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Varela V, Evdokimidis I, Potagas C. Binding objects to their spatiotemporal context: Age gradient and neuropsychological correlates of What-Where-When task performance. APPLIED NEUROPSYCHOLOGY. ADULT 2023; 30:214-226. [PMID: 34053387 DOI: 10.1080/23279095.2021.1924719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A number of recent studies have shown that the ability to accurately recall bound object and spatiotemporal aspects of an experienced event develops gradually in children and is greatly impaired in the elderly, reflecting developmental discontinuities in the integrity of the underlying medial temporal lobe network. Using a novel What-Where-When (WWW) visuospatial reconstruction task, the experiential memory performance of a group of healthy older adults (aged 60-80) was compared to that of a group of younger adults (aged 20-40). Both groups were equated on their general cognitive ability, their executive functioning, and on the presence of depression, anxiety, and stress symptomatology. As hypothesized, the performance of the older adults in the binding task was significantly lower, with younger participants recalling three times the amount of bound object and spatiotemporal triads than their older counterparts. Psychomotor speed was found to be lower in older adults and was the only neuropsychological index to significantly affect success on the WWW binding task. Based on this and other relevant studies, the selective associative memory impairment obtained using a non-verbal What-Where-When paradigm emerges as a marker for the detection of early pre-clinical signs of experiential memory pathology.
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Affiliation(s)
- Vasiliki Varela
- Eginition Hospital, Department of Neurology, School of Medicine, University of Athens, Athens, Greece
| | - Ioannis Evdokimidis
- Eginition Hospital, Department of Neurology, School of Medicine, University of Athens, Athens, Greece
| | - Constantin Potagas
- Eginition Hospital, Department of Neurology, School of Medicine, University of Athens, Athens, Greece
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Rocca MA, Schoonheim MM, Valsasina P, Geurts JJG, Filippi M. Task- and resting-state fMRI studies in multiple sclerosis: From regions to systems and time-varying analysis. Current status and future perspective. Neuroimage Clin 2022; 35:103076. [PMID: 35691253 PMCID: PMC9194954 DOI: 10.1016/j.nicl.2022.103076] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 01/12/2023]
Abstract
Functional MRI is able to detect adaptive and maladaptive abnormalities at different MS stages. Increased fMRI activity is a feature of early MS, while progressive exhaustion of adaptive mechanisms is detected later on in the disease. Collapse of long-range connections and impaired hub integration characterize MS network reorganization. Time-varying connectivity analysis provides useful and complementary pieces of information to static functional connectivity. New perspectives might be the use of multimodal MRI and artificial intelligence.
Multiple sclerosis (MS) is a neurological disorder affecting the central nervous system and features extensive functional brain changes that are poorly understood but relate strongly to clinical impairments. Functional magnetic resonance imaging (fMRI) is a non-invasive, powerful technique able to map activity of brain regions and to assess how such regions interact for an efficient brain network. FMRI has been widely applied to study functional brain changes in MS, allowing to investigate functional plasticity consequent to disease-related structural injury. The first studies in MS using active fMRI tasks mainly aimed to study such plastic changes by identifying abnormal activity in salient brain regions (or systems) involved by the task. In later studies the focus shifted towards resting state (RS) functional connectivity (FC) studies, which aimed to map large-scale functional networks of the brain and to establish how MS pathology impairs functional integration, eventually leading to the hypothesized network collapse as patients clinically progress. This review provides a summary of the main findings from studies using task-based and RS fMRI and illustrates how functional brain alterations relate to clinical disability and cognitive deficits in this condition. We also give an overview of longitudinal studies that used task-based and RS fMRI to monitor disease evolution and effects of motor and cognitive rehabilitation. In addition, we discuss the results of studies using newer technologies involving time-varying FC to investigate abnormal dynamism and flexibility of network configurations in MS. Finally, we show some preliminary results from two recent topics (i.e., multimodal MRI analysis and artificial intelligence) that are receiving increasing attention. Together, these functional studies could provide new (conceptual) insights into disease stage-specific mechanisms underlying progression in MS, with recommendations for future research.
