Lee J, Andronesi OC, Torrado-Carvajal A, Ratai E-M, Loggia ML, Weerasekera A, Berry MP, Ellingsen D-M, Isaro L, Lazaridou A, Paschali M, Grahl A, Wasan AD, Edwards RR, Napadow V. 3D magnetic resonance spectroscopic imaging reveals links between brain metabolites and multidimensional pain features in fibromyalgia [Internet]. European Journal of Pain 2021; Publisher's VersionAbstract
Abstract Background Fibromyalgia is a centralized multidimensional chronic pain syndrome, but its pathophysiology is not fully understood. Methods We applied 3D magnetic resonance spectroscopic imaging (MRSI), covering multiple cortical and subcortical brain regions, to investigate the association between neuro-metabolite (e.g. combined glutamate and glutamine, Glx; myo-inositol, mIno; and combined (total) N-acetylaspartate and N-acetylaspartylglutamate, tNAA) levels and multidimensional clinical/behavioural variables (e.g. pain catastrophizing, clinical pain severity and evoked pain sensitivity) in women with fibromyalgia (N = 87). Results Pain catastrophizing scores were positively correlated with Glx and tNAA levels in insular cortex, and negatively correlated with mIno levels in posterior cingulate cortex (PCC). Clinical pain severity was positively correlated with Glx levels in insula and PCC, and with tNAA levels in anterior midcingulate cortex (aMCC), but negatively correlated with mIno levels in aMCC and thalamus. Evoked pain sensitivity was negatively correlated with levels of tNAA in insular cortex, MCC, PCC and thalamus. Conclusions These findings support single voxel placement targeting nociceptive processing areas in prior 1H-MRS studies, but also highlight other areas not as commonly targeted, such as PCC, as important for chronic pain pathophysiology. Identifying target brain regions linked to multidimensional symptoms of fibromyalgia (e.g. negative cognitive/affective response to pain, clinical pain, evoked pain sensitivity) may aid the development of neuromodulatory and individualized therapies. Furthermore, efficient multi-region sampling with 3D MRSI could reduce the burden of lengthy scan time for clinical research applications of molecular brain-based mechanisms supporting multidimensional aspects of fibromyalgia. Significance This large N study linked brain metabolites and pain features in fibromyalgia patients, with a better spatial resolution and brain coverage, to understand a molecular mechanism underlying pain catastrophizing and other aspects of pain transmission. Metabolite levels in self-referential cognitive processing area as well as pain-processing regions were associated with pain outcomes. These results could help the understanding of its pathophysiology and treatment strategies for clinicians.
Sclocco R, Nguyen C, Staley R, Fisher H, Mendez A, Velez C, Kettner NW, Kuo B, Napadow V. Non‐uniform gastric wall kinematics revealed by 4D Cine magnetic resonance imaging in humans. Neurogastroenterology and Motility 2021;
Mawla I, Ichesco E, Zöllner HJ, Edden RAE, Chenevert T, Buchtel H, Bretz MD, Sloan H, Kaplan CM, Harte SE, Mashour GA, Clauw DJ, Napadow V, Harris RE. Greater Somatosensory Afference with Acupuncture Increases Primary Somatosensory Connectivity and Alleviates Fibromyalgia Pain via Insular GABA: A Randomized Neuroimaging Trial. Arthritis & Rheumatology. Arthritis and Rheumatology 2021;
Ellingsen D-M, Beissner F, Moher Alsady T, Lazaridou A, Paschali M, Berry M, Isaro L, Grahl A, Lee J, Wasan AD, Edwards RR, Napadow V. A picture is worth a 1000 words: linking fibromyalgia pain widespreadness from digital pain drawings with pain catastrophizing and brain cross-network connectivity [Internet]. PAIN 2021;162(5):1352-1363. Publisher's VersionAbstract
