Influence of patient-clinician relationship style on acupuncture outcomes in functional dyspepsia: A multi-site randomized controlled trial in Korea.

INTRODUCTION: Research suggests that a warm and empathic "patient-centered" patient-clinician relationship produces better clinical outcomes when compared with a more neutral "disease-centered" relationship. Acupuncturists performed both styles of therapy for patients with functional dyspepsia in Korea. METHODS: The present randomized controlled trial assigned patients (n = 73) to identical acupuncture treatment with either patient-centered augmented care or disease-centered limited care. The Korean version of the Nepean Dyspepsia Index (NDI-K) was the primary outcome measure. Secondary outcome measures included Consultation And Relational Empathy (CARE) scale. RESULTS: Both groups showed improvement in NDI-K. Patient-centered augmented acupuncture produced less effective symptom improvement compared to disease-centered limited acupuncture (NDI-K sum score and frequency; P = 0.008 and P = 0.037 respectively). CARE scores were higher for the augmented versus limited group (P = 0.001), supporting the fidelity of the experimentally controlled patient/clinician relationship. There were no significant differences between the groups in any of other secondary outcomes. CONCLUSION: Patients demonstrated greater improvement following acupuncture conducted with a more neutral, "disease-centered" style of relationship. This result is counter to similar research conducted in Western countries and suggests that cultural factors can significantly shape optimum styles of acupuncture therapy. PRACTICE IMPLICATIONS: Clinicians should consider cultural differences when applying acupuncture therapy.

Thalamic neurometabolite alterations in chronic low back pain: a common phenomenon across musculoskeletal pain conditions?

ABSTRACT: Recently, we showed that patients with knee osteoarthritis (KOA) demonstrate alterations in the thalamic concentrations of several metabolites compared with healthy controls: higher myo-inositol (mIns), lower N-acetylaspartate (NAA), and lower choline (Cho). Here, we evaluated whether these metabolite alterations are specific to KOA or could also be observed in patients with a different musculoskeletal condition, such as chronic low back pain (cLBP). Thirty-six patients with cLBP and 20 healthy controls were scanned using 1 H-magnetic resonance spectroscopy (MRS) and a PRESS (Point RESolved Spectroscopy) sequence with voxel placement in the left thalamus. Compared with healthy controls, patients with cLBP demonstrated lower absolute concentrations of NAA ( P = 0.0005) and Cho ( P < 0.05) and higher absolute concentrations of mIns ( P = 0.01) when controlling for age, as predicted by our previous work in KOA. In contrast to our KOA study, mIns levels in this population did not significantly correlate with pain measures (eg, pain severity or duration). However, exploratory analyses revealed that NAA levels in patients were negatively correlated with the severity of sleep disturbance ( P < 0.01), which was higher in patients compared with healthy controls ( P < 0.001). Additionally, also in patients, both Cho and mIns levels were positively correlated with age ( P < 0.01 and P < 0.05, respectively). Altogether, these results suggest that thalamic metabolite changes may be common across etiologically different musculoskeletal chronic pain conditions, including cLBP and KOA, and may relate to symptoms often comorbid with chronic pain, such as sleep disturbance. The functional and clinical significance of these brain changes remains to be fully understood.

Causal influence of brainstem response to transcutaneous vagus nerve stimulation on cardiovagal outflow.

BACKGROUND: The autonomic response to transcutaneous auricular vagus nerve stimulation (taVNS) has been linked to the engagement of brainstem circuitry modulating autonomic outflow. However, the physiological mechanisms supporting such efferent vagal responses are not well understood, particularly in humans. HYPOTHESIS: We present a paradigm for estimating directional brain-heart interactions in response to taVNS. We propose that our approach is able to identify causal links between the activity of brainstem nuclei involved in autonomic control and cardiovagal outflow. METHODS: We adopt an approach based on a recent reformulation of Granger causality that includes permutation-based, nonparametric statistics. The method is applied to ultrahigh field (7T) functional magnetic resonance imaging (fMRI) data collected on healthy subjects during taVNS. RESULTS: Our framework identified taVNS-evoked functional brainstem responses with superior sensitivity compared to prior conventional approaches, confirming causal links between taVNS stimulation and fMRI response in the nucleus tractus solitarii (NTS). Furthermore, our causal approach elucidated potential mechanisms by which information is relayed between brainstem nuclei and cardiovagal, i.e., high-frequency heart rate variability, in response to taVNS. Our findings revealed that key brainstem nuclei, known from animal models to be involved in cardiovascular control, exert a causal influence on taVNS-induced cardiovagal outflow in humans. CONCLUSION: Our causal approach allowed us to noninvasively evaluate directional interactions between fMRI BOLD signals from brainstem nuclei and cardiovagal outflow.