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Affiliation(s)
- Maria A Rocca
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy; Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
| | - Menno M Schoonheim
- Department of Anatomy and Neurosciences, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Paola Valsasina
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Jeroen J G Geurts
- Department of Anatomy and Neurosciences, MS Center Amsterdam, Amsterdam Neuroscience, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Massimo Filippi
- Neuroimaging Research Unit, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Milan, Italy; Neurology Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy; Neurorehabilitation Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy; Neurophysiology Service, IRCCS San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
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3
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Clinical and MRI predictors of cognitive decline in patients with relapsing-remitting multiple sclerosis: a 2-year longitudinal study. Mult Scler Relat Disord 2022; 65:103838. [DOI: 10.1016/j.msard.2022.103838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/16/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022]
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Gu XQ, Liu Y, Gu JB, Li LF, Fu LL, Han XM. Correlations between hippocampal functional connectivity, structural changes, and clinical data in patients with relapsing-remitting multiple sclerosis: a case-control study using multimodal magnetic resonance imaging. Neural Regen Res 2021; 17:1115-1124. [PMID: 34558540 PMCID: PMC8552851 DOI: 10.4103/1673-5374.324855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Multiple sclerosis is associated with structural and functional brain alterations leading to cognitive impairments across multiple domains including attention, memory, and the speed of information processing. The hippocampus, which is a brain important structure involved in memory, undergoes microstructural changes in the early stage of multiple sclerosis. In this study, we analyzed hippocampal function and structure in patients with relapsing-remitting multiple sclerosis and explored correlations between the functional connectivity of the hippocampus to the whole brain, changes in local brain function and microstructure, and cognitive function at rest. We retrospectively analyzed data from 20 relapsing-remitting multiple sclerosis patients admitted to the Department of Neurology at the China-Japan Union Hospital of Jilin University, China, from April 2015 to November 2019. Sixteen healthy volunteers were recruited as the healthy control group. All participants were evaluated using a scale of extended disability status and the Montreal cognitive assessment within 1 week before and after head diffusion tensor imaging and functional magnetic resonance imaging. Compared with the healthy control group, the patients with relapsing-remitting multiple sclerosis had lower Montreal cognitive assessment scores and regions of simultaneously enhanced and attenuated whole-brain functional connectivity and local functional connectivity in the bilateral hippocampus. Hippocampal diffusion tensor imaging data showed that, compared with the healthy control group, patients with relapsing-remitting multiple sclerosis had lower hippocampal fractional anisotropy values and higher mean diffusivity values, suggesting abnormal hippocampal structure. The left hippocampus whole-brain functional connectivity was negatively correlated with the Montreal cognitive assessment score (r = −0.698, P = 0.025), and whole-brain functional connectivity of the right hippocampus was negatively correlated with extended disability status scale score (r = −0.649, P = 0.042). The mean diffusivity value of the left hippocampus was negatively correlated with the Montreal cognitive assessment score (r = −0.729, P = 0.017) and positively correlated with the extended disability status scale score (r = 0.653, P = 0.041). The right hippocampal mean diffusivity value was positively correlated with the extended disability status scale score (r = 0.684, P = 0.029). These data suggest that the functional connectivity and presence of structural abnormalities in the hippocampus in patients with relapse-remission multiple sclerosis are correlated with the degree of cognitive function and extent of disability. This study was approved by the Ethics Committee of China-Japan Union Hospital of Jilin University, China (approval No. 201702202) on February 22, 2017.
