Hypersensitivity and hyperalgesia in somatoform pain disorders

Mirror Therapy in Patients with Somatoform Pain Disorders-A Pilot Study

Patients with chronic pain report reduced quality of life and high symptom burden while often responding insufficiently to treatment options. Mirror therapy has been proven to be effective in treating phantom limb pain and other conditions such as CRPS. This study was designed to investigate the efficacy of mirror therapy in patients with somatoform pain disorders on symptom severity and associated physiological parameters. Fifteen patients with persistent somatoform pain disorder (F45.40) or chronic pain disorder with somatic and psychological factors (F45.41) participated and received four weeks of tablet-based mirror therapy. Symptom severity was measured with established questionnaires, and their thermal detection, pain thresholds, and heart rate variability (HRV) were also assessed. After mirror therapy, pain intensity was reduced (z = -2.878, p = 0.004), and pain thresholds for cold stimuli were also diminished, i.e., the subjects became more sensitive to cold stimuli (z = -2.040, p = 0.041). In addition, a reduction of absolute power in the low-frequency band of HRV (t(13) = 2.536, p = 0.025) was detected. These findings indicate that this intervention may reduce pain intensity and modulate associated physiological parameters. As these results are limited by several factors, e.g., a small sample size and no control group, they should be validated in further studies investigating this novel intervention in these patients.

War experiences and relationship problems predict pain sensitivity cross-sectionally among patients with chronic primary pain

BACKGROUND

Most patients suffering from chronic pain are more susceptible to pain and pressure due to higher pain sensitivity. Since psychosocial factors play a central role in developing and maintaining chronic pain, investigating associations between pain sensitivity and psychosocial stressors promises to advance the biopsychosocial understanding of chronic pain.

OBJECTIVES

We aimed to replicate Studer et al.'s (2016) findings about associations of psychosocial stressors with pain sensitivity in a new sample of patients with chronic primary pain (ICD-11, MG30.0).

METHODS

A pain provocation test was used on both middle fingers and earlobes to assess pain sensitivity among 460 inpatients with chronic primary pain. Potentially life-threatening accidents, war experiences, relationship problems, certified inability to work, and adverse childhood experiences were assessed as potential psychosocial stressors. Structural equation modeling was used to investigate associations between psychosocial stressors and pain sensitivity.

RESULTS

We partially replicated Studer et al.'s findings. Similar to the original study, patients with chronic primary pain showed enhanced pain sensitivity values. Within the investigated group, war experiences (β = 0.160, p < .001) and relationship problems (β = 0.096, p = .014) were associated with higher pain sensitivity. In addition, the control variables of age, sex, and pain intensity also showed a predictive value for higher pain sensitivity. Unlike Studer et al., we could not identify a certified inability to work as a predictor of higher pain sensitivity.

CONCLUSIONS

This study showed that beyond age, sex, and pain intensity, the psychosocial stressors of war experiences and relationship problems were associated with higher pain sensitivity.

Interoceptive accuracy and bias in somatic symptom disorder, illness anxiety disorder, and functional syndromes: A systematic review and meta-analysis

Somatic symptom disorder, illness anxiety disorder, and functional syndromes are characterized by burdensome preoccupation with somatic symptoms. Etiological models propose either increased interoceptive accuracy through hypervigilance to the body, or decreased and biased interoception through top-down predictions about sensory events. This systematic review and meta-analysis summarizes findings of 68 studies examining interoceptive accuracy and 8 studies examining response biases in clinical or non-clinical groups. Analyses yielded a medium population effect size for decreased interoceptive accuracy in functional syndromes, but no observable effect in somatic symptom disorder and illness anxiety disorder. The overall effect size was highly heterogeneous. Regarding response bias, there was a small significant effect in somatic symptom disorder and illness anxiety disorder. Our findings strengthen the notion of top-down factors that result in biased rather than accurate perception of body signals in somatic symptom disorder and illness anxiety disorder.

