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Objectives Despite increasing evidence demonstrating structural and functional alterations within the central nervous system in diabetic peripheral neuropathy (DPN), the neuroanatomical correlates of Painful- and Painless-DPN have yet to be identified. Focusing on structural magnetic resonance (MR) imaging, the aims of this study were to 1) define the brain morphological alterations in Painful- and Painless-DPN and 2) explore the relationships between brain morphology and clinical/neurophysiological assessments. Research Design and Methods 277 participants with type 1 and 2 diabetes (No-DPN [n=57]; Painless-DPN [n=77]; and Painful-DPN [n=77]) and 66 healthy volunteers (HV) were enrolled. All underwent detailed clinical/neurophysiological assessment and brain MR imaging at 3-Tesla. Painful-DPN participants were subdivided into the irritable nociceptor (IR) and the non-irritable nociceptor (NIR) phenotype using the German Research Network on Neuropathic Painprotocol. Cortical reconstruction and volumetric segmentation were performed with FreeSurfer software and voxel-based morphometry implemented in FSL. Results Both Painful- and Painless-DPN had significant reduction in primary somatosensory and motor cortical thickness compared to HV and No-DPN [P=0.02; F(3,275)=3.36 and P=0.01; F(3,275)=3.80 respectively]. Somatomotor cortical thickness correlated with neurophysiological measures of DPN severity. There was also reduction in ventrobasal thalamic nuclei volume in both Painless- and Painful-DPN. Painful-DPN subjects with the NIR nociceptor phenotype had reduced primary somatosensory, posterior cingulate cortical and thalamic volume compared to the IR nociceptor phenotype. Conclusions In this, the largest neuroimaging study in DPN to date, we have demonstrated significant structural alterations in key somatomotor/nociceptive brain regions specific to Painless-DPN and Painful-DPN including the IR and NIR nociceptor phenotype.

Painful diabetic neuropathy (DN) is a common and distressing complication. New approaches are required to identify novel targets that will serve as a catalyst for future drug discovery programmes. We have demonstrated that responders to neuropathic pain treatment have greater functional connectivity between the insula cortex and the corticolimbic system compared to non-responders. Activity within these networks is mediated by endogenous opioid receptor systems and may hold clues to possible future treatment targets. Methods: 43 painful-DN subjects [responders (VAS Disclosure K.Teh: None. G.P.Sloan: None. I.D.Wilkinson: None. S.Tesfaye: Advisory Panel; Astellas Pharma Inc., Bayer AG, Grünenthal Group, Nevro Corp., Wörwag Pharma GmbH & Co. KG, Speaker's Bureau; Eva Pharma, Pfizer Inc., Viatris Inc. D.Selvarajah: None. Funding National Institute of Health Research EME grant; European Foundation for the Study of Diabetes

Objective: We have previously demonstrated increased thalamic blood volume and preserved HMRS neuronal metabolite ratios in painful diabetic peripheral neuropathy (P-DPN) . We hypothesised that perfusion measures and neuronal function measured by metabolite ratios may be related. However, as brain metabolite ratios may also be affected by mood disorders, common in P-DPN, this may be a significant confounding factor. Methods: 52 type 1 diabetes (T1D) subjects (18 P-DPN, 23 DPN, 13 without neuropathy-DM-NN) and 18 healthy volunteers (HV) were recruited. 1HMRS was performed at 3T (Philips, Netherlands) . Single voxel spectra were obtained from a 2.25cm3 (15x10x15mm) volume of interest within the thalamus, TE=135ms, TR=1600ms, NSA=256 using point resolved (PRESS) technique. Metabolite ratios were calculated for choline, Creatine, and N-Acetyl Aspartate (NAA) . MR-DSC images were obtained at 3T using a T2*-weighted technique (TR/TE=1250/35ms; 72 dynamics) to assess the passage of bolus intravenous gadolinium-chelate through the thalamus. Results: There was significant negative correlation between NAA/Cr (measure of neuronal function) and measures of depression: Hospital Anxiety and Depression Scale R= -0.33 (p=0.01) , Becks Depression Inventory R= -0.25 (p=.048) ; and anxiety: State-Trait Anxiety inventory- State (STAI-S) R= -.37 (p=.002) , STAI- Trait (T) R= -.32 (p=0.01) and Behavioural Inhibition R= -0.25 (p=0.04) . There were no differences in metabolite ratios between groups; and no significant correlations between perfusion measures and metabolite ratios. Conclusion: This is the first study to show thalamic 1HMRS metabolite ratios are correlated with measures of mood disorders in T1D. The high prevalence of mood disorders in P-DPN and DPN have confounded previous 1HMRS studies and may explain conflicting reports in the literature. The link between neuropathy and mood disorders needs further exploration to understand whether both may arise from a common neurobiological pathway. Disclosure M.Greig: None. G.P.Sloan: None. P.Shillo: None. D.Selvarajah: None. I.D.Wilkinson: None. S.Tesfaye: Advisory Panel; Astellas Pharma Inc., Bayer AG, Grünenthal Group, Nevro Corp., Wörwag Pharma GmbH & Co. KG, Speaker's Bureau; Eva Pharma, Pfizer Inc., Viatris Inc. Funding European Foundation for the Study of Diabetes (EFSD)

