Heterogeneity was large and significant (I2 = 84.5%, Q(24) = 155.16, p < .001). Studies that measured general pelvic pain rather than cyclical pelvic pain specifically and those that used multi-item rather than single-item measures of pain had significantly higher correlations. Age and depression did not moderate the relationship between catastrophizing and pain.

CONCLUSION

A systematic review and meta-analysis found that catastrophizing had a small but significant positive association with pain ratings. Patients experiencing cyclical pelvic pain may benefit from interventions targeting the psychological management of pain.

REGISTRATION

This meta-analysis was registered in PROSPERO on 14 January 2022. Registration number: CRD42022295328.

The connections of physical and psychosocial symptoms among patients with terminal illnesses: A network analysis

BACKGROUND

Patients with terminal illnesses have different symptoms. The goal of palliative care is to alleviate the suffering induced by these symptoms. Available research on symptoms has focused on their prevalence or identification of clusters. Little is known about the central symptoms contributing to the maintenance of the whole system of symptoms or the mechanism of influence between symptoms, particularly between physical and psychosocial symptoms.

AIM

The study used network analysis to explore symptom clusters among patients with terminal illnesses and identify the central symptoms, the bridge symptoms, and pathways between physical and psychosocial symptoms.

DESIGN AND SETTING/PARTICIPANTS

This is a retrospective cohort study using baseline symptom assessment of 677 adults with terminal illnesses receiving care from the Integrated Community End-of-Life Care Support Teams.

RESULTS

Three symptom clusters were identified: physical, psychological, and practical clusters. "Weakness or lack of energy" was identified as the crucial symptom affecting the changes of other symptoms, followed by depression and anxiety. Three connections between the psychological and physical symptoms were identified: anxiety-pain, depression-constipation, and perceived family anxiety-poor appetite pathways. Pathways of practical concern-peace and practical concern-depression were indicated between practical and psychological symptoms.

CONCLUSIONS

This study is the first of its kind to investigate the connections and mechanism of influence between symptoms among patients with terminal illnesses. It offers clear pathways for intervention with the most influential symptoms of weakness, anxiety, and depression.

The Use of Virtual Reality to Reduce Pain and Anxiety in Surgical Procedures of the Oral Cavity: A Scoping Review

PURPOSE

Virtual reality (VR) is considered a nonpharmacological intervention to manage pain and anxiety for different procedures. We aimed to review the literature about the role of VR in reducing pain and anxiety in surgical procedures performed in the oral cavity.

METHODS

A literature review was conducted using Medline and Embase with no restrictions on language or publication date. Our inclusion criteria were articles related to the use of VR to manage perioperative pain and anxiety on procedures in the oral cavity.

RESULTS

Twenty-seven articles met the inclusion criteria. The number of publications increased significantly from 2 studies between 2000-2010 to 25 between 2011 and 2021. Of the 27 included studies, 22 (81.4%) studied patients undergoing dental procedures, and 5 (18.5%) in oral and maxillofacial surgery (OMS). There was heterogeneity in the VR software used in the different studies. Thirteen studies (41.9%) evaluated self or observational assessments of pain and anxiety. Pain alone was evaluated in 9 studies (29%) and anxiety alone in 8 studies (25.8%). Also, 6 studies (19.3%) evaluated physiological parameters such as heart rate and respiratory rate as objective measures of pain and anxiety. In oral surgery studies, VR was effective at reducing acute pain, fear, and anxiety levels.

CONCLUSIONS

There is a paucity of research in OMS compared to dentistry. Given that this specialty involves highly stimulating and anxiety-provoking procedures, OMS could benefit from VR intervention for improved patient care.

Mechanical Affective Touch Therapy for Anxiety Disorders: Effects on Resting State Functional Connectivity

OBJECTIVES

Mechanical Affective Touch Therapy (MATT) is a safe, novel form of noninvasive peripheral nerve stimulation. Although mechanical stimulation activates nerves, we know little about its impact on psychiatric symptoms and their underlying cortical mechanisms. We examined the effects of open-label MATT on resting state functional connectivity (RSFC) and its relationship with anxiety and affective symptomatology (clinical results in separate report).