Guilt is effectively induced by a written auto-biographical essay but not reduced by experimental pain

Introduction

The aim of the present study was (1) to validate the method of guilt-induction by means of a written auto-biographical essay and (2) to test whether experimental pain is apt to alleviate the mental burden of guilt, a concept receiving support from both empirical research and clinical observation.

Methods

Three independent groups of healthy male participants were recruited. Group allocation was not randomized but within group pain/sham administration was counterbalanced over the two test-days. Groups were tested in the following consecutive order: Group A: guilt induction, heat-pain/sham, N = 59; Group B: guilt induction, cold-pressure-pain/sham, N = 43; Group C: emotionally neutral induction, heat-pain/sham, N = 39. Guilt was induced on both test-days in group A and B before pain/sham administration. Visual analog scale (VAS) guilt ratings immediately after pain/sham stimulation served as the primary outcome. In a control group C the identical heat-pain experiment was performed like in group A but a neutral emotional state was induced.

Results

A consistently strong overall effect of guilt-induction (heat-pain: p &lt; 0.001, effect size r = 0.71; CPT-pain p &lt; 0.001, r = 0.67) was found when compared to the control-condition (p = 0.25, r = 0.08). As expected, heat- and cold-pressure-stimuli were highly painful in all groups (p &lt; 0.0001, r = 0.89). However, previous research supporting the hypothesis that pain is apt to reduce guilt was not replicated.

Conclusion

Although guilt-induction was highly effective on both test-days no impact of pain on behavioral guilt-ratings in healthy individuals could be identified. Guilt induction per se did not depend on the order of testing. The result questions previous experimental work on the impact of pain on moral emotions.

Are Anxiety and Depression Taking Sides with Knee-Pain in Osteoarthritis?

INTRODUCTION

Total knee arthroplasty (TKA) bears a potential of rendering patients unsatisfied with the operation as a result of negative affectivity related to osteoarthritis and TKA. Not only is pain a lateralized experience, but negative affect and other psychosomatic correlates of pain might also be processed on grounds of lateralization. Lateralization in this context is likely linked to the amygdalae, which display differential left/right patterns of association with psychopathology. What is noteworthy is that osteoarthritis itself is linked not only to negative effects but also to childhood abuse.

METHOD

The present study tests lateralization of psychosomatic correlates of knee-pain using the brief symptom inventory-18 (BSI-18), the dissociative experiences scale (FDS-20), the pain catastrophizing scale (PCS), the Tampa scale of kinesiophobia (TSK), the childhood trauma screener (CTS) and WOMAC. More precisely, we were interested in predicting the side of operations by means of the above-mentioned constructs using binary logistic regression, based on 150 participants (78 left knees) awaiting TKA for knee-osteoarthritis.

RESULTS

Somatization (p = 0.003), childhood abuse (p = 0.04) and pain-catastrophizing (p = 0.04) predicted operations on the right side. Anxiety (p = 0.001) and kinesiophobia (p = 0.002) predicted operations on the left side.

CONCLUSIONS

Knee-pain may be differentially modulated by its psychosomatic correlates as a result of lateralization and corresponding patterns of psychosomatic reagibility.

Das Fibromyalgiesyndrom aus der psychosomatischen Perspektive: Ein Überblick

Das Fibromyalgiesyndrom (FMS) wird im psychosomatischen Kontext als stressinduzierte Schmerzerkrankung durch eine Sensibilisierung der zentralnervösen schmerzverarbeitenden Systeme verstanden. Das FMS zeigt hohe Komorbiditäten mit psychischen bzw. psychosomatischen Störungen wie Depression, Angststörungen, somatoformen Störungen und Persönlichkeitsstörungen. Biografisch frühe Stresserfahrungen und Traumatisierungen wie körperlicher oder sexueller Missbrauch in der Kindheit bilden eine Vulnerabilität für die spätere Entwicklung eines FMS. Die Gruppe der FMS-Patient/innen ist hinsichtlich der pathophysiologischen Entstehungswege heterogen, weshalb eine mechanismenbasierte Differenzierung von Subgruppen sinnvoll erscheint. Typische Teufelskreise der Chronifizierung des FMS werden beschrieben und die Wichtigkeit einer gelingenden Arzt-Patient/in-Beziehung herausgestellt. Schwergegradgestuftes Vorgehen und Kommunikationsstrategien werden am Fallbeispiel dargestellt.

