Publications by authors named "Vincent Noblet"

49 Publications

Mapping the living mouse brain neural architecture: strain-specific patterns of brain structural and functional connectivity.

Brain Struct Funct 2021 Feb 26. Epub 2021 Feb 26.

Department of Radiology, Medical Physics, Medical Center, Faculty of Medicine, University of Freiburg, Breisacher Straße 60a, 79106, Freiburg, Germany.

Mapping brain structural and functional connectivity (FC) became an essential approach in neuroscience as network properties can underlie behavioral phenotypes. In mouse models, revealing strain-related patterns of brain wiring is crucial, since these animals are used to answer questions related to neurological or neuropsychiatric disorders. C57BL/6 and BALB/cJ strains are two of the primary "genetic backgrounds" for modeling brain disease and testing therapeutic approaches. However, extensive literature describes basal differences in the behavioral, neuroanatomical and neurochemical profiles of the two strains, which raises questions on whether the observed effects are pathology specific or depend on the genetic background of each strain. Here, we performed a systematic comparative exploration of brain structure and function of C57BL/6 and BALB/cJ mice using Magnetic Resonance Imaging (MRI). We combined deformation-based morphometry (DBM), diffusion MRI and high-resolution fiber mapping (hrFM) along with resting-state functional MRI (rs-fMRI) and demonstrated brain-wide differences in the morphology and "connectome" features of the two strains. Essential inter-strain differences were depicted regarding the size and the fiber density (FD) within frontal cortices, along cortico-striatal, thalamic and midbrain pathways as well as genu and splenium of corpus callosum. Structural dissimilarities were accompanied by specific FC patterns, emphasizing strain differences in frontal and basal forebrain functional networks as well as hubness characteristics. Rs-fMRI data further indicated differences of reward-aversion circuitry and default mode network (DMN) patterns. The inter-hemispherical FC showed flexibility and strain-specific adjustment of their patterns in agreement with the structural characteristics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00429-020-02190-8DOI Listing
February 2021

Analysis of factors associated with discrepancies between predicted and observed liver weight in liver transplantation.

Liver Int 2021 Feb 8. Epub 2021 Feb 8.

ICube, Université de Strasbourg, CNRS UMR 7357, Illkirch, France.

Background: Even using predictive formulas based on anthropometrics in about 30% of subjects, liver weight (LW) cannot be predicted with a ≤20% margin of error. We aimed to identify factors associated with discrepancies between predicted and observed LW.

Methods: In 500 consecutive liver grafts, we tested LW predictive performance using 17 formulas based on anthropometric characteristics. Hashimoto's formula (961.3 × BSA_D-404.8) was associated with the lowest mean absolute error and used to predict LW for the entire cohort. Clinical factors associated with a ≥20% margin of error were identified in a multivariable analysis after propensity score matching (PSM) of donors with similar anthropometric characteristics.

Results: The total LW was underestimated with a ≥20% margin of error in 53/500 (10.6%) donors and overestimated in 62/500 (12%) donors. After PSM analysis, ages ≥ 65, (OR = 3.21; CI95% = 1.63-6.31; P = .0007), age ≤ 30 years, (OR = 2.92; CI95% = 1.15-7.40; P = .02), and elevated gamma-glutamyltransferase (GGT) levels (OR = 0.98; CI95% = 0.97-0.99; P = .006), influenced the risk of LW overestimation. Age ≥ 65 years, (OR = 5.98; CI95% = 2.28-15.6; P = .0002), intensive care unit (ICU) stay with ventilation > 7 days, (OR = 0.32; CI95% = 0.12-0.85; P = .02) and waist circumference increase (OR = 1.02; CI95% = 1.00-1.04; P = .04) were factors associated with LW underestimation.

Conclusions: Increased waist circumference, age, prolonged ICU stay with ventilation, elevated GGT were associated with an increase in the margin of error in LW prediction. These factors and anthropometric characteristics could help transplant surgeons during the donor-recipient matching process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/liv.14819DOI Listing
February 2021

The hippocampal region is necessary for text comprehension and memorization: a combined VBM/DTI study in neuropsychological patients.

Brain Imaging Behav 2021 Jan 7. Epub 2021 Jan 7.

ICube Laboratory (UMR 7357), University of Strasbourg and CNRS, Strasbourg, France.

According to the Construction-Integration model (Kintsch 1988; Kintsch 1998), two forms of representation are activated during the reading and the comprehension of a text: 1) the text base, which includes semantic propositions and 2) the situation model, corresponding to the integration of the information contained in the text to the memories and knowledge of the reader. Functional neuroimaging studies in healthy subjects have shown that the text base is underpinned by frontal regions and lateral temporal regions whereas the situation model would rather depend on the posterior cingulate cortex, the precuneus and other regions depending on the dimension studied. However, the brain regions highlighted so far were only involved in comprehension and not necessary for this cognitive ability. For the first time, we explored the brain structures necessary to understand texts using a combined VBM/DTI approach in neuropsychological patients with whom we obtained comprehension scores (text base and situation model) after the reading of narrative texts. To our great surprise and contrary to our hypotheses, which were based on the results of functional neuroimaging studies, our own results show that it is the hippocampal region that is necessary to activate and memorize/remember the text base and the situation model. The highlighting of a link between the integrity of a portion of the uncinate fasciculus which is well known to play a role in semantic processing and the performance scores of the text base suggests that the hippocampal region is necessary not only for the retrieval of the text base and of the situation model thanks to episodic memory, but also for the activation of the text base during the reading and the comprehension of a text.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11682-020-00432-1DOI Listing
January 2021

Association of cerebral microbleeds with cerebrospinal fluid Alzheimer-biomarkers and clinical symptoms in early dementia with Lewy bodies.

Int J Geriatr Psychiatry 2020 Dec 9. Epub 2020 Dec 9.

IMIS Team and IRIS Plateform, ICube Laboratory, UMR 7357, French National Centre for Scientific Research (CNRS), Strasbourg, France.

Objectives: To determine the prevalence, localization and associations of cerebral microbleeds (CMB) in dementia with Lewy bodies (DLB) with its core clinical symptoms and cerebrospinal fluid (CSF) biomarkers of Alzheimer's disease (AD). We hypothesize DLB patients with CMB have increased amyloid burden compared to those without CMB, which could also translate into clinical differences.

Methods: Retrospective cross-sectional analysis from the AlphaLewyMA study (https://clinicaltrials.gov/ct2/show/NCT01876459). Patients underwent a standardized protocol of brain MRI including 3D T1, 3D FLAIR and T2* sequences, and CSF analysis of AD biomarkers. CMB and white matter hyperintensities (WMHs) were visually assessed in prodromal and mild demented (DLB, N = 91) and AD (AD, N = 67) patients.