Aim: Our study predicted treatment responses in patients with painful DPN (diabetic peripheral neuropathy) by developing a deep learning model using resting state functional magnetic resonance imaging (fMRI) neuroimaging datasets. Methods: Forty-three consecutive patients who received intravenous lidocaine treatment for painful DPN were assessed. All subjects (responders n=29 and non-responders n=14) underwent detailed clinical and neurophysiological assessments to phenotype their pain sensory profile. Subjects also underwent brain resting-state fMRI. After pre-processing we performed a group concatenated independent component analysis (ICA) set to 30 components and automatically chose 7 highly correlated (p Results: The deep learning treatment response classification in a ten-fold cross validation experiment using 7 ICA spatial maps has a mean AUC of 0.85 and an F1-Score of 0.90. However, with the extra information of all 30 ICA maps the mean AUROC increased to 0.97 with an F1-Score of 0.95. Using only pre-processed resting-state fMRI data achieved suboptimal F1-Score of 69% and AUC score of 44%. Conclusion: Through the use of our deep learning model, we have demonstrated high classification performance. Our method improves painful DPN treatment efficiency by stratifying patients to receive the correct treatment from the outset. We believe to our knowledge this is the first study utilising deep learning methods to classify treatment response in painful DPN. Disclosure K.Teh: None. I.D.Wilkinson: None. G.P.Sloan: None. S.Tesfaye: Advisory Panel; Astellas Pharma Inc., Bayer AG, Grünenthal Group, Nevro Corp., Wörwag Pharma GmbH & Co. KG, Speaker's Bureau; Eva Pharma, Pfizer Inc., Viatris Inc. D.Selvarajah: None. Funding National Instituteof Health Research Efficacy and Mechanism Evaluation Programme (NIHR 129921) European Foundation for the Study of Diabetes (Microvascular Complications Project Grant) University of Sheffield, Health Education England, Knowledge Exchange

We report a consanguineous family in which schizophrenia segregates in a manner consistent with recessive inheritance of a rare, partial-penetrance susceptibility allele. From 4 marriages between 2 sets of siblings who are half first cousins, 6 offspring have diagnoses of psychotic disorder. Homozygosity mapping revealed a 6.1-Mb homozygous region on chromosome 13q22.2-31.1 shared by all affected individuals, containing 13 protein-coding genes. Microsatellite analysis confirmed homozygosity for the affected haplotype in 12 further apparently unaffected members of the family. Psychiatric reports suggested an endophenotype of milder psychiatric illness in 4 of these individuals. Exome and genome sequencing revealed no potentially pathogenic coding or structural variants within the risk haplotype. Filtering for noncoding variants with a minor allele frequency of

Painful diabetic peripheral neuropathy (DPN) is difficult to manage, as treatment response is often varied. The primary aim of this study was to examine differences in pain phenotypes between responders and nonresponders to intravenous lidocaine treatment using quantitative sensory testing. The secondary aim was to explore differences in brain structure and functional connectivity with treatment response. Forty-five consecutive patients who received intravenous lidocaine treatment for painful DPN were screened. Twenty-nine patients who met the eligibility criteria (responders, n = 14, and nonresponders, n = 15) and 26 healthy control subjects underwent detailed sensory profiling. Subjects also underwent multimodal brain MRI. A greater proportion of patients with the irritable (IR) nociceptor phenotype were responders to intravenous lidocaine treatment compared with nonresponders. The odds ratio of responding to intravenous lidocaine was 8.67 times greater (95% CI 1.4–53.8) for the IR nociceptor phenotype. Responders to intravenous lidocaine also had significantly greater mean primary somatosensory cortex cortical volume and functional connectivity between the insula cortex and the corticolimbic circuitry. This study provides preliminary evidence for a mechanism-based approach for individualizing therapy in patients with painful DPN.

Background Schizophrenia endophenotypes may help elucidate functional effects of genetic risk variants in multiply affected consanguineous families that segregate recessive risk alleles of large effect size. We studied the association between a schizophrenia risk locus involving a 6.1Mb homozygous region on chromosome 13q22–31 in a consanguineous multiplex family and cognitive functioning, haemodynamic response and white matter integrity using neuroimaging. Methods We performed CANTAB neuropsychological testing on four affected family members (all homozygous for the risk locus), ten unaffected family members (seven homozygous and three heterozygous) and ten healthy volunteers, and tested neuronal responses on fMRI during an n-back working memory task, and white matter integrity on diffusion tensor imaging (DTI) on four affected and six unaffected family members (four homozygous and two heterozygous) and three healthy volunteers. For cognitive comparisons we used a linear mixed model (Kruskal–Wallis) test, followed by posthoc Dunn's pairwise tests with a Bonferroni adjustment. For fMRI analysis, we counted voxels exceeding the p < 0.05 corrected threshold. DTI analysis was observational. Results Family members with schizophrenia and unaffected family members homozygous for the risk haplotype showed attention (p < 0.01) and working memory deficits (p < 0.01) compared with healthy controls; a neural activation laterality bias towards the right prefrontal cortex (voxels reaching p < 0.05, corrected) and observed lower fractional anisotropy in the anterior cingulate cortex and left dorsolateral prefrontal cortex. Conclusions In this family, homozygosity at the 13q risk locus was associated with impaired cognition, white matter integrity, and altered laterality of neural activation.

Background Clinical phenotypic heterogeneity represents a major barrier to trials in motor neuron disease (MND) and objective surrogate outcome measures are required, especially for slowly progressive patients. We assessed responsiveness of clinical, electrophysiological and radiological muscle-based assessments to detect MND-related progression. Materials and methods A prospective, longitudinal cohort study of 29 MND patients and 22 healthy controls was performed. Clinical measures, electrophysiological motor unit number index/size (MUNIX/MUSIX) and relative T2- and diffusion-weighted whole-body muscle magnetic resonance (MR) were assessed three times over 12 months. Multi-variable regression models assessed between-group differences, clinico-electrophysiological associations, and longitudinal changes. Standardized response means (SRMs) assessed sensitivity to change over 12 months. Results MND patients exhibited 18% higher whole-body mean muscle relative T2-signal than controls (95% CI 7–29%, p p p Conclusion MUNIX and relative T2-weighted MR represent objective surrogate markers of progressive denervation in MND. Radiological changes were maximal in leg muscles, irrespective of clinical onset-site.