MATERIALS AND METHODS

A total of 22 adults with an Axis I anxiety disorder were recruited from the community. After two initial sessions assisted by research staff, participants self-administered 20-minute sessions of MATT at home at least twice daily for four weeks. Self-report measures of mood and anxiety severity were collected at baseline, two weeks, and four weeks. Resting state functional magnetic resonance imaging was collected before the initial MATT session (n = 20), immediately after the first session (n = 18), and following four weeks of MATT (n = 14). Seed-based whole-brain functional connectivity analyses identified brain connectivity patterns correlated with responsiveness to MATT. Seeds were based on Neurosynth meta-analytic maps for "anxiety" and "pain" given MATT's hypothesized role in anxiety symptom amelioration and potential mechanism of action through C-tactile afferents, which play an important role in detecting pain and its affective components. Connectivity results were corrected for multiple comparisons (voxel p < 0.005, cluster p-FDR < 0.05).

RESULTS

Baseline RSFC is predictive of symptom improvement with chronic MATT. Acute increases in insula connectivity were observed between mid-cingulate cortex and postcentral motor regions following the first MATT session. Chronic MATT was associated with increased connectivity between pain and anxiety regions of interest (ROIs) and posterior default mode network (DMN) regions involved in memory and self-reflection; the connectivity changes correlated with decreases in stress and depression symptoms.

CONCLUSIONS

MATT is associated with alterations in RSFC in the DMN of anxiety disorder patients both acutely and after long-term administration, and baseline RSFC is predictive of post-treatment symptom improvement.

The Effect of Preoperative Oral Melatonin on Postoperative Pain after Lumbar Disc Surgery: A Double-Blinded Randomized Clinical Trial

Background

Despite advances in surgical and anesthesiology techniques, many patients continue to experience postoperative pain after lumbar disc surgeries. The aim of this study was to investigate the effect of preoperative oral melatonin on the severity of postoperative pain after lumbar laminectomy/discectomy.

Methods

In this double blinded randomized controlled clinical trial 80 patients undergoing an elective mini-open microdiscectomy surgery at Imam Khomeini educational hospital in Sari, Iran, were selected and randomly assigned into one of four groups. Patients in group A, B, C, and D received 3, 5 and 10 mg melatonin or placebo tablets one hour before surgery, respectively. Using the visual analogue scale (VAS) the severity of pain, nausea and vomiting, pruritus, and use of narcotics were assessed immediately after surgery and before leaving the post-anesthesia care unit, 6, 12 and 24 hours postoperatively.

Results

In all three groups receiving melatonin at all three different doses, postoperative pain was significantly less than the placebo group (P<0.01). There were no statistically significant differences in postoperative pain level between the three groups receiving melatonin (P>0.05). The amount of opioid received by the patients within 24 hours after surgery had statistically significant differences within the groups (P=0.043, F=2.58). The results of post hoc analysis in terms of postoperative pain intensity showed statistically significant differences between the two groups receiving melatonin at a dose of 5 mg and the placebo group (P=0.04). No serious side effects reported in four groups.

Conclusion

The use of oral melatonin with a dose of 5 mg, 1 hour before the surgery as an inexpensive method can effectively reduce pain intensity as well as the amount opioid use after lumbar laminectomy and discectomy.

Virtual Reality Animal Rescue World: Pediatric virtual reality analgesia during just noticeable pressure pain in children aged 2-10 years old (crossover design)

BACKGROUND AND AIMS

Excessive pain during medical procedures is a worldwide medical problem. Most scald burns occur in children under 6, who are often undermedicated. Adjunctive Virtual Reality (VR) distraction has been shown to reduce pain in children aged 6-17, but little is known about VR analgesia in young children. This study tests whether desktop VR (VR Animal Rescue World) can reduce the just noticeable pressure pain of children aged 2-10.

METHODS

A within-subject repeated measures design was used. With treatment order randomized, each healthy volunteer pediatric participant underwent brief cutaneous pressure stimuli under three conditions: (1) no distraction, (2) a verbal color naming task (no VR), and (3) a large TV-based desktop VR distraction. A hand-held Wagner pressure pain stimulation device was used to generate just noticeable pain sensations. Participants indicated when a steadily increasing non-painful pressure stimulus first turned into a painful pressure sensation (just noticeable pain).

