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Hafiz R, Alajlani L, Ali A, Algarni GA, Aljurfi H, Alammar OAM, Ashqan MY, Alkhashan A. The Latest Advances in the Diagnosis and Treatment of Dementia. Cureus 2023; 15:e50522. [PMID: 38222245 PMCID: PMC10787596 DOI: 10.7759/cureus.50522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2023] [Indexed: 01/16/2024] Open
Abstract
Dementia is a debilitating neurological condition that is characterized by persistent cognitive decline. It is a global health challenge, with a rapidly increasing prevalence due to an increasing aging population. Although definitive diagnosis of various conditions of dementia is only possible by autopsy, clinical diagnosis can be performed by a specialist. The diagnostic process has evolved with recent breakthroughs in diagnostic tools, such as advanced imaging techniques and biomarkers. These tools facilitate early and accurate identification of the condition. Early diagnosis is vital, as it enables timely interventions to improve the quality of life for affected individuals. Treatment strategies for dementia encompass both pharmacological and non-pharmacological approaches. Non-pharmacological treatments include cognitive training and lifestyle modifications. Among pharmacological treatments, acetyl-cholinesterase inhibitors including donepezil, rivastigmine, and galantamine can be used in various doses based on the severity of the disease. Apart from these, N-methyl-D-aspartate receptor antagonists such as memantine can also be used. Furthermore, personalized treatments have also gained significant attention in dementia treatment. Interdisciplinary care, involving healthcare professionals, social workers, and support networks, is crucial for comprehensive and holistic dementia management.
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Affiliation(s)
- Rehab Hafiz
- Family Medicine, Al Takassusi Primary Healthcare Center, Makkah, SAU
| | - Lama Alajlani
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, SAU
| | - Albatool Ali
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, SAU
| | - Ghadah A Algarni
- College of Medicine, Fakeeh College for Medical Sciences, Jeddah, SAU
| | - Hassan Aljurfi
- Family Medicine, Alfath Care Center, Madinah Health Cluster, Ministry of Health, Madinah, SAU
| | | | - Maria Y Ashqan
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, SAU
| | - Alanoud Alkhashan
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Jeddah, SAU
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Purushotham M, Tashrifwala F, Jena R, Vudugula SA, Patil RS, Agrawal A. The Association Between Alzheimer's Disease and Epilepsy: A Narrative Review. Cureus 2022; 14:e30195. [DOI: 10.7759/cureus.30195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2022] [Indexed: 11/07/2022] Open
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Liu S, Jie C, Zheng W, Cui J, Wang Z. Investigation of Underlying Association Between Whole Brain Regions and Alzheimer’s Disease: A Research Based on an Artificial Intelligence Model. Front Aging Neurosci 2022; 14:872530. [PMID: 35747447 PMCID: PMC9211045 DOI: 10.3389/fnagi.2022.872530] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common form of dementia, causing progressive cognitive decline. Radiomic features obtained from structural magnetic resonance imaging (sMRI) have shown a great potential in predicting this disease. However, radiomic features based on the whole brain segmented regions have not been explored yet. In our study, we collected sMRI data that include 80 patients with AD and 80 healthy controls (HCs). For each patient, the T1 weighted image (T1WI) images were segmented into 106 subregions, and radiomic features were extracted from each subregion. Then, we analyzed the radiomic features of specific brain subregions that were most related to AD. Based on the selective radiomic features from specific brain subregions, we built an integrated model using the best machine learning algorithms, and the diagnostic accuracy was evaluated. The subregions most relevant to AD included the hippocampus, the inferior parietal lobe, the precuneus, and the lateral occipital gyrus. These subregions exhibited several important radiomic features that include shape, gray level size zone matrix (GLSZM), and gray level dependence matrix (GLDM), among others. Based on the comparison among different algorithms, we constructed the best model using the Logistic regression (LR) algorithm, which reached an accuracy of 0.962. Conclusively, we constructed an excellent model based on radiomic features from several specific AD-related subregions, which could give a potential biomarker for predicting AD.
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Medvedev AV. Assessment of Cognitive Reserve using Near Infrared Spectroscopy. JOURNAL OF ANALYTICAL TECHNIQUES AND RESEARCH 2022; 4:89-101. [PMID: 35999855 PMCID: PMC9394433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Cognitive reserve (CR) is the ability to preserve cognitive functions in the presence of brain pathology. In the context of Alzheimer's disease (AD), patients with higher CR show better cognitive performance relative to brain damage therefore higher CR reduces the risk of dementia. There is a strong need to develop a neurophysiological biomarker of CR given the growing interest in understanding protective brain mechanisms in AD. FMRI studies indicate that frontoparietal network plays an important role in cognitive reserve. We calculated intraregional functional connectivity of lateral prefrontal cortex (FC LPFC) using functional near infrared spectroscopy (fNIRS) in the resting state of 13 healthy individuals who were also assessed for IQ and motoric skills (the Purdue Pegboard test, PPT). FC LPFC was found to positively correlate with IQ (a proxy measure of cognitive reserve) while showing a lack of or negative correlation with the PPT scores. The results demonstrate that the cost-effective, noninvasive and widely applicable fNIRS technology can be used to evaluate cognitive reserve in individuals at risk for and patients with AD with possible numerous applications in the context of healthy aging and other age-related cognitive disorders.
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Affiliation(s)
- Andrei V. Medvedev
- Corresponding Author: Andrei Medvedev, Ph.D, Center for Functional and Molecular Imaging, Department of Neurology, Georgetown University Medical Center, Washington DC, USA
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5
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Talwar P, Kushwaha S, Chaturvedi M, Mahajan V. Systematic Review of Different Neuroimaging Correlates in Mild Cognitive Impairment and Alzheimer's Disease. Clin Neuroradiol 2021; 31:953-967. [PMID: 34297137 DOI: 10.1007/s00062-021-01057-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 06/18/2021] [Indexed: 10/20/2022]
Abstract
Alzheimer's disease (AD) is a heterogeneous progressive neurocognitive disorder. Although different neuroimaging modalities have been used for the identification of early diagnostic and prognostic factors of AD, there is no consolidated view of the findings from the literature. Here, we aim to provide a comprehensive account of different neural correlates of cognitive dysfunction via magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), functional MRI (fMRI) (resting-state and task-related), positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) modalities across the cognitive groups i.e., normal cognition, mild cognitive impairment (MCI), and AD. A total of 46 meta-analyses met the inclusion criteria, including relevance to MCI, and/or AD along with neuroimaging modality used with quantitative and/or functional data. Volumetric MRI identified early anatomical changes involving transentorhinal cortex, Brodmann area 28, followed by the hippocampus, which differentiated early AD from healthy subjects. A consistent pattern of disruption in the bilateral precuneus along with the medial temporal lobe and limbic system was observed in fMRI, while DTI substantiated the observed atrophic alterations in the corpus callosum among MCI and AD cases. Default mode network hypoconnectivity in bilateral precuneus (PCu)/posterior cingulate cortices (PCC) and hypometabolism/hypoperfusion in inferior parietal lobules and left PCC/PCu was evident. Molecular imaging revealed variable metabolite concentrations in PCC. In conclusion, the use of different neuroimaging modalities together may lead to identification of an early diagnostic and/or prognostic biomarker for AD.
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Affiliation(s)
- Puneet Talwar
- Department of Neurology, Institute of Human Behaviour and Allied Sciences (IHBAS), 110095, Dilshad Garden, Delhi, India.
| | - Suman Kushwaha
- Department of Neurology, Institute of Human Behaviour and Allied Sciences (IHBAS), 110095, Dilshad Garden, Delhi, India.
| | - Monali Chaturvedi
- Department of Neuroradiology, Institute of Human Behaviour and Allied Sciences (IHBAS), 110095, Dilshad Garden, Delhi, India
| | - Vidur Mahajan
- Centre for Advanced Research in Imaging, Neuroscience and Genomics (CARING), Mahajan Imaging, New Delhi, India
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Chen J, Han G, Cai H, Yang D, Laurienti PJ, Styner M, Wu G. Learning Common Harmonic Waves on Stiefel Manifold - A New Mathematical Approach for Brain Network Analyses. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:419-430. [PMID: 33021935 PMCID: PMC7838011 DOI: 10.1109/tmi.2020.3029063] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Converging evidence shows that disease-relevant brain alterations do not appear in random brain locations, instead, their spatial patterns follow large-scale brain networks. In this context, a powerful network analysis approach with a mathematical foundation is indispensable to understand the mechanisms of neuropathological events as they spread through the brain. Indeed, the topology of each brain network is governed by its native harmonic waves, which are a set of orthogonal bases derived from the Eigen-system of the underlying Laplacian matrix. To that end, we propose a novel connectome harmonic analysis framework that provides enhanced mathematical insights by detecting frequency-based alterations relevant to brain disorders. The backbone of our framework is a novel manifold algebra appropriate for inference across harmonic waves. This algebra overcomes the limitations of using classic Euclidean operations on irregular data structures. The individual harmonic differences are measured by a set of common harmonic waves learned from a population of individual Eigen-systems, where each native Eigen-system is regarded as a sample drawn from the Stiefel manifold. Specifically, a manifold optimization scheme is tailored to find the common harmonic waves, which reside at the center of the Stiefel manifold. To that end, the common harmonic waves constitute a new set of neurobiological bases to understand disease progression. Each harmonic wave exhibits a unique propagation pattern of neuropathological burden spreading across brain networks. The statistical power of our novel connectome harmonic analysis approach is evaluated by identifying frequency-based alterations relevant to Alzheimer's disease, where our learning-based manifold approach discovers more significant and reproducible network dysfunction patterns than Euclidean methods.
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Weissberger GH, Mosqueda L, Nguyen AL, Axelrod J, Nguyen CP, Boyle PA, Spreng N, Han SD. Functional Connectivity Correlates of Perceived Financial Exploitation in Older Adults. Front Aging Neurosci 2020; 12:583433. [PMID: 33304266 PMCID: PMC7693621 DOI: 10.3389/fnagi.2020.583433] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/14/2020] [Indexed: 12/28/2022] Open
Abstract
Financial exploitation (FE) in old age is devastating and common; however, the neural correlates of FE are poorly understood. Previous studies of FE in older adults have implicated declines in decision making and social cognition as two risk factors for FE in later life. Here we examined whether functional connectivity among brain regions implicated in decision making and social cognition differed for those with an experience of FE vs. those without. Participants included 16 older adults without cognitive impairment who reported FE (Mean age = 70.5, 62.5% female, Mean education = 16.0 years) and 16 demographically and cognitively matched adults who denied a history of FE (Mean age = 65.1, 37.5% female, Mean education = 15.1 years). Measures of whole-brain resting-state functional connectivity in the hippocampus, insula, and medial frontal cortex were derived for each group. Compared to the non-FE group, FE was associated with greater functional connectivity between the right hippocampus and bilateral temporal regions, and less functional connectivity between the right hippocampus and the right cerebellum and bilateral lingual gyri. The FE group showed less connectivity between the right and left insula and cingulate cortex, and between the right insula and regions of the left lateral temporal gyrus and dorsolateral prefrontal cortex. Finally, the FE group showed greater functional connectivity between the medial frontal cortex and the right lateral temporal gyrus and orbitofrontal cortex, and less functional connectivity with the right pre- and postcentral gyri. Results suggest that perceived FE in old age is associated with whole-brain functional connectivity differences involving the hippocampus, insula, and medial frontal cortex, consistent with models implicating age-associated changes in decision making and social cognition in FE.