Results: CMB prevalence did not differ among DLB and AD (24.2% vs. 37.3%; p = 0.081). CMB were mainly distributed in lobar topographies in both DLB (74%) and AD (89%). CMB in DLB was not associated with global cognitive performance, executive functioning, speed of information processing, or AD CSF biomarkers. Similarly, there was no difference regarding specific clinical symptoms: fluctuations, psychotic phenomena, sleep behavior disorder and Parkinsonism between DLB patients with and without CMB. AD patients with CMB had increased burden of WMH compared to those without (2.1 ± 0.86 vs. 1.4 ± 0.89; p = 0.005), according to Fazekas scale, whereas no significant difference was observed in DLB patients (1.68 ± 0.95 vs. 1.42 ± 0.91; p = 0.25).

Conclusion: CMB were equally prevalent with similar topographic distribution in both DLB and AD patients. CMB was not associated with CSF AD biomarkers or core clinical symptoms in DLB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/gps.5485DOI Listing
December 2020

Brain network remodelling reflects tau-related pathology prior to memory deficits in Thy-Tau22 mice.

Brain 2020 12;143(12):3748-3762

Laboratory of Engineering, Informatics and Imaging (ICube), Integrative multimodal imaging in healthcare (IMIS), UMR 7357, University of Strasbourg, 67000 Strasbourg, France.

In Alzheimer's disease, the tauopathy is known as a major mechanism responsible for the development of cognitive deficits. Early biomarkers of such affectations for diagnosis/stratification are crucial in Alzheimer's disease research, and brain connectome studies increasingly show their potential establishing pathology fingerprints at the network level. In this context, we conducted an in vivo multimodal MRI study on young Thy-Tau22 transgenic mice expressing tauopathy, performing resting state functional MRI and structural brain imaging to identify early connectome signatures of the pathology, relating with histological and behavioural investigations. In the prodromal phase of tauopathy, before the emergence of cognitive impairments, Thy-Tau22 mice displayed selective modifications of brain functional connectivity involving three main centres: hippocampus (HIP), amygdala (AMG) and the isocortical areas, notably the somatosensory (SS) cortex. Each of these regions showed differential histopathological profiles. Disrupted ventral HIP-AMG functional pathway and altered dynamic functional connectivity were consistent with high pathological tau deposition and astrogliosis in both hippocampus and amygdala, and significant microglial reactivity in amygdalar nuclei. These patterns were concurrent with widespread functional hyperconnectivity of memory-related circuits of dorsal hippocampus-encompassing dorsal HIP-SS communication-in the absence of significant cortical histopathological markers. These findings suggest the coexistence of two intermingled mechanisms of response at the functional connectome level in the early phases of pathology: a maladaptive and a likely compensatory response. Captured in the connectivity patterns, such first responses to pathology could further be used in translational investigations as a lead towards an early biomarker of tauopathy as well as new targets for future treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awaa312DOI Listing
December 2020

The learning curve for piggyback liver transplantation: identifying factors challenging surgery.

Surgery 2020 Nov 2. Epub 2020 Nov 2.

Hepato-Pancreato-Biliary Surgery and Liver Transplantation, Pôle des Pathologies Digestives, Hépatiques et de la Transplantation, Hôpital de Hautepierre-Hôpitaux Universitaires de Strasbourg, Université de Strasbourg, France.

Background: This study aimed to quantify the learning curve of piggyback liver transplantation and to identify factors that impact the operative time and blood transfusion during the learning curve.

Methods: A retrospective review was performed on consecutive cases of patients' first piggyback liver transplantations that were performed by a single surgeon. The learning curve for the operative time was evaluated using the cumulative sum method.

Results: There were 181, consecutive, first-time piggyback liver transplantations. The median operative time was 345 minutes (range: 180-745 minutes) with a median transfusion rate of 4 packed red blood cell units (range: 0-23 units). The cumulative sum learning curve identified 3 phases: an initial phase (1-70 piggyback liver transplantations), a plateau phase (71-101 piggyback liver transplantations), and a stable phase (102-181 piggyback liver transplantations). Over the 3 phases, there were significant decreases in the median duration of the surgery (388.8 vs 344.8 vs 326.9 minutes; P = .004, P = .0004, P ≤ .0001) and the number of red blood cell units transfused (6.00 vs 3.90 vs 3.71; P = .02, P = .79, P = .0006). Multivariable analysis identified that the following factors impacted the operative time: surgeon experience (P = .00006), previous upper abdominal surgery (P = .01), portocaval shunt fashioning (P = .0003), early portal section (P = .00001), multiple arterial graft reconstruction (P = .03), and the length of the retrohepatic inferior vena covered by segment 1 (P = .0006). Independent risk factors for increased blood loss were surgeon experience (P = .0001), previous upper abdominal surgery (P = .002), the retrohepatic inferior vena cava encirclement by segment 1 (P = .0001), severe portal hypertension (P = .01), early portal section (P = .001), and low prothrombin time (P = .00001).

Conclusion: Easily identifiable factors related to recipients (segment 1 morphology, previous upper abdominal surgery, severe portal hypertension) and to surgeon (operative experience, portocaval shunt fashioning, early portal section, and multiple arterial reconstructions) impact operative time and blood loss during the learning curve of piggyback liver transplantation. These factors can be used for grading the difficulties of liver transplantation to tailor the surgical strategy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.surg.2020.09.036DOI Listing
November 2020

The insula, a grey matter of tastes: a volumetric MRI study in dementia with Lewy bodies.

Alzheimers Res Ther 2020 07 6;12(1):79. Epub 2020 Jul 6.

CMRR (Memory Resources and Research Centre), University Hospital of Strasbourg, Strasbourg, France.

Background: Despite the growing number of discoveries during the past decades about its functions, the insula remains a mysterious 'island'. In addition to its involvement in basic functions such as gustation and interoception, the insular cortex is now considered a key region for integrated functions such as emotion/motivation processing, decision-making and self-consciousness. We hypothesized that this structure, standing at the crossroads of such functions, could ground personal tastes in general, beyond food preferences and aesthetic judgements. Given that dementia with Lewy bodies is characterized by a focal atrophy within the insular cortex from the early stages, this condition provides an opportunity to test such a hypothesis.

Methods: We developed a questionnaire to assess potential changes in personal tastes, submitted it to a cohort of 23 patients with early-stage dementia with Lewy bodies and compared their questionnaire results to those of 20 age-matched healthy controls. Furthermore, we performed a global and regional neuroimaging study to test for a potential correlation between the patients' scores for changes in personal tastes and their insular cortex volumes.