The relationship of cortical activity induced by pain stimulation with clinical and cognitive features of somatic symptom disorder: A controlled functional near infrared spectroscopy study

OBJECTIVE

The neurobiological correlates of Somatic Symptom Disorder (SSD) introduced in the DSM-5 has been the focus of a limited investigation. We aimed to examine the cortical response to painful stimuli and its relationship to symptom severity as well as cognitive and psychological characteristics in proposed models of somatoform disorders.

METHODS

We measured hemodynamic responses by 52-channel functional near-infrared spectroscopy. We compared the cortical response to painful stimuli in index patients with SSD (N = 21) versus age, and gender matched healthy control subjects (N = 21). We used brush stimulation as the control condition. We analyzed the relationship of cortical activity with SSD symptom severity as well as somatosensory amplification (SSA), alexithymia, dysfunctional illness behaviour, worry, and neuroticism.

RESULTS

Patients with SSD had higher somatic symptom severity, SSA, alexithymia, neuroticism, illness-related worry, and behaviour. Somatic symptom severity was predicted by a model including SSA and subjective feeling of pain in the index patients. Activity in the left-angular and right-middle temporal gyri was higher in the SSD subjects than the controls during pain stimulation. Positive correlations were detected between mean pain threshold levels and left middle occipital gyrus activity, as well as between SSA-scores and right-angular gyrus activity during pain condition in the index patients with SSD.

CONCLUSION

We present the first evidence that representation of pain in terms of cortical activity is different in subjects with SSD than healthy controls. SSA has functional neuroanatomic correlates and predicts symptom severity in SSD and therefore is involved as a valid intermediate phenotype in SSD pathophysiology.

Age and Gender as Factors of Pressure Sensitivity of Pain-Free Persons: Are They Meaningful?

Purpose

Prior findings suggest that women and elderly persons are more sensitive to pressure than men and younger persons; however, the magnitudes of these differences are substantially inconsistent. We answered the question whether the higher sensitivity of women and elderly persons is quantitatively meaningful. Specifically, we investigated if it is large enough to hamper the diagnosis, classification and follow-up of pain conditions by clinicians.

Materials and Methods

From each age stratum (18–20, 21–30, 31–40, 41–50, 51–60, 61–70, 71–80, and >80 years), 40 pain-free women and 40 pain-free men were recruited. They rated the intensity of pressure of ten Newtons over ten seconds on an analogue zero to ten rating scale. The pressure was applied on their middle fingers and ear lobes with a threshold algometer. Centile curves visualized the sex- and age-dependent fluctuation of pressure sensitivity.

Results

Over the entire age range from 20 to 80 years, the median curves fluctuated within the interval of less than two points. The distance between the median curves of men and women was also less than two points. On the average, the median difference was half a point on the finger (p = 0.249) and the ear lobe (p = 0.083).

Conclusion

Less than two points is below the minimal clinically important difference for a zero to ten analogue pain rating scale; differences smaller than one point are even below the resolution of the scale. Sex differences and age fluctuations of pressure sensitivity are negligible.

The Role of Descending Pain Modulation in Chronic Primary Pain: Potential Application of Drugs Targeting Serotonergic System

Chronic primary pain (CPP) is a group of diseases with long-term pain and functional disorders but without structural or specific tissue pathologies. CPP is becoming a serious health problem in clinical practice due to the unknown cause of intractable pain and high cost of health care yet has not been satisfactorily addressed. During the past decades, a significant role for the descending pain modulation and alterations due to specific diseases of CPP has been emphasized. It has been widely established that central sensitization and alterations in neuroplasticity induced by the enhancement of descending pain facilitation and/or the impairment of descending pain inhibition can explain many chronic pain states including CPP. The descending serotonergic neurons in the raphe nuclei target receptors along the descending pain circuits and exert either pro- or antinociceptive effects in different pain conditions. In this review, we summarize the possible underlying descending pain regulation mechanisms in CPP and the role of serotonin, thus providing evidence for potential application of analgesic medications based on the serotonergic system in CPP patients.