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Affiliation(s)
- Gali H. Weissberger
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
- Interdisciplinary Department of Social Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Laura Mosqueda
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
- USC School of Gerontology, Los Angeles, CA, United States
| | - Annie L. Nguyen
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
| | - Jenna Axelrod
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
| | - Caroline P. Nguyen
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
| | - Patricia A. Boyle
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, United States
- Department of Behavioral Sciences and Psychiatry, Rush University Medical Center, Chicago, IL, United States
| | - Nathan Spreng
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Departments of Psychiatry and Psychology, McGill University, Montreal, QC, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - S. Duke Han
- Department of Family Medicine, USC Keck School of Medicine, Alhambra, CA, United States
- USC School of Gerontology, Los Angeles, CA, United States
- Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, United States
- Department of Behavioral Sciences and Psychiatry, Rush University Medical Center, Chicago, IL, United States
- Department of Psychology, USC Dornsife College of Letters, Arts, and Sciences, Los Angeles, CA, United States
- Department of Neurology, USC Keck School of Medicine, Los Angeles, CA, United States
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Lam AD, Noebels J. Night Watch on the Titanic: Detecting Early Signs of Epileptogenesis in Alzheimer Disease. Epilepsy Curr 2020; 20:369-374. [PMID: 33081517 PMCID: PMC7818196 DOI: 10.1177/1535759720964775] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Aberrant cortical network excitability is an inextricable feature of Alzheimer disease (AD) that can negatively impact memory and accelerate cognitive decline. Surface electroencephalogram spikes and intracranial recordings of nocturnal silent seizures in human AD, coupled with the abnormal neural synchrony that precedes development of behavioral seizures in mouse AD models, build the case for epileptogenesis as an early therapeutic target for AD. Since most individuals with AD do not develop overt seizures, leveraging functional biomarkers of epilepsy risk to stratify a heterogeneous AD patient population for treatment is research priority for successful clinical trial design. Who will benefit from antiseizure interventions, which one, and when should it begin?
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Affiliation(s)
- Alice D. Lam
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Jeffrey Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
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Ioulietta L, Kostas G, Spiros N, Vangelis OP, Anthoula T, Ioannis K, Magda T, Dimitris K. A Novel Connectome-Based Electrophysiological Study of Subjective Cognitive Decline Related to Alzheimer's Disease by Using Resting-State High-Density EEG EGI GES 300. Brain Sci 2020; 10:brainsci10060392. [PMID: 32575641 PMCID: PMC7349850 DOI: 10.3390/brainsci10060392] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022] Open
Abstract
Aim: To investigate for the first time the brain network in the Alzheimer’s disease (AD) spectrum by implementing a high-density electroencephalography (HD-EEG - EGI GES 300) study with 256 channels in order to seek if the brain connectome can be effectively used to distinguish cognitive impairment in preclinical stages. Methods: Twenty participants with AD, 30 with mild cognitive impairment (MCI), 20 with subjective cognitive decline (SCD) and 22 healthy controls (HC) were examined with a detailed neuropsychological battery and 10 min resting state HD-EEG. We extracted correlation matrices by using Pearson correlation coefficients for each subject and constructed weighted undirected networks for calculating clustering coefficient (CC), strength (S) and betweenness centrality (BC) at global (256 electrodes) and local levels (29 parietal electrodes). Results: One-way ANOVA presented a statistically significant difference among the four groups at local level in CC [F (3, 88) = 4.76, p = 0.004] and S [F (3, 88) = 4.69, p = 0.004]. However, no statistically significant difference was found at a global level. According to the independent sample t-test, local CC was higher for HC [M (SD) = 0.79 (0.07)] compared with SCD [M (SD) = 0.72 (0.09)]; t (40) = 2.39, p = 0.02, MCI [M (SD) = 0.71 (0.09)]; t (50) = 0.41, p = 0.004 and AD [M (SD) = 0.68 (0.11)]; t (40) = 3.62, p = 0.001 as well, while BC showed an increase at a local level but a decrease at a global level as the disease progresses. These findings provide evidence that disruptions in brain networks in parietal organization may potentially represent a key factor in the ability to distinguish people at early stages of the AD continuum. Conclusions: The above findings reveal a dynamically disrupted network organization of preclinical stages, showing that SCD exhibits network disorganization with intermediate values between MCI and HC. Additionally, these pieces of evidence provide information on the usefulness of the 256 HD-EEG in network construction.
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Affiliation(s)
- Lazarou Ioulietta
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
- 1st Department of Neurology, G.H. “AHEPA”, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (AUTH), 54124 Thessaloniki, Greece
- Correspondence:
| | - Georgiadis Kostas
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
- Informatics Department, Aristotle University of Thessaloniki (AUTH), 54124 Thessaloniki, Greece
| | - Nikolopoulos Spiros
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
| | - Oikonomou P. Vangelis
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
| | - Tsolaki Anthoula
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
- Greek Association of Alzheimer’s Disease and Related Disorders (GAADRD), 54643 Thessaloniki, Greece
| | - Kompatsiaris Ioannis
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
| | - Tsolaki Magda
- Information Technologies Institute, Centre for Research and Technology Hellas (CERTH-ITI), 57001 Thessaloniki, Greece; (G.K.); (N.S.); (O.V.P.); (T.A.); (K.I.); (T.M.)
- 1st Department of Neurology, G.H. “AHEPA”, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (AUTH), 54124 Thessaloniki, Greece
- Greek Association of Alzheimer’s Disease and Related Disorders (GAADRD), 54643 Thessaloniki, Greece
| | - Kugiumtzis Dimitris
- Department of Electrical and Computer Engineering, Faculty of Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
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Musaeus CS, Engedal K, Høgh P, Jelic V, Khanna AR, Kjaer TW, Mørup M, Naik M, Oeksengaard AR, Santarnecchi E, Snaedal J, Wahlund LO, Waldemar G, Andersen BB. Changes in the left temporal microstate are a sign of cognitive decline in patients with Alzheimer's disease. Brain Behav 2020; 10:e01630. [PMID: 32338460 PMCID: PMC7303403 DOI: 10.1002/brb3.1630] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/05/2020] [Accepted: 03/20/2020] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION Large-scale brain networks are disrupted in the early stages of Alzheimer's disease (AD). Electroencephalography microstate analysis, a promising method for studying brain networks, parses EEG signals into topographies representing discrete, sequential network activations. Prior studies indicate that patients with AD show a pattern of global microstate disorganization. We investigated whether any specific microstate changes could be found in patients with AD and mild cognitive impairment (MCI) compared to healthy controls (HC). MATERIALS AND METHODS Standard EEGs were obtained from 135 HC, 117 patients with MCI, and 117 patients with AD from six Nordic memory clinics. We parsed the data into four archetypal microstates. RESULTS There was significantly increased duration, occurrence, and coverage of microstate A in patients with AD and MCI compared to HC. When looking at microstates in specific frequency bands, we found that microstate A was affected in delta (1-4 Hz), theta (4-8 Hz), and beta (13-30 Hz), while microstate D was affected only in the delta and theta bands. Microstate features were able to separate HC from AD with an accuracy of 69.8% and HC from MCI with an accuracy of 58.7%. CONCLUSIONS Further studies are needed to evaluate whether microstates represent a valuable disease classifier. Overall, patients with AD and MCI, as compared to HC, show specific microstate alterations, which are limited to specific frequency bands. These alterations suggest disruption of large-scale cortical networks in AD and MCI, which may be limited to specific frequency bands.
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Affiliation(s)
- Christian S Musaeus
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Knut Engedal
- Norwegian National Advisory Unit on Ageing and Health (Ageing and Health), Vestfold Hospital Trust and Oslo University Hospital, Ullevaal, Oslo, Norway
| | - Peter Høgh
- Regional Dementia Research Center, Department of Neurology, Zealand University Hospital, Roskilde, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Vesna Jelic
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.,Department of Geriatric Medicine, Memory Clinic, Karolinska University Hospital, Huddinge, Sweden
| | - Arjun R Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Troels Wesenberg Kjaer
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.,Neurophysiology Center, Zealand University Hospital, Roskilde, Denmark
| | - Morten Mørup
- Section for Cognitive Systems, DTU Compute, Technical University of Denmark, Lyngby, Denmark
| | - Mala Naik
- Department of Geriatric Medicine, Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Anne-Rita Oeksengaard
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jon Snaedal
- Department of Geriatric Medicine, Landspítali University Hospital, Reykjavik, Iceland
| | - Lars-Olof Wahlund
- Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Gunhild Waldemar
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Birgitte B Andersen
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Costumero V, d'Oleire Uquillas F, Diez I, Andorrà M, Basaia S, Bueichekú E, Ortiz-Terán L, Belloch V, Escudero J, Ávila C, Sepulcre J. Distance disintegration delineates the brain connectivity failure of Alzheimer's disease. Neurobiol Aging 2020; 88:51-60. [PMID: 31941578 PMCID: PMC7085436 DOI: 10.1016/j.neurobiolaging.2019.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 01/03/2023]
Abstract
Alzheimer's disease (AD) is associated with brain network dysfunction. Network-based investigations of brain connectivity have mainly focused on alterations in the strength of connectivity; however, the network breakdown in AD spectrum is a complex scenario in which multiple pathways of connectivity are affected. To integrate connectivity changes that occur under AD-related conditions, here we developed a novel metric that computes the connectivity distance between cortical regions at the voxel level (or nodes). We studied 114 individuals with mild cognitive impairment, 24 with AD, and 27 healthy controls. Results showed that areas of the default mode network, salience network, and frontoparietal network display a remarkable network separation, or greater connectivity distances, from the rest of the brain. Furthermore, this greater connectivity distance was associated with lower global cognition. Overall, the investigation of AD-related changes in paths and distances of connectivity provides a novel framework for characterizing subjects with cognitive impairment; a framework that integrates the overall network topology changes of the brain and avoids biases toward unreferenced connectivity effects.
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Affiliation(s)
- Víctor Costumero
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Center for Brain and Cognition, University Pompeu Fabra, Barcelona, Catalonia, Spain; Neuropsychology and Functional Neuroimaging Group, Department of basic Psychology, University Jaume I, Castellón, Valencian Community, Spain
| | | | - Ibai Diez
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Neurotechnology Laboratory, Tecnalia Health Department, Basque Country, Spain
| | - Magi Andorrà
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Center of Neuroimmunology, Department of Neurology, Hospital Clinic of Barcelona, Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | - Silvia Basaia
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Neuroimaging Research Unit Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, Italy
| | - Elisenda Bueichekú
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Neuropsychology and Functional Neuroimaging Group, Department of basic Psychology, University Jaume I, Castellón, Valencian Community, Spain
| | - Laura Ortiz-Terán
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | | | - Joaquin Escudero
- Department of Neurology, General Hospital of Valencia, Valencia, Valencian Community, Spain
| | - César Ávila
- Neuropsychology and Functional Neuroimaging Group, Department of basic Psychology, University Jaume I, Castellón, Valencian Community, Spain
| | - Jorge Sepulcre
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.
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Lu J, Testa N, Jordan R, Elyan R, Kanekar S, Wang J, Eslinger P, Yang QX, Zhang B, Karunanayaka PR. Functional Connectivity between the Resting-State Olfactory Network and the Hippocampus in Alzheimer's Disease. Brain Sci 2019; 9:brainsci9120338. [PMID: 31775369 PMCID: PMC6955985 DOI: 10.3390/brainsci9120338] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/15/2019] [Accepted: 11/18/2019] [Indexed: 01/03/2023] Open
Abstract
Olfactory impairment is associated with prodromal Alzheimer's disease (AD) and is a risk factor for the development of dementia. AD pathology is known to disrupt brain regions instrumental in olfactory information processing, such as the primary olfactory cortex (POC), the hippocampus, and other temporal lobe structures. This selective vulnerability suggests that the functional connectivity (FC) between the olfactory network (ON), consisting of the POC, insula and orbital frontal cortex (OFC) (Tobia et al., 2016), and the hippocampus may be impaired in early stage AD. Yet, the development trajectory of this potential FC impairment remains unclear. Here, we used resting-state functional magnetic resonance imaging (rs-fMRI) data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) to investigate FC changes between the ON and hippocampus in four groups: aged-matched cognitively normal (CN), early mild cognitive impairment (EMCI), late mild cognitive impairment (LMCI), and AD. FC was calculated using low frequency fMRI signal fluctuations in the ON and hippocampus (Tobia et al., 2016). We found that the FC between the ON and the right hippocampus became progressively disrupted across disease states, with significant differences between EMCI and LMCI groups. Additionally, there were no significant differences in gray matter hippocampal volumes between EMCI and LMCI groups. Lastly, the FC between the ON and hippocampus was significantly correlated with neuropsychological test scores, suggesting that it is related to cognition in a meaningful way. These findings provide the first in vivo evidence for the involvement of FC between the ON and hippocampus in AD pathology. Results suggest that functional connectivity (FC) between the olfactory network (ON) and hippocampus may be a sensitive marker for Alzheimer's disease (AD) progression, preceding gray matter volume loss.