Background: Apathy is a common and early symptom in Alzheimer’s disease (AD) and is linked to poorer prognosis. Theoretical interpretations of apathy implicate alterations of connections amongst fronto-striatal and limbic regions. Objective: To test the association between presence of apathy and patterns of brain functional connectivity in patients with clinically-established AD. Methods: Seventy AD patients were included. Thirty-five patients experienced apathy as defined by the screening question of the Neuropsychiatric Inventory, and thirty-five did not. All patients agreed to undergo an MRI protocol inclusive of resting-state acquisitions. The hemodynamic-dependent signal was extracted bilaterally from five regions of interest: ventromedial prefrontal cortices, anterior cingulate cortices, dorsolateral prefrontal cortices, insulae and amygdalae. t tests were run to compare connectivity maps of apathetic and non-apathetic patients. Age, education, Mini Mental State Examination score, gray matter volumes and gray matter fractions served as covariates. Results: At a pFWE < 0.05 threshold, apathetic patients had reduced connectivity between the left insula and right superior parietal cortex. Apathetic patients had also increased connectivity between the right dorsolateral prefrontal seed and the right superior parietal cortex. Patients with apathy were significantly more likely to experience other psychiatric symptoms. Conclusion: Our findings support a role of frontal and insular connections in coordinating value-based decisions in AD. Both down-regulation and maladaptive up-regulation mechanisms appear to be at play in these regions.

Accurate and reliable quantification of brain metabolites measured in vivo using 1H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological challenge. In this study, spectrally edited γ-aminobutyric acid (GABA) MRS data were analyzed and GABA levels were quantified relative to an internal tissue water reference. Data from 284 volunteers scanned across 25 research sites were collected using GABA+ (GABA + co-edited macromolecules (MM)) and MM-suppressed GABA editing. The unsuppressed water signal from the volume of interest was acquired for concentration referencing. Whole-brain T1-weighted structural images were acquired and segmented to determine gray matter, white matter and cerebrospinal fluid voxel tissue fractions. Water-referenced GABA measurements were fully corrected for tissue-dependent signal relaxation and water visibility effects. The cohort-wide coefficient of variation was 17% for the GABA + data and 29% for the MM-suppressed GABA data. The mean within-site coefficient of variation was 10% for the GABA + data and 19% for the MM-suppressed GABA data. Vendor differences contributed 53% to the total variance in the GABA + data, while the remaining variance was attributed to site- (11%) and participant-level (36%) effects. For the MM-suppressed data, 54% of the variance was attributed to site differences, while the remaining 46% was attributed to participant differences. Results from an exploratory analysis suggested that the vendor differences were related to the unsuppressed water signal acquisition. Discounting the observed vendor-specific effects, water-referenced GABA measurements exhibit similar levels of variance to creatine-referenced GABA measurements. It is concluded that quantification using internal tissue water referencing is a viable and reliable method for the quantification of in vivo GABA levels. ispartof: NEUROIMAGE vol:191 pages:537-548 ispartof: location:United States status: published

BackgroundSporadic Parkinson’s disease (sPD) is an aetiologically heterogeneous disorder. Identification of distinct pathogenic mechanisms causing sPD will be crucial to develop future “Precision Medicine” approaches. 31P-MRS is a non-invasive tool that can quantify key bionenergetic metabolites in individual patients.ObjectiveTo determine whether 31P-MRS can identify mitochondrial dysfunction in the midbrain/sub- stantia nigra of individual PD patients and correlates with trial-relevant clinical aspects of PD.Methods31P-MRS spectra were obtained from 35 sPD patients and 25 healthy, age-matched controls. Spectra were analysed using the jMRUI software package and AMARES spectral fitting algorithm. Clinical assessment included widely utilised clinical rating scales, genetic analysis and the calculation of predicted risk of rapid disease progression.ResultsThere was a significantly broader variance in 31P-MRS midbrain ATP with 1/3 of all PD patients having ATP levels > 2 standard deviations outside the mean control values (p=0.0030). Higher midbrain phosphocreatine was associated with greater risk of rapid disease progression (p= 0.0384).Conclusions31P-MRS may help to identify a subgroup of sPD with significant mitochondrial dysfunction or at higher risk of more rapid progression and facilitate stratification for future precision medicine neu- roprotective trials. Longitudinal studies are required to characterise if changes 31P-MRS measures mirror clinical progression.

Background Glutathione (GSH) is an important brain antioxidant and a number of studies have reported its measurement by edited and nonedited localized 1 H spectroscopy techniques within a range of applications in healthy volunteers and disease states. Good test-retest reproducibility is key when assessing the efficacy of treatments aimed at modulating GSH levels within the central nervous system or when noninvasively assessing changes in GSH content over time. Purpose To evaluate the intraday (in vitro and in vivo) and 1-month apart (in vivo) test-retest reproducibility of GSH measurements from GSH-edited MEGA-PRESS acquisitions at 3 T in a phantom and in the brain of a cohort of middle-aged and older healthy volunteers. Study type Prospective. Subjects/phantoms A phantom containing physiological concentrations of GSH and metabolites with overlapping spectral signatures and 10 healthy volunteers (4 F, 6 M, 55 ± 14 years old). Field strength/sequence GSH-edited spectra were acquired at 3 T using the MEGA-PRESS sequence. Assessment The phantom was scanned twice and the healthy subjects were scanned three times (on two separate days, 1 month apart). GSH was quantified from each acquisition, with the in vivo voxels placed at the primary motor cortex (PMC) and the occipital cortex (OCC). Statistical tests Mean coefficients of variation (CV) were used to assess short-term (in vitro and in vivo) and longer-term (in vivo) test-retest reproducibility. Results In vitro, the CV was 2.3%. In vivo, the mean intraday CV was 3.3% in the PMC and 2.4% in the OCC, while the CVs at 1 month apart were 4.6% in the PMC and 7.8% in the OCC. Data conclusion GSH-edited MEGA-PRESS spectroscopy allows measurement of GSH with excellent precision. Evidence level 1 TECHNICAL EFFICACY: Stage 2.