Rethinking the criteria for fibromyalgia in 2019: the ABC indicators

PURPOSE

Diagnostic criteria for fibromyalgia have been subject to debate and controversy for many years. The preliminary diagnostic criteria introduced in 2010 and 2011 have been criticized for different reasons, including questionable diagnostic specificity and a lack of an etiopathogenetic foundation. The "ABC indicators" presented in this study reflect a further development of the 2011 criteria and refer to (A) algesia, (B) bilateral, axial-symmetric pain distribution, and (C) chronic distress.

PATIENTS AND METHODS

We compared the diagnostic performance of the ABC indicators with that of the 2011 criteria by analyzing the data of 409 inpatients with chronic functional pain divided into two subgroups of pain patients: Those with whole-body pain and those with pain not involving the whole body. Under the premise that FM phenotypically represents a whole-body pain disorder, sensitivity, specificity, correct classification and diagnostic odds ratios were calculated.

RESULTS

The 2011 criteria demonstrated a specificity of 68.1%, a sensitivity of 75.5%, a correct classification of 71.0% and a diagnostic odds ratio of 6.56 (CI: 4.17-10.31). The ABC indicators achieved a specificity of 88.3%, a sensitivity of 62.3%, a correct classification of 78.6%, and a diagnostic odds ratio of 12.47 (CI: 7.30-21.28).

CONCLUSION

The ABC fibromyalgia indicators demonstrated better specificity, lower sensitivity, and better overall diagnostic effectiveness than the original 2011 criteria.

Hyperexcitability of Cortical Oscillations in Patients with Somatoform Pain Disorder: A Resting-State EEG Study

Patients with somatoform pain disorder (SPD) suffer from somatic pain that cannot be fully explained by specific somatic pathology. While the pain experience requires the integration of sensory and contextual processes, the cortical oscillations have been suggested to play a crucial role in pain processing and integration. The present study is aimed at identifying the abnormalities of spontaneous cortical oscillations among patients with SPD, thus for a better understanding of the ongoing brain states in these patients. Spontaneous electroencephalography data during a resting state with eyes open were recorded from SPD patients and healthy controls, and their cortical oscillations as well as functional connectivity were compared using both electrode-level and source-level analysis. Compared with healthy controls, SPD patients exhibited greater resting-state alpha oscillations (8.5-12.5 Hz) at the parietal region, as reflected by both electrode-level spectral power density and exact low-resolution brain electromagnetic tomography (eLORETA) cortical current density. A significant correlation between parietal alpha oscillation and somatization severity was observed in SPD patients, after accounting for the influence of anxiety and depression. Functional connectivity analysis further revealed a greater frontoparietal connectivity of the resting-state alpha oscillations in SPD patients, which was indexed by the coherence between pairs of electrodes and the linear connectivity between pairs of eLORETA cortical sources. The enhanced resting-state alpha oscillation in SPD patients could be relevant with attenuated sensory information gating and excessive integration of pain-related information, while the enhanced frontoparietal connectivity could be reflecting their sustained attention to bodily sensations and hypervigilance to somatic sensations.

Altered Brain Functional Hubs and Connectivity Underlie Persistent Somatoform Pain Disorder