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Affiliation(s)
- Jiaming Lu
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
- Medical School of Nanjing University, Nanjing 210008, China;
| | - Nicole Testa
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
| | - Rebecca Jordan
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
| | - Rommy Elyan
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
| | - Sangam Kanekar
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
| | - Jianli Wang
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
| | - Paul Eslinger
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
- Department of Neurology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Qing X. Yang
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Bing Zhang
- Medical School of Nanjing University, Nanjing 210008, China;
| | - Prasanna R. Karunanayaka
- Department of Radiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.L.); (N.T.); (R.J.); (R.E.); (P.E.); (Q.X.Y.)
- Department of Neural and Behavioral Sciences, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
- Department of Public Health Sciences, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
- Correspondence: ; Tel.: +1-717-531-6069; Fax: +1-717-531-8486
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Zheng W, Cui B, Han Y, Song H, Li K, He Y, Wang Z. Disrupted Regional Cerebral Blood Flow, Functional Activity and Connectivity in Alzheimer's Disease: A Combined ASL Perfusion and Resting State fMRI Study. Front Neurosci 2019; 13:738. [PMID: 31396033 PMCID: PMC6668217 DOI: 10.3389/fnins.2019.00738] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 07/02/2019] [Indexed: 11/13/2022] Open
Abstract
Recent studies have demonstrated a close relationship between regional cerebral blood flow (rCBF) and resting state functional connectivity changes in normal healthy people. However, little is known about the parameter changes in the most vulnerable regions in Alzheimer's disease (AD). Forty AD patients and 30 healthy controls participated in this study. The data of resting-state perfusion and functional magnetic resonance imaging (fMRI) was collected. By using voxel-wise arterial spin labeling (ASL) perfusion, we identified several regions of altered rCBF in AD patients. Then, by using resting state fMRI analysis, including amplitude low frequency fluctuation (ALFF) and seed-based functional connectivity, we investigated the changes of functional activity and connectivity among the identified rCBF regions. We extracted cognition-related parameters and searched for a sensitive biomarker to differentiate the AD patients from the normal controls (NC). Compared with controls, AD patients showed special disruptions in rCBF, which were mainly located in the left posterior cingulate cortex (PCC), the left and right dorsolateral prefrontal cortex (DLPFC), the left inferior parietal lobule (IPL), the right middle temporal gyrus (MTG), the left middle occipital gyrus (MOG), and the left precuneus (PCu). ALFF was performed based on the seven regions identified by the ASL method, and AD patients presented significantly decreased ALFF in the left PCC, left IPL, right MTG, left MOG, and left PCu and increased ALFF in the bilateral DLPFC. We constituted the network based on the seven regions and found that there was decreased connectivity among the identified regions in the AD patients, which predicted a disruption in the default mode network (DMN), executive control network (ECN) and visual network (VN). Furthermore, these abnormal parameters are closely associated with cognitive performances in AD patients. We combined the rCBF and ALFF value of PCC/PCu as a biomarker to differentiate the two groups and reached a sensitivity of 85.3% and a specificity of 88.5%. Our findings suggested that there was disrupted rCBF, functional activity and connectivity in specific cognition-related regions in Alzheimer's disease, which can be used as a valuable imaging biomarker for the diagnosis of AD.
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Affiliation(s)
- Weimin Zheng
- Department of Radiology, Aerospace Center Hospital, Beijing, China
| | - Bin Cui
- Department of Radiology, Aerospace Center Hospital, Beijing, China
| | - Ying Han
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Haiqing Song
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics, Beijing, China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
- IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China
| | - Zhiqun Wang
- Department of Radiology, Aerospace Center Hospital, Beijing, China
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14
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Weil RS, Hsu JK, Darby RR, Soussand L, Fox MD. Neuroimaging in Parkinson's disease dementia: connecting the dots. Brain Commun 2019; 1:fcz006. [PMID: 31608325 PMCID: PMC6777517 DOI: 10.1093/braincomms/fcz006] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 05/17/2019] [Accepted: 06/14/2019] [Indexed: 12/11/2022] Open
Abstract
Dementia is a common and devastating symptom of Parkinson's disease but the anatomical substrate remains unclear. Some evidence points towards hippocampal involvement but neuroimaging abnormalities have been reported throughout the brain and are largely inconsistent across studies. Here, we test whether these disparate neuroimaging findings for Parkinson's disease dementia localize to a common brain network. We used a literature search to identify studies reporting neuroimaging correlates of Parkinson's dementia (11 studies, 385 patients). We restricted our search to studies of brain atrophy and hypometabolism that compared Parkinson's patients with dementia to those without cognitive involvement. We used a standard coordinate-based activation likelihood estimation meta-analysis to assess for consistency in the neuroimaging findings. We then used a new approach, coordinate-based network mapping, to test whether neuroimaging findings localized to a common brain network. This approach uses resting-state functional connectivity from a large cohort of normative subjects (n = 1000) to identify the network of regions connected to a reported neuroimaging coordinate. Activation likelihood estimation meta-analysis failed to identify any brain regions consistently associated with Parkinson's dementia, showing major heterogeneity across studies. In contrast, coordinate-based network mapping found that these heterogeneous neuroimaging findings localized to a specific brain network centred on the hippocampus. Next, we tested whether this network showed symptom specificity and stage specificity by performing two further analyses. We tested symptom specificity by examining studies of Parkinson's hallucinations (9 studies, 402 patients) that are frequently co-morbid with Parkinson's dementia. We tested for stage specificity by using studies of mild cognitive impairment in Parkinson's disease (15 studies, 844 patients). Coordinate-based network mapping revealed that correlates of visual hallucinations fell within a network centred on bilateral lateral geniculate nucleus and correlates of mild cognitive impairment in Parkinson's disease fell within a network centred on posterior default mode network. In both cases, the identified networks were distinct from the hippocampal network of Parkinson's dementia. Our results link heterogeneous neuroimaging findings in Parkinson's dementia to a common network centred on the hippocampus. This finding was symptom and stage-specific, with implications for understanding Parkinson's dementia and heterogeneity of neuroimaging findings in general.
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Affiliation(s)
- Rimona S Weil
- Dementia Research Centre, UCL, London,Wellcome Centre for Human Neuroimaging, UCL, London,Berenson-Allen Center, Beth Israel Deaconess Medical Center, Harvard Medical Center, Boston, MA, USA,Correspondence to: Rimona S. Weil UCL Dementia Research Centre, 8-11 Queen Square, London WC1N 3BG UK E-mail:
| | - Joey K Hsu
- Berenson-Allen Center, Beth Israel Deaconess Medical Center, Harvard Medical Center, Boston, MA, USA
| | - Ryan R Darby
- Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Louis Soussand
- Berenson-Allen Center, Beth Israel Deaconess Medical Center, Harvard Medical Center, Boston, MA, USA
| | - Michael D Fox
- Berenson-Allen Center, Beth Israel Deaconess Medical Center, Harvard Medical Center, Boston, MA, USA,Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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15
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Musaeus CS, Nielsen MS, Høgh P. Microstates as Disease and Progression Markers in Patients With Mild Cognitive Impairment. Front Neurosci 2019; 13:563. [PMID: 31263397 PMCID: PMC6584800 DOI: 10.3389/fnins.2019.00563] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/15/2019] [Indexed: 11/13/2022] Open
Abstract
Network dysfunction is well established in patients with Alzheimer's disease (AD) and has been shown to be present early in the disease. This is especially interesting in patients with mild cognitive impairment (MCI) since they are more likely to develop AD. In EEG, one type of network analysis is microstates where the EEG is divided into quasi-stable states and these microstates have been linked to networks found with resting state functional MRI. In the current exploratory study, we therefore wanted to explore the changes in microstates in MCI, and AD compared to healthy controls (HC) and whether microstates were able to separate patients with MCI who progressed (pMCI) and those who remained stable (sMCI). EEGs were recorded at baseline for 17 patients with AD, 27 patients with MCI, and 38 older HC and the patients were followed for 3 years. To investigate whole-brain dynamics we extracted different microstate parameters. We found that patients with MCI, and AD had significantly higher occurrence (p-value = 0.028), and coverage (p-value = 0.010) for microstate A compared to HC. However, we did not find any significant systematic deviation of the transition probabilities from randomness for any of the groups. No significant differences were found between pMCI and sMCI but the largest difference in duration was found for microstate D. Microstate A has been linked to the temporal lobes in studies combining EEG and fMRI and the temporal lobes are the most affected by AD pathology in the early stages of the disease. This supports our idea that microstate A may be the first affected microstate in early AD. Even though not significant between pMCI and sMCI, Microstate D has previously been shown to be associated with both frontal and parietal areas as measured with fMRI and may correspond to underlying pathological changes in the progression of MCI to AD. However, larger studies are needed to confirm these findings.
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Affiliation(s)
- Christian Sandøe Musaeus
- Department of Neurology, Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Malene Schjønning Nielsen
- Regional Dementia Research Centre, Department of Neurology, Zealand University Hospital, Roskilde, Denmark
| | - Peter Høgh
- Regional Dementia Research Centre, Department of Neurology, Zealand University Hospital, Roskilde, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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16
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Eyler LT, Elman JA, Hatton SN, Gough S, Mischel AK, Hagler DJ, Franz CE, Docherty A, Fennema-Notestine C, Gillespie N, Gustavson D, Lyons MJ, Neale MC, Panizzon MS, Dale AM, Kremen WS. Resting State Abnormalities of the Default Mode Network in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis. J Alzheimers Dis 2019; 70:107-120. [PMID: 31177210 PMCID: PMC6697380 DOI: 10.3233/jad-180847] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Large-scale brain networks such as the default mode network (DMN) are often disrupted in Alzheimer's disease (AD). Numerous studies have examined DMN functional connectivity in those with mild cognitive impairment (MCI), a presumed AD precursor, to discover a biomarker of AD risk. Prior reviews were qualitative or limited in scope or approach. OBJECTIVE We aimed to systematically and quantitatively review DMN resting state fMRI studies comparing MCI and healthy comparison (HC) groups. METHODS PubMed was searched for relevant articles. Study characteristics were abstracted and the number of studies showing no group difference or hyper- versus hypo-connnectivity in MCI was tallied. A voxel-wise (ES-SDM) meta-analysis was conducted to identify regional group differences. RESULTS Qualitatively, our review of 57 MCI versus HC comparisons suggests substantial inconsistency; 9 showed no group difference, 8 showed MCI > HC and 22 showed HC > MCI across the brain, and 18 showed regionally-mixed directions of effect. The meta-analysis of 31 studies revealed areas of significant hypo- and hyper-connectivity in MCI, including hypoconnectivity in the posterior cingulate cortex/precuneus (z = -3.1, p < 0.0001). Very few individual studies, however, showed patterns resembling the meta-analytic results. Methodological differences did not appear to explain inconsistencies. CONCLUSIONS The pattern of altered resting DMN function or connectivity in MCI is complex and variable across studies. To date, no index of DMN connectivity qualifies as a useful biomarker of MCI or risk for AD. Refinements to MCI diagnosis, including other biological markers, or longitudinal studies of progression to AD, might identify DMN alterations predictive of AD risk.