Aims: Neuroimaging studies have found structural alterations in brain regions involved in the somatomotor system in diabetic peripheral neuropathy (DPN) and painful-DPN (pDPN). However, most of these studies have had small cohorts of subjects, without consideration of pDPN phenotypes. Here we present the largest DPN neuroimaging study, which examines differences in brain morphology in DPN and phenotypes of painful-DPN. Methods: 229 participants were enrolled, 177 with diabetes (46 no-DPN, 56 painless-DPN and 75 pDPN; 25 irritable [IR] and 50 non-irritable [NIR] phenotype), and 52 healthy volunteers underwent detailed clinical, neurophysiological and quantitative sensory testing (DFNS) assessments, and 3-dimensional T1-weighted brain MRI (3.0T, Phillips). Brain volumetry was performed using Freesurfer. Results: At the post-central gyrus, in comparison with HV (1.92mm±0.11) and NoDPN (1.90mm±0.14), there was a significantly reduced cortical thickness in DPN (1.85mm±0.14), in pDPN (1.87mm±0.12) cortical thickness was reduced compared with HV. At the precentral gyrus, both DPN (2.29mm±0.16) and pDPN (2.28mm±0.16) had significantly reduced cortical thickness compared with HV (2.37mm±0.14) and NoDPN (2.36mm±0.13). At the insula, compared with HV (2.93mm±0.15) the cortical thickness was reduced in DPN (2.85mm±0.18) and pDPN (2.84mm±0.17). The cortical thickness at the pre and postcentral gyrus, and insula correlated with measures of nerve conduction. Moreover, the mean anterior cingulate cortical (ACC) thickness was significantly reduced in the IR- (2.40mm±0.23) compared to NIR-pDPN (2.58mm±0.20; p=0.003). Conclusions: Key somatomotor brain regions have a reduced cortical thickness in patients with DPN and pDPN, which correlate with neurophysiological measures suggestive of an ascending axonopathy. Moreover, the cortical thickness at the ACC differentiated IR and NIR, suggesting neuroplasticity in this region may play a role determining clinical phenotypes in pDPN. Disclosure G. P. Sloan: None. D. Selvarajah: None. K. Teh: None. P. Shillo: None. I. D. Wilkinson: None. S. Tesfaye: Advisory Panel; Self; Angellini, Bayer AG, Eva Pharma, Wörwag Pharma, Speaker’s Bureau; Self; Abbott, AstraZeneca, Grunenthal Group, MSD Corporation, Novo Nordisk, Pfizer Inc.

Objective: We have previously reported increased thalamic vascularity in painful diabetic peripheral neuropathy (PDPN) but the microvascular perfusion characteristics of the other pain processing areas of the brain (Pain Matrix - PM) with or without pain at the time of scanning have not been assessed. The aim thus was to measure the cerebral perfusion of the PM areas using MR-Dynamic Susceptibility Contrast (MR-DSC). Methods: 55 T1DM subjects (20 PDPN, 23 painless-DPN, 13 no-DPN) and 19 healthy volunteers (HV) underwent clinical, neurophysiological and MR-DSC of the passage of IV-gadolinium-chelate through the cerebral vascular bed (3-Tesla, Philips, Netherlands) at rest. The PDPN group was further divided into those that had neuropathic pain during scan - P+ and no pain - P-) and the intensity of pain at the time of scanning was recorded. The Mean Transit Time -MTT and the time-to-peak -TTP concentrations of gadolinium in PM areas (Thalamus, Insular Cortex - IC, Anterior Cingulate Cortex - ACC) were measured. Results: Subjects experiencing spontaneous neuropathic pain (P+, n=10, VAS score≥4) during scanning had shorter mean TTP at the Right-Thalamus: P+ vs. painless-DPN p=0.017, P+ vs. HV p=0.033; Right-IC: P+ vs. painless-DPN p=0.048; and POWM: P+ vs. P- p=0.009, P+ vs. painless-DPN p=0.034, P+ vs. HV p=0.011. The MTT at the Right-Thalamus: P+ vs. HV p=0.043 and at the Left-IC: HV vs. No-DPN p=036, were also significant. Conclusion: This is the first study to show there is altered cerebral perfusion in the pain processing areas of of the brain, with shorter TTP during spontaneous pain at the time of scanning. This seems to be related to a bolus dispersal factor as MTT, and CBF do not match the TTP and the control area is also affected. However, whether this altered perfusion is primary or secondary to the experience of pain is yet to be determined. This novel finding may serve as objective marker of spontaneous neuropathic pain, and a target for the development of novel treatments. Disclosure M. Greig: None. G. P. Sloan: None. P. Shillo: None. D. Selvarajah: None. I. D. Wilkinson: None. S. Tesfaye: Advisory Panel; Self; Angellini, Bayer AG, Eva Pharma, Wörwag Pharma, Speaker’s Bureau; Self; Abbott, AstraZeneca, Grunenthal Group, MSD Corporation, Novo Nordisk, Pfizer Inc. Funding European Foundation for the Study of Diabetes

Painful diabetic neuropathy (DN) is a common, distressing complication of diabetes that is discordant with the degree of peripheral nerve pathology. Very little is known about the cerebral processes involved in pain processing in painful DN. Here we investigated resting-state brain connectivity associated with prolonged pain in DN. Methods: 58 subjects and 36 matched controls were compared with regard to both behavioural measures of pain perception and resting-resting state functional Magnetic Resonance Imaging. The resting-state fMRI brain connectivity was investigated using 20 seed regions located in cardinal pain processing brain regions. Resting-state fMRI analysis was performed using the NITRC Functional Connectivity (CONN) Toolbox and SPM8 (welcome Trust Centre for Neuroimaging London, UK) in Matlab 2014a (the MathWorks, Natick, MA, USA). Functional connectivity matrices between the pre-specified seeds were calculated and the HV versus painful DN phenotype interaction examined. Results: Relative to controls, painful DPN patients displayed increased brain connectivity predominately for the supplementary motor areas (p Conclusion: Our study provides experimental evidence of increased connectivity between frontal midline regions that are implicated in affective pain processing and bilateral sensorimotor regions in painful DPN patients. Disclosure K. Teh: None. I. D. Wilkinson: None. P. Shillo: None. G. P. Sloan: None. S. Tesfaye: Advisory Panel; Self; Angellini, Bayer AG, Eva Pharma, Wörwag Pharma, Speaker’s Bureau; Self; Abbott, AstraZeneca, Grunenthal Group, MSD Corporation, Novo Nordisk, Pfizer Inc. D. Selvarajah: None. Funding Health Education England/University of Sheffield Knowledge Exchange Fund; National Institute for Health Research; EME