Results: Our results indicate that the patients presented significant changes in personal tastes compared to the controls, in both food and non-food domains. Moreover, imaging analyses confirmed the involvement of the insular cortex atrophy in the changes in personal tastes using global analysis, and in both food and non-food domains using regional analysis.

Conclusions: These results bring new insights into the role of the insula as a 'grey matter of tastes', this structure supporting personal preferences in general, beyond the food domain. The insular cortex could be involved through its role in motivational processes by the representation of subjective awareness of bodily states during the phenomenological experience of stimulus appraisal. However, we also argue that it could support the abstract representations of personal tastes as self-concepts, acutely exemplifying embodied cognition. Finally, the questionnaire on changes in tastes could constitute an interesting tool to help early diagnosis of dementia with Lewy bodies and to assess insular dysfunction more generally.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13195-020-00645-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336457PMC
July 2020

A Multicenter Preclinical MRI Study: Definition of Rat Brain Relaxometry Reference Maps.

Front Neuroinform 2020 19;14:22. Epub 2020 May 19.

INSERM, U1216, Grenoble Institut des Neurosciences, Université Grenoble Alpes, Grenoble, France.

Similarly to human population imaging, there are several well-founded motivations for animal population imaging, the most notable being the improvement of the validity of statistical results by pooling a sufficient number of animal data provided by different imaging centers. In this paper, we demonstrate the feasibility of such a multicenter animal study, sharing raw data from forty rats and processing pipelines between four imaging centers. As specific use case, we focused on T1 and T2 mapping of the healthy rat brain at 7T. We quantitatively report about the variability observed across two MR data providers and evaluate the influence of image processing steps on the final maps, using three fitting algorithms from three centers. Finally, to derive relaxation times from different brain areas, two multi-atlas segmentation pipelines from different centers were performed on two different platforms. Differences between the two data providers were 2.21% for T1 and 9.52% for T2. Differences between processing pipelines were 1.04% for T1 and 3.33% for T2. These maps, obtained in healthy conditions, may be used in the future as reference when exploring alterations in animal models of pathology.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fninf.2020.00022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7248563PMC
May 2020

Large-for-Size Orthotopic Liver Transplantation: a Systematic Review of Definitions, Outcomes, and Solutions.

J Gastrointest Surg 2020 05 9;24(5):1192-1200. Epub 2020 Jan 9.

Hepato-Pancreato-Biliary Surgery and Liver transplantation, Pôle des Pathologies Digestives, Hépatiques et de la Transplantation, Hôpital de Hautepierre-Hôpitaux Universitaires de Strasbourg, Université de Strasbourg, 1, Avenue Moliere, 67098, Strasbourg, France.

Background: We systematically reviewed the literature on definitions and outcomes of large-for-size (LFS) syndrome in orthotopic liver transplantation (LT).

Methods: This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Cochrane Library, PubMed, and Embase were searched (January 1990-January 2019) for studies reporting LFS in LT. Primary outcomes were definitions and mortality of LFS LT.

Results: Eleven studies reporting patients with LFS LT were identified. Four different formulas (graft-to-recipient weight ratio (GRWR), body surface area index (BSAi), donor standardized total liver volume (sTLV)-to-recipient sTLV ratio, and graft weight/right anteroposterior distance (RAP) ratio) with their critical thresholds were found. There were 81 patients (54% women) with a median weight and height of 62.5 kg (range, 40-105 kg) and 165 cm (range, 145-180 cm). The median graft weight was 1772 g (range, 1290-2400 g), and the median GWRW was 2.77% (range, 2.1-4.00%). Graft venous outflow obstruction was described in seven patients (8.6%). At the time of LT, fascial closure was not achieved in 24 patients (29.6%) and the graft size was reduced by a liver resection in three patients (3.7%). Thirteen deaths (16%) were reported in the first 90 postoperative days with two patients undergoing re-transplant.

Conclusions: LFS LT remains heterogeneously defined but characterized by high mortality rates despite the use of tailored surgical solutions (graft reduction and open abdomen). A composite definition is proposed in order to better describe LFS clinical syndrome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11605-019-04505-5DOI Listing
May 2020

Changes in gray matter volume and functional connectivity in dementia with Lewy bodies compared to Alzheimer's disease and normal aging: implications for fluctuations.

Alzheimers Res Ther 2020 01 6;12(1). Epub 2020 Jan 6.

ICube Laboratory UMR 7357 and FMTS (Fédération de Médecine Translationnelle de Strasbourg), Team IMIS, University of Strasbourg and CNRS, Strasbourg, France.

Background: Fluctuations are one of the core clinical features characterizing dementia with Lewy bodies (DLB). They represent a determining factor for its diagnosis and strongly impact the quality of life of patients and their caregivers. However, the neural correlates of this complex symptom remain poorly understood. This study aimed to investigate the structural and functional changes in DLB patients, compared to Alzheimer's disease (AD) patients and healthy elderly subjects, and their potential links with fluctuations.

Methods: Structural and resting-state functional MRI data were collected from 92 DLB patients, 70 AD patients, and 22 control subjects, who also underwent a detailed clinical examination including the Mayo Clinic Fluctuation Scale. Gray matter volume changes were analyzed using whole-brain voxel-based morphometry, and resting-state functional connectivity was investigated using a seed-based analysis, with regions of interest corresponding to the main nodes of the salience network (SN), frontoparietal network (FPN), dorsal attention network (DAN), and default mode network (DMN).

Results: At the structural level, fluctuation scores in DLB patients did not relate to the atrophy of insular, temporal, and frontal regions typically found in this pathology, but instead showed a weak correlation with more subtle volume reductions in different regions of the cholinergic system. At the functional level, the DLB group was characterized by a decreased connectivity within the SN and attentional networks, while the AD group showed decreases within the SN and DMN. In addition, higher fluctuation scores in DLB patients were correlated to a greater connectivity of the SN with the DAN and left thalamus, along with a decreased connectivity between the SN and DMN, and between the right thalamus and both the FPN and DMN.

Conclusions: Functional connectivity changes, rather than significant gray matter loss, could play an important role in the emergence of fluctuations in DLB. Notably, fluctuations in DLB patients appeared to be related to a disturbed external functional connectivity of the SN, which may lead to less relevant transitions between different cognitive states in response to internal and environmental stimuli. Our results also suggest that the thalamus could be a key region for the occurrence of this symptom.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13195-019-0575-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6945518PMC
January 2020

Pay attention to the basal ganglia: a volumetric study in early dementia with Lewy bodies.

Alzheimers Res Ther 2019 12 21;11(1):108. Epub 2019 Dec 21.

Geriatrics and Neurology Departments, Research and Resources Memory Center (CM2R), Strasbourg University Hospital, Strasbourg, France.