Graded brain fMRI response to somatic and visual acupuncture stimulation.

Increased stimulation can enhance acupuncture clinical response; however, the impact of acupuncture stimulation as "dosage" has rarely been studied. Furthermore, acupuncture can include both somatic and visual components. We assessed both somatic and visual acupuncture dosage effects on sensory ratings and brain response. Twenty-four healthy participants received somatic (needle inserted, manually stimulated) and visual (needle video, no manual stimulation) acupuncture over the leg at three different dosage levels (control, low-dose, and high-dose) during functional magnetic resonance imaging (fMRI). Participants reported the perceived deqi sensation for each acupuncture dose level. Blood-oxygen-level dependent imaging data were analyzed by general linear model and multivariate pattern analysis. For both somatic and visual acupuncture, reported deqi sensation increased with increased dosage of acupuncture stimulation. Brain fMRI analysis demonstrated that higher dosage of somatic acupuncture produced greater brain responses in sensorimotor processing areas, including anterior and posterior insula and secondary somatosensory cortex. For visual acupuncture, higher dosage of stimulation produced greater brain responses in visual-processing areas, including the middle temporal visual areas (V5/MT+) and occipital cortex. Psychophysical and psychophysiological responses to both somatic and visual acupuncture were graded in response to higher doses. Our findings suggest that acupuncture response may be enhanced by the dosage of needling-specific and nonspecific components, represented by different neural mechanisms.

Increased insula response to interoceptive attention following mindfulness training is associated with increased body trusting among patients with depression.

Interoceptive dysfunction is often present in anxiety and depression. We investigated the effects of an 8-week intervention, Mindfulness Training for Primary Care (MTPC), on brain mechanisms of interoceptive attention among patients with anxiety and/or depression. We hypothesized that fMRI brain response to interoception in the insula, a region known for interoceptive processing, would increase following the MTPC intervention, and that such increases would be associated with post-intervention changes in self-reported measures of interoceptive awareness. Adults (n = 28) with anxiety and/or depression completed baseline and post-intervention fMRI visits, including a task in which they alternated between focusing on their heartbeat (interoception (INT)) and a control visual attention task (exteroception (EXT)). Following MTPC, we observed increased evoked fMRI response (relative to baseline) in left anterior insula during the INT-EXT task contrast (z > 3.1, p < 0.001 corrected). In patients with moderate-to-severe depression as defined by the Patient Reported Outcomes Measurement Information System (PROMIS), increased post-intervention insula response was associated with increased Body Trusting, a subscale of the Multidimensional Assessment of Interoceptive Awareness (z > 3.1, p = 0.007 corrected). This study demonstrates that patients with mood disorders may respond differentially to mindfulness-based treatment depending on depression severity, and that among those who are more depressed, increased trusting in one's own body sensations and experiencing the body as a safe place to attend to may be necessary components of positive responses to mindfulness-based interventions.

Skin Temperature of Acupoints in Health and Disease: A Systematic Review.