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Affiliation(s)
- Lisa T. Eyler
- Department of Psychiatry, University of California San Diego
- Desert Pacific Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System
| | - Jeremy A. Elman
- Department of Psychiatry, University of California San Diego
| | - Sean N Hatton
- Department of Psychiatry, University of California San Diego
- Department of Neurosciences, University of California San Diego
| | - Sarah Gough
- Department of Psychiatry, University of California San Diego
| | - Anna K. Mischel
- Department of Psychiatry, University of California San Diego
| | | | - Carol E. Franz
- Department of Psychiatry, University of California San Diego
| | - Anna Docherty
- Departments of Psychiatry & Human Genetics, University of Utah School of Medicine
| | - Christine Fennema-Notestine
- Department of Psychiatry, University of California San Diego
- Department of Radiology, University of California San Diego
| | - Nathan Gillespie
- Departments of Psychiatry and Human and Molecular Genetics, Virginia Commonwealth University
| | | | | | - Michael C. Neale
- Departments of Psychiatry and Human and Molecular Genetics, Virginia Commonwealth University
| | | | - Anders M. Dale
- Department of Neurosciences, University of California San Diego
- Department of Radiology, University of California San Diego
| | - William S. Kremen
- Department of Psychiatry, University of California San Diego
- Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System
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17
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Cummings J. The Role of Biomarkers in Alzheimer's Disease Drug Development. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1118:29-61. [PMID: 30747416 DOI: 10.1007/978-3-030-05542-4_2] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Biomarkers have a key role in Alzheimer's disease (AD) drug development. Biomarkers can assist in diagnosis, demonstrate target engagement, support disease modification, and monitor for safety. The amyloid (A), tau (T), neurodegeneration (N) Research Framework emphasizes brain imaging and CSF measures relevant to disease diagnosis and staging and can be applied to drug development and clinical trials. Demonstration of target engagement in Phase 2 is critical before advancing a treatment candidate to Phase 3. Trials with biomarker outcomes are shorter and smaller than those required to show clinical benefit and are important to understanding the biological impact of an agent and inform go/no-go decisions. Companion diagnostics are required for safe and effective use of treatments and may emerge in AD drug development programs. Complementary biomarkers inform the use of therapies but are not mandatory for use. Biomarkers promise to de-risk AD drug development, attract sponsors to AD research, and accelerate getting new drugs to those with or at risk for AD.
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Affiliation(s)
- Jeffrey Cummings
- Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA.
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18
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Qiao J, Lv Y, Cao C, Wang Z, Li A. Multivariate Deep Learning Classification of Alzheimer's Disease Based on Hierarchical Partner Matching Independent Component Analysis. Front Aging Neurosci 2018; 10:417. [PMID: 30618723 PMCID: PMC6304436 DOI: 10.3389/fnagi.2018.00417] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 12/03/2018] [Indexed: 12/11/2022] Open
Abstract
Machine learning and pattern recognition have been widely investigated in order to look for the biomarkers of Alzheimer’s disease (AD). However, most existing methods extract features by seed-based correlation, which not only requires prior information but also ignores the relationship between resting state functional magnetic resonance imaging (rs-fMRI) voxels. In this study, we proposed a deep learning classification framework with multivariate data-driven based feature extraction for automatic diagnosis of AD. Specifically, a three-level hierarchical partner matching independent components analysis (3LHPM-ICA) approach was proposed first in order to address the issues in spatial individual ICA, including the uncertainty of the numbers of components, the randomness of initial values, and the correspondence of ICs of multiple subjects, resulting in stable and reliable ICs which were applied as the intrinsic brain functional connectivity (FC) features. Second, Granger causality (GC) was utilized to infer directional interaction between the ICs that were identified by the 3LHPM-ICA method and extract the effective connectivity features. Finally, a deep learning classification framework was developed to distinguish AD from controls by fusing the functional and effective connectivities. A resting state fMRI dataset containing 34 AD patients and 34 normal controls (NCs) was applied to the multivariate deep learning platform, leading to a classification accuracy of 95.59%, with a sensitivity of 97.06% and a specificity of 94.12% with leave-one-out cross validation (LOOCV). The experimental results demonstrated that the measures of neural connectivities of ICA and GC followed by deep learning classification represented the most powerful methods of distinguishing AD clinical data from NCs, and these aberrant brain connectivities might serve as robust brain biomarkers for AD. This approach also allows for expansion of the methodology to classify other psychiatric disorders.
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Affiliation(s)
- Jianping Qiao
- Shandong Province Key Laboratory of Medical Physics and Image Processing Technology, Institute of Data Science and Technology, School of Physics and Electronics, Shandong Normal University, Jinan, China
| | - Yingru Lv
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Chongfeng Cao
- Department of Emergency, Jinan Central Hospital Affiliated to Shandong University, Jinan, China
| | - Zhishun Wang
- Department of Psychiatry, Columbia University, New York, NY, United States
| | - Anning Li
- Department of Radiology, Qilu Hospital of Shandong University, Jinan, China
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Zhen D, Xia W, Yi ZQ, Zhao PW, Zhong JG, Shi HC, Li HL, Dai ZY, Pan PL. Alterations of brain local functional connectivity in amnestic mild cognitive impairment. Transl Neurodegener 2018; 7:26. [PMID: 30443345 PMCID: PMC6220503 DOI: 10.1186/s40035-018-0134-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 10/11/2018] [Indexed: 11/10/2022] Open
Abstract
Background Resting-state functional magnetic resonance imaging studies using a regional homogeneity (ReHo) method have reported that amnestic mild cognitive impairment (aMCI) was associated with abnormalities in local functional connectivity. However, their results were not conclusive. Methods Seed-based d Mapping was used to conduct a coordinate-based meta-analysis to identify consistent ReHo alterations in aMCI. Results We identified 10 studies with 11 datasets suitable for inclusion, including 378 patients with aMCI and 435 healthy controls. This meta-analysis identified significant ReHo alterations in patients with aMCI relative to healthy controls, mainly within the default mode network (DMN) (bilateral posterior cingulate cortex [PCC], right angular gyrus, bilateral middle temporal gyri, and left parahippocampal gyrus/hippocampus), executive control network (right superior parietal lobule and dorsolateral prefrontal cortex), visual network (right lingual gyrus and left middle occipital gyrus), and sensorimotor network (right paracentral lobule/supplementary motor area, right postcentral gyrus and left posterior insula). Significant heterogeneity of ReHo alterations in the bilateral PCC, left parahippocampal gyrus/hippocampus, and right superior parietal lobule/angular gyrus was observed. Exploratory meta-regression analyses indicated that general cognitive function, gender distribution, age, and education level partially contributed to this heterogeneity. Conclusions This study provides provisional evidence that aMCI is associated with abnormal ReHo within the DMN, executive control network, visual network, and sensorimotor network. These local functional connectivity alterations suggest coexistence of functional deficits and compensation in these networks. These findings contribute to the modeling of brain functional connectomes and to a better understanding of the neural substrates of aMCI. Confounding factors merit much attention and warrant future investigations. Electronic supplementary material The online version of this article (10.1186/s40035-018-0134-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dan Zhen
- 1School of Nursing, Jiangsu Vocational College of Medicine, Yancheng, People's Republic of China
| | - Wei Xia
- 2Department of Neurology, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Zhong Quan Yi
- 2Department of Neurology, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Pan Wen Zhao
- 2Department of Neurology, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Jian Guo Zhong
- 3Department of Central Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Hai Cun Shi
- 3Department of Central Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Hua Liang Li
- 3Department of Central Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Zhen Yu Dai
- 4Department of Radiology, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
| | - Ping Lei Pan
- 2Department of Neurology, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China.,3Department of Central Laboratory, Affiliated Yancheng Hospital, School of Medicine, Southeast University, West Xindu Road 2#, Yancheng, Jiangsu Province, 224001 People's Republic of China
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20
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Merlo S, Spampinato SF, Sortino MA. Early compensatory responses against neuronal injury: A new therapeutic window of opportunity for Alzheimer's Disease? CNS Neurosci Ther 2018; 25:5-13. [PMID: 30101571 DOI: 10.1111/cns.13050] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by extensive neurodegeneration and inflammation in selective brain areas, linked to severely disabling cognitive deficits. Before full manifestation, different stages appear with progressively increased brain pathology and cognitive impairment. This significantly extends the time lag between initial molecular triggers and appearance of detectable symptoms. Notably, a number of studies in the last decade have revealed that in the early stage of mild cognitive impairment, events that appear in contrast with neuronal distress may occur. These have been reproduced in vitro and in animal models and include increase in synaptic elements, increase in synaptic and metabolic activity, enhancement of neurotrophic milieu and changes in glial cell reactivity and inflammation. They have been interpreted as compensatory responses that could either delay disease progression or, in the long run, result detrimental. For this reason, these mechanisms define a new and previously undervalued window of opportunity for intervention. Their importance resides especially in their early appearance. Directing efforts to better characterize this stage, in order to identify new pharmacological targets, is an exciting new avenue to future advances in AD research.
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Affiliation(s)
- Sara Merlo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Simona Federica Spampinato
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
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21
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Mandelli ML, Welch AE, Vilaplana E, Watson C, Battistella G, Brown JA, Possin KL, Hubbard HI, Miller ZA, Henry ML, Marx GA, Santos-Santos MA, Bajorek LP, Fortea J, Boxer A, Rabinovici G, Lee S, Deleon J, Rosen HJ, Miller BL, Seeley WW, Gorno-Tempini ML. Altered topology of the functional speech production network in non-fluent/agrammatic variant of PPA. Cortex 2018; 108:252-264. [PMID: 30292076 DOI: 10.1016/j.cortex.2018.08.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/07/2018] [Accepted: 08/02/2018] [Indexed: 12/13/2022]
Abstract
Non-fluent/agrammatic primary progressive aphasia (nfvPPA) is caused by neurodegeneration within the left fronto-insular speech and language production network (SPN). Graph theory is a branch of mathematics that studies network architecture (topology) by quantifying features based on its elements (nodes and connections). This approach has been recently applied to neuroimaging data to explore the complex architecture of the brain connectome, though few studies have exploited this technique in PPA. Here, we used graph theory on functional MRI resting state data from a group of 20 nfvPPA patients and 20 matched controls to investigate topological changes in response to focal neurodegeneration. We hypothesized that changes in the network architecture would be specific to the affected SPN in nfvPPA, while preserved in the spared default mode network (DMN). Topological configuration was quantified by hub location and global network metrics. Our findings showed a less efficiently wired and less optimally clustered SPN, while no changes were detected in the DMN. The SPN in the nfvPPA group showed a loss of hubs in the left fronto-parietal-temporal area and new critical nodes in the anterior left inferior-frontal and right frontal regions. Behaviorally, speech production score and rule violation errors correlated with the strength of functional connectivity of the left (lost) and right (new) regions respectively. This study shows that focal neurodegeneration within the SPN in nfvPPA is associated with network-specific topological alterations, with the loss and gain of crucial hubs and decreased global efficiency that were better accounted for through functional rather than structural changes. These findings support the hypothesis of selective network vulnerability in nfvPPA and may offer biomarkers for future behavioral intervention.
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Affiliation(s)
- Maria Luisa Mandelli
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA.
| | - Ariane E Welch
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Eduard Vilaplana
- Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau - Biomedical Research Institute Sant Pau - Universitat Autonoma de Barcelona, Spain; Centro de Investigacion Biomedica en Red de Enfermedades Neurodegenerativas - CIBERNED, Spain
| | - Christa Watson
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Giovanni Battistella
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Jesse A Brown
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Katherine L Possin
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Honey I Hubbard
- Department of Communication Science and Disorders, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Zachary A Miller
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Maya L Henry
- Department of Communication Sciences and Disorders, University of Texas, Austin, USA
| | - Gabe A Marx
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Miguel A Santos-Santos
- Cognition and Brain Plasticity Group [Bellvitge Biomedical Research Institute-IDIBELL], L'Hospitalet de Llobregat, Barcelona, Spain; Fundació ACE Memory Clinic and Research Center, Institut Catalá de Neurociències Aplicades, Barcelona, Spain
| | - Lynn P Bajorek
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Juan Fortea
- Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau - Biomedical Research Institute Sant Pau - Universitat Autonoma de Barcelona, Spain
| | - Adam Boxer
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Gil Rabinovici
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Suzee Lee
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Jessica Deleon
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Howard J Rosen
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - Bruce L Miller
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA
| | - William W Seeley
- Department of Neurology, Memory and Aging Center, University of California San Francisco, CA, USA; Department of Pathology, University of California San Francisco, CA, USA
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22
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Eliassen CF, Reinvang I, Selnes P, Fladby T, Hessen E. Convergent Results from Neuropsychology and from Neuroimaging in Patients with Mild Cognitive Impairment. Dement Geriatr Cogn Disord 2018; 43:144-154. [PMID: 28152536 DOI: 10.1159/000455832] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/04/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS To investigate the correspondence between neuropsychological single measures and variation in fludeoxyglucose positron emission tomography (FDG PET) glucose metabolism and magnetic resonance imaging (MRI) cortical thickness in mild cognitive impairment (MCI) patients. METHODS Forty-two elderly controls and 73 MCI subjects underwent FDG PET and MRI scanning. Backward regression analyses with PET and MRI regions were used as dependent variables, while Rey Auditory Verbal Memory Test (RAVLT) recall, Trail Making Test B (TMT B), and a composite test score (RAVLT learning and immediate recall, TMT A, COWAT, and letter-number sequencing) were used as predictor variables. RESULTS The composite score predicted variation in cortical metabolism; supplementary analyses showed that TMT B was significantly correlated with PET metabolism as well. RAVLT and TMT B were significant predictors of variation in MRI cortical thickness. CONCLUSION Our results indicate that RAVLT and TMT B are sensitive to variation in Alzheimer disease neuroimaging markers.