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Affiliation(s)
- Xin-Quan Gu
- China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
| | - Ying Liu
- Cardre's Ward, Changchun Central hospital, Changchun, Jilin Province, China
| | - Jie-Bing Gu
- First Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
| | - Lin-Fang Li
- First Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
| | - Ling-Ling Fu
- First Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
| | - Xue-Mei Han
- First Department of Neurology, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China
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Structural and functional brain changes in X-linked Charcot-Marie-Tooth disease: insights from a multimodal neuroimaging study. Neuroradiology 2021; 64:543-552. [PMID: 34498107 DOI: 10.1007/s00234-021-02730-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/29/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Brain involvement in X-linked Charcot-Marie-Tooth disease (CMTX) has been previously reported. We studied the brain structural and functional integrity using a multimodal neuroimaging approach in patients with no current central nervous system (CNS) symptoms, in order to further delineate the disease's phenotype. METHODS Seventeen CMTX patients with no current CNS symptoms and 24 matched healthy controls underwent brain magnetic resonance imaging (MRI). Structural integrity was evaluated performing Gray matter analysis with voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) of diffusion tensor imaging (DTI). Functional integrity was evaluated with resting-state functional MRI (rs-fMRI). RESULTS Decreased gray matter density was detected in CMTX patients compared to healthy controls in bilateral hippocampus, left thalamus, left postcentral gyrus, left superior parietal lobule, left cerebellum crus I and II, and vermis VI. DTI analysis showed increased fractional anisotropy and radial diffusivity in the right anterior insula and increased axial diffusivity in right cerebellum crus I in CMTX patients. rs-fMRI revealed decreased spontaneous neural activity on left precentral gyrus in patients compared to healthy controls. CONCLUSION Advanced magnetic resonance (MR) neuroimaging techniques in CMTX patients revealed structural and functional involvement of multiple motor and extra-motor brain areas. MR neuroimaging techniques have the potential to delineate the CNS phenotype of a peripheral neuropathy like CMTX.
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Jandric D, Doshi A, Scott R, Paling D, Rog D, Chataway J, Schoonheim M, Parker G, Muhlert N. A systematic review of resting state functional MRI connectivity changes and cognitive impairment in multiple sclerosis. Brain Connect 2021; 12:112-133. [PMID: 34382408 DOI: 10.1089/brain.2021.0104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Cognitive impairment in multiple sclerosis (MS) is increasingly being investigated with resting state functional MRI (rs-fMRI) functional connectivity (FC) . However, results remain difficult to interpret, showing both high and low FC associated with cognitive impairment. We conducted a systematic review of rs-fMRI studies in MS to understand whether the direction of FC change relates to cognitive dysfunction, and how this may be influenced by the choice of methodology. METHODS Embase, Medline and PsycINFO were searched for studies assessing cognitive function and rs-fMRI FC in adults with MS. RESULTS Fifty-seven studies were included in a narrative synthesis. Of these, 50 found an association between cognitive impairment and FC abnormalities. Worse cognition was linked to high FC in 18 studies, and to low FC in 17 studies. Nine studies found patterns of both high and low FC related to poor cognitive performance, in different regions or for different MR metrics. There was no clear link to increased FC during early stages of MS and reduced FC in later stages, as predicted by common models of MS pathology. Throughout, we found substantial heterogeneity in study methodology, and carefully consider how this may impact on the observed findings. DISCUSSION These results indicate an urgent need for greater standardisation in the field - in terms of the choice of MRI analysis and the definition of cognitive impairment. This will allow us to use rs-fMRI FC as a biomarker in future clinical studies, and as a tool to understand mechanisms underpinning cognitive symptoms in MS.