Background: Cortical and subcortical cognitive impairments are usually found in dementia with Lewy bodies (DLB). Roughly, they comprise visuo-constructive/executive function and attention/processing speed impairments, whereas memory would remain relatively spared. In this study, we focused on the neuro-anatomical substrates of attention and processing speed, which is still poorly understood. For the purpose of the study, we examined the correlations between behavioral scores measuring the speed of processing and the degree of cerebral atrophy in patients with prodromal to moderate DLB.

Methods: Ninety-three prodromal to moderate DLB patients (mean MMSE = 25.5) were selected to participate in the study as well as 28 healthy elderly subjects (mean MMSE = 28.9), matched in terms of age and educational level. The Trail Making Test A (TMTA) and the Digit Symbol Substitution Test (DSST) were used to assess attention and processing speed. Behavioral performances were compared between patients and healthy control subjects. Three-dimensional MRI images were acquired for all participants, and correlational analyses were performed in the patient group using voxel-based morphometry (VBM).

Results: The behavioral results on both the TMTA (p = .026) and the DSST (p < .001) showed significantly impaired performances in patients in comparison with control subjects. In addition, correlational analyses using VBM revealed for the TMTA negative correlations in the caudate nucleus (left cluster peak significant at .05 FWE corrected), the putamen, the left thalamus, and the subthalamic nuclei (p < .05 FDR corrected). Some positive correlations associated with the DSST were found in the right inferior frontal gyrus, the left thalamus, and the left cerebellum (p < .001 uncorrected).

Conclusions: The behavioral results are in line with the literature on the DLB cognitive profile and confirm the existence of attention and processing speed impairment. Interestingly, VBM analysis revealed the involvement of the basal ganglia, in particular, the left caudate nucleus, which is part of the attention cerebral network, suggesting an important role of this structure for attentional processing speed. This also suggests the clinical implication of damage in this region relatively early in the course of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13195-019-0568-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925479PMC
December 2019

Quantitative background parenchymal enhancement to predict recurrence after neoadjuvant chemotherapy for breast cancer.

Sci Rep 2019 12 16;9(1):19185. Epub 2019 Dec 16.

Department of Gynecology and Obstetrics, Strasbourg University Hospital, Strasbourg, France.

Breast background parenchymal enhancement (BPE) is an increasingly studied MRI parameter that reflects the microvasculature of normal breast tissue, which has been shown to change during neoadjuvant chemotherapy (NAC) for breast cancer. We aimed at evaluating the BPE in patients undergoing NAC and its prognostic value to predict recurrence. MRI BPE was visually and quantitatively evaluated before and after NAC in a retrospective cohort of 102 women with unilateral biopsy-proven invasive breast cancer. Pre-therapeutic BPE was not predictive of pathological response or recurrence. Quantitative post-therapeutic BPE was significantly decreased compared to pre-therapeutic value. Post-therapeutic quantitative BPE significantly predicted recurrence (HR = 6.38 (0.71, 12.06), p < 0.05).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-55820-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914793PMC
December 2019

A Brain Imaging-Based Diagnostic Biomarker for Periodic Catatonia: Preliminary Evidence Using a Bayesian Approach.

Neuropsychobiology 2020 10;79(4-5):352-365. Epub 2019 Sep 10.

Pôle de Psychiatrie, Santé Mentale et Addictologie, University Hospital Strasbourg, Strasbourg, France.

Periodic catatonia (PC) is a psychomotor phenotype with a progressive-remitting course. While it can fit any disorder diagnosis of the schizoaffective spectrum, its core features consist of a mix of hypo- and hyperkinesias resulting in distortions of expressive movements such as grimacing and parakinesias. The replication of cerebral blood flow (CBF) increases in the left supplementary motor area (L-SMA) and lateral premotor cortex (L-LPM) in acute and remitting PC patients indicates that these increases could be used as diagnostic biomarkers. In this proof-of-concept study, 2 different MRI sequences were repeated on 3 separate days to get reliable measurement values of CBF in 9 PC and 26 non-PC patients during different cognitive tasks. Each patient was compared to 37 controls. In L-SMA [-9; +10; +60] and L-LPM [-46; -12; +43], a test was positive if the t value was >2.02 (α < 0.05; two tailed). The measurements had good analytical performance. Regarding the tests, their sensitivities and specificities were significantly different from the chance level on both measures, except for L-SMA sensitivities. When combining all the tests, among regions and methods, sensitivity was 98% (95% credible interval [CI] 76-100%) and specificity 88% (72-97%). Bayesian inferences of its negative predictive values for PC were >95% regardless of the context, while its positive predictive values reached 94% but only when used in combination with clinical criteria. The case-by-case analysis suggests that non-PC patients with neurological motor deficits are at risk to be false positive.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1159/000501830DOI Listing
September 2019

Evaluation of the effects of chemotherapy on brain glucose metabolism in children with Hodgkin's lymphoma.

Ann Nucl Med 2019 Aug 13;33(8):564-569. Epub 2019 May 13.

Service de Biophysique Et de Médecine Nucléaire, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, 1, Avenue Molière, 67098, Strasbourg Cedex 09, France.

Objective: Chemobrain is a recently proposed pathological entity. F-FDG PET/CT can show objective abnormalities to explain brain disorders caused by chemotherapy, although no study has investigated these phenomena in children to date. The main objective of the present study was to examine quantitatively the effects of chemotherapy on brain metabolism in a homogeneous population of children treated for Hodgkin's lymphoma using 18F-FDG PET/CT.

Methods: In this retrospective study, we included 20 children, newly diagnosed with Hodgkin's lymphoma, who underwent F-FDG PET/CT at initial staging and at least one PET/CT in follow-up. The SPM12 software provided t-maps to show the difference in metabolism between these PET/CTs. The statistical maps were analyzed with xjView software to identify the brain regions associated with the clusters detected.

Results: Altered glucose metabolism was found in the frontal, cingular, and temporoinsular regions after two cycles of chemotherapy. Results in children were compared to a group of 35 adults. For the same statistical threshold, the extent and depth of the metabolic alterations were less in the adult group than in children.

Conclusions: F-FDG PET/CT is useful in providing objective data to explain brain disorders caused by chemotherapy. This could lead to better care and should be compared to neuropsychological test results.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12149-019-01363-8DOI Listing
August 2019

Liver tissue segmentation in multiphase CT scans using cascaded convolutional neural networks.

Int J Comput Assist Radiol Surg 2019 Aug 30;14(8):1275-1284. Epub 2019 Apr 30.

Department of Hepato-Biliary and Pancreatic Surgery, Nouvel Hôpital Civil, Institut Hospitalo-Universitaire de Strasbourg, 1 place de l'Hôpital, 67000, Strasbourg, France.