Copyright © 2021– The authors. Background: How the relationship between obesity and MRI-defined neural properties varies across distinct stages of cognitive impairment due to Alzheimer’s disease is unclear. Objective: We used multimodal neuroimaging to clarify this relationship. Methods: Scans were acquired from 47 patients clinically diagnosed with mild Alzheimer’s disease dementia, 68 patients with mild cognitive impairment, and 57 cognitively healthy individuals. Voxel-wise associations were run between maps of gray matter volume, white matter integrity, and cerebral blood flow, and global/visceral obesity. Results: Negative associations were found in cognitively healthy individuals between obesity and white matter integrity and cerebral blood flow of temporo-parietal regions. In mild cognitive impairment, negative associations emerged in frontal, temporal, and brainstem regions. In mild dementia, a positive association was found between obesity and gray matter volume around the right temporoparietal junction. Conclusion: Obesity might contribute toward neural tissue vulnerability in cognitively healthy individuals and mild cognitive impairment, while a healthy weight in mild Alzheimer’s disease dementia could help preserve brain structure in the presence of age and disease-related weight loss. European Union Seventh Framework Programme (FP7/2007– 2013) under grant agreement no. 601055, VPH-DARE@IT; Neurocare; University of Sheffield, Faculty of Medicine, Dentistry and Health PhD scholarship.

One of the fundamental challenges when dealing with medical imaging datasets is class imbalance. Class imbalance happens where an instance in the class of interest is relatively low, when compared to the rest of the data. This study aims to apply oversampling strategies in an attempt to balance the classes and improve classification performance. We evaluated four different classifiers from k-nearest neighbors (k-NN), support vector machine (SVM), multilayer perceptron (MLP) and decision trees (DT) with 73 oversampling strategies. In this work, we used imbalanced learning oversampling techniques to improve classification in datasets that are distinctively sparser and clustered. This work reports the best oversampling and classifier combinations and concludes that the usage of oversampling methods always outperforms no oversampling strategies hence improving the classification results.

Cognitive impairments are commonly observed in patients with multiple sclerosis and are associated with lower levels of quality of life. No consensus has been reached on how to tackle effectively cognitive decline in this clinical population non-pharmacologically. This exploratory case-control study aims to investigate the effectiveness of a hypothesis-based cognitive training designed to target multiple domains by promoting the synchronous co-activation of different brain areas and thereby improve cognition and induce changes in functional connectivity in patients with relapsing-remitting multiple sclerosis. Forty-five patients (36 females and 9 males, mean age 44.62 +/- 8.80 years) with clinically stable relapsing-remitting multiple sclerosis were assigned to either a standard cognitive training or to control groups (sham training and non-active control). The standard training included twenty sessions of computerized exercises involving various cognitive functions supported by distinct brain networks. The sham training was a modified version of the standard training that comprised the same exercises and number of sessions but with increased processing speed load. The non-active control group received no cognitive training. All patients underwent comprehensive neuropsychological and magnetic resonance imaging assessments at baseline and after 5 weeks. Cognitive and resting-state magnetic resonance imaging data were analyzed using repeated measures models. At reassessment, the standard training group showed significant cognitive improvements compared to both control groups in memory tasks not specifically targeted by the training: the Buschke Selective Reminding Test and the Semantic Fluency test. The standard training group showed reductions in functional connectivity of the salience network, in the anterior cingulate cortex, associated with improvements on the Buschke Selective Reminding Test. No changes were observed in the sham training group. These findings suggest that multi-domain training that stimulates multiple brain areas synchronously may improve cognition in people with relapsing-remitting multiple sclerosis if sufficient time to process training material is allowed. The associated reduction in functional connectivity of the salience network suggests that training-induced neuroplastic functional reorganization may be the mechanism supporting performance gains. This study was approved by the Regional Ethics Committee of Yorkshire and Humber (approval No. 12/YH/0474) on November 20, 2013.

Aims/hypothesis The aim of this work was to investigate whether different clinical pain phenotypes of diabetic polyneuropathy (DPN) are distinguished by functional connectivity at rest. Methods This was an observational, cohort study of 43 individuals with painful DPN, divided into irritable (IR, n = 10) and non-irritable (NIR, n = 33) nociceptor phenotypes using the German Research Network of Neuropathic Pain quantitative sensory testing protocol. In-situ brain MRI included 3D T1-weighted anatomical and 6 min resting-state functional MRI scans. Subgroup differences in resting-state functional connectivity in brain regions involved with somatic (thalamus, primary somatosensory cortex, motor cortex) and non-somatic (insular and anterior cingulate cortices) pain processing were examined. Multidimensional reduction of MRI datasets was performed using a machine-learning approach to classify individuals into each clinical pain phenotype. Results Individuals with the IR nociceptor phenotype had significantly greater thalamic–insular cortex (p false discovery rate [FDR] = 0.03) and reduced thalamus–somatosensory cortex functional connectivity (p-FDR = 0.03). We observed a double dissociation such that self-reported neuropathic pain score was more associated with greater thalamus–insular cortex functional connectivity (r = 0.41; p = 0.01) whereas more severe nerve function deficits were more related to lower thalamus–somatosensory cortex functional connectivity (r = −0.35; p = 0.03). Machine-learning group classification performance to identify individuals with the NIR nociceptor phenotype achieved an accuracy of 0.92 (95% CI 0.08) and sensitivity of 90%. Conclusions/interpretation This study demonstrates differences in functional connectivity in nociceptive processing brain regions between IR and NIR phenotypes in painful DPN. We also establish proof of concept for the utility of multimodal MRI as a biomarker for painful DPN by using a machine-learning approach to classify individuals into sensory phenotypes. Graphical abstract

