ORCID Profile
0000-0002-9699-6329
Current Organisations
Spaulding Rehabilitation Hospital
,
University Medical Center Hamburg-Eppendorf
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Publisher: IEEE
Date: 07-2020
Publisher: Elsevier BV
Date: 05-2021
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-11-2020
DOI: 10.1097/J.PAIN.0000000000002134
Abstract: 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.
Publisher: Elsevier BV
Date: 05-2021
Publisher: eLife Sciences Publications, Ltd
Date: 20-03-2018
DOI: 10.7554/ELIFE.32930
Abstract: In placebo hypoalgesia research, the strength of treatment expectations and experiences are key components. However, the reliability or precision of expectations had been mostly ignored although being a likely source for interin idual differences. In the present study, we adopted a Bayesian framework, naturally combining expectation magnitudes and precisions. This postulates that expectations (prior) are integrated with incoming nociceptive information (likelihood) and both are weighted by their relative precision to form the pain percept and placebo effect. Sixty-two healthy subjects received heat pain during fMRI. Placebo effects were more pronounced in subjects with more precise treatment expectations and correlated positively with the relative precision of the prior expectation. Neural correlates of this precision were observed in the periaqueductal gray and the rostral ventromedial medulla, indicating that already at the level of the brainstem the precision of an expectation can influence pain perception presenting strong evidence for Bayesian integration in placebo hypoalgesia.
Publisher: Wiley
Date: 10-03-2022
DOI: 10.1002/ART.42013
Abstract: Abnormal central pain processing is a leading cause of pain in fibromyalgia (FM) and is perceptually characterized with the psychophysical measure of temporal summation of pain (TSP). TSP is the perception of increasingly greater pain in response to repetitive or tonic noxious stimuli. Previous neuroimaging studies have used static (i.e., summary) measures to examine the functional magnetic resonance imaging (fMRI) correlates of TSP in FM. However, functional brain activity rapidly and dynamically reorganizes over time, and, similarly, TSP is a temporally evolving process. This study was undertaken to demonstrate how a complete understanding of the neural circuitry supporting TSP in FM thus requires a dynamic measure that evolves over time. We utilized novel methods for analyzing dynamic functional brain connectivity in patients with FM in order to examine how TSP‐associated fluctuations are linked to the dynamic functional reconfiguration of the brain. In 84 FM patients and age‐ and sex‐matched healthy controls, we collected high‐temporal‐resolution fMRI data during a resting state and during a state in which sustained cuff pressure pain was applied to the leg. FM patients experienced greater TSP than healthy controls (mean ± SD TSP score 17.93 ± 19.24 in FM patients versus 9.47 ± 14.06 in healthy controls P = 0.028), but TSP scores varied substantially between patients. In the brain, the presence versus absence of TSP in patients with FM was marked by more sustained enmeshment between sensorimotor and salience networks during the pain period. Furthermore, dynamic enmeshment was noted solely in FM patients with high TSP, as interactions with all other brain networks were d ened during the pain period. This study elucidates the dynamic brain processes underlying facilitated central pain processing in FM. Our findings will enable future investigation of dynamic symptoms in FM.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.NEUROIMAGE.2013.06.010
Abstract: Progressing from 3T to 7 T functional MRI enables marked improvements of human brain imaging in vivo. Although direct comparisons demonstrated advantages concerning blood oxygen level dependent (BOLD) signal response and spatial specificity, these mostly focused on single brain regions with rather simple tasks. Considering that physiological noise also increases with higher field strength, it is not entirely clear whether the advantages of 7T translate equally to the entire brain during tasks which elicit more complex neuronal processing. Therefore, we investigated the difference between 3T and 7 T in response to transcutaneous electrical painful and non-painful stimulation in 22 healthy subjects. For painful stimuli vs. baseline, stronger activations were observed at 7 T in several brain regions including the insula and supplementary motor area, but not the secondary somatosensory cortex (p<0.05 FWE-corrected). Contrasting painful vs. non-painful stimulation limited the differences between the field strengths to the periaqueductal gray (PAG, p<0.001 uncorrected) due to a similar signal increase at 7 T for both the target and specific control condition in most brain regions. This regional specificity obtained for the PAG at higher field strengths was confirmed by an additional spatial normalization strategy optimized for the brainstem. Here, robust BOLD responses were obtained in the dorsal PAG at 7 T (p<0.05 FWE-corrected), whereas at 3T activation was completely missing for the contrast against non-painful stimuli. To summarize, our findings support previously reported benefits obtained at ultra-high field strengths also for complex activation patterns elicited by painful electrical stimulation. However, this advantage depends on the region and even more on the contrast of interest. The greatest gain at 7 T was observed within the small brainstem region of the PAG, where the increased field strength offered marked improvement for the localization of activation foci with high spatial specificity.
