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Objectives: The study aimed to investigate brain metabolites in type 1 diabetes and the associations with disease characteristics. We explored the metabolic profiles predicting different neuropathic phenotypes using multiple linear regression analyses., Methods: We compared brain metabolites in 55 adults with type 1 diabetes (including painful diabetic peripheral neuropathy (DPN), painless DPN, without DPN) with 20 healthy controls. Proton magnetic resonance spectroscopy measurements (N-acetylaspartate (NAA), glutamate (glu), myo-inositol (mI), and glycerophosphocholine (GPC) were obtained in ratios to creatine (cre)) from the parietal region, anterior cingulate cortex and thalamus., Results: The overall diabetes group revealed decreased parietal NAA/cre compared to healthy controls (1.41 ± 0.12 vs. 1.55 ± 0.13,p < 0.001) and increased mI/cre (parietal: 0.62 ± 0.08 vs. 0.57 ± 0.07,p = 0.025, cingulate: 0.65 ± 0.08 vs. 0.60 ± 0.08,p = 0.033). Reduced NAA/cre was associated with more severe DPN (all p ≤ 0.04) whereas increased mI/cre was associated with higher hemoglobin A 1c (HbA 1c ) (p = 0.02). Diabetes was predicted from decreased parietal NAA/cre, increased parietal ml/cre, and decreased thalamic glu/cre. DPN was predicted from decreased parietal NAA/cre and increased GPC/cre. Painful DPN was predicted from increased parietal GPC/cre and thalamic glu/cre., Conclusions: Specific metabolic brain profiles were linked to the different phenotypes of diabetes, DPN and painful DPN., Significance: Assessment of metabolic profiles could be relevant for detailed understanding of central neuropathy in diabetes., Competing Interests: Declarations of interest None., (Copyright © 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: The functional connectivity of the brain in chronic pancreatitis (CP) remains unknown. This study aimed to investigate functional connectivity in CP patients using resting state functional magnetic resonance imaging (fMRI) and explore the associations to clinical parameters and altered cerebral metabolites., Methods: Seed-based and ROI-to-ROI analyses were performed to assess connectivity within and between the default mode network (DMN) and salience network (SN). Additionally, functional connectivity in these networks were investigated in relation to clinical parameters (CP etiology, pain, medication, etc.) and cerebral glutamate/creatine level in the anterior cingulate cortex., Results: Thirty CP patients and 23 healthy controls were analyzed. CP patients showed hyper-connectivity in DMN and SN as compared to healthy controls. Furthermore, CP patients had reduced anti-correlated functional connectivity between DMN and SN (all P ≤ 0.009). The altered DMN connectivity correlated to glutamate/creatine level (r = 0.503, P = 0.020) in patients with pain, but not to the clinical parameters., Conclusions: CP patients had altered functional connectivity within and between brain networks. Altered DMN functional connectivity had an association to cerebral metabolic changes., Significance: Altered functional connectivity in CP share similarities with other chronic pain conditions, and support our understanding of altered brain circuitry associated with the CP disease., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Aims: Emerging evidence shows, that distal symmetric peripheral neuropathy (DSPN) also involves alterations in the central nervous system. Hence, the aims were to investigate brain metabolites in white matter of adults with diabetes and DSPN, and to compare any cerebral disparities with peripheral nerve characteristics., Methods: In type 1 diabetes, brain metabolites of 47 adults with confirmed DSPN were compared with 28 matched healthy controls using proton magnetic resonance spectroscopy (H-MRS) in the parietal region including the sensorimotor fiber tracts., Results: Adults with diabetes had 9.3% lower ratio of N-acetylaspartate/creatine (NAA/cre) in comparison to healthy (p < 0.001). Lower NAA/cre was associated with lower sural (p = 0.01) and tibial (p = 0.04) nerve amplitudes, longer diabetes duration (p = 0.03) and higher age (p = 0.03). In addition, NAA/cre was significantly lower in the subgroup with proliferative retinopathy as compared to the subgroup with non-proliferative retinopathy (p = 0.02)., Conclusions: The association to peripheral nerve dysfunction, indicates concomitant presence of DSPN and central neuropathies, supporting the increasing recognition of diabetic neuropathy being, at least partly, a disease leading to polyneuropathy. Decreased NAA, is a potential promising biomarker of central neuronal dysfunction or loss, and thus may be useful to measure progression of neuropathy in diabetes or other neurodegenerative diseases., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: Temporal information about the structural brain changes in chronic pancreatitis (CP) and its relation to the clinical manifestations is lacking. This study investigated changes in morphological brain parameters over 7 years in painful CP patients, compared with controls., Methods: In this 7-year longitudinal magnetic resonance imaging study, we included 23 CP patients and 14 controls. Gray matter volume (GMV) and cortical thickness were examined using voxel-based and surface-based morphometry. In addition, patients completed pain questionnaires and diary., Results: At baseline, patients had reduced GMV and cortical thickness in widespread brain areas compared with controls. After 7 years of follow-up, the GMV loss was more pronounced in patients compared with controls, particularly in precentral gyrus and putamen. Moreover, an increase in pain scores was associated with a less reduction of thalamic GMV (P = 0.046), whereas an increase in brief pain inventory score was associated with more reduction in cortical thickness of precentral (P = 0.005) and superior temporal gyri (P = 0.019), indicating that brain morphological alterations are associated with the pain., Conclusions: Chronic pancreatitis pain is associated with morphological brain changes over time in several areas, reflecting that brain plasticity may be a consequence of repeated long-term nociceptive signaling.