Pain catastrophizing is prominent in chronic pain conditions such as fibromyalgia and has been proposed to contribute to the development of pain widespreadness. However, the brain mechanisms responsible for this association are unknown. We hypothesized that increased resting salience network (SLN) connectivity to nodes of the default mode network (DMN), representing previously reported pain-linked cross-network enmeshment, would be associated with increased pain catastrophizing and widespreadness across body sites. We applied functional magnetic resonance imaging (fMRI) and digital pain drawings (free-hand drawing over a body outline, analyzed using conventional software for multivoxel fMRI analysis) to investigate precisely quantified measures of pain widespreadness and the associations between pain catastrophizing (Pain Catastrophizing Scale), resting brain network connectivity (Dual-regression Independent Component Analysis, 6-minute multiband accelerated fMRI), and pain widespreadness in fibromyalgia patients (N = 79). Fibromyalgia patients reported pain in multiple body areas (most frequently the spinal region, from the lower back to the neck), with moderately high pain widespreadness (mean ± SD: 26.1 ± 24.1% of total body area), and high pain catastrophizing scale scores (27.0 ± 21.9, scale range: 0-52), which were positively correlated (r = 0.26, P = 0.02). A whole-brain regression analysis focused on SLN connectivity indicated that pain widespreadness was also positively associated with SLN connectivity to the posterior cingulate cortex, a key node of the DMN. Moreover, we found that SLN-posterior cingulate cortex connectivity statistically mediated the association between pain catastrophizing and pain widespreadness (P = 0.01). In conclusion, we identified a putative brain mechanism underpinning the association between greater pain catastrophizing and a larger spatial extent of body pain in fibromyalgia, implicating a role for brain SLN-DMN cross-network enmeshment in mediating this association.Corresponding author. Address. Department of Psychology, University of Oslo, Forskningsveien 3A, 0373 Oslo, Norway. Tel.: +47 458 57 434. E-mail address: (D.-M. Ellingsen).Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site ( August 05, 2020Received in revised form September 28, 2020Accepted October 01, 2020© 2021 International Association for the Study of Pain
Isenburg K, Mawla I, Loggia ML, Ellingsen D-M, Protsenko E, Kowalski MH, Swensen D, O'Dwyer-Swensen D, Edwards RR, Napadow V, Kettner N. Increased Salience Network Connectivity Following Manual Therapy is Associated with Reduced Pain in Chronic Low Back Pain Patients [Internet]. The Journal of Pain 2020; Publisher's VersionAbstract
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.
Napadow V. Neuroimaging Somatosensory and Therapeutic Alliance Mechanisms Supporting Acupuncture. Medical Acupuncture 2020;32(6):400-402. napadow-2020-neuroimaging-somatosensory-and-ther.pdf
Ellingsen D-M, Isenburg K, Jung C, Lee J, Gerber J, Mawla I, Sclocco R, Jensen KB, Edwards RR, Kelley JM, Kirsch I, Kaptchuk TJ, Napadow V. Dynamic brain-to-brain concordance and behavioral mirroring as a mechanism of the patient-clinician interaction [Internet]. Science Advances 2020;6(43):eabc1304. Publisher's VersionAbstract
The patient-clinician interaction can powerfully shape treatment outcomes such as pain but is often considered an intangible “art of medicine” and has largely eluded scientific inquiry. Although brain correlates of social processes such as empathy and theory of mind have been studied using single-subject designs, specific behavioral and neural mechanisms underpinning the patient-clinician interaction are unknown. Using a two-person interactive design, we simultaneously recorded functional magnetic resonance imaging (hyperscanning) in patient-clinician dyads, who interacted via live video, while clinicians treated evoked pain in patients with chronic pain. Our results show that patient analgesia is mediated by patient-clinician nonverbal behavioral mirroring and brain-to-brain concordance in circuitry implicated in theory of mind and social mirroring. Dyad-based analyses showed extensive dynamic coupling of these brain nodes with the partners’ brain activity, yet only in dyads with pre-established clinical rapport. These findings introduce a putatively key brain-behavioral mechanism for therapeutic alliance and psychosocial analgesia.