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23
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Modulation of functional activity and connectivity by acupuncture in patients with Alzheimer disease as measured by resting-state fMRI. PLoS One 2018; 13:e0196933. [PMID: 29763448 PMCID: PMC5953467 DOI: 10.1371/journal.pone.0196933] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/23/2018] [Indexed: 01/09/2023] Open
Abstract
Acupuncture has been used in the therapy of Alzheimer disease (AD); however, its neural mechanisms are still unclear. The aim of this study is to examine the effect of acupuncture on the functional connectivity in AD by using resting-state functional magnetic resonance imaging (rs-fMRI). Twenty-eight subjects (14 AD and 14 normal controls) participated in this study. The rs-fMRI data were acquired before and after acupuncture stimulation at the acupoints of Tai chong (Liv3) and Hegu (LI4). During the baseline resting state, by using the amplitude of low-frequency fluctuations (ALFF), we found a significantly decreased or increased ALFF in the AD patients relative to the controls. These regions were located in the right superior frontal gyrus (SFG), left postcentral gyrus, subgenual cingulate cortex (SCC), right middle cingulate cortex (MCC), right inferior frontal gyrus (IFG), right hippocampus and the right inferior temporal gyrus (ITG). Then, we selected these brain regions as seeds to investigate whether regional activity and functional connectivity could be modulated by acupuncture in the AD patients. When compared to the pre-acupuncture stage, several of the above regions showed an increased or decreased ALFF after acupuncture in the AD patients. In addition, the functional connectivity between the hippocampus and the precentral gyrus showed enhancement after acupuncture in the AD patients. Finally, there were close correlations between the functional activity, connectivity and clinical performance in the AD patients. The current study confirmed that acupuncture at Tai chong (Liv3) and He gu (LI4) can modulate functional activity and connectivity of specific cognition-related regions in AD patients.
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24
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Huo L, Li R, Wang P, Zheng Z, Li J. The Default Mode Network Supports Episodic Memory in Cognitively Unimpaired Elderly Individuals: Different Contributions to Immediate Recall and Delayed Recall. Front Aging Neurosci 2018; 10:6. [PMID: 29416508 PMCID: PMC5787535 DOI: 10.3389/fnagi.2018.00006] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/09/2018] [Indexed: 01/21/2023] Open
Abstract
While the neural correlates of age-related decline in episodic memory have been the subject of much interest, the spontaneous functional architecture of the brain for various memory processes in elderly adults, such as immediate recall (IR) and delayed recall (DR), remains unclear. The present study thus examined the neural correlates of age-related decline of various memory processes. A total of 66 cognitively normal older adults (aged 60–80 years) participated in this study. Memory processes were measured using the Auditory Verbal Learning Test as well as resting-state brain images, which were analyzed using both regional homogeneity (ReHo) and correlation-based functional connectivity (FC) approaches. We found that both IR and DR were significantly correlated with the ReHo of these critical regions, all within the default mode network (DMN), including the parahippocampal gyrus, posterior cingulate cortex/precuneus, inferior parietal lobule, and medial prefrontal cortex. In addition, DR was also related to the FC between these DMN regions. These results suggest that the DMN plays different roles in memory retrieval across different retention intervals, and connections between the DMN regions contribute to memory consolidation of past events in healthy older people.
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Affiliation(s)
- Lijuan Huo
- Key Laboratory of Mental Health, Center on Aging Psychology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Rui Li
- Key Laboratory of Mental Health, Center on Aging Psychology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Pengyun Wang
- Key Laboratory of Mental Health, Center on Aging Psychology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Zhiwei Zheng
- Key Laboratory of Mental Health, Center on Aging Psychology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Juan Li
- Key Laboratory of Mental Health, Center on Aging Psychology, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.,Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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25
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Effect of Voluntary Wheel Running on Striatal Dopamine Level and Neurocognitive Behaviors after Molar Loss in Rats. Behav Neurol 2017; 2017:6137071. [PMID: 29358845 PMCID: PMC5735578 DOI: 10.1155/2017/6137071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/25/2017] [Accepted: 10/02/2017] [Indexed: 12/12/2022] Open
Abstract
The aim of the present study is to evaluate the effect of voluntary wheel running on striatal dopamine level and behavior of cognition and emotion in molar loss rats. Twenty-four Sprague-Dawley rats were enrolled in this study and randomly divided into following 4 groups: control group (C group), molar loss group (ML group), 1-week physical exercise before molar loss group (1W-ML group), and 4-week physical exercise before molar loss group (4W-ML group). The rats both in 4W-ML and 1W-ML groups were placed in the voluntary running wheel in order to exercise for 4 weeks and 1 week, respectively. Then, the rats in 4W-ML, 1W-M, and ML groups received bilateral molar loss operation. After 10 days, striatal dopamine level was detected by in vivo microdialysis coupled with high-performance liquid chromatography (HPLC) and electrochemical detection. All the rats received behavior test after microdialysis detection. The behavior tests including passive avoidance test were used to assess cognition and elevated plus maze test for emotion. The results indicated that voluntary wheel running promoted striatal dopamine level in rats of molar loss. Behavioral data indicated that voluntary wheel running promoted cognition and emotion recovery after molar loss. Therefore, we concluded physical exercise significantly improved the neurocognitive behaviors and increased the striatal dopamine level after molar loss in rats.
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26
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Krajcovicova L, Barton M, Elfmarkova-Nemcova N, Mikl M, Marecek R, Rektorova I. Changes in connectivity of the posterior default network node during visual processing in mild cognitive impairment: staged decline between normal aging and Alzheimer’s disease. J Neural Transm (Vienna) 2017; 124:1607-1619. [DOI: 10.1007/s00702-017-1789-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Accepted: 08/31/2017] [Indexed: 02/13/2023]
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27
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Guo S, Lai C, Wu C, Cen G. Conversion Discriminative Analysis on Mild Cognitive Impairment Using Multiple Cortical Features from MR Images. Front Aging Neurosci 2017; 9:146. [PMID: 28572766 PMCID: PMC5435825 DOI: 10.3389/fnagi.2017.00146] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/01/2017] [Indexed: 01/18/2023] Open
Abstract
Neuroimaging measurements derived from magnetic resonance imaging provide important information required for detecting changes related to the progression of mild cognitive impairment (MCI). Cortical features and changes play a crucial role in revealing unique anatomical patterns of brain regions, and further differentiate MCI patients from normal states. Four cortical features, namely, gray matter volume, cortical thickness, surface area, and mean curvature, were explored for discriminative analysis among three groups including the stable MCI (sMCI), the converted MCI (cMCI), and the normal control (NC) groups. In this study, 158 subjects (72 NC, 46 sMCI, and 40 cMCI) were selected from the Alzheimer's Disease Neuroimaging Initiative. A sparse-constrained regression model based on the l2-1-norm was introduced to reduce the feature dimensionality and retrieve essential features for the discrimination of the three groups by using a support vector machine (SVM). An optimized strategy of feature addition based on the weight of each feature was adopted for the SVM classifier in order to achieve the best classification performance. The baseline cortical features combined with the longitudinal measurements for 2 years of follow-up data yielded prominent classification results. In particular, the cortical thickness produced a classification with 98.84% accuracy, 97.5% sensitivity, and 100% specificity for the sMCI–cMCI comparison; 92.37% accuracy, 84.78% sensitivity, and 97.22% specificity for the cMCI–NC comparison; and 93.75% accuracy, 92.5% sensitivity, and 94.44% specificity for the sMCI–NC comparison. The best performances obtained by the SVM classifier using the essential features were 5–40% more than those using all of the retained features. The feasibility of the cortical features for the recognition of anatomical patterns was certified; thus, the proposed method has the potential to improve the clinical diagnosis of sub-types of MCI and predict the risk of its conversion to Alzheimer's disease.
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Affiliation(s)
- Shengwen Guo
- Department of Biomedical Engineering, South China University of TechnologyGuangzhou, China
| | - Chunren Lai
- Department of Biomedical Engineering, South China University of TechnologyGuangzhou, China
| | - Congling Wu
- Department of Biomedical Engineering, South China University of TechnologyGuangzhou, China
| | - Guiyin Cen
- Guangdong General HospitalGuangzhou, China
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28
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Zheng W, Liu X, Song H, Li K, Wang Z. Altered Functional Connectivity of Cognitive-Related Cerebellar Subregions in Alzheimer's Disease. Front Aging Neurosci 2017; 9:143. [PMID: 28559843 PMCID: PMC5432635 DOI: 10.3389/fnagi.2017.00143] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/29/2017] [Indexed: 01/27/2023] Open
Abstract
Alzheimer’s disease (AD) is the most common cause of dementia. Previous studies have found disrupted resting state functional connectivities (rsFCs) in various brain networks in the AD patients. However, few studies have focused on the rsFCs of the cerebellum and its sub-regions in the AD patients. In this study, we collected resting-state functional magnetic resonance imaging (rs-fMRI) data including 32 AD patients and 38 healthy controls (HCs). We selected two cognitive-related subregions of the cerebellum as seed region and mapped the whole-brain rsFCs for each subregion. We identified several distinct rsFC patterns of the two cognitive-related cerebellar subregions: default-mode network (DMN), frontoparietal network (FPN), visual network (VN) and sensorimotor network (SMN). Compared with the controls, the AD patients showed disrupted rsFCs in several different networks (DMN, VN and SMN), predicting the impairment of the functional integration in the cerebellum. Notably, these abnormal rsFCs of the two cerebellar subregions were closely associated with cognitive performance. Collectively, we demonstrated the distinct rsFCs patterns of cerebellar sub-regions with various functional networks, which were differentially impaired in the AD patients.
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Affiliation(s)
- Weimin Zheng
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese MedicineBeijing, China
| | - Xingyun Liu
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese MedicineBeijing, China
| | - Haiqing Song
- Department of Neurology, Xuanwu Hospital of Capital Medical UniversityBeijing, China
| | - Kuncheng Li
- Department of Radiology, Xuanwu Hospital of Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China
| | - Zhiqun Wang
- Department of Radiology, Dongfang Hospital, Beijing University of Chinese MedicineBeijing, China
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29
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Abstract
Although brain network analysis in neurodegenerative disease is still a fairly young discipline, expectations are high. The robust theoretical basis, the straightforward detection and explanation of otherwise intangible complex system phenomena, and the correlations of network features with pathology and cognitive status are qualities that show the potential power of this new instrument. We expect “connectomics” to eventually better explain and predict that essential but still poorly understood aspect of dementia: the relation between pathology and cognitive symptoms. But at this point, our newly acquired knowledge has not yet translated into practical methods or applications in the medical field, and most doctors regard brain connectivity analysis as a wonderful but exotic research niche that is too technical and abstract to benefit patients directly. This article aims to provide a personal perspective on how brain connectivity research may get closer to obtaining a clinical role. I will argue that network intervention modeling, which unites the strengths of network analysis and computational modeling, is a great candidate for this purpose, as it can offer an attractive test environment in which positive and negative influences on network integrity can be explored, with the ultimate aim to find effective countermeasures against neurodegenerative network damage. The virtual trial approach might become what both dementia and connectivity researchers have been waiting for: a versatile tool that turns our growing connectome knowledge into clinical predictions.