Background: Abnormal central nervous system processing of visceral sensation may be a part of the pathogenesis behind idiopathic fecal incontinence (IFI). Our aim was to characterize brain differences in patients with IFI and healthy controls by means of structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI)., Methods: In 21 female patients with IFI and 15 female healthy controls, whole-brain structural differences in gray matter volume (GMV), cortical thickness, and white matter tracts fractional anisotropy (FA) were quantified. For this purpose, we used voxel-based morphometry, surface based morphometry and tract-based spatial statistic, respectively. Furthermore, associations between structural brain characteristics and latencies of rectal sensory evoked electroencephalography potentials were determined., Key Results: Compared to healthy controls, IFI patients had significantly reduced FA values, reflecting reduced white matter tract integrity, in the left hemisphere superior longitudinal fasciculus (SLF), posterior thalamic radiation, and middle frontal gyrus (MFG), all P<.05. No differences were observed in GMV or in cortical thickness. The reduced FA values in the SLF and MFG were correlated with prolonged latencies of cortical potentials evoked by rectal stimuli (all P<.05)., Conclusions & Inferences: This explorative study suggests that IFI patients have no macrostructural brain changes, but exhibit microstructural changes in white matter tracts relevant for sensory processing. The clinical relevance of this finding is supported by its correlations with prolonged latencies of cortical potentials evoked by rectal stimulation. This supports the theories of central nervous system changes as part of the pathogenesis in IFI patients., (© 2017 John Wiley & Sons Ltd.)

Symptoms relating to esophageal sensory abnormalities can be encountered in the clinical environment. Such sensory abnormalities may be present in demonstrable disease, such as erosive esophagitis, and in the ostensibly normal esophagus, such as non-erosive reflux disease or functional chest pain. In this review, the authors discuss esophageal sensation and the esophageal pain system. In addition, the authors provide a primer concerning the techniques that are available for investigating the autonomic nervous system, neuroimaging and neurophysiology of esophageal sensory function. Such technological advances, whilst not readily available in the clinic may facilitate the stratification and individualization of therapy in disorders of esophageal sensation in the future.