Introduction: Despite substantial progress made in the field of acupuncture research, the existence and specificity of acupoints remain controversial. In recent years, the concept of acupoint sensitization has emerged as a theoretical framework for understanding acupoints as dynamic functional entities that are sensitized in pathological conditions. Based on this premise, some have claimed that specific acupoints are thermally distinct between healthy and clinical populations, but no systematic review has been conducted to synthesize and evaluate the quality of studies supporting such claims. In this review, we provide a summary and quality assessment of the existing literature addressing the question of whether changes in skin temperature at specific acupoints are indicative of pathological conditions. Methods: A systematic literature search was performed in PubMed, EMBASE, and AltHealthWatch (EBSCO Host), by combining variations of search terms relevant to acupoints and temperature. The search was limited to the English language, and publication dates ranged from database inception to December 2020. Two authors independently screened all resulting abstracts and subsequently read full-text articles for eligibility. Information on study design, sample, acupoints, parameters of skin temperature assessments, and main findings were extracted from included studies. Quality of the thermal sensing methodology was evaluated using a thermal assessment checklist, adapted from the Thermographic Imaging in Sports and Exercise Medicine (TISEM) consensus checklist, and a modified Newcastle-Ottawa Scale (NOS) for case-control studies. Results: The search strategy yielded a total of 1771 studies, of which 10 articles met the eligibility criteria. Eight studies compared skin temperature at acupoints in healthy versus clinical populations, and two studies assessed within-subject changes in temperature of acupoints in relation to changes in health status. There were seven clinical conditions examined in the included studies: chronic bronchial asthma, chronic hepatitis, hyperplasia of mammary glands, infertility, intracranial hypertension, obesity, and primary dysmenorrhea. There were numerous methodological quality issues related to skin temperature measurements. Eight studies with case-control designs reported significant differences between healthy and clinical populations in temperature at certain acupoints. Two studies with pre-post designs reported that changes in health-disease status could be associated with changes in temperature at specific acupoints. Conclusion: A review of the available literature suggests that certain acupoints may be thermally distinct between healthy and unhealthy states. However, given the methodological limitations and heterogeneity across included studies, no definitive conclusion could be drawn as to whether changes in skin temperature at specific acupoints are indicative of pathological conditions.

The Effects of Combined Respiratory-Gated Auricular Vagal Afferent Nerve Stimulation and Mindfulness Meditation for Chronic Low Back Pain: A Pilot Study.

OBJECTIVE: Respiratory-gated Auricular Vagal Afferent Nerve stimulation (RAVANS) is a safe nonpharmacological approach to managing chronic pain. The purpose of the current study was to examine (1) the feasibility and acceptability of RAVANS, combined with mindful meditation (MM) for chronic low back pain (CLBP), (2) the potential synergy of MM+RAVANS on improving pain, and (3) possible moderators of the influence of MM+RAVANS on pain. DESIGN: Pilot feasibility and acceptability study. SETTING: Pain management center at large academic medical center. SUBJECTS: Nineteen adults with CLBP and previous MM training. METHODS: Participants attended two sessions during which they completed quantitative sensory testing (QST), rated pain severity, and completed a MM+stimulation session. Participants received RAVANS during one visit and sham stimulation during the other, randomized in order. Following intervention, participants repeated QST. RESULTS: MM+RAVANS was well tolerated, acceptable, and feasible to provide relief for CLBP. Both MM+stimulation sessions resulted in improved back pain severity, punctate pain ratings, and pressure pain threshold. Individuals with greater negative affect showed greater back pain improvement from MM+RAVANS while those with greater mindfulness showed greater back pain improvement from MM+sham. CONCLUSIONS: Results suggest that for CLBP patients with prior MM training, the analgesic effects of MM may have overshadowed effects of RAVANS given the brief single session MM+RAVANS intervention. However, those with greater negative affect may benefit from combined MM+RAVANS.

S1 Brain Connectivity in Carpal Tunnel Syndrome Underlies Median Nerve and Functional Improvement Following Electro-Acupuncture.