Berry MP, Lutz J, Schuman-Olivier Z, Germer C, Pollak S, Edwards RR, Gardiner P, Desbordes G, Napadow V. Brief Self-Compassion Training Alters Neural Responses to Evoked Pain for Chronic Low Back Pain: A Pilot Study [Internet]. Pain Medicine 2020;21(10):2172-2185. Publisher's VersionAbstract
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).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.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.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.
Jung C, Ichesco E, Ratai E-M, Gonzalez RG, Burdo T, Loggia ML, Harris RE, Napadow V. Magnetic resonance imaging of neuroinflammation in chronic pain: a role for astrogliosis? [Internet]. PAIN 2020;161(7):1555-1564. Publisher's VersionAbstract
Noninvasive measures of neuroinflammatory processes in humans could substantially aid diagnosis and therapeutic development for many disorders, including chronic pain. Several proton magnetic resonance spectroscopy (1H-MRS) metabolites have been linked with glial activity (ie, choline and myo-inositol) and found to be altered in chronic pain patients, but their role in the neuroinflammatory cascade is not well known. Our multimodal study evaluated resting functional magnetic resonance imaging connectivity and 1H-MRS metabolite concentration in insula cortex in 43 patients suffering from fibromyalgia, a chronic centralized pain disorder previously demonstrated to include a neuroinflammatory component, and 16 healthy controls. Patients demonstrated elevated choline (but not myo-inositol) in anterior insula (aIns) (P = 0.03), with greater choline levels linked with worse pain interference (r = 0.41, P = 0.01). In addition, reduced resting functional connectivity between aIns and putamen was associated with both pain interference (whole brain analysis, pcorrected < 0.01) and elevated aIns choline (r = −0.37, P = 0.03). In fact, aIns/putamen connectivity statistically mediated the link between aIns choline and pain interference (P < 0.01), highlighting the pathway by which neuroinflammation can impact clinical pain dysfunction. To further elucidate the molecular substrates of the effects observed, we investigated how putative neuroinflammatory 1H-MRS metabolites are linked with ex vivo tissue inflammatory markers in a nonhuman primate model of neuroinflammation. Results demonstrated that cortical choline levels were correlated with glial fibrillary acidic protein, a known marker for astrogliosis (Spearman r = 0.49, P = 0.03). Choline, a putative neuroinflammatory 1H-MRS-assessed metabolite elevated in fibromyalgia and associated with pain interference, may be linked with astrogliosis in these patients.
Kim H, Mawla I, Lee J, Gerber J, Walker K, Kim J, Ortiz A, Chan ST, Loggia ML, Wasan AD, Edwards RR, Kong J, Kaptchuk TJ, Gollub RL, Rosen, B. R., Napadow V. Reduced tactile acuity in chronic low back pain is linked with structural neuroplasticity in primary somatosensory cortex and is modulated by acupuncture therapy. Neuroimage 2020;217:116899. neuroimage2020.pdf
Sclocco R, Garcia RG, Kettner NW, Fisher HP, Isenburg K, Makarovsky M, Stowell JA, Goldstein J, Barbieri R, Napadow V. Stimulus frequency modulates brainstem response to respiratory-gated transcutaneous auricular vagus nerve stimulation. Brain Stimulation 2020;13(4):970-978.Abstract


The therapeutic potential of transcutaneous auricular VNS (taVNS) is currently being explored for numerous clinical applications. However, optimized response for different clinical indications may depend on specific neuromodulation parameters, and systematic assessments of their influence are still needed to optimize this promising approach.


We proposed that stimulation frequency would have a significant effect on nucleus tractus solitarii (NTS) functional MRI (fMRI) response to respiratory-gated taVNS (RAVANS).


Brainstem fMRI response to auricular RAVANS (cymba conchae) was assessed for four different stimulation frequencies (2, 10, 25, 100 Hz). Sham (no current) stimulation was used to control for respiration effects on fMRI signal.