Knowledge about cerebral mechanisms underlying pain perception and effect of analgesic drugs is important for developing methods for diagnosis and treatment of pain. The aim was to explore altered brain activation before and after morphine treatment using functional magnetic resonance imaging recorded during experimental painful heat stimulation. Functional magnetic resonance imaging data were recorded and analysed in 20 healthy volunteers (13 men and 7 women, 24.9 ± 2.6 years) in a randomized, double-blind, placebo-controlled, cross-over study. Painful stimulations were applied to the right forearm using a contact heat evoked potential stimulator (CHEPS) before and after treatment with 30 mg oral morphine and placebo. CHEPS stimulations before treatment induced activation in the anterior cingulate cortex, secondary somatosensory cortex/insula, thalamus and cerebellum (n = 16, p < 0.05). In response to morphine treatment, the spatial extent of these pain-specific areas decreased (n = 20). Reduced pain-induced activation was seen in the right insula, anterior cingulate cortex and inferior parietal cortex after morphine treatment compared to before treatment (n = 16, p < 0.05), and sensory ratings of pain perception were significantly reduced after morphine treatment (p = 0.02). No effect on pain-induced brain activation was seen after placebo treatment compared to before treatment (n = 12, p > 0.05). In conclusion, heat stimulation activated areas in the 'pain matrix' and a clinically relevant dose of orally administered morphine revealed significant changes in brain areas where opioidergic pathways are predominant. The method may be useful to investigate the mechanisms of analgesics., (© 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).)

Background: Increasing evidence points to association between long-term diabetes mellitus and abnormal brain processing. The aim of this study was to investigate central changes due to electrical stimulation in esophagus in patients with upper gastrointestinal (GI) symptoms due to diabetic neuropathy., Methods: Twenty-three diabetes patients with upper GI symptoms and 27 healthy controls were included. A standard ambulatory 24-h electrocardiography was carried out. 122-channel esophageal evoked brain potentials to electrical stimulation were acquired. Brain source/network analysis was performed. Gastroparesis Cardinal Symptom Index was used to evaluate upper GI symptoms and SF-36 questionnaire was utilized to assess patients' quality of life (QOL)., Key Results: Diabetes patients with GI symptoms showed modifications in three brain networks: (i) brainstem/operculum/frontal cortex, (ii) operculum/cingulate, and (iii) mid-cingulate/anterior-cingulate/operculum/deep limbic structures. Operculum brain source in patients was localized deeper and more anterior in all three networks. The shift of operculum source was correlated with the severity of upper GI symptoms, decreased heart beat-to-beat interval, and decreased SD of the intervals. The activation of the first network was delayed in patients. Operculum source had higher activity than cingulate in the second network in patients, and this was correlated with decreased physical QOL. Deep limbic source was localized deeper in patients, which also correlated with decreased physical QOL., Conclusions & Inferences: This study indicates involvement of central nervous system in diabetes. Reorganization within opercular cortex was correlated with GI symptoms suggesting that operculo-cingulate cortex could contribute to development and maintenance of GI symptoms in diabetes patients.