RESULTS

A total of 40 healthy children participated (43% aged 2-5 years; and 57% aged 6-10 years). Compared to the no distraction condition, the 40 children showed significant VR analgesia (i.e., a significant reduction in pain sensitivity during the VR Animal Rescue World condition), t(39) = 9.83, p < 0.001, SD = 6.24. VR was also significantly more effective at reducing pain sensitivity vs. an auditory color naming task, t(39) = 5.42, p < 0.001, SD = 5.94. The subset of children aged 2-5 showed significant reductions in pain during VR. Children under 6 showed greater sensitivity to pain during no distraction than children aged 6-10.

CONCLUSION

During no distraction, children under 6 years old were significantly more sensitive to pain than children aged 6-10. Virtual reality (VR) significantly reduced the "just noticeable" pressure pain sensitivity of children in both age groups.

Young female participants show blunted placebo effects associated with blunted responses to a cue predicting a safe stimulus in the right dorsolateral prefrontal cortex

Discrimination of cues predicting non-nociceptive/nociceptive stimuli is essential for predicting whether a non-painful or painful stimulus will be administered and for eliciting placebo/nocebo (pain reduction/pain enhancement) effects. Dysfunction of the neural system involved in placebo effects has been implicated in the pathology of chronic pain, while female sex is one of the important risk factors for development of chronic pain in young adults. The dorsolateral prefrontal cortex (dl-PFC) is suggested to be involved in placebo effects and is sensitive to sex and age. In this study, to examine the neural mechanisms by which sex and age alter placebo and nocebo effects, we analyzed cerebral hemodynamic activities in the dl-PFC in different sex and age groups during a differential conditioning task. During the training session, two different sounds were followed by low- and high-intensity electrical shocks. In the following recording session, electrical shocks, the intensity of which was mismatched to the sounds, were occasionally administered to elicit placebo and nocebo effects. In young female participants, both placebo effects and hemodynamic responses to the conditioned sounds in the right dl-PFC were significantly lower than those in elderly female participants, while there were no age differences in male participants. The hemodynamic responses to the sound paired with the safe stimulus in the right dl-PFC were significantly correlated with placebo effects, except in the young female group. These results suggest that blunted placebo effects in the young female participants are ascribed to blunted responses to the sound associated with the safe stimulus in the right dl-PFC, and that sex- and age-related factors may alter the responsiveness of the right dl-PFC to associative cues predicting a safe stimulus.

Disrupted Spontaneous Neural Activity and Its Interaction With Pain and Emotion in Temporomandibular Disorders

Background and Purpose

Temporomandibular disorders (TMD), especially pain-related TMD, are closely related to social and psychological factors. We aimed to measure changes in spontaneous brain activity and its related functional connectivity (FC), as well as FC characteristics within the mood-regulating circuits (MRC) in TMD patients by resting-state functional magnetic resonance imaging (RS-fMRI), and to analyze the relationship between these parameters and emotional symptoms.

Materials and Methods

Twenty-one adult TMD patients and thirty demographically matched healthy controls (HCs) underwent clinical scale evaluation and RS-fMRI scanning. After processing RS-fMRI data, the values of the amplitude of low-frequency fluctuation (ALFF) between the two groups were compared. Regions with abnormal ALFF values were selected as areas of interest (ROIs) to compare the differences of whole-brain seed-based FC between groups. The FCs between regions within MRC were also analyzed and compared. In addition, the relationships between RS-fMRI characteristics and pain and mood were explored by correlation and mediation analyses.

Results

Compared with HCs, TMD patients showed increased ALFF in the right parahippocampal gyrus (PHG), the right supplementary motor area, and the bilateral precentral gyrus, with decreased ALFF in the right cerebelum_crus2. Patients showed enhanced right PHG-related FC in the vermis and posterior cingulate cortex, orbitofrontal cortex (OFC)-related FC in the striatal-frontal regions, while decreased dorsolateral prefrontal cortex-related FC in the amygdala. In TMD patients, ALFF values in the right PHG and FC values between the right PHG and the vermis were positively correlated with depressive symptoms. Abnormal FCs in the left striatal-orbitofrontal pathway were correlated with pain and depressive symptoms. More importantly, mediation analysis revealed that chronic pain mediates the relationship between FC of right PHG with vermis and depressive symptoms, and abnormal FC in the left striatal-orbitofrontal pathway can mediate the association between pain and depressive symptoms.