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Affiliation(s)
- Willem de Haan
- Department of Neurology, VU University Medical Center Amsterdam, Netherlands
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30
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Kuzmickienė J, Kaubrys G. Specific Features of Executive Dysfunction in Alzheimer-Type Mild Dementia Based on Computerized Cambridge Neuropsychological Test Automated Battery (CANTAB) Test Results. Med Sci Monit 2016; 22:3605-3613. [PMID: 27717954 PMCID: PMC5063414 DOI: 10.12659/msm.900992] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 09/07/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The primary manifestation of Alzheimer's disease (AD) is decline in memory. Dysexecutive symptoms have tremendous impact on functional activities and quality of life. Data regarding frontal-executive dysfunction in mild AD are controversial. The aim of this study was to assess the presence and specific features of executive dysfunction in mild AD based on Cambridge Neuropsychological Test Automated Battery (CANTAB) results. MATERIAL AND METHODS Fifty newly diagnosed, treatment-naïve, mild, late-onset AD patients (MMSE ≥20, AD group) and 25 control subjects (CG group) were recruited in this prospective, cross-sectional study. The CANTAB tests CRT, SOC, PAL, SWM were used for in-depth cognitive assessment. Comparisons were performed using the t test or Mann-Whitney U test, as appropriate. Correlations were evaluated by Pearson r or Spearman R. Statistical significance was set at p<0.05. RESULTS AD and CG groups did not differ according to age, education, gender, or depression. Few differences were found between groups in the SOC test for performance measures: Mean moves (minimum 3 moves): AD (Rank Sum=2227), CG (Rank Sum=623), p<0.001. However, all SOC test time measures differed significantly between groups: SOC Mean subsequent thinking time (4 moves): AD (Rank Sum=2406), CG (Rank Sum=444), p<0.001. Correlations were weak between executive function (SOC) and episodic/working memory (PAL, SWM) (R=0.01-0.38) or attention/psychomotor speed (CRT) (R=0.02-0.37). CONCLUSIONS Frontal-executive functions are impaired in mild AD patients. Executive dysfunction is highly prominent in time measures, but minimal in performance measures. Executive disorders do not correlate with a decline in episodic and working memory or psychomotor speed in mild AD.
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31
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Ruzzoli M, Pirulli C, Mazza V, Miniussi C, Brignani D. The mismatch negativity as an index of cognitive decline for the early detection of Alzheimer's disease. Sci Rep 2016; 6:33167. [PMID: 27616726 PMCID: PMC5018736 DOI: 10.1038/srep33167] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/12/2016] [Indexed: 01/02/2023] Open
Abstract
Evidence suggests that Alzheimer's disease (AD) is part of a continuum, characterized by long preclinical phases before the onset of clinical symptoms. In several cases, this continuum starts with a syndrome, defined as mild cognitive impairment (MCI), in which daily activities are preserved despite the presence of cognitive decline. The possibility of having a reliable and sensitive neurophysiological marker that can be used for early detection of AD is extremely valuable because of the incidence of this type of dementia. In this study, we aimed to investigate the reliability of auditory mismatch negativity (aMMN) as a marker of cognitive decline from normal ageing progressing from MCI to AD. We compared aMMN elicited in the frontal and temporal locations by duration deviant sounds in short (400 ms) and long (4000 ms) inter-trial intervals (ITI) in three groups. We found that at a short ITI, MCI showed only the temporal component of aMMN and AD the frontal component compared to healthy elderly who presented both. At a longer ITI, aMMN was elicited only in normal ageing subjects at the temporal locations. Our study provides empirical evidence for the possibility to adopt aMMN as an index for assessing cognitive decline in pathological ageing.
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Affiliation(s)
- Manuela Ruzzoli
- Departament de Tecnologies de la Informació i les Comunicacions, Center for Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain
| | - Cornelia Pirulli
- Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Veronica Mazza
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy
| | - Carlo Miniussi
- Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy
| | - Debora Brignani
- Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
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32
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Moretti DV. Electroencephalography-driven approach to prodromal Alzheimer's disease diagnosis: from biomarker integration to network-level comprehension. Clin Interv Aging 2016; 11:897-912. [PMID: 27462146 PMCID: PMC4939982 DOI: 10.2147/cia.s103313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Decay of the temporoparietal cortex is associated with prodromal Alzheimer's disease (AD). Additionally, shrinkage of the temporoparietal cerebral area has been connected with an increase in α3/α2 electroencephalogram (EEG) power ratio in prodromal AD. Furthermore, a lower regional blood perfusion has been exhibited in patients with a higher α3/α2 proportion when contrasted with low α3/α2 proportion. Furthermore, a lower regional blood perfusion and reduced hippocampal volume has been exhibited in patients with higher α3/α2 when contrasted with lower α3/α2 EEG power ratio. Neuropsychological evaluation, EEG recording, and magnetic resonance imaging were conducted in 74 patients with mild cognitive impairment (MCI). Estimation of cortical thickness and α3/α2 frequency power ratio was conducted for each patient. A subgroup of 27 patients also underwent single-photon emission computed tomography evaluation. In view of α3/α2 power ratio, the patients were divided into three groups. The connections among cortical decay, cerebral perfusion, and memory loss were evaluated by Pearson's r coefficient. Results demonstrated that higher α3/α2 frequency power ratio group was identified with brain shrinkage and cutdown perfusion inside the temporoparietal projections. In addition, decay and cutdown perfusion rate were connected with memory shortfalls in patients with MCI. MCI subgroup with higher α3/α2 EEG power ratio are at a greater risk to develop AD dementia.
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Affiliation(s)
- Davide Vito Moretti
- Rehabilitation in Alzheimer’s Disease Operative Unit, IRCCS San Giovanni di Dio, Fatebenefratelli, Brescia, Italy
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33
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Regulation of the Postsynaptic Compartment of Excitatory Synapses by the Actin Cytoskeleton in Health and Its Disruption in Disease. Neural Plast 2016; 2016:2371970. [PMID: 27127658 PMCID: PMC4835652 DOI: 10.1155/2016/2371970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/09/2016] [Indexed: 02/07/2023] Open
Abstract
Disruption of synaptic function at excitatory synapses is one of the earliest pathological changes seen in wide range of neurological diseases. The proper control of the segregation of neurotransmitter receptors at these synapses is directly correlated with the intact regulation of the postsynaptic cytoskeleton. In this review, we are discussing key factors that regulate the structure and dynamics of the actin cytoskeleton, the major cytoskeletal building block that supports the postsynaptic compartment. Special attention is given to the complex interplay of actin-associated proteins that are found in the synaptic specialization. We then discuss our current understanding of how disruption of these cytoskeletal elements may contribute to the pathological events observed in the nervous system under disease conditions with a particular focus on Alzheimer's disease pathology.
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34
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Xie L, Dolui S, Das SR, Stockbower GE, Daffner M, Rao H, Yushkevich PA, Detre JA, Wolk DA. A brain stress test: Cerebral perfusion during memory encoding in mild cognitive impairment. Neuroimage Clin 2016; 11:388-397. [PMID: 27222794 PMCID: PMC4821452 DOI: 10.1016/j.nicl.2016.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 02/16/2016] [Accepted: 03/01/2016] [Indexed: 11/24/2022]
Abstract
Arterial spin labeled perfusion magnetic resonance imaging (ASL MRI) provides non-invasive quantification of cerebral blood flow, which can be used as a biomarker of brain function due to the tight coupling between cerebral blood flow (CBF) and brain metabolism. A growing body of literature suggests that regional CBF is altered in neurodegenerative diseases. Here we examined ASL MRI CBF in subjects with amnestic mild cognitive impairment (n = 65) and cognitively normal healthy controls (n = 62), both at rest and during performance of a memory-encoding task. As compared to rest, task-enhanced ASL MRI improved group discrimination, which supports the notion that physiologic measures during a cognitive challenge, or "stress test", may increase the ability to detect subtle functional changes in early disease stages. Further, logistic regression analysis demonstrated that ASL MRI and concomitantly acquired structural MRI provide complementary information of disease status. The current findings support the potential utility of task-enhanced ASL MRI as a biomarker in early Alzheimer's disease.
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Key Words
- AAL, Anatomical Automatic Labeling
- ASL, arterial spin labeled
- Alzheimer's disease
- Arterial spin labeling
- BOLD, blood oxygen level dependent
- Biomarker
- CBF, cerebral blood flow
- CSF, cerebrospinal fluid
- FDG PET, flourodeoyglucose positron emission tomography
- FWER, familywise error rate
- HC, health control
- MCI, mild cognitive impairment
- MMSE, mini-mental status exam
- MNI, Montreal Neurological Institute
- MTL, medial temporal lobe
- Medial temporal lobe
- PASL, pulsed ASL
- PCC, posterior cingulate cortex
- ROI, region of interest
- SCORE, structural correlation based outlier rejection
- Scene-encoding memory task
- a-MCI, amnestic mild cognitive impairment
- aCBF, absolute cerebral blood flow
- pCASL, pseudo-continuous ASL
- rCBF, relative cerebral blood flow
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Affiliation(s)
- Long Xie
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
| | - Sudipto Dolui
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Sandhitsu R Das
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Grace E Stockbower
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Molly Daffner
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hengyi Rao
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Yushkevich
- Penn Image Computing and Science Laboratory (PICSL), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - John A Detre
- Center for Functional Neuroimaging, Department of Neurology, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - David A Wolk
- Penn Memory Center, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
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Bayesian Inference for Functional Dynamics Exploring in fMRI Data. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2016; 2016:3279050. [PMID: 27034708 PMCID: PMC4791514 DOI: 10.1155/2016/3279050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/01/2016] [Indexed: 11/25/2022]
Abstract
This paper aims to review state-of-the-art Bayesian-inference-based methods applied to functional magnetic resonance imaging (fMRI) data. Particularly, we focus on one specific long-standing challenge in the computational modeling of fMRI datasets: how to effectively explore typical functional interactions from fMRI time series and the corresponding boundaries of temporal segments. Bayesian inference is a method of statistical inference which has been shown to be a powerful tool to encode dependence relationships among the variables with uncertainty. Here we provide an introduction to a group of Bayesian-inference-based methods for fMRI data analysis, which were designed to detect magnitude or functional connectivity change points and to infer their functional interaction patterns based on corresponding temporal boundaries. We also provide a comparison of three popular Bayesian models, that is, Bayesian Magnitude Change Point Model (BMCPM), Bayesian Connectivity Change Point Model (BCCPM), and Dynamic Bayesian Variable Partition Model (DBVPM), and give a summary of their applications. We envision that more delicate Bayesian inference models will be emerging and play increasingly important roles in modeling brain functions in the years to come.
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Moretti DV. Conversion of mild cognitive impairment patients in Alzheimer's disease: prognostic value of Alpha3/Alpha2 electroencephalographic rhythms power ratio. Alzheimers Res Ther 2015; 7:80. [PMID: 26715588 PMCID: PMC4696332 DOI: 10.1186/s13195-015-0162-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 11/04/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The increase in electroencephalogram (EEG) alpha3/alpha2 frequency power ratio has been demonstrated as a biomarker characteristic of subjects with mild cognitive impairment (MCI) who will develop Alzheimer's disease (AD). METHODS Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, EEG recording, and high-resolution 3D magnetic resonance imaging (MRI). This group has been evaluated after a three years follow-up. Twenty-seven of these subjects underwent perfusion single-photon emission computed tomography (SPECT) evaluation also. Increasing alpha3/alpha2 power ratio, was computed for each subject. Differences in EEG markers, cortical thickness, brain perfusion among the groups were estimated. RESULTS In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex. After a follow-up of three years, these patients converted in AD. CONCLUSION High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe. Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context.
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Affiliation(s)
- D V Moretti
- Alzheimer' Disease Rehabilitation Unit, IRCCS S. Giovanni di Dio Fatebenefratelli, Brescia, Italy.