Carpal Tunnel Syndrome (CTS) is a median nerve entrapment neuropathy that alters primary somatosensory cortex (S1) organization. While electro-acupuncture (EA), a form of peripheral neuromodulation, has been shown to improve clinical and neurophysiological CTS outcomes, the role of EA-evoked brain response during therapy (within and beyond S1) for improved outcomes is unknown. We investigated S1-associated whole brain fMRI connectivity during both a resting and sustained EA stimulation state in age-matched healthy controls (N = 28) and CTS patients (N = 64), at baseline and after 8 weeks of acupuncture therapy (local, distal, or sham EA). Compared to healthy controls, CTS patients at baseline showed decreased resting state functional connectivity between S1 and thalamic pulvinar nucleus. Increases in S1/pulvinar connectivity strength following verum EA therapy (combined local and distal) were correlated with improvements in median nerve velocity (r = 0.38, p = 0.035). During sustained local EA, compared to healthy controls, CTS patients demonstrated increased functional connectivity between S1 and anterior hippocampus (aHipp). Following 8 weeks of local EA therapy, S1/aHipp connectivity significantly decreased and greater decrease was associated with improvement in patients' functional status (r = 0.64, p = 0.01) and increased median nerve velocity (r = -0.62, p = 0.013). Thus, connectivity between S1 and other brain areas is also disrupted in CTS patients and may be improved following EA therapy. Furthermore, stimulus-evoked fMRI connectivity adds therapy-specific, mechanistic insight to more common resting state connectivity approaches. Specifically, local EA modulates S1 connectivity to sensory and affective processing regions, linked to patient function and median nerve health.

Greater Somatosensory Afference With Acupuncture Increases Primary Somatosensory Connectivity and Alleviates Fibromyalgia Pain via Insular γ-Aminobutyric Acid: A Randomized Neuroimaging Trial.

OBJECTIVE: Acupuncture is a complex multicomponent treatment that has shown promise in the treatment of fibromyalgia (FM). However, clinical trials have shown mixed results, possibly due to heterogeneous methodology and lack of understanding of the underlying mechanism of action. The present study was undertaken to understand the specific contribution of somatosensory afference to improvements in clinical pain, and the specific brain circuits involved. METHODS: Seventy-six patients with FM were randomized to receive either electroacupuncture (EA), with somatosensory afference, or mock laser acupuncture (ML), with no somatosensory afference, twice a week over 8 treatments. Patients with FM in each treatment group were assessed for pain severity levels, measured using Brief Pain Inventory (BPI) scores, and for levels of functional brain network connectivity, assessed using resting state functional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy in the right anterior insula, before and after treatment. RESULTS: Fibromyalgia patients who received EA therapy experienced a greater reduction in pain severity, as measured by the BPI, compared to patients who received ML therapy (mean difference in BPI from pre- to posttreatment was -1.14 in the EA group versus -0.46 in the ML group; P for group × time interaction = 0.036). Participants receiving EA treatment, as compared to ML treatment, also exhibited resting functional connectivity between the primary somatosensory cortical representation of the leg (S1leg ; i.e. primary somatosensory subregion activated by EA) and the anterior insula. Increased S1leg -anterior insula connectivity was associated with both reduced levels of pain severity as measured by the BPI (r = -0.44, P = 0.01) and increased levels of γ-aminobutyric acid (GABA+) in the anterior insula (r = 0.48, P = 0.046) following EA therapy. Moreover, increased levels of GABA+ in the anterior insula were associated with reduced levels of pain severity as measured by the BPI (r = -0.59, P = 0.01). Finally, post-EA treatment changes in levels of GABA+ in the anterior insula mediated the relationship between changes in S1leg -anterior insula connectivity and pain severity on the BPI (bootstrap confidence interval -0.533, -0.037). CONCLUSION: The somatosensory component of acupuncture modulates primary somatosensory functional connectivity associated with insular neurochemistry to reduce pain severity in FM.

Increased Salience Network Connectivity Following Manual Therapy is Associated with Reduced Pain in Chronic Low Back Pain Patients.