Our findings demonstrated that RAVANS delivered at 100 Hz evoked the strongest brainstem response, localized to a cluster in the left (ipsilateral) medulla and consistent with purported NTS. A co-localized, although weaker, response was found for 2 Hz RAVANS. Furthermore, RAVANS delivered at 100 Hz also evoked stronger fMRI responses for important monoamine neurotransmitter source nuclei (LC, noradrenergic; MR, DR, serotonergic) and pain/homeostatic regulation nuclei (i.e. PAG).


Our fMRI results support previous localization of taVNS afference to pontomedullary aspect of NTS in the human brainstem, and demonstrate the significant influence of the stimulation frequency on brainstem fMRI response.

Napadow V. The mindful migraine: does mindfulness-based stress reduction relieve episodic migraine?. PAIN 2020;161(8):1685-1687. napadow-2020-the-mindful-migraine.pdf
Napadow V, Sclocco R, Henderson LA. Brainstem neuroimaging of nociception and pain circuitries. Pain Rep 2019;4(4):e745.Abstract
The brainstem is known to be an important brain area for nociception and pain processing, and both relaying and coordinating signaling between the cerebrum, cerebellum, and spinal cord. Although preclinical models of pain have characterized the many roles that brainstem nuclei play in nociceptive processing, the degree to which these circuitries extend to humans is not as well known. Unfortunately, the brainstem is also a very challenging region to evaluate in humans with neuroimaging. The challenges for human brainstem imaging arise from the location of this elongated brain structure, proximity to cardiorespiratory noise sources, and the size of its constituent nuclei. These challenges can require dedicated approaches to brainstem imaging, which should be adopted when study hypotheses are focused on brainstem processing of nociception or modulation of pain perception. In fact, our review will highlight many pain neuroimaging studies that have reported some brainstem involvement in nociceptive processing and chronic pain pathology. However, we note that with recent advances in neuroimaging leading to improved spatial and temporal resolution, more studies are needed that take advantage of data collection and analysis methods focused on the challenges of brainstem neuroimaging.
Valenza G, Sclocco R, Duggento A, Passamonti L, Napadow V, Barbieri R, Toschi N. The central autonomic network at rest: Uncovering functional MRI correlates of time-varying autonomic outflow. Neuroimage 2019;197:383-390.Abstract
Peripheral measures of autonomic nervous system (ANS) activity at rest have been extensively employed as putative biomarkers of autonomic cardiac control. However, a comprehensive characterization of the brain-based central autonomic network (CAN) sustaining cardiovascular oscillations at rest is missing, limiting the interpretability of these ANS measures as biomarkers of cardiac control. We evaluated combined cardiac and fMRI data from 34 healthy subjects from the Human Connectome Project to detect brain areas functionally linked to cardiovagal modulation at rest. Specifically, we combined voxel-wise fMRI analysis with instantaneous heartbeat and spectral estimates obtained from inhomogeneous linear point-process models. We found exclusively negative associations between cardiac parasympathetic activity at rest and a widespread network including bilateral anterior insulae, right dorsal middle and left posterior insula, right parietal operculum, bilateral medial dorsal and ventrolateral posterior thalamic nuclei, anterior and posterior mid-cingulate cortex, medial frontal gyrus/pre-supplementary motor area. Conversely, we found only positive associations between instantaneous heart rate and brain activity in areas including frontopolar cortex, dorsomedial prefrontal cortex, anterior, middle and posterior cingulate cortices, superior frontal gyrus, and precuneus. Taken together, our data suggests a much wider involvement of diverse brain areas in the CAN at rest than previously thought, which could reflect a differential (both spatially and directionally) CAN activation according to the underlying task. Our insight into CAN activity at rest also allows the investigation of its impairment in clinical populations in which task-based fMRI is difficult to obtain (e.g., comatose patients or infants).