Introduction: Therapy-induced injury to normal brain tissue is a concern in the treatment of all types of brain tumours. The purpose of this study was to investigate if magnetic resonance diffusion tensor imaging (DTI) could serve as a potential biomarker for the assessment of radiation-induced long-term white matter injury., Material and Methods: DTI- and T1-weighted images of the brain were obtained in 19 former radiotherapy patients [nine men and 10 women diagnosed with astrocytoma (4), pituitary adenoma (6), meningioma (8) and craniopharyngioma (1), average age 57.8 (range 35-71) years]. Average time from radiotherapy to DTI scan was 4.6 (range 2.0-7.1) years. NordicICE software (NIC) was used to calculate apparent diffusion coefficient maps (ADC-maps). The co-registration between T1 images and ADC-maps were done using the auto function in NIC. The co-registration between the T1 images and the patient dose plans were done using the auto function in the treatment planning system Eclipse from Varian. Regions of interest were drawn on the T1-weighted images in NIC based on isocurves from Eclipse. Data was analysed by t-test. Estimates are given with 95% CI., Results: A mean ADC difference of 4.6(0.3;8.9)× 10(-5) mm(2)/s, p = 0.03 was found between paired white matter structures with a mean dose difference of 31.4 Gy. Comparing the ADC-values of the areas with highest dose from the paired data (dose > 33 Gy) with normal white matter (dose < 5 Gy) resulted in a mean dose difference of 44.1 Gy and a mean ADC difference of 7.87(3.15;12.60)× 10(-5) mm(2)/s, p = 0.003. Following results were obtained when looking at differences between white matter mean ADC in average dose levels from 5 to 55 Gy in steps of 10 Gy with normal white matter mean ADC: 5 Gy; 1.91(-1.76;5.58)× 10(-5) mm(2)/s, p = 0.29; 15 Gy; 5.81(1.53;10.11)× 10(-5) mm(2)/s, p = 0.01; 25 Gy; 5.80(2.43;9.18)× 10(-5) mm(2)/s, p = 0.002; 35 Gy; 5.93(2.89;8.97)× 10(-5) mm(2)/s, p = 0.0007; 45 Gy; 4.32(-0.24;8.89)× 10(-5) mm(2)/s, p = 0.06; 55 Gy; -4.04(-14.96;6.89)× 10(-5) mm(2)/s, p = 0.39., Conclusion: The results indicate that the structural integrity of white matter, assessed by ADC-values based on DTI, undergoes changes after radiation therapy starting as early as total dose levels between 5 and 15 Gy.

Introduction: It has been shown that patients with type 1 diabetes mellitus and gastrointestinal (GI) symptoms have abnormal processing of sensory information following stimulation in the oesophagus. In order to find less invasive stimuli to study visceral afferent processing and to further elaborate the gut-brain network in diabetes, we studied brain networks following rectal electrical stimulations., Methods: Twelve type 1 diabetes patients with GI symptoms and twelve healthy controls were included. A standard ambulatory 24-h electrocardiography was performed. 122-channel-evoked brain potentials to electrical stimulation in the rectum were recorded. Brain source-connectivity analysis was done. GI symptoms were assessed with the gastroparesis cardinal symptom index and quality of life (QOL) with SF-36. Any changes in brain source connectivity were correlated to duration of the disease, heart beat-to-beat intervals (RRs), clinical symptoms, and QOL of the patients., Results: Diabetic patients with GI symptoms showed changes relative to controls in the operculum-cingulate network with the operculum source localized deeper and more anterior (P≤0.001) and the cingulate source localized more anterior (P=0.03). The shift of operculum source was correlated with the duration of the disease, severity of GI symptoms, and decreased RR (P<0.05). The shift of the cingulate source was correlated with the mental QOL (P=0.04). In healthy controls, the contribution of the cingulate source to the network was higher than the contribution of the operculum source (P≤0.001), whereas in patients the contribution of the two sources was comparable., Conclusion: This study gives further evidence for CNS involvement in diabetes. Since network reorganizations were correlated to GI symptoms, irregularities of rectal-evoked potentials can be viewed as a proxy for abnormal bottom-up visceral afferent processing. The network changes might serve as a biomarker for disturbed sensory visceral processing of GI symptoms in diabetes patients., (Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.)