Chronic low back pain (cLBP) has been associated with changes in brain plasticity. Nonpharmacological therapies such as Manual Therapy (MT) have shown promise for relieving cLBP. However, translational neuroimaging research is needed to understand potential central mechanisms supporting MT. We investigated the effect of MT on resting-state salience network (SLN) connectivity, and whether this was associated with changes in clinical pain. Fifteen cLBP patients, and 16 matched healthy controls (HC) were scanned with resting functional Magnetic Resonance Imaging (fMRI), before and immediately after a MT intervention (cross-over design with two separate visits, pseudorandomized, grades V 'Manipulation' and III 'Mobilization' of the Maitland Joint Mobilization Grading Scale). Patients rated clinical pain (0-100) pre- and post-therapy. SLN connectivity was assessed using dual regression probabilistic independent component analysis. Both manipulation (Pre: 39.43 ± 16.5, Post: 28.43 ± 16.5) and mobilization (Pre: 38.83 ± 17.7, Post: 31.76 ± 19.4) reduced clinical back pain (P < .05). Manipulation (but not mobilization) significantly increased SLN connectivity to thalamus and primary motor cortex. Additionally, a voxelwise regression indicated that greater MT-induced increase in SLN connectivity to the lateral prefrontal cortex was associated with greater clinical back pain reduction immediately after intervention, for both manipulation (r = -0.8) and mobilization (r = -0.54). Our results suggest that MT is successful in reducing clinical low back pain by both spinal manipulation and spinal mobilization. Furthermore, this reduction post-manipulation occurs via modulation of SLN connectivity to sensorimotor, affective, and cognitive processing regions. PERSPECTIVE: MT both reduces clinical low back pain and modulates brain activity important for the processing of pain. This modulation was shown by increased functional brain connectivity between the salience network and brain regions involved in cognitive, affective, and sensorimotor processing of pain.

Feasibility of Auricular Field Stimulation in Fibromyalgia: Evaluation by Functional Magnetic Resonance Imaging, Randomized Trial.

OBJECTIVE: To evaluate the feasibility of recruitment, preliminary efficacy, and acceptability of auricular percutaneous electrical nerve field stimulation (PENFS) for the treatment of fibromyalgia in veterans, using neuroimaging as an outcome measure and a biomarker of treatment response. DESIGN: Randomized, controlled, single-blind. SETTING: Government hospital. SUBJECTS: Twenty-one veterans with fibromyalgia were randomized to standard therapy (ST) control or ST with auricular PENFS treatment. METHODS: Participants received weekly visits with a pain practitioner over 4 weeks. The PENFS group received reapplication of PENFS at each weekly visit. Resting-state functional connectivity magnetic resonance imaging (rs-fcMRI) data were collected within 2 weeks prior to initiating treatment and 2 weeks following the final treatment. Analysis of rs-fcMRI used a right posterior insula seed. Pain and function were assessed at baseline and at 2, 6, and 12 weeks post-treatment. RESULTS: At 12 weeks post-treatment, there was a nonsignificant trend toward improved pain scores and significant improvements in pain interference with sleep among the PENFS treatment group as compared with the ST controls. Neuroimaging data displayed increased connectivity to areas of the cerebellum and executive control networks in the PENFS group as compared with the ST control group following treatment. CONCLUSIONS: There was a trend toward improved pain and function among veterans with fibromyalgia in the ST + PENFS group as compared with the ST control group. Pain and functional outcomes correlated with altered rs-fcMRI network connectivity. Neuroimaging results differed between groups, suggesting an alternative underlying mechanism for PENFS analgesia.

Interventions and Manipulations of Interoception.

Interoceptive pathways may be manipulated at various levels to develop interventions to improve symptoms in a range of disorders. Primarily through the lens of the respiratory system, we outline various pathways that can be manipulated at neural, behavioral, and psychological levels to change the representation of and attention to interoceptive signals, which can alter interconnected physiological systems and improve functioning and adaptive behavior. Interventions can alter interoception via neuromodulation of the vagus nerve, slow breathing to change respiratory rate and depth, or awareness processes such as mindfulness-based interventions. Aspects of this framework may be applied to other physiological systems and future research may integrate interventions across multiple levels of manipulation or bodily systems.

Neuroimaging Somatosensory and Therapeutic Alliance Mechanisms Supporting Acupuncture.