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Affiliation(s)
- Danka Jandric
- The University of Manchester, 5292, Oxford Road, Manchester, United Kingdom of Great Britain and Northern Ireland, M13 9PL;
| | - Anisha Doshi
- University College London, 4919, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Richelle Scott
- The University of Manchester, 5292, Manchester, United Kingdom of Great Britain and Northern Ireland;
| | - David Paling
- Royal Hallamshire Hospital, 105629, Sheffield, Sheffield, United Kingdom of Great Britain and Northern Ireland;
| | - David Rog
- Salford Royal Hospital, 105621, Salford, Salford, United Kingdom of Great Britain and Northern Ireland;
| | - Jeremy Chataway
- University College London, 4919, London, London, United Kingdom of Great Britain and Northern Ireland;
| | - Menno Schoonheim
- Amsterdam UMC Locatie VUmc, 1209, Anatomy & Neurosciences, Amsterdam, Noord-Holland, Netherlands;
| | - Geoff Parker
- University College London, 4919, London, London, United Kingdom of Great Britain and Northern Ireland.,The University of Manchester, 5292, Manchester, United Kingdom of Great Britain and Northern Ireland;
| | - Nils Muhlert
- The University of Manchester, 5292, Manchester, United Kingdom of Great Britain and Northern Ireland;
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Zhang J, Cortese R, De Stefano N, Giorgio A. Structural and Functional Connectivity Substrates of Cognitive Impairment in Multiple Sclerosis. Front Neurol 2021; 12:671894. [PMID: 34305785 PMCID: PMC8297166 DOI: 10.3389/fneur.2021.671894] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/19/2021] [Indexed: 02/05/2023] Open
Abstract
Cognitive impairment (CI) occurs in 43 to 70% of multiple sclerosis (MS) patients at both early and later disease stages. Cognitive domains typically involved in MS include attention, information processing speed, memory, and executive control. The growing use of advanced magnetic resonance imaging (MRI) techniques is furthering our understanding on the altered structural connectivity (SC) and functional connectivity (FC) substrates of CI in MS. Regarding SC, different diffusion tensor imaging (DTI) measures (e.g., fractional anisotropy, diffusivities) along tractography-derived white matter (WM) tracts showed relevance toward CI. Novel diffusion MRI techniques, including diffusion kurtosis imaging, diffusion spectrum imaging, high angular resolution diffusion imaging, and neurite orientation dispersion and density imaging, showed more pathological specificity compared to the traditional DTI but require longer scan time and mathematical complexities for their interpretation. As for FC, task-based functional MRI (fMRI) has been traditionally used in MS to brain mapping the neural activity during various cognitive tasks. Analysis methods of resting fMRI (seed-based, independent component analysis, graph analysis) have been applied to uncover the functional substrates of CI in MS by revealing adaptive or maladaptive mechanisms of functional reorganization. The relevance for CI in MS of SC–FC relationships, reflecting common pathogenic mechanisms in WM and gray matter, has been recently explored by novel MRI analysis methods. This review summarizes recent advances on MRI techniques of SC and FC and their potential to provide a deeper understanding of the pathological substrates of CI in MS.
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Affiliation(s)
- Jian Zhang
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Rosa Cortese
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Nicola De Stefano
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Antonio Giorgio
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
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Boscheron J, Ruet A, Deloire M, Charré-Morin J, Saubusse A, Brochet B, Tourdias T, Koubiyr I. Insights on the Relationship Between Hippocampal Connectivity and Memory Performances at the Early Stage of Multiple Sclerosis. Front Neurol 2021; 12:667531. [PMID: 34093415 PMCID: PMC8170471 DOI: 10.3389/fneur.2021.667531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
While memory impairment in multiple sclerosis (MS) is known to be associated with hippocampal alterations, whether hippocampal networks could dynamically reorganize as a compensation mechanism is still a matter of debate. In this context, our aim was to identify the patterns of structural and functional connectivity between the hippocampus and the rest of the brain and their possible relevance to memory performances in early MS. Thirty-two patients with a first episode suggestive of MS together with 10 matched healthy controls were prospectively explored at baseline, 1 and 5 years follow up. They were scanned with MRI and underwent a neuropsychological battery of tests that included the Selective Reminding Test and the Brief Visual Memory Test Revised to assess verbal and visuo-spatial memory, respectively. Hippocampal volume was computed together with four graph theory metrics to study the structural and functional connectivity of both hippocampi with the rest of the brain. Associations between network parameters and memory performances were assessed using linear mixed-effects (LME) models. Considering cognitive abilities, verbal memory performances of patients decreased over time while visuo-spatial memory performances were maintained. In parallel, hippocampal volumes decreased significantly while structural and functional connectivity metrics were modified, with an increase in hippocampal connections over time. More precisely, these modifications were indicating a reinforcement of hippocampal short-distance connections. LME models revealed that the drop in verbal memory performances was associated with hippocampal volume loss, while the preservation of visuo-spatial memory performances was linked to decreased hippocampal functional shortest path length. In conclusion, we demonstrated a differential impairment in memory performances in the early stages of MS and an important interplay between hippocampal-related structural and functional networks and those performances. As the structural damage increases, functional reorganization seems to be able to maintain visuo-spatial memory performances with strengthened short-distance connections.