Publisher: eLife Sciences Publications, Ltd
Date: 02-02-2018
Publisher: Elsevier BV
Date: 05-2021
Publisher: Springer Science and Business Media LLC
Date: 12-10-2021
DOI: 10.1186/S12891-021-04740-5
Abstract: Chronic pain can have detrimental effects on quality of life and a profound impact on one’s identity. The Pictorial Representation of Illness- and Self-Measure (PRISM), is a visual tool designed to measure the self-illness separation (SIS) that represents the degree of schema-enmeshment (i.e., the degree to which the self-schema and the illness-schema come to overlap). Our aim was to investigate the relationship between schema-enmeshment and pain-related outcomes in patients with fibromyalgia. In this cross-sectional study, 114 patients with fibromyalgia completed self-report assessments of pain catastrophizing, pain severity and interference, impact of symptoms, anxiety, and depression. SIS was assessed using an iPad version of PRISM. Mediation analyses evaluated the mediating role of schema-enmeshment on the association between pain catastrophizing and fibromyalgia impact. A higher degree of schema-enmeshment was associated with greater pain catastrophizing, pain severity and interference, impact of symptoms, and depression. Moreover, a mediation analysis revealed that schema-enmeshment significantly mediated the association between pain catastrophizing and fibromyalgia impact ( p 0.001). Our results indicate that schema-enmeshment is associated with greater intrusiveness of chronic pain on everyday life, thereby posing significant limitations on the emotional and physical well-being of fibromyalgia patients. Schema-enmeshment also appears to partly account for the deleterious effect of pain catastrophizing on disease impact. The PRISM is a simple tool that may uniquely capture the extent to which chronic pain and illness infiltrates and affects one’s self-concept.
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.BIOPSYCHO.2014.12.007
Abstract: The present study investigated whether the same visual stimulus indicating zero-value feedback (€0) elicits feedback-related negativity (FRN) variation, depending on whether the outcomes correspond with expectations or not. Thirty-one volunteers performed a monetary incentive delay (MID) task while EEG was recorded. FRN litudes were comparable and more negative when zero-value outcome deviated from expectations than with expected gain or loss, supporting theories emphasising the impact of unexpectedness and salience on FRN litudes. Surprisingly, expected zero-value outcomes elicited the most negative FRNs. However, source localisation showed that such outcomes evoked less activation in cingulate areas than unexpected zero-value outcomes. Our study illustrates the context dependency of identical zero-value feedback stimuli. Moreover, the results indicate that the incentive cues in the MID task evoke different reward prediction error signals. These prediction signals differ in FRN litude and neuronal sources, and have to be considered in the design and interpretation of future studies.
Publisher: Wiley
Date: 16-10-2014
DOI: 10.1002/HBM.22661
Publisher: Wiley
Date: 22-06-2021
DOI: 10.1002/EJP.1820
Abstract: Fibromyalgia is a centralized multidimensional chronic pain syndrome, but its pathophysiology is not fully understood. 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). 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. These findings support single voxel placement targeting nociceptive processing areas in prior 1 H‐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 in idualized therapies. Furthermore, efficient multi‐region s ling 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. 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.
Location: United States of America
No related grants have been discovered for Arvina Grahl.