This study investigated the degree of brain functional impairment in persistent somatoform pain disorder (PSPD) by examining changes in the patterns of brain functional hubs. Resting-state functional magnetic resonance imaging was performed in 21 PSPD patients with headache as the main symptom and 17 sex- and age-matched healthy controls. Degree centrality (DC) analysis as well as the connectivity among these hubs by functional connectivity (FC) analysis and Granger causality analysis (GCA) were performed to characterize abnormal brain networks in PSPD (Gaussian random field corrected: P < 0.001, Z > 3.09). The relationships between DC and connectivity and clinical parameters were also examined. DC values in the bilateral inferior occipital gyrus (IOG), bilateral calcarine fissure (CAL), and left paracentral lobule (PCL) and FC values of right IOG–left CAL, right IOG–right CAL, right IOG–left IOG, left CAL–right CAL, left CAL–left IOG, left CAL–left PCL, right CAL–left PCL, and left IOG–left PCL were lower in PSPD patients as compared to controls. A negative causal effect from the left CAL to the left paracentral lobule and a positive effect from the right CAL to the right IOG were observed in PSPD patients. Abnormal DC, FC, and signed-path coefficients in PSPD patients were negatively correlated with self-rating anxiety and depression scale scores. These results indicate that altered functional hubs and connectivity patterns in the somatosensory cortex may reflect emotional disturbance in PSPD patients.

[Influence of early childhood stress exposure and traumatic life events on pain perception]

Adult pain perception is influenced substantially by interactions between mind, body, and social environment during early life. Early stress exposure and traumatic life events induce powerful psychophysical stress reactions that exert multiple neurofunctional processes. This has significant implications for pain perception and pain processing. As part of this review, the complex relationships between traumatic stress experiences and associated psychobiological mechanisms of chronic pain will be discussed. Based on selected studies, psychophysiological findings are presented and possible underlying mechanisms are discussed. The article concludes with a discussion of potential implications for treatment.

Altered Neural Correlates of Emotion Associated Pain Processing in Persistent Somatoform Pain Disorder: An fMRI Study

Patients with persistent somatoform pain disorder (PSPD) suffer from long-term pain and emotional conflicts. Recently, accumulating evidence indicated that emotion has a significant role in pain perception of somatoform pain disorder. To further understand the association between emotion and pain-related brain activities, functional activities of patients with PSPD fulfilling ICD-10 criteria and healthy controls were assessed using functional magnetic resonance imaging technology, while participants viewed a series of positive, neutral, or negative pictures with or without pinprick pain stimulation. Results showed that patients with PSPD had altered brain activities in the parietal gyrus, temporal gyrus, posterior cingulate cortex, prefrontal cortex, and parahippocampus in response to pinprick pain stimuli during different emotions compared with the healthy control group. Moreover, patients with PSPD consistently showed hyperactivities in the prefrontal, the fusiform gyrus and the insula in response to negative stimuli under pinprick pain vs. non-pain condition. The current findings provide some insights into the underlying relationship between emotion and pain-related brain activity in patients with PSPD, which is of both theoretical and clinical importance.

Cost-Saving Early Diagnosis of Functional Pain in Nonmalignant Pain: A Noninferiority Study of Diagnostic Accuracy

Objectives. We compared two index screening tests for early diagnosis of functional pain: pressure pain measurement by electronic diagnostic equipment, which is accurate but too specialized for primary health care, versus peg testing, which is cost-saving and more easily manageable but of unknown sensitivity and specificity. Early distinction of functional (altered pain perception; nervous sensitization) from neuropathic or nociceptive pain improves pain management. Methods. Clinicians blinded for the index screening tests assessed the reference standard of this noninferiority diagnostic accuracy study, namely, comprehensive medical history taking with all previous findings and treatment outcomes. All consenting patients referred to a university hospital for nonmalignant musculoskeletal pain participated. The main analysis compared the receiver operating characteristic (ROC) curves of both index screening tests. Results. The area under the ROC curve for peg testing was not inferior to that of electronic equipment: it was at least 95% as large for finger measures (two-sided p = 0.038) and at least equally as large for ear measures (two-sided p = 0.003). Conclusions. Routine diagnostic testing by peg, which is accessible for general practitioners, is at least as accurate as specialized equipment. This may shorten time-to-treatment in general practices, thereby improving the prognosis and quality of life.