Conclusion

TMD patients have dysregulated spontaneous activity and FC in the default mode network, sensorimotor network and pain-related regions, as well as dysfunction of the fronto-striatal-limbic circuits. The development of negative emotions in TMD may be related to the dysfunction of components within the reward system (especially hippocampus complex, OFC, striatum) due to chronic pain.

The Effect of Binaural Beat Audio on Operative Pain and Anxiety in Cataract Surgery under Topical Anaesthesia: A Randomized Controlled Trial

Background: The aim of this paper was to examine the analgesic and anxiolytic effects of binaural beat audio in patients undergoing cataract surgery under topical anaesthesia. Methods: This was a prospective, randomized controlled trial of 61 patients undergoing cataract surgery under topical anaesthesia. They were divided into two research conditions; the binaural beat audio group, and a sham-control group (ear phones with no music). Patients completed the State-Trait Anxiety Inventory questionnaire (STAI), and their blood pressure (BP) and heart rate (HR) were measured pre- and post-intervention. Intraoperative pain levels were ascertained using a visual analog scale (VAS) completed immediately after the surgery. Results: The binaural beat group had significantly lower pain scores (p < 0.001), HR (p < 0.001), diastolic BP (p = 0.003), mean arterial pressure (p = 0.007) and anxiety (p = 0.009) than the control group. Within the binaural beat group, subjects experienced a statistically significant reduction in HR (p = 0.004) and anxiety (p < 0.001) levels compared to baseline values, while all parameters, except anxiety, increased significantly in the control group. Conclusions: Binaural beat audio decreases operative pain and anxiety in cataract surgery under topical anaesthesia. It may have additional benefits in modulating the tachycardic response to stress.

The influence of a manipulation of threat on experimentally-induced secondary hyperalgesia

Pain is thought to be influenced by the threat value of the particular context in which it occurs. However, the mechanisms by which a threat achieves this influence on pain are unclear. Here, we explore how threat influences experimentally-induced secondary hyperalgesia, which is thought to be a manifestation of central sensitization. We developed an experimental study to investigate the effect of a manipulation of threat on experimentally-induced secondary hyperalgesia in 26 healthy human adults (16 identifying as female; 10 as male). We induced secondary hyperalgesia at both forearms using high-frequency electrical stimulation. Prior to the induction, we used a previously successful method to manipulate threat of tissue damage at one forearm (threat site). The effect of the threat manipulation was determined by comparing participant-rated anxiety, perceived threat, and pain during the experimental induction of secondary hyperalgesia, between the threat and control sites. We hypothesized that the threat site would show greater secondary hyperalgesia (primary outcome) and greater surface area (secondary outcome) of induced secondary hyperalgesia than the control site. Despite a thorough piloting procedure to test the threat manipulation, our data showed no main effect of site on pain, anxiety, or threat ratings during high-frequency electrical stimulation. In the light of no difference in threat between sites, the primary and secondary hypotheses cannot be tested. We discuss reasons why we were unable to replicate the efficacy of this established threat manipulation in our sample, including: (1) competition between threats, (2) generalization of learned threat value, (3) safety cues, (4) trust, and requirements for participant safety, (5) sampling bias, (6) sample-specific habituation to threat, and (7) implausibility of (sham) skin examination and report. Better strategies to manipulate threat are required for further research on the mechanisms by which threat influences pain.

Increased gray matter following mindfulness-based stress reduction in breast cancer survivors with chronic neuropathic pain: preliminary evidence using voxel-based morphometry

PURPOSE

To investigate the impact of Mindfulness-Based Stress Reduction (MBSR) on gray matter volume (GMV) in female breast cancer survivors who suffer from chronic neuropathic pain (CNP).

METHODS

Voxel-based morphometry (VBM) was used to explore differences in GMV in 13 MBSR trainees and 10 waitlisted controls, with MRI scans and self-report measures completed pre- and post-8 weeks of training.

RESULTS

Compared to controls, the MBSR group had greater GMV in the angular gyrus and middle frontal gyrus post-training. The MBSR group's right parahippocampal gyrus GMV increased from pre- to post-training, whereas the control group's left parahippocampal gyrus, precuneus, middle temporal gyrus, and right cuneus GMV decreased over the same time period. Pain interference was significantly reduced and mindfulness was significantly increased following MBSR for the intervention group only.

CONCLUSIONS

MBSR was associated with increased GMV in regions where GMV is known to (1) increase with mindfulness and reorientation of attention and (2) decrease with the experience of chronic neuropathic pain. By contrast, the control group's decreases in GMV may be due to the negative effects of CNP which potentially may be reduced with MBSR, though further research is needed.