Purpose: We address the automatic segmentation of healthy and cancerous liver tissues (parenchyma, active and necrotic parts of hepatocellular carcinoma (HCC) tumor) on multiphase CT images using a deep learning approach.

Methods: We devise a cascaded convolutional neural network based on the U-Net architecture. Two strategies for dealing with multiphase information are compared: Single-phase images are concatenated in a multi-dimensional features map on the input layer, or output maps are computed independently for each phase before being merged to produce the final segmentation. Each network of the cascade is specialized in the segmentation of a specific tissue. The performances of these networks taken separately and of the cascaded architecture are assessed on both single-phase and on multiphase images.

Results: In terms of Dice coefficients, the proposed method is on par with a state-of-the-art method designed for automatic MR image segmentation and outperforms previously used technique for interactive CT image segmentation. We validate the hypothesis that several cascaded specialized networks have a higher prediction accuracy than a single network addressing all tasks simultaneously. Although the portal venous phase alone seems to provide sufficient contrast for discriminating tumors from healthy parenchyma, the multiphase information brings significant improvement for the segmentation of cancerous tissues (active versus necrotic part).

Conclusion: The proposed cascaded multiphase architecture showed promising performances for the automatic segmentation of liver tissues, allowing to reliably estimate the necrosis rate, a valuable imaging biomarker of the clinical outcome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11548-019-01989-zDOI Listing
August 2019

Emotional disturbances in multiple sclerosis: A neuropsychological and fMRI study.

Cortex 2019 08 1;117:205-216. Epub 2019 Mar 1.

University of Strasbourg and CNRS, ICube Laboratory UMR 7357 and FMTS (Fédération de Médecine Translationnelle de Strasbourg), Team IMIS/Neurocrypto, Strasbourg, France; University Hospitals of Strasbourg, CMRR (Memory Resources and Research Centre), Geriatric Day Hospital, Geriatrics Department, Strasbourg, France.

Background: Emotional disturbances in multiple sclerosis (MS) are often explored in terms of affect recognition, with controversial results that likely reflect the high lesional heterogeneity. Patients' emotional experience, however, has seldom been studied and has never been explored using fMRI.

Objectives: To explore the emotional experience in MS and compare these data with fMRI measurements using for the first time real-life emotional scenes differing in valence and arousal.

Methods: Twenty-five right-handed women with relapsing-remitting MS and 27 right-handed age-, sex-, and education-matched healthy controls visualized during an fMRI session, emotional scenes taken from the international affect picture system (IAPS) and differing in valence (positive, negative, neutral) and arousal (ranging from calm to excited). During a post-scanning debriefing, participants were asked to look again at each image and score it in terms of valence and arousal sensation on a scale of 1-9.

Results: Cognitively well-preserved MS subjects presented a significantly more scattered emotional experience compared to controls in response to positive and negative pictures. In fMRI, MS patients also presented a higher variability of response when compared to controls in left inferior orbitofrontal cortex for positive stimulations. For negative condition, no significant results were observed between the two groups. However, a trend was detected in left amygdala, right fusiform gyrus, right caudate nucleus and right pallidum for negative stimulations.

Conclusion: In response to emotional stimuli, MS subjects presented a scattered emotional experience subtended by a greater variability of brain response, highlighting an emotional pattern not previously reported in MS patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cortex.2019.02.017DOI Listing
August 2019

Prospective evaluation of ultra-low-dose contrast-enhanced 100-kV abdominal computed tomography with tin filter: effect on radiation dose reduction and image quality with a third-generation dual-source CT system.

Eur Radiol 2019 Apr 15;29(4):2107-2116. Epub 2018 Oct 15.

Service de Radiologie B, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, 1, place de l'hôpital, BP 426, 67091, Strasbourg Cedex, France.

Objectives: To investigate the radiation dose exposure, image quality, and diagnostic performance of enhanced 100-kVp abdominopelvic single-energy CT protocol with tin filter (TF).

Methods: Ninety-three consecutive patients referred for a single-phase enhanced abdominopelvic CT were prospectively included after informed consent. They underwent in addition to a standard protocol (SP) an acquisition with TF. Both examinations were performed on a third-generation dual-source CT system (DSCT), in single energy, using automatic tube current modulation, identical pitch, and identical level of iterative reconstruction. Radiation metrics were compared. Size-specific dose estimates (SSDE), contrast to noise ratio (CNR), and figure of merit (FOM) were calculated. Diagnostic confidence for the assessment of a predetermined list of abdominal lesions was rated by two independent readers.

Results: The mean dose of the TF protocol was significantly lower (CDTI 1.56 ± 0.43 mGy vs. 8.13 ± 3.32, p < 0.001; SSDE 9.94 ± 3.08 vs. 1.93 ± 0.39, p < 0.001), with an effective dose close to 1 mSv (1.14 mSv ± 0.34; p < 0.001). TF group exhibited non-significant lower liver CNR (2.76 vs. 3.03, p = 0.56) and was more dose efficient (FOM 10.6 vs. 2.49/mSv, p < 0.001) in comparison to SP. The mean diagnostic confidence for visceral, bone, and peritoneal tumors was equivalent between both groups.

Conclusions: Enhanced 100-kVp abdominopelvic CT acquired after spectral shaping with tin filtration can achieve similar diagnostic performance and CNR compared to a standard CT protocol, while reducing the radiation dose by 81%.

Key Points: • 100-kVp spectral filtration enables enhanced abdominal CT with high-dose efficiency. • The radiation dose reaches the 1-mSv range. • Predetermined abdominopelvic lesions can be assessed without impairing on diagnostic confidence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00330-018-5750-2DOI Listing
April 2019

Survey on deep learning for radiotherapy.

Comput Biol Med 2018 07 17;98:126-146. Epub 2018 May 17.

ICube-UMR 7357, Strasbourg, France.

More than 50% of cancer patients are treated with radiotherapy, either exclusively or in combination with other methods. The planning and delivery of radiotherapy treatment is a complex process, but can now be greatly facilitated by artificial intelligence technology. Deep learning is the fastest-growing field in artificial intelligence and has been successfully used in recent years in many domains, including medicine. In this article, we first explain the concept of deep learning, addressing it in the broader context of machine learning. The most common network architectures are presented, with a more specific focus on convolutional neural networks. We then present a review of the published works on deep learning methods that can be applied to radiotherapy, which are classified into seven categories related to the patient workflow, and can provide some insights of potential future applications. We have attempted to make this paper accessible to both radiotherapy and deep learning communities, and hope that it will inspire new collaborations between these two communities to develop dedicated radiotherapy applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.compbiomed.2018.05.018DOI Listing
July 2018

Automatic detection and segmentation of brain metastases on multimodal MR images with a deep convolutional neural network.