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Affiliation(s)
| | - Aurélie Ruet
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.,CHU de Bordeaux, Service de Neurologie, Bordeaux, France
| | | | | | | | - Bruno Brochet
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
| | - Thomas Tourdias
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France.,CHU de Bordeaux, Neuroimagerie diagnostique et thérapeutique, Bordeaux, France
| | - Ismail Koubiyr
- Univ. Bordeaux, INSERM, Neurocentre Magendie, U1215, Bordeaux, France
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Doskas T, Vavougios GD, Karampetsou P, Kormas C, Synadinakis E, Stavrogianni K, Sionidou P, Serdari A, Vorvolakos T, Iliopoulos I, Vadikolias Κ. Neurocognitive impairment and social cognition in multiple sclerosis. Int J Neurosci 2021; 132:1229-1244. [PMID: 33527857 DOI: 10.1080/00207454.2021.1879066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
PURPOSE/AIM OF THE STUDY The impairment of neurocognitive functions occurs in all subtypes of multiple sclerosis, even from the earliest stages of the disease. Commonly reported manifestations of cognitive impairment include deficits in attention, conceptual reasoning, processing efficiency, information processing speed, memory (episodic and working), verbal fluency (language), and executive functions. Multiple sclerosis patients also suffer from social cognition impairment, which affects their social functioning. The objective of the current paper is to assess the effect of neurocognitive impairment and its potential correlation with social cognition performance and impairment in multiple sclerosis patients. MATERIALS AND METHODS An overview of the available-to-date literature on neurocognitive impairment and social cognition performance in multiple sclerosis patients by disease subtype was performed. RESULTS It is not clear if social cognition impairment occurs independently or secondarily to neurocognitive impairment. There are associations of variable strengths between neurocognitive and social cognition deficits and their neural basis is increasingly investigated. CONCLUSIONS The prompt detection of neurocognitive predictors of social cognition impairment that may be applicable to all multiple sclerosis subtypes and intervention are crucial to prevent further neural and social cognition decline in multiple sclerosis patients.
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Affiliation(s)
- Triantafyllos Doskas
- Department of Neurology, Athens Naval Hospital, Athens, Greece.,Department of Neurology, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | | | | | | | | | | | | | - Aspasia Serdari
- Department of Psychiatry, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | - Theofanis Vorvolakos
- Department of Psychiatry, University Hospital of Alexandroupolis, Alexandroupolis, Greece
| | - Ioannis Iliopoulos
- Department of Neurology, University Hospital of Alexandroupolis, Alexandroupolis, Greece
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Andravizou A, Siokas V, Artemiadis A, Bakirtzis C, Aloizou AM, Grigoriadis N, Kosmidis MH, Nasios G, Messinis L, Hadjigeorgiou G, Dardiotis E, Peristeri E. Clinically reliable cognitive decline in relapsing remitting multiple sclerosis: Is it the tip of the iceberg? Neurol Res 2020; 42:575-586. [PMID: 32427076 DOI: 10.1080/01616412.2020.1761175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
OBJECTIVES Cognitive impairment is common in multiple sclerosis, but the brain MRI correlates in relapsing remitting multiple sclerosis remain controversial. The current study aimed to investigate whether cognitive decline can be predicted by global and/or regional brain atrophy. METHODS Sixty-three patients with relapsing remitting multiple sclerosis (36 men, mean age 39.9 ± 9.4 years old, mean EDSS 1.4 ± 1.2, mean disease duration 4.9 ± 4.3 years) and 46 healthy controls (21 men, mean age 37.5 ± 10.8 years old) were included. Demographic data were obtained, and a longitudinal neuropsychological and global and regional MRI brain volume assessment was performed. RESULTS The patients performed worse than controls in most neuropsychological tests at baseline. The percentage of patients with clinically meaningful cognitive decline ranged from only 0% to 7.9%. Statistically significant volume reduction was found for all MRI measures except for the left accumbens nucleus. Whole or regional brain atrophy ranged from -0.02% to -0.25%, with subcortical structures showing the largest atrophy rates. A total of 22.2% to 93.7% patients showed atrophy across the brain structures assessed volumetrically. DISCUSSION It was regional rather than whole-brain changes that significantly predicted cognitive decline for the patients in the tasks that tested processing speed, visuo-spatial and inhibition skills. The overall data suggest that the progression of cognitive impairment in relapsing remitting multiple sclerosis as captured by conventional neuropsychological testing is the tip of the iceberg of neurodegenerative sequelae in the disease. Also, regional volumetric changes are better than whole-brain atrophy at predicting cognitive dysfunction.