Kim J, Mawla I, Kong J, Lee J, Gerber J, Ortiz A, Kim H, Chan S-T, Loggia ML, Wasan A, Edwards RR, Gollub RL, Rosen BR, Napadow V. Somatotopically-specific primary somatosensory connectivity to salience and default mode networks encodes clinical pain [Internet]. Pain 2019; Publisher's VersionAbstract
While several studies have found that chronic pain is characterized by increased cross-network connectivitybetween salience, sensorimotor, and default mode (DMN) networks, a large sample-size investigation allowing a more reliable evaluation of somatotopic specificity and subgroup analyses with linkage to clinical pain intensity has been lacking. We enrolled healthy adults and a large cohort of patients (N=181) suffering from chronic low back pain (cLBP). To specifically link brain connectivity with clinical pain intensity, patients were scanned at baseline and after performing physical maneuvers that exacerbated pain. Compared to healthy adults, cLBP patients demonstrated increased connectivity between the functionally-localized back representation in primary somatosensory cortex (S1back) and both salience and DMN networks. Pain exacerbation maneuvers increased S1back connectivity to salience network regions, but decreased connectivity to DMN, with greater pain intensity increase associated with greater shifts in these connectivity patterns. Furthermore, only in cLBP patients reporting high pain catastrophizing, DMN connectivity was increased to a cardinal node of the salience network, anterior insula cortex, which was correlated with increased post-maneuver pain in this cLBP subgroup. Hence, increased information transfer between salience processing regions, particularly anterior insula, and DMN may be strongly influenced by pain catastrophizing. Increased information transfer between salience network and S1 likely plays an important role in shifting nociceptive afference away from self-referential processing, re-allocating attentional focus and affective coding of nociceptive afference from specific body areas. These results demonstrate S1 somatotopic specificity for cross-network connectivity in encoding clinical back pain, and moderating influence of catastrophizing for DMN/insula connectivity.
Sclocco R, Garcia RG, Kettner NW, Isenburg K, Fisher HP, Hubbard CS, Ay I, Polimeni JR, Goldstein J, Makris N, Toschi N, Barbieri R, Napadow V. The influence of respiration on brainstem and cardiovagal response to auricular vagus nerve stimulation: A multimodal ultrahigh-field (7T) fMRI study [Internet]. Brain Stimulation 2019; Publisher's VersionAbstract
Background Brainstem-focused mechanisms supporting transcutaneous auricular VNS (taVNS) effects are not well understood, particularly in humans. We employed ultrahigh field (7T) fMRI and evaluated the influence of respiratory phase for optimal targeting, applying our respiratory-gated auricular vagal afferent nerve stimulation (RAVANS) technique. Hypothesis We proposed that targeting of nucleus tractus solitarii (NTS) and cardiovagal modulation in response to taVNS stimuli would be enhanced when stimulation is delivered during a more receptive state, i.e. exhalation. Methods Brainstem fMRI response to auricular taVNS (cymba conchae) was assessed for stimulation delivered during exhalation (eRAVANS) or inhalation (iRAVANS), while exhalation-gated stimulation over the greater auricular nerve (GANctrl, i.e. earlobe) was included as control. Furthermore, we evaluated cardiovagal response to stimulation by calculating instantaneous HF-HRV from cardiac data recorded during fMRI. Results Our findings demonstrated that eRAVANS evoked fMRI signal increase in ipsilateral pontomedullary junction in a cluster including purported NTS. Brainstem response to GANctrl localized a partially-overlapping cluster, more ventrolateral, consistent with spinal trigeminal nucleus. A region-of-interest analysis also found eRAVANS activation in monoaminergic source nuclei including locus coeruleus (LC, noradrenergic) and both dorsal and median raphe (serotonergic) nuclei. Response to eRAVANS was significantly greater than iRAVANS for all nuclei, and greater than GANctrl in LC and raphe nuclei. Furthermore, eRAVANS, but not iRAVANS, enhanced cardiovagal modulation, confirming enhanced eRAVANS response on both central and peripheral neurophysiological levels. Conclusion 7T fMRI localized brainstem response to taVNS, linked such response with autonomic outflow, and demonstrated that taVNS applied during exhalation enhanced NTS targeting.