Comput Biol Med 2018 04 9;95:43-54. Epub 2018 Feb 9.

Department of Medical Physics, Paul Strauss Center, Strasbourg, France; ICube-UMR 7357, Strasbourg, France. Electronic address:

Stereotactic treatments are today the reference techniques for the irradiation of brain metastases in radiotherapy. The dose per fraction is very high, and delivered in small volumes (diameter <1 cm). As part of these treatments, effective detection and precise segmentation of lesions are imperative. Many methods based on deep-learning approaches have been developed for the automatic segmentation of gliomas, but very little for that of brain metastases. We adapted an existing 3D convolutional neural network (DeepMedic) to detect and segment brain metastases on MRI. At first, we sought to adapt the network parameters to brain metastases. We then explored the single or combined use of different MRI modalities, by evaluating network performance in terms of detection and segmentation. We also studied the interest of increasing the database with virtual patients or of using an additional database in which the active parts of the metastases are separated from the necrotic parts. Our results indicated that a deep network approach is promising for the detection and the segmentation of brain metastases on multimodal MRI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.compbiomed.2018.02.004DOI Listing
April 2018

Henry, where have you lost your Self?

Cortex 2017 10 14;95:37-50. Epub 2017 Jul 14.

CMRR (Memory Resources and Research Centre), University Hospital of Strasbourg, Strasbourg, France; ICube Laboratory (UMR 7357) and FMTS, University of Strasbourg and CNRS, Strasbourg, France; Geriatrics Department, University Hospital of Strasbourg, Strasbourg, France.

The Self is a complex construct encompassing distinct components, including episodic and semantic autobiographical memory, the Self-concept, and the subjective sense of Self, which highest level consists of Self-awareness. The neuro-anatomical correlates are complex, and it is debated as to whether a common region could support these different components of the Self, with a particular interest for the cortical midline structures and the medial prefrontal cortex (MPFC). Alzheimer's disease (AD) constitutes an interesting model for the study of Self as autobiographical memory typically deteriorates as the disease progresses. Here, we report the unexpected case of Henry, a patient with MCI due to AD who was unable to produce any personal autobiographical memories, nor describe his Self-concept, had a poor personal semantic memory, and disclosed unusual anosognosia for this stage of the disease. His cognitive performance was compared to a group of matched AD patients and a group of healthy controls confirming that the main components of his Self were degraded. We hypothesized that it was due to a marked atrophy within the cortical midline, as visually assessed on his MRI. We further elucidated these findings through Voxel-based morphometry analysis, which confirmed a significant atrophy of the MPFC that was specific to this patient. Moreover, this revealed significant atrophy within the bilateral insular cortex. Given the stage of the disease, the degradation of the Self is unlikely to be accounted for by deficient mnemonic processes, especially as the presence of discrete temporal atrophy was noted. We suggest that this specific pattern of MPFC and insular atrophy is responsible for the systematic collapse of the patient's Self, through the breakdown of the subjective sense of Self, which is proposed as a prerequisite to all other components, according to the model proposed by Prebble, Addis, and Tippett (2013).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cortex.2017.06.019DOI Listing
October 2017

Insular atrophy at the prodromal stage of dementia with Lewy bodies: a VBM DARTEL study.

Sci Rep 2017 08 25;7(1):9437. Epub 2017 Aug 25.

ICube, UMR 7357, CNRS, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France.

Diffuse atrophy including the insula was previously demonstrated in dementia with Lewy bodies (DLB) patients but little is known about the prodromal stage of DLB (pro-DLB). In this prospective study, we used SPM8-DARTEL to measure gray matter (GM) and white matter (WM) atrophy in pro-DLB patients (n = 54), prodromal Alzheimer's disease (pro-AD) patients (n = 16), DLB patients at the stage of dementia (mild-DLB) (n = 15), and Alzheimer's disease patients at the stage of dementia (mild-AD) (n = 28), and compared them with healthy elderly controls (HC, n = 22). Diminished GM volumes were found in bilateral insula in pro-DLB patients, a trend to significance in right hippocampus and parahippocampal gyrus in pro-AD patients, in left insula in mild-DLB patients, and in medial temporal lobes and insula in mild-AD patients. The comparison between prodromal groups did not showed any differences. The comparison between groups with dementia revealed atrophy around the left middle temporal gyrus in mild-AD patients. Reduced WM volume was observed in mild-DLB in the pons. The insula seems to be a key region in DLB as early as the prodromal stage. MRI studies looking at perfusion, and functional and anatomical connectivity are now needed to better understand the role of this region in DLB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-017-08667-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5573371PMC
August 2017

Megavoltage 2D topographic imaging: An attractive alternative to megavoltage CT for the localization of breast cancer patients treated with TomoDirect.

Phys Med 2017 Jul 20;39:33-38. Epub 2017 Jun 20.

ICube-UMR 7357, Strasbourg, France.

Purpose: To show the usefulness of topographic 2D megavoltage images (MV2D) for the localization of breast cancer patients treated with TomoDirect (TD), a radiotherapy treatment technique with fixed-angle beams performed on a TomoTherapy system.

Methods: A method was developed to quickly localize breast cancer patients treated with TD by registering the MV2D images produced before a TD treatment with reference images reconstructed from a kilovoltage CT simulation scanner and by using the projection of the beam-eye-view TD treatment field. Dose and image quality measurements were performed to determine the optimal parameters for acquiring MV2D images. A TD treatment was simulated on a chest phantom equipped with a breast attachment. MVCT and MV2D images were performed for 7 different shifted positions of the phantom and registered by 10 different operators with the simulation kilovoltage CT images.

Results: Compared to MVCT, MV2D imaging reduces the dose by a factor of up to 45 and the acquisition time by a factor of up to 49. Comparing the registration shift values obtained for the phantom images obtained with MVCT in the coarse mode to those obtained with MV2D, the mean difference is 1.0±1.1mm, -1.1mm±1.1, and -0.1±2.2mm, respectively, in the lateral, longitudinal, and vertical directions.

Conclusions: With dual advantages (very fast imaging and a potentially reduced dose to the heart and contralateral organs), MV2D topographic images may be an attractive alternative to MVCT for the localization of breast cancer patients treated with TomoDirect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2017.06.015DOI Listing
July 2017

Scale-adaptive supervoxel-based random forests for liver tumor segmentation in dynamic contrast-enhanced CT scans.

Int J Comput Assist Radiol Surg 2017 Feb 22;12(2):223-233. Epub 2016 Oct 22.

Department of Hepato-Biliary and Pancreatic Surgery, Nouvel Hôpital Civil, Institut Hospitalo-Universitaire de Strasbourg, 1 place de l'Hôpital, 67000, Strasbourg, France.