IntroductionThere are no disease-modifying treatments for Parkinson’s disease (PD). We undertook the first drug screen in PD patient tissue and idntified ursodeoxycholic acid (UDCA) as a promising mitochondrial rescue agent. The aims of this trial are to determine safety and tolerability of UDCA in PD at 30 mg/kg, confirm the target engagement of UDCA, apply a novel motion sensor-based approach to quantify disease progression objectively, and estimate the mean effect size and its variance on the change in motor severity.Methods and analysisThis is a phase II, two-centre, double-blind, randomised, placebo-controlled trial of UDCA at a dose of 30 mg/kg in 30 participants with early PD. Treatment duration is 48 weeks, followed by an 8-week washout phase. Randomisation is 2:1, drug to placebo. Assessments are performed at baseline, week 12, 24, 36, 48 and 56. The primary outcome is safety and tolerability. Secondary outcomes will compare the change between baseline and week 48 using the following three approaches: the Movement Disorders Society Unified Parkinson’s Disease Rating Scale Part 3 in the practically defined ‘OFF’ medication state; confirmation of target engagement, applying 31Phosphorus MR Spectroscopy to assess the levels of ATP and relevant metabolites in the brain; and objective quantification of motor impairment, using a validated, motion sensor-based approach. The primary outcome will be reported using descriptive statistics and comparisons between treatment groups. For each secondary outcome, the change from baseline will be summarised within treatment groups using summary statistics and appropriate statistical tests assessing for significant differences. All outcomes will use an intention-to-treat analysis population.Ethics and disseminationThis trial has been approved by the East of England – Cambridgeshire and Hertfordshire Research Ethics committee. Results will be disseminated in peer-reviewed journals, presentations at scientific meetings and to patients in a lay-summary format.Trial registration numberNCT03840005.

Aims: The management of painful diabetic peripheral neuropathy (pDPN) is inadequate because the disease mechanisms are not fully understood. We assessed cerebral cellular bioenergetics using phosphorus magnetic resonance spectroscopy (31P-MRS) to determine whether high energy phosphate metabolite levels are altered in the pain processing regions of the brain in pDPN. Methods: A total of 66 subjects, 44 with type 2 diabetes (12 no-DPN, 13 painless-DPN and 19 pDPN) and 12 healthy volunteers (HV), underwent detailed clinical and neurophysiological assessments, and 31P-MRS brain imaging at 3-Tesla (Ingenia, Phillips Healthcare) with voxels placed over the right somatosensory cortex and the thalamus (TR 4s, TR 0.26ms, voxel size 21 x 21 x 40mm3). Measures reflecting cellular bioenergetics (mitochondrial function), ATP to phosphocreatine (PCr) and inorganic phosphate (Pi) ratios (ATP:PCr and ATP:Pi) were calculated. Results: There was a significant group effect in the ATP:PCr ratio at the thalamus (p=0.016) and somatosensory cortex (p=0.025). The ATP:PCr at the thalamus was significantly higher in the pDPN group (0.50±0.06) compared to HV (0.44±0.04, p=0.024) and no-DPN (0.42±0.07, p=0.006). Moreover, the ATP:PCr ratio at the somatosensory cortex was significantly higher in pDPN (0.48 ±0.1) compared to HV (0.38 ±0.1, p=0.035). In addition, the ratio correlated with the numeric pain score ratings during the MRI scan at both brain regions. Conclusions: This is the first study to use 31P-MRS to study cerebral energetics in human-DPN and peripheral painful neuropathies. We demonstrated significantly higher ATP:PCr ratios in patients with pDPN in the somatosensory cortex and thalamus, which correlated with pain severity. This is suggestive of increased cellular energy usage in pain processing regions of the brain, perhaps due to continuous nociceptive inputs. Altered cerebral phosphorus metabolite ratios may serve as a biomarker of neuropathic pain in diabetes. Disclosure G.P. Sloan: None. A. Anton: None. D. Selvarajah: None. S. Tesfaye: Advisory Panel; Self; Mitsubishi Tanabe Pharma Corporation, Wörwag Pharma. Speaker’s Bureau; Self; Abbott, AstraZeneca, Grunenthal Group, Napp Pharmaceuticals, Novo Nordisk Inc., Pfizer Inc. I.D. Wilkinson: None.

Diabetic distal symmetrical peripheral polyneuropathy (DSP) results in decreased somatosensory cortical gray matter volume, indicating that the disease process may produce morphological changes in the brains of those affected. However, no study has examined whether changes in brain volume alter the functional organization of the somatosensory cortex and how this relates to the various painful DSP clinical phenotypes. In this case-controlled, multimodal brain MRI study of 44 carefully phenotyped subjects, we found significant anatomical and functional changes in the somatosensory cortex. Subjects with painful DSP insensate have the lowest somatosensory cortical thickness, with expansion of the area representing pain in the lower limb to include face and lip regions. Furthermore, there was a significant relationship between anatomical and functional changes within the somatosensory cortex and severity of the peripheral neuropathy. These data suggest a dynamic plasticity of the brain in DSP driven by the neuropathic process. It demonstrates, for the first time in our knowledge, a pathophysiological relationship between a clinically painful DSP phenotype and alterations in the somatosensory cortex.