Acupuncture consists of multiple components, and neuroimaging studies are beginning to tease apart potential brain-based mechanisms supporting this nonpharmacologic intervention. Brain imaging in patient populations is important for the acupuncture neuroimaging field, and recent studies have incorporated neuroimaging into a clinical trial framework for improved ecological validity in extending results to be more relevant for clinical practice. For instance, functional magnetic resonance imaging (fMRI) research with patients suffering from carpal tunnel syndrome has suggested cortical plasticity as a mechanism supporting acupuncture analgesia. In turn, the patient-acupuncturist relationship is another important aspect of acupuncture analgesia, and recent hyperscan fMRI research has begun to explore brain-based mechanisms underlying therapeutic alliance between patient and clinician, and how this might impact acupuncture analgesia. Ultimately, neuroimaging has shown great promise in the past several decades in opening a window into brain function to better appreciate the mechanisms supporting acupuncture. As acupuncture likely operates via multiple distinct mechanisms of action, teasing apart the constituent aspects of acupuncture therapy in humans will be an important goal for current and future neuroimaging research studies.

Brief Self-Compassion Training Alters Neural Responses to Evoked Pain for Chronic Low Back Pain: A Pilot Study.

OBJECTIVE: Self-compassion meditation, which involves compassion toward the self in moments of suffering, shows promise for improving pain-related functioning, but its underlying mechanisms are unknown. This longitudinal, exploratory pilot study investigated the effects of a brief (eight contact hours, two weeks of home practice) self-compassion training on pain-related brain processing in chronic low back pain (cLBP). METHODS: We evaluated functional magnetic resonance imaging (fMRI) response to evoked pressure pain and its anticipation during a self-compassionate state and compared altered brain responses following training with changes on self-reported measures of self-compassion (Self-Compassion Scale [SCS]), interoceptive awareness (Multidimensional Assessment of Interoceptive Awareness [MAIA]), and clinical pain intensity. RESULTS: In a sample of participants with cLBP (N = 20 total, N = 14 with complete longitudinal data) who underwent self-compassion training, we observed reduced clinical pain intensity and disability (P < 0.01) and increased trait self-compassion and interoceptive awareness (all P < 0.05) following training. Evoked pressure pain response in the right temporo-parietal junction (TPJ) was reduced following training, and decreases were associated with reduced clinical pain intensity. Further, increased fMRI responses to pain anticipation were observed in the right dorsolateral prefrontal cortex (dlPFC) and ventral posterior cingulate cortex (vPCC), and these increases were associated with mean post-training changes in SCS scores and scores from the body listening subscale of the MAIA. DISCUSSION: These findings, though exploratory and lacking comparison with a control condition, suggest that self-compassion training supports regulation of pain through the involvement of self-referential (vPCC), salience-processing (TPJ), and emotion regulatory (dlPFC) brain areas. The results also suggest that self-compassion could be an important target in the psychotherapeutic treatment of cLBP, although further studies using controlled experimental designs are needed to determine the specificity of these effects.

Acupuncture Treatment Modulates the Connectivity of Key Regions of the Descending Pain Modulation and Reward Systems in Patients with Chronic Low Back Pain.

Chronic low back pain (cLBP) is a common disorder with unsatisfactory treatment options. Acupuncture has emerged as a promising method for treating cLBP. However, the mechanism underlying acupuncture remains unclear. In this study, we investigated the modulation effects of acupuncture on resting state functional connectivity (rsFC) of the periaqueductal gray (PAG) and ventral tegmental area (VTA) in patients with cLBP. Seventy-nine cLBP patients were recruited and assigned to four weeks of real or sham acupuncture. Resting state functional magnetic resonance imaging data were collected before the first and after the last treatment. Fifty patients completed the study. We found remission of pain bothersomeness in all treatment groups after four weeks, with greater pain relief after real acupuncture compared to sham acupuncture. We also found that real acupuncture can increase VTA/PAG rsFC with the amygdala, and the increased rsFC was associated with decreased pain bothersomeness scores. Baseline PAG-amygdala rsFC could predict four-week treatment response. Our results suggest that acupuncture may simultaneously modulate the rsFC of key regions in the descending pain modulation (PAG) and reward systems (VTA), and the amygdala may be a key node linking the two systems to produce antinociceptive effects. Our findings highlight the potential of acupuncture for chronic low back pain management.