Purpose: Toward an efficient clinical management of hepatocellular carcinoma (HCC), we propose a classification framework dedicated to tumor necrosis rate estimation from dynamic contrast-enhanced CT scans. Based on machine learning, it requires weak interaction efforts to segment healthy, active and necrotic liver tissues.

Methods: Our contributions are two-fold. First, we apply random forest (RF) on supervoxels using multi-phase supervoxel-based features that discriminate tissues based on their dynamic in response to contrast agent injection. Second, we extend this technique in a hierarchical multi-scale fashion to deal with multiple spatial extents and appearance heterogeneity. It translates in an adaptive data sampling scheme combining RF and hierarchical multi-scale tree resulting from recursive supervoxel decomposition. By concatenating multi-phase features across the hierarchical multi-scale tree to describe leaf supervoxels, we enable RF to automatically infer the most informative scales without defining any explicit rules on how to combine them.

Results: Assessment on clinical data confirms the benefits of multi-phase information embedded in a multi-scale supervoxel representation for HCC tumor segmentation.

Conclusion: Dedicated but not limited only to HCC management, both contributions reach further steps toward more accurate multi-label tissue classification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11548-016-1493-1DOI Listing
February 2017

Benefits from an autobiographical memory facilitation programme in relapsing-remitting multiple sclerosis patients: a clinical and neuroimaging study.

Neuropsychol Rehabil 2018 Oct 9;28(7):1110-1130. Epub 2016 Oct 9.

a Cognitive Neuropsychology and Physiopathology of Schizophrenia (INSERM UMR 1114) , University of Strasbourg , Strasbourg , France.

While the efficacy of mental visual imagery (MVI) to alleviate autobiographical memory (AM) impairment in multiple sclerosis (MS) patients has been documented, nothing is known about the brain changes sustaining that improvement. To explore this issue, 20 relapsing-remitting MS patients showing AM impairment were randomly assigned to two groups, experimental (n = 10), who underwent the MVI programme, and control (n = 10), who followed a sham verbal programme. Besides the stringent AM assessment, the patients underwent structural and functional MRI sessions, consisting in retrieving personal memories, within a pre-/post-facilitation study design. Only the experimental group showed a significant AM improvement in post-facilitation, accompanied by changes in brain activation (medial and lateral frontal regions), functional connectivity (posterior brain regions), and grey matter volume (parahippocampal gyrus). Minor activations and functional connectivity changes were observed in the control group. The MVI programme improved AM in MS patients leading to functional and structural changes reflecting (1) an increase reliance on brain regions sustaining a self-referential process; (2) a decrease of those reflecting an effortful research process; and (3) better use of neural resources in brain regions sustaining MVI. Functional changes reported in the control group likely reflected ineffective attempts to use the sham strategy in AM.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/09602011.2016.1240697DOI Listing
October 2018

Which is the most appropriate strategy for conducting multivariate voxel-based group studies on diffusion tensors?

Neuroimage 2016 Nov 27;142:99-112. Epub 2016 May 27.

ICube, University of Strasbourg, CNRS, Fédération de Médecine Translationnelle de Strasbourg (FMTS), France.

There is a real need in the neuroscience community for efficient tools to compare Diffusion Tensor Magnetic Resonance Imaging across cohorts of subjects. Most studies focus on the comparison of scalar images such as fractional anisotropy or mean diffusivity. Although different statistical frameworks have been proposed to compare the whole diffusion tensor information, they are still seldom used in neuroimaging studies. In this paper, we investigate on both simulated and real data whether there is a real added value of considering the whole tensor information for conducting voxel-based group studies. Then, we compare two statistical tests dedicated to tensor, namely the Cramér test and a tensor-based extension of the General Linear Model (GLM), the latter presenting the advantage to account for covariates. We also evaluate the impact of different metrics (Euclidean, Log-Euclidean and affine-invariant Riemannian metrics) for estimating the GLM parameters. Finally, we address the problem of interpreting the change detection maps obtained by tensor-based methods by proposing a way to characterize each of the detected clusters according to several scalar indices. Our study suggests that if there is no prior assumption about the nature of the expected changes, it is really preferable to use tensor-based rather than scalar-based statistical analysis. The Cramér test can advantageously be used when no confounding variable hampers the group comparison, otherwise the GLM should be considered. Finally, the different metrics show similar performance in the real scenario, with a significant computational overhead for the Riemannian framework.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuroimage.2016.05.040DOI Listing
November 2016

Functional and structural cerebral changes in key brain regions after a facilitation programme for episodic future thought in relapsing-remitting multiple sclerosis patients.

Brain Cogn 2016 06 2;105:34-45. Epub 2016 Apr 2.

Cognitive Neuropsychology and Physiopathology of Schizophrenia (INSERM UMR 1114), University of Strasbourg, Strasbourg, France. Electronic address:

Increasingly studied, episodic future thought (EFT) impairment negatively affects patients' daily life. Along these lines, working with relapsing-remitting multiple sclerosis (RR-MS) patients, we documented the clinical effectiveness of a mental visual imagery (MVI)-based facilitation programme on EFT impairment related to executive function difficulties. We aimed at improving the characterisation of the cognitive and neural underpinnings of RR-MS patients' EFT amelioration, by exploring the structural and functional brain changes following the MVI programme. Seventeen non-depressed RR-MS patients were recruited and randomly assigned in the (i) experimental group (n=10), who followed the MVI programme or in the control group (n=7), who followed a verbal control programme. Using an adapted version of the Autobiographical Interview to assess EFT, after facilitation, significant improvement was observed in the experimental group only. This was accompanied by increased activation in the prefrontal region during the generation of future events and was positively correlated with grey matter volume increase in this same brain area. Increased activations in the parahippocampal and the middle temporal gyri were also observed in the experimental group in post-facilitation. Likewise, functional connectivity changes were observed in the posterior brain regions after facilitation. Only minor cerebral changes were observed in the control group, likely reflecting practice effects. Our study showed that EFT improvement following the MVI programme led to functional and structural changes in brain regions sustaining contextual processing, visual imagery, the integration and maintenance of multimodal information. Taken together, these findings suggest that a cognitive intervention focusing on scene construction can be efficient to alleviate EFT impairment related to executive dysfunction. As such, this study opens the way to the development of tailor-made rehabilitation programmes using the different cognitive mechanisms involved in EFT.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bandc.2016.03.007DOI Listing
June 2016

Cognitive and affective theory of mind in dementia with Lewy bodies and Alzheimer's disease.

Alzheimers Res Ther 2016 Mar 16;8(1):10. Epub 2016 Mar 16.

Neuropsychology Unit, Memory Resource and Research Centre (CMRR), Department of Neurology, University Hospital of Strasbourg, Strasbourg, France.