Mitochondrial dysfunction is postulated to be central to amyotrophic lateral sclerosis pathophysiology. Evidence comes primarily from disease models and conclusive data to support bioenergetic dysfunction in vivo in patients is currently lacking. This study is the first to assess mitochondrial dysfunction in brain and muscle in people living with amyotrophic lateral sclerosis using phosphorus-31 magnetic resonance spectroscopy, the modality of choice to assess energy metabolism in vivo. We recruited twenty patients and 10 healthy age and gender-matched controls in this cross-sectional clinico-radiological study. Phosphorus-31 magnetic resonance spectroscopy was acquired from cerebral motor regions and from tibialis anterior during rest and exercise. Bioenergetic parameter estimates were derived including: adenosine triphosphate, phosphocreatine, inorganic phosphate, adenosine diphosphate, Gibbs free energy of adenosine triphosphate hydrolysis, phosphomonoesters, phosphodiesters, pH, free magnesium concentration, and muscle dynamic recovery constants. Linear regression was used to test for associations between brain data and clinical parameters (revised amyotrophic functional rating scale, slow vital capacity, and upper motor neuron score) and between muscle data and clinico-neurophysiological measures (motor unit number and size indices, force of contraction, and speed of walking). Evidence for primary dysfunction of mitochondrial oxidative phosphorylation was detected in brainstem where Gibbs free energy of adenosine triphosphate hydrolysis and phosphocreatine were reduced. Alterations were also detected in skeletal muscle in patients where resting inorganic phosphate, pH, and phosphomonoesters were increased, whereas resting Gibbs free energy of adenosine triphosphate hydrolysis, magnesium, and dynamic phosphocreatine to inorganic phosphate recovery were decreased. Phosphocreatine in brainstem correlated with respiratory dysfunction and disability; in muscle, energy metabolites correlated with motor unit number index, muscle power, and speed of walking. This study provides in vivo evidence for bioenergetic dysfunction in amyotrophic lateral sclerosis in brain and skeletal muscle, which appears clinically and electrophysiologically relevant. Phosphorus-31 magnetic resonance spectroscopy represents a promising technique to assess the pathophysiology of mitochondrial function in vivo in amyotrophic lateral sclerosis and a potential tool for future clinical trials targeting bioenergetic dysfunction.

Background The hardware and software differences between MR vendors and individual sites influence the quantification of MR spectroscopy data. An analysis of a large data set may help to better understand sources of the total variance in quantified metabolite levels. Purpose To compare multisite quantitative brain MR spectroscopy data acquired in healthy participants at 26 sites by using the vendor-supplied single-voxel point-resolved spectroscopy (PRESS) sequence. Materials and Methods An MR spectroscopy protocol to acquire short-echo-time PRESS data from the midparietal region of the brain was disseminated to 26 research sites operating 3.0-T MR scanners from three different vendors. In this prospective study, healthy participants were scanned between July 2016 and December 2017. Data were analyzed by using software with simulated basis sets customized for each vendor implementation. The proportion of total variance attributed to vendor-, site-, and participant-related effects was estimated by using a linear mixed-effects model. P values were derived through parametric bootstrapping of the linear mixed-effects models (denoted Pboot). Results In total, 296 participants (mean age, 26 years ± 4.6; 155 women and 141 men) were scanned. Good-quality data were recorded from all sites, as evidenced by a consistent linewidth of N-acetylaspartate (range, 4.4-5.0 Hz), signal-to-noise ratio (range, 174-289), and low Cramér-Rao lower bounds (≤5%) for all of the major metabolites. Among the major metabolites, no vendor effects were found for levels of myo-inositol (Pboot > .90), N-acetylaspartate and N-acetylaspartylglutamate (Pboot = .13), or glutamate and glutamine (Pboot = .11). Among the smaller resonances, no vendor effects were found for ascorbate (Pboot = .08), aspartate (Pboot > .90), glutathione (Pboot > .90), or lactate (Pboot = .28). Conclusion Multisite multivendor single-voxel MR spectroscopy studies performed at 3.0 T can yield results that are coherent across vendors, provided that vendor differences in pulse sequence implementation are accounted for in data analysis. However, the site-related effects on variability were more profound and suggest the need for further standardization of spectroscopic protocols. © RSNA, 2020 Online supplemental material is available for this article. ispartof: RADIOLOGY vol:295 issue:1 pages:171-180 ispartof: location:United States status: published

Aim: Recent studies have reported an association between low vitamin D levels and diabetic peripheral neuropathy. However, many of these did not differentiate between people with painful diabetic peripheral neuropathy and those with painless diabetic peripheral neuropathy, or assess major confounding factors including sunlight exposure and daily activity. Our study addressed these limitations and evaluated vitamin D levels in people with carefully phenotyped diabetic peripheral neuropathy and controls. Methods: Forty-five white Europeans with Type 2 diabetes and 14 healthy volunteers underwent clinical and neurophysiological assessments. People with Type 2 diabetes were then divided into three groups (17 with painful diabetic peripheral neuropathy, 14 with painless diabetic peripheral neuropathy and 14 with no diabetic peripheral neuropathy). All had seasonal sunlight exposure and daily activity measured, underwent a lower limb skin biopsy and had 25-hydroxyvitamin D measured during the summer months, July to September. Results: After adjusting for age, BMI, activity score and sunlight exposure, 25-hydroxyvitamin D levels (nmol/l) (se) were significantly lower in people with painful diabetic peripheral neuropathy [painful diabetic peripheral neuropathy 34.9 (5.8), healthy volunteers 62.05 (6.7), no diabetic peripheral neuropathy 49.6 (6.1), painless diabetic peripheral neuropathy 53.1 (6.2); ANCOVAP = 0.03]. Direct logistic regression was used to assess the impact of seven independent variables on painful diabetic peripheral neuropathy. Vitamin D was the only independent variable to make a statistically significant contribution to the model with an inverted odds ratio of 1.11. Lower 25-hydroxyvitamin D levels also correlated with lower cold detection thresholds (r = 0.39, P = 0.02) and subepidermal nerve fibre densities (r = 0.42, P = 0.01). Conclusions: We have demonstrated a significant difference in 25-hydroxyvitamin D levels in well-characterized people with painful diabetic peripheral neuropathy, while accounting for the main confounding factors. This suggests a possible role for vitamin D in the pathogenesis of painful diabetic peripheral neuropathy. Further prospective and intervention trials are required to prove causality between low vitamin D levels and painful diabetic peripheral neuropathy.