Altered Spontaneous Activity in Patients with Persistent Somatoform Pain Disorder Revealed by Regional Homogeneity

Persistent somatoform pain disorder (PSPD) is a mental disorder un-associated with any somatic injury and can cause severe somatosensory and emotional impairments in patients. However, so far, the neuro-pathophysiological mechanism of the functional impairments in PSPD is still unclear. The present study assesses the difference in regional spontaneous activity between PSPD and healthy controls (HC) during a resting state, in order to elucidate the neural mechanisms underlying PSPD. Resting-state functional Magnetic Resonance Imaging data were obtained from 13 PSPD patients and 23 age- and gender-matched HC subjects in this study. Kendall’s coefficient of concordance was used to measure regional homogeneity (ReHo), and a two-sample t-test was subsequently performed to investigate the ReHo difference between PSPD and HC. Additionally, the correlations between the mean ReHo of each survived area and the clinical assessments were further analyzed. Compared with the HC group, patients with PSPD exhibited decreased ReHo in the bilateral primary somatosensory cortex, posterior cerebellum, and occipital lobe, while increased ReHo in the prefrontal cortex (PFC) and default mode network (including the medial PFC, right inferior parietal lobe (IPL), and left supramarginal gyrus). In addition, significant positive correlations were found between the mean ReHo of both right IPL and left supramarginal gyrus and participants’ Self-Rating Anxiety Scale (SAS) scores, and between the mean ReHo of the left middle frontal gyrus and Visual Analogue Scale (VAS) scores. Our results suggest that abnormal spontaneous brain activity in specific brain regions during a resting state may be associated with the dysfunctions in pain, memory and emotional processing commonly observed in patients with PSPD. These findings help us to understand the neural mechanisms underlying PSPD and suggest that the ReHo metric could be used as a clinical marker for PSPD.

Expectations and effects of a single yoga session on pain perception

Background:

Several studies show yoga may benefit chronic pain management. We investigated the effect of a single yoga session on the perception of pain, measured by a standardized pain provocation test in healthy yoga participants while also comparing pain perception to participants’ own expectations.

Materials and Methods:

Ninety yoga participants were recruited at hatha yoga schools in Switzerland. Pain perception was measured with a standardized algometric pain provocation test; i.e., a calibrated peg was applied for 10 seconds after which the participant rated pain intensity on a 0–10 numerical rating scale. The test was applied to the middle finger, ear lobe, and second toe before and after a 60-minute yoga session.

Results:

Sixty out of 90 (66.7%) yoga participants expected a reduced pain perception after the yoga session. However, 36 (40%) participants actually experienced less pain after compared to before the yoga session. But overall, pain perception statistically did not significantly change from before to after the yoga session at any of the three body locations assessed. The expectations and also the previous yoga experience did not significantly influence the participants’ pain perception.

Conclusions:

Regardless of the high positive expectations on the influence of yoga on pain, a single yoga session does not significantly influence pain perception induced by a pain provocation test. Hypoalgesic effects of yoga should be explained otherwise.

An observational study of buprenorphine treatment of the prescription opioid dependent pain patient

BACKGROUND AND OBJECTIVES

In some countries, particularly the United States and Canada, there has been a growing problem of opioid dependence associated with the treatment of chronic pain. Controversy exists regarding the efficacy and safety of opioid therapy, particularly in high doses for extended periods of time. This study reports on the outcome of chronic pain patients treated with buprenorphine in an outpatient psychiatric consultation clinic.

METHODS

Forty three consecutive outpatient clinic chronic pain patients with a DSM-IV diagnosis of opioid dependence and treated with buprenorphine during a 3-year period were monitored for follow-up periods of up to 5 years. All subjects were dependent on drugs prescribed for pain and were divided into two groups: those who had a history of abuse of alcohol or drugs and those who did not Historical, physical, demographic, and outcome data were collected.

RESULTS

The majority of patients were male, not working, and between the ages of 45-60. Follow-up revealed that treatment with buprenorphine was effective. Most patients had improved pain with treatment of the opioid dependence. There were no differences between those with or without a history of substance abuse.

DISCUSSION AND CONCLUSIONS

Patients often improved with much less preoccupation with pain, expressing great satisfaction with buprenorphine treatment.

SCIENTIFIC SIGNIFICANCE

Buprenorphine is an effective tool when treating the opioid-dependent chronic pain patient.