Objective: In patients with long-standing diabetes mellitus (DM), there is increasing evidence for abnormal processing of gastrointestinal sensations in the central nervous system. Using magnetic resonance diffusion tensor imaging, we characterized brain microstructure in areas involved in visceral sensory processing and correlated these findings to clinical parameters., Research Design and Methods: Twenty-six patients with DM and gastrointestinal symptoms and 23 healthy control subjects were studied in a 3T scanner. The apparent diffusion coefficient (i.e., diffusivity of water) and fractional anisotropy (FA) (i.e., organization of fibers) were assessed in the "sensory matrix" (cingulate cortex, insula, prefrontal and secondary sensory cortex, amygdala, and corona radiata) and in corpus callosum., Results: Patients had decreased FA values compared with control subjects in 1) all areas (P = 0.025); 2) anterior (P < 0.001), mid- (P = 0.001), and posterior (P < 0.001) cingulate cortex; 3) prefrontal cortex gray matter (P < 0.001); 4) corona radiata (P < 0.001); 5) secondary sensory cortex (P = 0.008); and 6) anterior white matter (P = 0.045), anterior gray matter (P = 0.002), and posterior gray matter (P = 0.002) insula. No difference was found in corpus callosum (P > 0.05). The microstructural changes in some areas correlated with clinical parameters such as bloating (anterior insula), mental well-being (anterior insula, prefrontal cortex, and mid-cingulated and corona radiata), autonomic function based on electrocardiographic results (posterior insula and anterior cingulate), and presence of gastroparesis (anterior insula)., Conclusions: The findings of this explorative study indicate that microstructural changes of brain areas involved in visceral sensory processing are associated with autonomic dysfunction and therefore may be involved in the pathogenesis of gastrointestinal symptoms in DM patients.

Diabetes mellitus (DM) is a multi-factorial and complex disease causing autonomic neuropathy and gastrointestinal symptoms in some patients. The neural mechanisms behind these symptoms are poorly understood, but it is believed that both peripheral and central mechanisms are involved. To gain further knowledge of the central mechanisms, the aim of this study was to identify biomarkers for the altered brain activity in type-1 DM patients compared to healthy volunteers (HV), and to correlate the obtained biomarkers to clinical patient scores. The study included 14 DM patients and 15 HV, with brain activity recorded as multi-channel electroencephalography evoked brain potentials (EPs) elicited by painful electrical stimulations in the esophagus. The single-sweep EPs were decomposed by an optimized discrete wavelet transform (DWT), and averaged for each channel. The DWT features from the DM patients were discriminated from the HV by a support vector machine (SVM) applied in regression mode. For the optimal DWT, the discriminative features were extracted and the SVM regression value representing the overall alteration of the EP was correlated to the clinical scores. A classification performance of 86.2% (P=0.01) was obtained by applying a majority voting scheme to the 5 best performing channels. The biomarker was identified as decreased theta band activity. The regression value was correlated to symptoms reported by the patients (P=0.04). The methodology is an improvement of the present approach to study central mechanisms in diabetes mellitus, and may provide a future application for a clinical tool to optimize treatment in individual patients.

Background and Aims: Autonomic neuropathy seems to play a central role in the development of gastrointestinal symptoms in diabetes. In order to explore the neuronal mechanisms behind the symptoms we evaluated the brain processing of painful visceral stimuli., Methods: Evoked brain potentials were recorded to assess the response to painful oesophageal electrical stimuli in 15 healthy volunteers and 14 type-1 diabetes patients with autonomic neuropathy and related gastrointestinal symptoms. Source reconstruction analysis (fixed Multiple Signal Classification (MUSIC) algorithm) was applied to estimate the location of the evoked electrical activity in the brain., Results: The patients had increased oesophageal sensory thresholds compared to the controls (P=0.004). The latencies of the evoked brain potentials at vertex (Cz) were increased (P=0.007) and amplitudes reduced (P=0.011) in diabetics. Compared with controls the patients had a posterior shift of the electrical sources in the anterior cingulate cortex at 54 ms, and additional sources close to the posterior insula at 95 ms and in medial frontal gyrus at 184 ms., Conclusions: There is evidence of altered central processing to visceral stimulation, and both peripheral and central mechanisms seem involved. Central neuronal reorganisation may contribute to our understanding of the gastrointestinal symptoms in patients with diabetic autonomic neuropathy and this may guide development and evaluation of new treatment modalities., (Copyright © 2010 European Federation of International Association for the Study of Pain Chapters. Published by Elsevier Ltd. All rights reserved.)