Purpose Detection of endogenous metabolites using multiplexed editing substantially improves the efficiency of edited magnetic resonance spectroscopy. Multiplexed editing (i.e., performing more than one edited experiment in a single acquisition) requires a tailored, robust approach for correction of frequency and phase offsets. Here, a novel method for frequency and phase correction (FPC) based on spectral registration is presented and compared against previously presented approaches. Methods One simulated dataset and 40 γ-aminobutyric acid-/glutathione-edited HERMES datasets acquired in vivo at three imaging centers were used to test four FPC approaches: no correction; spectral registration; spectral registration with post hoc choline-creatine alignment; and multistep FPC. The performance of each routine for the simulated dataset was assessed by comparing the estimated frequency/phase offsets against the known values, whereas the performance for the in vivo data was assessed quantitatively by calculation of an alignment quality metric based on choline subtraction artifacts. Results The multistep FPC approach returned corrections that were closest to the true values for the simulated dataset. Alignment quality scores were on average worst for no correction, and best for multistep FPC in both the γ-aminobutyric acid- and glutathione-edited spectra in the in vivo data. Conclusions Multistep FPC results in improved correction of frequency/phase errors in multiplexed γ-aminobutyric acid-/glutathione-edited magnetic resonance spectroscopy experiments. The optimal FPC strategy is experiment-specific, and may even be dataset-specific. Magn Reson Med 80:21-28, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

ObjectiveTo assess clinical, electrophysiological and whole-body muscle MRI measurements of progression in patients with motor neuron disease (MND), as tools for future clinical trials, and to probe pathophysiological mechanisms in vivo.MethodsA prospective, longitudinal, observational, clinicoelectrophysiological and radiological cohort study was performed. Twenty-nine patients with MND and 22 age-matched and gender-matched healthy controls were assessed with clinical measures, electrophysiological motor unit number index (MUNIX) and T2-weighted whole-body muscle MRI, at first clinical presentation and 4 months later. Between-group differences and associations were assessed using age-adjusted and gender-adjusted multivariable regression models. Within-subject longitudinal changes were assessed using paired t-tests. Patterns of disease spread were modelled using mixed-effects multivariable regression, assessing associations between muscle relative T2 signal and anatomical adjacency to site of clinical onset.ResultsPatients with MND had 30% higher relative T2 muscle signal than controls at baseline (all regions mean, 95% CI 15% to 45%, pConclusionsWhole-body muscle MRI offers a new approach to objective assessment of denervation over short timescales in MND and enables investigation of patterns of disease spread in vivo. Muscles inaccessible to conventional clinical and electrophysiological assessment may be investigated using this methodology.

Using advanced MR neuroimaging we have demonstrated altered brain structure and functional connectivity that could serve as a potential Central Pain Signature (CPS) for painful diabetic neuropathy (DN). However, the key challenge is how to apply this potential biomarker for routine diagnostic purposes. The aim of this study was to examine if the CPS can accurately classify painful DN patients based on a patient’s pain severity. Methods: 53 painful DN patients underwent detailed clinical and neurophysiological assessments. The NTSS-6, a validated questionnaire that measures both the frequency and the intensity of neuropathic pain was used to assess pain severity. Patients were divided into high pain (NTSS-6 score >7) and low pain ( Results: There was no age or gender difference (p > 0.05) between the high and low pain groups. The CPS classified painful DN patients based on their pain intensity with 94% accuracy (AUC 0.98). The positive and negative predictive values were 0.80 and 1.00 respectively. The F1 scores for predicting high pain and low pain were 0.89 and 0.96 respectively. Brain regions identified as the best classifier were the left and right postcentral gyri, thalami, and anterior and posterior cingulate cortices. Conclusions: This novel study demonstrates that a simple, 15-minute MR brain scan can accurately classify painful DN patients according to pain intensities with high accuracy. This assessment tool has a great potential as a biomarker of diabetic neuropathic pain and may serve as a target for future trials of analgesic compounds for painful DN. Disclosure D. Selvarajah: None. K. Teh: None. G.P. Sloan: None. P. Shillo: None. I.D. Wilkinson: None. S. Tesfaye: Advisory Panel; Self; Mitsubishi Tanabe Pharma Corporation, WÖRWAG Pharma. Speaker's Bureau; Self; AstraZeneca, Merck & Co., Inc., NAPP Pharmaceuticals Limited, Neurometrix, Novo Nordisk Inc., Pfizer Inc. Other Relationship; Self; Impeto Medical. Funding European Foundation for the Study of Diabetes

Purpose of Review The prevalence of diabetes mellitus and its chronic complications are increasing to epidemic proportions. This will unfortunately result in massive increases in diabetic distal symmetrical polyneuropathy (DPN) and its troublesome sequelae, including disabling neuropathic pain (painful-DPN), which affects around 25% of patients with diabetes. Why these patients develop neuropathic pain, while others with a similar degree of neuropathy do not, is not clearly understood. This review will look at recent advances that may shed some light on the differences between painful and painless-DPN. Recent Findings Gender, clinical pain phenotyping, serum biomarkers, brain imaging, genetics, and skin biopsy findings have been reported to differentiate painful- from painless-DPN. Summary Painful-DPN seems to be associated with female gender and small fiber dysfunction. Moreover, recent brain imaging studies have found neuropathic pain signatures within the central nervous system; however, whether this is the cause or effect of the pain is yet to be determined. Further research is urgently required to develop our understanding of the pathogenesis of pain in DPN in order to develop new and effective mechanistic treatments for painful-DPN.