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Moretti DV. Association of EEG, MRI, and regional blood flow biomarkers is predictive of prodromal Alzheimer's disease. Neuropsychiatr Dis Treat 2015; 11:2779-91. [PMID: 26604762 PMCID: PMC4629965 DOI: 10.2147/ndt.s93253] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Thinning in the temporoparietal cortex, hippocampal atrophy, and a lower regional blood perfusion is connected with prodromal stage of Alzheimer's disease (AD). Of note, an increase of electroencephalography (EEG) upper/low alpha frequency power ratio has also been associated with these major landmarks of prodromal AD. METHODS Clinical and neuropsychological assessment, EEG recording, and high-resolution three-dimensional magnetic resonance imaging were done in 74 grown up subjects with mild cognitive impairment. This information was gathered and has been assessed 3 years postliminary. EEG recording and perfusion single-photon emission computed tomography assessment was done in 27 subjects. Alpha3/alpha2 frequency power ratio, including cortical thickness, was figured for every subject. Contrasts in cortical thickness among the groups were assessed. Pearson's r relationship coefficient was utilized to evaluate the quality of the relationship between cortical thinning, brain perfusion, and EEG markers. RESULTS The higher alpha3/alpha2 frequency power ratio group corresponded with more prominent cortical decay and a lower perfusional rate in the temporoparietal cortex. In a subsequent meetup after 3 years, these patients had AD. CONCLUSION High EEG upper/low alpha power ratio was connected with cortical diminishing and lower perfusion in the temporoparietal brain area. The increase in EEG upper/low alpha frequency power ratio could be helpful in recognizing people in danger of conversion to AD dementia and this may be quality information in connection with clinical assessment.
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Li W, Ward BD, Liu X, Chen G, Jones JL, Antuono PG, Li SJ, Goveas JS. Disrupted small world topology and modular organisation of functional networks in late-life depression with and without amnestic mild cognitive impairment. J Neurol Neurosurg Psychiatry 2015; 86:1097-105. [PMID: 25433036 PMCID: PMC4465874 DOI: 10.1136/jnnp-2014-309180] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 11/10/2014] [Indexed: 12/23/2022]
Abstract
BACKGROUND The topological architecture of the whole-brain functional networks in those with and without late-life depression (LLD) and amnestic mild cognitive impairment (aMCI) are unknown. AIMS To investigate the differences in the small-world measures and the modular community structure of the functional networks between patients with LLD and aMCI when occurring alone or in combination and cognitively healthy non-depressed controls. METHODS 79 elderly participants (LLD (n=23), aMCI (n=18), comorbid LLD and aMCI (n=13), and controls (n=25)) completed neuropsychiatric assessments. Graph theoretical methods were employed on resting-state functional connectivity MRI data. RESULTS LLD and aMCI comorbidity was associated with the greatest disruptions in functional integration measures (decreased global efficiency and increased path length); both LLD groups showed abnormal functional segregation (reduced local efficiency). The modular network organisation was most variable in the comorbid group, followed by patients with LLD-only. Decreased mean global, local and nodal efficiency metrics were associated with greater depressive symptom severity but not memory performance. CONCLUSIONS Considering the whole brain as a complex network may provide unique insights on the neurobiological underpinnings of LLD with and without cognitive impairment.
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Affiliation(s)
- Wenjun Li
- Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, Wis. USA
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - B. Douglas Ward
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Xiaolin Liu
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Gang Chen
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Jennifer L Jones
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Piero G. Antuono
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Shi-Jiang Li
- Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, Wis. USA
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wis. USA
| | - Joseph S. Goveas
- Department of Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, Wis. USA
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Moretti VD. Atrophy and lower regional perfusion of temporo-parietal brain areas are correlated with impairment in memory performances and increase of EEG upper alpha power in prodromal Alzheimer's disease. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2015; 4:13-27. [PMID: 26389016 PMCID: PMC4568770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 08/28/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Temporo-parietal cortex thinning is associated with mild cognitive impairment (MCI) due to Alzheimer's disease (AD). The increase of the EEG upper/low alpha power ratio has been associated with MCI due to AD subjects and to the atrophy of temporo-parietal brain areas. Moreover, subjects with a higher alpha3/alpha2 frequency power ratio showed lower brain perfusion than in the low alpha3/alpha2 group. The two groups have significantly different hippocampal volumes and correlation with the theta frequency activity. METHODS 74 adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording, and high resolution 3D magnetic resonance imaging (MRI). 27 of them underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The alpha3/alpha2 power ratio as well as cortical thickness was computed for each subject. The difference in cortical thickness between the groups was estimated. Pearson's r was used to assess the correlation topography between cortical thinning as well as between brain perfusion and memory impairment. RESULTS In the higher upper/low alpha group, memory impairment was more pronounced both in the MRI group and the SPECT MCI group. Moreover, it was correlated with greater cortical atrophy and lower perfusional rate in temporo-parietal cortex. CONCLUSION High EEG upper/low alpha power ratio was associated with cortical thinning lower perfusion in temporo-parietal. Moreover, atrophy and lower perfusional rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context.
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Saura CA, Parra-Damas A, Enriquez-Barreto L. Gene expression parallels synaptic excitability and plasticity changes in Alzheimer's disease. Front Cell Neurosci 2015; 9:318. [PMID: 26379494 PMCID: PMC4548151 DOI: 10.3389/fncel.2015.00318] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/03/2015] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by abnormal accumulation of β-amyloid and tau and synapse dysfunction in memory-related neural circuits. Pathological and functional changes in the medial temporal lobe, a region essential for explicit memory encoding, contribute to cognitive decline in AD. Surprisingly, functional imaging studies show increased activity of the hippocampus and associated cortical regions during memory tasks in presymptomatic and early AD stages, whereas brain activity declines as the disease progresses. These findings suggest an emerging scenario where early pathogenic events might increase neuronal excitability leading to enhanced brain activity before clinical manifestations of the disease, a stage that is followed by decreased brain activity as neurodegeneration progresses. The mechanisms linking pathology with synaptic excitability and plasticity changes leading to memory loss in AD remain largely unclear. Recent studies suggest that increased brain activity parallels enhanced expression of genes involved in synaptic transmission and plasticity in preclinical stages, whereas expression of synaptic and activity-dependent genes are reduced by the onset of pathological and cognitive symptoms. Here, we review recent evidences indicating a relationship between transcriptional deregulation of synaptic genes and neuronal activity and memory loss in AD and mouse models. These findings provide the basis for potential clinical applications of memory-related transcriptional programs and their regulatory mechanisms as novel biomarkers and therapeutic targets to restore brain function in AD and other cognitive disorders.
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Affiliation(s)
- Carlos A. Saura
- Institut de Neurociències, Departament de Bioquímica i Biologia Molecular, Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Universitat Autònoma de BarcelonaBarcelona, Spain
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Predictive models of resting state networks for assessment of altered functional connectivity in mild cognitive impairment. Brain Imaging Behav 2015; 8:542-57. [PMID: 24293138 DOI: 10.1007/s11682-013-9280-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Due to the difficulties in establishing correspondences between functional regions across individuals and populations, systematic elucidation of functional connectivity alterations in mild cognitive impairment (MCI) in comparison with normal controls (NC) is still a challenging problem. In this paper, we assessed the functional connectivity alterations in MCI via novel, alternative predictive models of resting state networks (RSNs) learned from multimodal resting state fMRI (R-fMRI) and diffusion tensor imaging (DTI) data. First, ICA-clustering was used to construct RSNs from R-fMRI data in NC group. Second, since the RSNs in MCI are already altered and can hardly be constructed directly from R-fMRI data, structural landmarks derived from DTI data were employed as the predictive models of RSNs for MCI. Third, given that the landmarks are structurally consistent and correspondent across NC and MCI, functional connectivities in MCI were assessed based on the predicted RSNs and compared with those in NC. Experimental results demonstrated that the predictive models of RSNs based on multimodal R-fMRI and DTI data systematically and comprehensively revealed widespread functional connectivity alterations in MCI in comparison with NC.
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Moretti DV. Mild Cognitive Impairment: Structural, Metabolical, and Neurophysiological Evidence of a Novel EEG Biomarker. Front Neurol 2015. [PMID: 26217299 PMCID: PMC4491619 DOI: 10.3389/fneur.2015.00152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Recent studies demonstrate that the alpha3/alpha2 power ratio correlates with cortical atrophy, regional hypoperfusion, and memory impairment in subjects with mild cognitive impairment (MCI). METHODS Evidences were reviewed in subjects with MCI, who underwent EEG recording, magnetic resonance imaging (MRI) scans, and memory evaluation. Alpha3/alpha2 power ratio (alpha2 8.9-10.9 Hz range; alpha3 10.9-12.9 Hz range), cortical thickness, linear EEG coherence, and memory impairment have been evaluated in a large group of 74 patients. A subset of 27 subjects within the same group also underwent single photon emission computed tomography (SPECT) evaluation. RESULTS In MCI subjects with higher EEG upper/low alpha power ratio, a greater temporo-parietal and hippocampal atrophy was found as well as a decrease in regional blood perfusion and memory impairment. In this group, an increase of theta oscillations is associated with a greater interhemispheric coupling between temporal areas. CONCLUSION The increase of alpha3/alpha2 power ratio is a promising novel biomarker in identifying MCI subjects at risk for Alzheimer's disease.
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Vandenberghe R. The relationship between amyloid deposition, neurodegeneration, and cognitive decline in dementia. Curr Neurol Neurosci Rep 2015; 14:498. [PMID: 25224538 DOI: 10.1007/s11910-014-0498-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Amyloid imaging has been clinically approved for measuring β amyloid plaque load in patients being evaluated for Alzheimer's disease or other causes of cognitive decline. Here we explore a multidimensional approach to cognitive decline, where we situate amyloid plaque burden among a number of other relevant dimensions, such as aging, volume loss, other proteinopathies such as TDP43 and Lewy bodies, and functional reorganisation of cognitive brain systems. The multidimensional model incorporates a 'pure AD' trajectory, corresponding to e.g. monogenic Alzheimer's disease, but leaves room for other combinations of biomarker abnormalities (e.g. volume loss without amyloid positivity) and other trajectories. More tools will become available in the future that allow one to carve out a causal-mechanistic space for explaing cognitive decline in a personalized manner, enhancing progress towards more efficacious interventions.
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Affiliation(s)
- Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, University of Leuven, Leuven, Belgium,
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Jiang X, Zhang T, Zhu D, Li K, Chen H, Lv J, Hu X, Han J, Shen D, Guo L, Liu T. Anatomy-guided Dense Individualized and Common Connectivity-based Cortical Landmarks (A-DICCCOL). IEEE Trans Biomed Eng 2015; 62:1108-19. [PMID: 25420253 PMCID: PMC5307947 DOI: 10.1109/tbme.2014.2369491] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Establishment of structural and functional correspondences of human brain that can be quantitatively encoded and reproduced across different subjects and populations is one of the key issues in brain mapping. As an attempt to address this challenge, our recently developed Dense Individualized and Common Connectivity-based Cortical Landmarks (DICCCOL) system reported 358 connectional landmarks, each of which possesses consistent DTI-derived white matter fiber connection pattern that is reproducible in over 240 healthy brains. However, the DICCCOL system can be substantially improved by integrating anatomical and morphological information during landmark initialization and optimization procedures. In this paper, we present a novel anatomy-guided landmark discovery framework that defines and optimizes landmarks via integrating rich anatomical, morphological, and fiber connectional information for landmark initialization, group-wise optimization and prediction, which are formulated and solved as an energy minimization problem. The framework finally determined 555 consistent connectional landmarks. Validation studies demonstrated that the 555 landmarks are reproducible, predictable, and exhibited reasonably accurate anatomical, connectional, and functional correspondences across individuals and populations and thus are named anatomy-guided DICCCOL or A-DICCCOL. This A-DICCCOL system represents common cortical architectures with anatomical, connectional, and functional correspondences across different subjects and would potentially provide opportunities for various applications in brain science.