IMPLICATIONS FOR CANCER SURVIVORS

Given the poor efficiency of pharmacotherapies in a high percentage of women with neuropathic pain following breast cancer treatment, adjunct methods are required. MBSR may affect the brain to help alter attention and perception of pain, thus playing a potentially important role in the path to wellness for breast cancer survivors.

Anxiety and hippocampal neuronal activity: Relationship and potential mechanisms

The hippocampus has been implicated in modulating anxiety. It interacts with a variety of brain regions, both cortical and subcortical areas regulating emotion and stress responses, including prefrontal cortex, amygdala, hypothalamus, and the nucleus accumbens, to adjust anxiety levels in response to a variety of stressful conditions. Growing evidence indicates that anxiety is associated with increased neuronal excitability in the hippocampus, and alterations in local regulation of hippocampal excitability have been suggested to underlie behavioral disruptions characteristic of certain anxiety disorders. Furthermore, studies have shown that some anxiolytics can treat anxiety by altering the excitability and plasticity of hippocampal neurons. Hence, identifying cellular and molecular mechanisms and neural circuits that regulate hippocampal excitability in anxiety may be beneficial for developing targeted interventions for treatment of anxiety disorders particularly for the treatment-resistant cases. We first briefly review a role of the hippocampus in fear. We then review the evidence indicating a relationship between the hippocampal activity and fear/anxiety and discuss some possible mechanisms underlying stress-induced hippocampal excitability and anxiety-related behavior.

Music to My Senses: Functional Magnetic Resonance Imaging Evidence of Music Analgesia Across Connectivity Networks Spanning the Brain and Brainstem

Pain is often viewed and studied as an isolated perception. However, cognition, emotion, salience effects, and autonomic and sensory input are all integrated to create a comprehensive experience. Music-induced analgesia has been used for thousands of years, with moderate behavioural effects on pain perception, yet the neural mechanisms remain ambiguous. The purpose of this study was to investigate the effects of music analgesia through individual ratings of pain, and changes in connectivity across a network of regions spanning the brain and brainstem that are involved in limbic, paralimbic, autonomic, cognitive, and sensory domains. This is the first study of its kind to assess the effects of music analgesia using complex network analyses in the human brain and brainstem. Functional MRI data were collected from 20 healthy men and women with concurrent presentation of noxious stimulation and music, in addition to control runs without music. Ratings of peak pain intensity and unpleasantness were collected for each run and were analysed in relation to the functional data. We found that music alters connectivity across these neural networks between regions such as the insula, thalamus, hypothalamus, amygdala and hippocampus (among others), and is impacted by individual pain sensitivity. While these differences are important for how we understand pain and analgesia, it is essential to note that these effects are variable across participants and provide moderate pain relief at best. Therefore, a therapeutic strategy involving music should use it as an adjunct to pain management in combination with healthy lifestyle changes and/or pharmaceutical intervention.

Hippocampus mediates nocebo impairment of opioid analgesia through changes in functional connectivity

The neural mechanisms underlying placebo analgesia have attracted considerable attention over the recent years. In contrast, little is known about the neural underpinnings of a nocebo-induced increase in pain. We previously showed that nocebo-induced hyperalgesia is accompanied by increased activity in the hippocampus that scaled with the perceived level of anxiety. As a key node of the neural circuitry of perceived threat and fear, the hippocampus has recently been proposed to coordinate defensive behaviour in a context-dependent manner. Such a role requires close interactions with other regions involved in the detection of and responses to threat. Here, we investigated the functional connectivity of the hippocampus during nocebo-induced hyperalgesia. Our results show an increase in functional connectivity between hippocampus and brain regions implicated in the processing of sensory-discriminative aspects of pain (posterior insula and primary somatosensory/motor cortex) as well as the periaqueductal gray (PAG). This nocebo-induced increase in connectivity scaled with an individual's increase in anxiety. Moreover, hippocampus connectivity with the amygdala was negatively correlated with the pain intensity reported during nocebo hyperalgesia relative to the placebo condition. Our findings suggest that the hippocampus links nocebo-induced anxiety to a heightened responsiveness to nociceptive input through changes in its crosstalk with pain-modulatory brain areas.