Meints SM, Mawla I, Napadow V, Kong J, Gerber J, Chan S-T, Wasan AD, Kaptchuk TJ, McDonnell C, Carriere J, Rosen B, Gollub RL, Edwards RR. The relationship between catastrophizing and altered pain sensitivity in patients with chronic low back pain [Internet]. PAIN 2019;160 Publisher's VersionAbstract
Changes in central pain processing have been shown in patients with chronic low back pain (cLBP). We used quantitative sensory testing (QST) methods to identify differences in pain sensitization between patients with cLBP (N=167) and healthy controls (N=33). Results indicated that, compared to healthy pain-free controls, cLBP patients showed increased sensitivity and greater painful aftersensations for mechanical pressure and pin prick stimuli and lower tactile spatial acuity in the two-point discrimination task (ps<.05). Then, we examined the role of pain catastrophizing as a mediator of the group differences in pain sensitization. We found that catastrophizing partially accounted for group differences in pressure required to produce moderate pain. Finally, we examined the relationship between pain sensitization, catastrophizing, and clinical pain among patients with cLBP. We found that catastrophizing and deep-tissue pressure pain were associated with greater pain intensity in the past month, week, and at the visit as well aslow back pain bothersomeness. Further, deep-tissue pressure pain mediated the associations between catastrophizing and both pain in the past month and low back pain severity. Taken together, these results indicate that not only do patients with cLBP demonstrate increased pain sensitization and decreased sensitivity to innocuous stimuli, but these changes are also linked with increased catastrophizing. Furthermore, both catastrophizing and sensitization are associated with increased clinical pain among cLBP patients.Corresponding Author: Samantha M. Meints 850 Boylston St, Ste. 308 Chestnut Hill, MA 02467 Phone: 857-307-5405 Fax: 617-525-7900 Email:© 2018 International Association for the Study of Pain
Lee J, Mawla I, Kim J, Loggia ML, Ortiz A, Jung C, Chan S-T, Gerber J, Schmithorst VJ, Edwards RR, Wasan AD, Berna C, Kong J, Kaptchuk TJ, Gollub RL, Rosen BR, Napadow V. Machine learning–based prediction of clinical pain using multimodal neuroimaging and autonomic metrics [Internet]. PAIN 2019;160 Publisher's VersionAbstract
Although self-report pain ratings are the gold standard in clinical pain assessment, they are inherently subjective in nature and significantly influenced by multidimensional contextual variables. Although objective biomarkers for pain could substantially aid pain diagnosis and development of novel therapies, reliable markers for clinical pain have been elusive. In this study, individualized physical maneuvers were used to exacerbate clinical pain in patients with chronic low back pain (N = 53), thereby experimentally producing lower and higher pain states. Multivariate machine-learning models were then built from brain imaging (resting-state blood-oxygenation-level-dependent and arterial spin labeling functional imaging) and autonomic activity (heart rate variability) features to predict within-patient clinical pain intensity states (ie, lower vs higher pain) and were then applied to predict between-patient clinical pain ratings with independent training and testing data sets. Within-patient classification between lower and higher clinical pain intensity states showed best performance (accuracy = 92.45%, area under the curve = 0.97) when all 3 multimodal parameters were combined. Between-patient prediction of clinical pain intensity using independent training and testing data sets also demonstrated significant prediction across pain ratings using the combined model (Pearson's r = 0.63). Classification of increased pain was weighted by elevated cerebral blood flow in the thalamus, and prefrontal and posterior cingulate cortices, and increased primary somatosensory connectivity to frontoinsular cortex. Our machine-learning approach introduces a model with putative biomarkers for clinical pain and multiple clinical applications alongside self-report, from pain assessment in noncommunicative patients to identification of objective pain endophenotypes that can be used in future longitudinal research aimed at discovery of new approaches to combat chronic pain.Corresponding author. Address: Martinos Center for Biomedical Imaging, Building 149, Suite 2301, Charlestown, MA 02129, United States. Tel.: +1-617-724-3402; fax: +1-617-726-7422. E-mail address: (V. Napadow).Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site ( Lee and I. Mawla contributed equally to this work.Received July 13, 2018Accepted October 09, 2018© 2018 International Association for the Study of Pain