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Affiliation(s)
- Xi Jiang
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Tuo Zhang
- School of Automation, Northwestern Polytechnical University, Xi’an 710072, China
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Dajiang Zhu
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Kaiming Li
- School of Automation, Northwestern Polytechnical University, Xi’an 710072 China
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Hanbo Chen
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Jinglei Lv
- School of Automation, Northwestern Polytechnical University, Xi’an 710072 China
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA
| | - Xintao Hu
- School of Automation, Northwestern Polytechnical University, Xi’an 710072 China
| | - Junwei Han
- School of Automation, Northwestern Polytechnical University, Xi’an 710072 China
| | - Dinggang Shen
- Department of Radiology, University of North Carolina, Chapel Hill, NC 27599 USA
| | - Lei Guo
- School of Automation, Northwestern Polytechnical University, Xi’an 710072 China
| | - Tianming Liu
- T. Liu is with the Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA 30602 USA ()
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Li H, Hou X, Liu H, Yue C, He Y, Zuo X. Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: a meta-analysis of 75 fMRI studies. Hum Brain Mapp 2015; 36:1217-32. [PMID: 25411150 PMCID: PMC6869191 DOI: 10.1002/hbm.22689] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/03/2014] [Accepted: 11/03/2014] [Indexed: 11/11/2022] Open
Abstract
Most of the previous task functional magnetic resonance imaging (fMRI) studies found abnormalities in distributed brain regions in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and few studies investigated the brain network dysfunction from the system level. In this meta-analysis, we aimed to examine brain network dysfunction in MCI and AD. We systematically searched task-based fMRI studies in MCI and AD published between January 1990 and January 2014. Activation likelihood estimation meta-analyses were conducted to compare the significant group differences in brain activation, the significant voxels were overlaid onto seven referenced neuronal cortical networks derived from the resting-state fMRI data of 1,000 healthy participants. Thirty-nine task-based fMRI studies (697 MCI patients and 628 healthy controls) were included in MCI-related meta-analysis while 36 task-based fMRI studies (421 AD patients and 512 healthy controls) were included in AD-related meta-analysis. The meta-analytic results revealed that MCI and AD showed abnormal regional brain activation as well as large-scale brain networks. MCI patients showed hypoactivation in default, frontoparietal, and visual networks relative to healthy controls, whereas AD-related hypoactivation mainly located in visual, default, and ventral attention networks relative to healthy controls. Both MCI-related and AD-related hyperactivation fell in frontoparietal, ventral attention, default, and somatomotor networks relative to healthy controls. MCI and AD presented different pathological while shared similar compensatory large-scale networks in fulfilling the cognitive tasks. These system-level findings are helpful to link the fundamental declines of cognitive tasks to brain networks in MCI and AD.
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Affiliation(s)
- Hui‐Jie Li
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
| | - Xiao‐Hui Hou
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
- University of Chinese Academy of SciencesBeijing100049China
| | - Han‐Hui Liu
- Youth Work DepartmentChina Youth University of Political StudiesBeijing100089China
| | - Chun‐Lin Yue
- Institute of Sports MedicineSoochow UniversitySuzhou215006China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain ResearchBeijing Normal UniversityBeijing100875China
- Center for Collaboration and Innovation in Brain and Learning SciencesBeijing Normal UniversityBeijing100875China
| | - Xi‐Nian Zuo
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
- Center for Collaboration and Innovation in Brain and Learning SciencesBeijing Normal UniversityBeijing100875China
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Moretti DV. Electroencephalography reveals lower regional blood perfusion and atrophy of the temporoparietal network associated with memory deficits and hippocampal volume reduction in mild cognitive impairment due to Alzheimer's disease. Neuropsychiatr Dis Treat 2015; 11:461-70. [PMID: 25750526 PMCID: PMC4348123 DOI: 10.2147/ndt.s78830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND An increased electroencephalographic (EEG) upper/lower alpha power ratio has been associated with less regional blood perfusion, atrophy of the temporoparietal region of the brain, and reduction of hippocampal volume in subjects affected by mild cognitive impairment due to Alzheimer's disease as compared with subjects who do not develop the disease. Moreover, EEG theta frequency activity is quite different in these groups. This study investigated the correlation between biomarkers and memory performance. METHODS EEG α3/α2 power ratio and cortical thickness were computed in 74 adult subjects with prodromal Alzheimer's disease. Twenty of these subjects also underwent assessment of blood perfusion by single-photon emission computed tomography (SPECT). Pearson's r was used to assess the correlation between cortical thinning, brain perfusion, and memory impairment. RESULTS In the higher α3/α2 frequency power ratio group, greater cortical atrophy and lower regional perfusion in the temporoparietal cortex was correlated with an increase in EEG theta frequency. Memory impairment was more pronounced in the magnetic resonance imaging group and SPECT groups. CONCLUSION A high EEG upper/low alpha power ratio was associated with cortical thinning and less perfusion in the temporoparietal area. Moreover, atrophy and less regional perfusion were significantly correlated with memory impairment in subjects with prodromal Alzheimer's disease. The EEG upper/lower alpha frequency power ratio could be useful for identifying individuals at risk for progression to Alzheimer's dementia and may be of value in the clinical context.
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Affiliation(s)
- Davide Vito Moretti
- National Institute for the research and cure of Alzheimer’s disease, S. John of God, Fatebenefratelli, Brescia, Italy
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Moretti DV. Understanding early dementia: EEG, MRI, SPECT and memory evaluation. Transl Neurosci 2015; 6:32-46. [PMID: 28123789 PMCID: PMC4936613 DOI: 10.1515/tnsci-2015-0005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/01/2014] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND An increase in the EEG upper/low α power ratio has been associated with mild cognitive impairment (MCI) due to Alzheimer's disease (AD) and to the atrophy of temporoparietal brain areas. Subjects with a higher α3/α2 frequency power ratio showed lower brain perfusion than in the low α3/α2 group. The two groups show significantly different hippocampal volumes and correlation with θ frequency activity. METHODS Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, electroencephalogram (EEG) recording, and high resolution 3D magnetic resonance imaging (MRI). Twenty-seven of them underwent EEG recording and perfusion single-photon emission computed tomography (SPECT) evaluation. The α3/α2 power ratio and cortical thickness were computed for each subject. The difference in cortical thickness between the groups was estimated. RESULTS In the higher upper/low α group, memory impairment was more pronounced in both the MRI group and the SPECT MCI groups. An increase in the production of θ oscillations was associated with greater interhemisperic coupling between temporal areas. It also correlated with greater cortical atrophy and lower perfusional rate in the temporoparietal cortex. CONCLUSION High EEG upper/low α power ratio was associated with cortical thinning and lower perfusion in temporoparietal areas. Moreover, both atrophy and lower perfusion rate significantly correlated with memory impairment in MCI subjects. Therefore, the increase in the EEG upper/low α frequency power ratio could be useful in identifying individuals at risk for progression to AD dementia in a clinical context.
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Affiliation(s)
- Davide Vito Moretti
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Giovanni di Dio Fatebenefratelli, Brescia, Italy
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48
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Chen J, Zhang Z, Li S. Can multi-modal neuroimaging evidence from hippocampus provide biomarkers for the progression of amnestic mild cognitive impairment? Neurosci Bull 2015; 31:128-40. [PMID: 25595368 DOI: 10.1007/s12264-014-1490-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 11/06/2014] [Indexed: 02/01/2023] Open
Abstract
Impaired structure and function of the hippocampus is a valuable predictor of progression from amnestic mild cognitive impairment (aMCI) to Alzheimer's disease (AD). As a part of the medial temporal lobe memory system, the hippocampus is one of the brain regions affected earliest by AD neuropathology, and shows progressive degeneration as aMCI progresses to AD. Currently, no validated biomarkers can precisely predict the conversion from aMCI to AD. Therefore, there is a great need of sensitive tools for the early detection of AD progression. In this review, we summarize the specific structural and functional changes in the hippocampus from recent aMCI studies using neurophysiological and neuroimaging data. We suggest that a combination of advanced multi-modal neuroimaging measures in discovering biomarkers will provide more precise and sensitive measures of hippocampal changes than using only one of them. These will potentially affect early diagnosis and disease-modifying treatments. We propose a new sequential and progressive framework in which the impairment spreads from the integrity of fibers to volume and then to function in hippocampal subregions. Meanwhile, this is likely to be accompanied by progressive impairment of behavioral and neuropsychological performance in the progression of aMCI to AD.
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Affiliation(s)
- Jiu Chen
- Department of Neurology, Affiliated ZhongDa Hospital, Neuropsychiatric Institute and Medical School of Southeast University, Nanjing, 210009, China
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Adlard PA, Tran BA, Finkelstein DI, Desmond PM, Johnston LA, Bush AI, Egan GF. A review of β-amyloid neuroimaging in Alzheimer's disease. Front Neurosci 2014; 8:327. [PMID: 25400539 PMCID: PMC4215612 DOI: 10.3389/fnins.2014.00327] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/27/2014] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia worldwide. As advancing age is the greatest risk factor for developing AD, the number of those afflicted is expected to increase markedly with the aging of the world's population. The inability to definitively diagnose AD until autopsy remains an impediment to establishing effective targeted treatments. Neuroimaging has enabled in vivo visualization of pathological changes in the brain associated with the disease, providing a greater understanding of its pathophysiological development and progression. However, neuroimaging biomarkers do not yet offer clear advantages over current clinical diagnostic criteria for them to be accepted into routine clinical use. Nonetheless, current insights from neuroimaging combined with the elucidation of biochemical and molecular processes in AD are informing the ongoing development of new imaging techniques and their application. Much of this research has been greatly assisted by the availability of transgenic mouse models of AD. In this review we summarize the main efforts of neuroimaging in AD in humans and in mouse models, with a specific focus on β-amyloid, and discuss the potential of new applications and novel approaches.
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Affiliation(s)
- Paul A. Adlard
- Division of Mental Health, The Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
| | - Bob A. Tran
- Department of Radiology, University of MelbourneParkville, VIC, Australia
| | - David I. Finkelstein
- Division of Mental Health, The Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
| | - Patricia M. Desmond
- Department of Radiology, University of MelbourneParkville, VIC, Australia
- Department of Radiology, The Royal Melbourne HospitalParkville, VIC, Australia
| | - Leigh A. Johnston
- Division of Mental Health, The Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
- Department of Electrical and Electronic Engineering, University of MelbourneParkville, VIC, Australia
| | - Ashley I. Bush
- Division of Mental Health, The Florey Institute of Neuroscience and Mental Health, University of MelbourneParkville, VIC, Australia
| | - Gary F. Egan
- Monash Biomedical Imaging, Monash UniversityClayton, VIC, Australia
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
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Ou J, Xie L, Jin C, Li X, Zhu D, Jiang R, Chen Y, Zhang J, Li L, Liu T. Characterizing and Differentiating Brain State Dynamics via Hidden Markov Models. Brain Topogr 2014; 28:666-679. [PMID: 25331991 DOI: 10.1007/s10548-014-0406-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 09/30/2014] [Indexed: 10/24/2022]
Abstract
Functional connectivity measured from resting state fMRI (R-fMRI) data has been widely used to examine the brain's functional activities and has been recently used to characterize and differentiate brain conditions. However, the dynamical transition patterns of the brain's functional states have been less explored. In this work, we propose a novel computational framework to quantitatively characterize the brain state dynamics via hidden Markov models (HMMs) learned from the observations of temporally dynamic functional connectomics, denoted as functional connectome states. The framework has been applied to the R-fMRI dataset including 44 post-traumatic stress disorder (PTSD) patients and 51 normal control (NC) subjects. Experimental results show that both PTSD and NC brains were undergoing remarkable changes in resting state and mainly transiting amongst a few brain states. Interestingly, further prediction with the best-matched HMM demonstrates that PTSD would enter into, but could not disengage from, a negative mood state. Importantly, 84% of PTSD patients and 86% of NC subjects are successfully classified via multiple HMMs using majority voting.
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Affiliation(s)
- Jinli Ou
- School of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Li Xie
- School of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Changfeng Jin
- The Mental Health Institute, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xiang Li
- Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Dajiang Zhu
- Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA
| | - Rongxin Jiang
- School of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Yaowu Chen
- School of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China
| | - Jing Zhang
- Department of Mathematics and Statistics, Georgia State University, Atlanta, 30303, GA, USA.
| | - Lingjiang Li
- The Mental Health Institute, The Second Xiangya Hospital, Central South University, Changsha, China.
| | - Tianming Liu
- Department of Computer Science and Bioimaging Research Center, The University of Georgia, Athens, GA, USA.
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