Background: Theory of mind (ToM) refers to the ability to attribute mental states, thoughts (cognitive component) or feelings (affective component) to others. This function has been studied in many neurodegenerative diseases; however, to our knowledge, no studies investigating ToM in dementia with Lewy bodies (DLB) have been published. The aim of our study was to assess ToM in patients with DLB and to search for neural correlates of potential deficits.

Methods: Thirty-three patients with DLB (DLB group) and 15 patients with Alzheimer's disease (AD group), all in the early stage of the disease, as well as 16 healthy elderly control subjects (HC group), were included in the study. After a global cognitive assessment, we used the Faux Pas Recognition (FPR) test, the Reading the Mind in the Eyes (RME) test and Ekman's Facial Emotion Recognition test to assess cognitive and affective components of ToM. Patients underwent cerebral 3-T magnetic resonance imaging, and atrophy of grey matter was analysed using voxel-based morphometry. We performed a one-sample t test to investigate the correlation between each ToM score and grey matter volume and a two-sample t test to compare patients with DLB impaired with those non-impaired for each test.

Results: The DLB group performed significantly worse than the HC group on the FPR test (P = 0.033) and the RME test (P = 0.015). There was no significant difference between the AD group and the HC group or between the DLB group and the AD group. Some brain regions were associated with ToM impairments. The prefrontal cortex, with the inferior frontal cortex and the orbitofrontal cortex, was the main region, but we also found correlations with the temporoparietal junction, the precuneus, the fusiform gyrus and the insula.

Conclusions: This study is the first one to show early impairments of ToM in DLB. The two cognitive and affective components both appear to be affected in this disease. Among patients with ToM difficulties, we found atrophy in brain regions classically involved in ToM, which reinforces the neuronal network of ToM. Further studies are now needed to better understand the neural basis of such impairment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13195-016-0179-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4793654PMC
March 2016

Neural correlates of episodic future thinking impairment in multiple sclerosis patients.

J Clin Exp Neuropsychol 2015 ;37(10):1107-23

a Cognitive Neuropsychology and Physiopathology of Schizophrenia (INSERM UMR 1114) , Strasbourg University , Strasbourg , France.

Background: Recent clinical investigations showed impaired episodic future thinking (EFT) abilities in multiple sclerosis (MS) patients. On these bases, the aim of the current study was to explore the structural and functional correlates of EFT impairment in nondepressed MS patients.

Method: Twenty-one nondepressed MS patients and 20 matched healthy controls were assessed with the adapted Autobiographical Interview (AI), and patients were selected on the bases of an EFT impaired score criterion. The 41 participants underwent a functional magnetic resonance imaging (fMRI) session, distinguishing the construction and elaboration phases of the experimental EFT, and the categorical control tests. Structural images were also acquired.

Results: During the EFT fMRI task, increased cerebral activations were observed in patients (relative to healthy controls) within the EFT core network. These neural changes were particularly important during the construction phase of future events and involved mostly the prefrontal region. This was accompanied by an increased neural response mostly in anterior, and also posterior, cerebral regions, in association with the amount of detail produced by patients. In parallel, structural measures corroborated a main positive association between the prefrontal regions' volume and EFT performance. However, no association between the hippocampus and EFT performance was observed in patients, at both structural and functional levels.

Conclusion: We have documented significant overlaps between the structural and functional underpinnings of EFT impairment, with a main role of the prefrontal region in its clinical expression in MS patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/13803395.2015.1080228DOI Listing
June 2016

Different Temporal Patterns of Specific and General Autobiographical Memories across the Lifespan in Alzheimer's Disease.

Behav Neurol 2015 15;2015:963460. Epub 2015 Jun 15.

INSERM, Cognitive Neuropsychology and Pathophysiology of Schizophrenia (U1114), University of Strasbourg, 1 place de l'Hôpital, 12 rue Goethe, 67000 Strasbourg, France.

We compared specific (i.e., associated with a unique time and space) and general (i.e., extended or repeated events) autobiographical memories (AbM) in Alzheimer's disease (AD). The comparison aims at investigating the relationship between these two components of AbM across the lifespan and the volume of cerebral regions of interest within the temporal lobe. We hypothesized that the ability to elicit specific memories would correlate with hippocampal volume, whereas evoking general memories would be related to lateral temporal lobe. AbM was assessed using the modified Crovitz test in 18 patients with early AD and 18 matched controls. The proportions of total memories-supposed to reflect the ability to produce general memories-and specific memories retrieved were compared between AD patients and controls. Correlations to MRI volumes of temporal cortex were tested. We found different temporal patterns for specific and general memories in AD patients, with (i) relatively spared general memories, according to a temporal gradient that preserved remote memories, predominantly associated with right lateral temporal cortex volume. (ii) Conversely, the retrieval of specific AbMs was impaired for all life periods and correlated with bilateral hippocampal volumes. Our results highlight a shift from an initially episodic to a semantic nature of AbMs during AD, where the abstracted form of memories remains.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2015/963460DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4484842PMC
March 2016

Impaired emotional autobiographical memory associated with right amygdalar-hippocampal atrophy in Alzheimer's disease patients.

Front Aging Neurosci 2015 16;7:21. Epub 2015 Mar 16.

Cognitive Neuropsychology and Pathophysiology of Schizophrenia (U1114), University of Strasbourg and INSERM Strasbourg, France.

We studied the influence of emotions on autobiographical memory (AbM) in patients with Alzheimer's disease (AD), characteristically triggering atrophy in the hippocampus and the amygdala, two crucial structures sustaining memory and emotional processing. Our first aim was to analyze the influence of emotion on AbM in AD patients, on both the proportion and the specificity of emotional memories. Additionally, we sought to determine the relationship of emotional AbM to amygdalar-hippocampal volumes. Eighteen prodromal to mild AD patients and 18 age-matched healthy controls were included. We obtained 30 autobiographical memories per participant using the modified Crovitz test (MCT). Analyses were performed on global scores, rates and specificity scores of the emotional vs. neutral categories of memories. Amygdalar-hippocampal volumes were extracted from 3D T1-weighted MRI scans and tested for correlations with behavioral data. Overall, AD patients displayed a deficit in emotional AbMs as they elicited less emotional memories than the controls, however, the specificity of those memories was preserved. The deficit likely implied retrieval or storage as it was extended in time and without reminiscence bump effect. Global scores and rates of emotional memories, but not the specificity scores, were correlated to right amygdalar and hippocampal volumes, indicating that atrophy in these structures has a central role in the deficit observed. Conversely, emotional memories were more specific than neutral memories in both groups, reflecting an enhancement effect of emotion that could be supported by other brain regions that are spared during the early stages of the disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnagi.2015.00021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4360763PMC
April 2015