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Affiliation(s)
- Athina Andravizou
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece
| | - Vasileios Siokas
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece
| | - Artemios Artemiadis
- Department of Neurology, Medical School, University of Cyprus , Nicosia, Cyprus
| | - Christos Bakirtzis
- Multiple Sclerosis Center, 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki , Thessaloniki, Greece
| | - Athina-Maria Aloizou
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece
| | - Nikolaos Grigoriadis
- Multiple Sclerosis Center, 2nd Department of Neurology, AHEPA University Hospital, Aristotle University of Thessaloniki , Thessaloniki, Greece
| | - Mary H Kosmidis
- Lab of Cognitive Neuroscience, School of Psychology, Aristotle University of Thessaloniki , Thessaloniki, Greece
| | - Grigorios Nasios
- Department of Speech and Language Therapy, University of Ioannina , Ioannina, Greece
| | | | - Georgios Hadjigeorgiou
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece.,Department of Neurology, Medical School, University of Cyprus , Nicosia, Cyprus
| | - Efthimios Dardiotis
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece
| | - Eleni Peristeri
- Department of Neurology, Laboratory of Neurogenetics, Faculty of Medicine, University of Thessaly, University Hospital of Larissa , Larissa, Greece
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Nasios G, Bakirtzis C, Messinis L. Cognitive Impairment and Brain Reorganization in MS: Underlying Mechanisms and the Role of Neurorehabilitation. Front Neurol 2020; 11:147. [PMID: 32210905 PMCID: PMC7068711 DOI: 10.3389/fneur.2020.00147] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 02/14/2020] [Indexed: 12/29/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic, immune-mediated, inflammatory, and degenerative disease of the central nervous system (CNS) that affects both white and gray matter. Various mechanisms throughout its course, mainly regarding gray matter lesions and brain atrophy, result in cognitive network dysfunction and can cause clinically significant cognitive impairment in roughly half the persons living with MS. Altered cognition is responsible for many negative aspects of patients' lives, independently of physical disability, such as higher unemployment and divorce rates, reduced social activities, and an overall decrease in quality of life. Despite its devastating impact it is not included in clinical ratings and decision making in the way it should be. It is interesting that only half the persons with MS exhibit cognitive dysfunction, as this implies that the other half remain cognitively intact. It appears that a dynamic balance between brain destruction and brain reorganization is taking place. This balance acts in favor of keeping brain systems functioning effectively, but this is not so in all cases, and the effect does not last forever. When these systems collapse, functional brain reorganization is not effective anymore, and clinically apparent impairments are evident. It is therefore important to reveal which factors could make provision for the subpopulation of patients in whom cognitive impairment occurs. Even if we manage to detect this subpopulation earlier, effective pharmaceutical treatments will still be lacking. Nevertheless, recent evidence shows that cognitive rehabilitation and neuromodulation, using non-invasive techniques such as transcranial magnetic or direct current stimulation, could be effective in cognitively impaired patients with MS. In this Mini Review, we discuss the mechanisms underlying cognitive impairment in MS. We also focus on mechanisms of reorganization of cognitive networks, which occur throughout the disease course. Finally, we review theoretical and practical issues of neurorehabilitation and neuromodulation for cognition in MS as well as factors that influence them and prevent them from being widely applied in clinical settings.
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Affiliation(s)
- Grigorios Nasios
- Department of Speech and Language Therapy, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Christos Bakirtzis
- Department of Neurology, The Multiple Sclerosis Center, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Lambros Messinis
- Neuropsychology Section, Departments of Neurology and Psychiatry, University of Patras Medical School, Patras, Greece
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