Gebre M, Woodbury A, Napadow V, Krishnamurthy V, Krishnamurthy LC, Sniecinski R, Crosson B. Functional Magnetic Resonance Imaging Evaluation of Auricular Percutaneous Electrical Neural Field Stimulation for Fibromyalgia: Protocol for a Feasibility Study [Internet]. JMIR Res Protoc 2018;7(2):e39. Publisher's VersionAbstract
Background: Fibromyalgia is a chronic pain state that includes widespread musculoskeletal pain, fatigue, psychiatric symptoms, cognitive and sleep disturbances, and multiple somatic symptoms. Current therapies are often insufficient or come with significant risks, and while there is an increasing demand for non-pharmacologic and especially non-opioid pain management such as that offered through complementary and alternative medicine therapies, there is currently insufficient evidence to recommend these therapies. Percutaneous electrical neural stimulation (PENS) is an evidence-based treatment option for pain conditions that involves electrical current stimulation through needles inserted into the skin. Percutaneous electrical neural field stimulation (PENFS) of the auricle is similar to PENS, but instead of targeting a single neurovascular bundle, PENFS stimulates the entire ear, covering all auricular branches of the cranial nerves, including the vagus nerve. The neural mechanisms of PENFS for fibromyalgia symptom relief are unknown. Objective: We hypothesize that PENFS treatment will decrease functional brain connectivity between the default mode network (DMN) and right posterior insula in fibromyalgia patients. We expect that the decrease in functional connectivity between the DMN and insula will correlate with patient-reported analgesic improvements as indicated by the Defense and Veterans Pain Rating Scale (DVPRS) and will be anti-correlated with patient-reported analgesic medication consumption. Exploratory analyses will be performed for further hypothesis generation. Methods: A total of 20 adults from the Atlanta Veterans Affairs Medical Center diagnosed with fibromyalgia will be randomized into 2 groups: 10 subjects to a control (standard therapy) group and 10 subjects to a PENFS treatment group. The pragmatic, standard therapy group will include pharmacologic treatments such as anticonvulsants, non-steroidal anti-inflammatory drugs, topical agents and physical therapy individualized to patient comorbidities and preferences, prescribed by a pain management practitioner. The PENFS group will include the above therapies in addition to the PENFS treatments. The PENFS subject group will have the Neuro-Stim System placed on the ear for 5 days then removed and replaced once per week for 4 weeks. The primary outcome will be resting functional magnetic resonance imaging connectivity between DMN and insula, which will also be correlated with pain relief and functional improvements. This connectivity will be analyzed utilizing functional connectivity magnetic resonance imaging (fcMRI) and will be compared with patient-reported analgesic improvements as indicated by the DVPRS and patient-reported analgesic medication consumption. Pain and function will be further evaluated using Patient-Reported Outcomes Measurement Information System measures and measures describing a person's functional status from Activity and Participation section of the International Classification of Functioning Disability and Health. Results: This trial has been funded by the Veterans Health Administration Program Office. This study attained approval by the Emory University/Veterans Affairs (VA) institutional review board and VA Research & Development committee. Institutional review board expedited approval was granted on 2/7/17 (IRB00092224). The study start date is 6/1/17 and estimated completion date is 5/31/20. The recruitment started in June 2017. Conclusions: This is a feasibility study that is meant to demonstrate the practicality of using fcMRI to study the neural correlates of PENFS outcomes and provide information regarding power calculations in order to design and execute a larger randomized controlled clinical trial to determine the efficacy of PENFS for improving pain and function. Trial Registration: NCT03008837; (Archived by WebCite at
Lee YC, Napadow V, Loggia ML. Editorial: Functional Connectivity: Dissecting the Relationship Between the Brain and “Pain Centralization” in Rheumatoid Arthritis [Internet]. Arthritis & Rheumatology 2018;70(7):977-980. Publisher's Version