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Gaire BP, Koronyo Y, Fuchs DT, Shi H, Rentsendorj A, Danziger R, Vit JPS, Mirzaei N, Doustar J, Sheyn J, Hampel H, Vergallo A, Davis MR, Jallow O, Baldacci F, Verdooner SR, Barron E, Mirzaei M, Gupta VK, Graham SL, Tayebi M, Carare RO, Sadun AA, Miller CA, Dumitrascu OM, Lahiri S, Gao L, Black KL, Koronyo-Hamaoui M. Alzheimer's Disease Pathophysiology in the Retina. Prog Retin Eye Res 2024:101273. [PMID: 38759947 DOI: 10.1016/j.preteyeres.2024.101273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 04/23/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
The retina is an emerging CNS target for potential noninvasive diagnosis and tracking of Alzheimer's disease (AD). Studies have identified the pathological hallmarks of AD, including amyloid β-protein (Aβ) deposits and abnormal tau protein isoforms, in the retinas of AD patients and animal models. Moreover, structural and functional vascular abnormalities such as reduced blood flow, vascular Aβ deposition, and blood-retinal barrier damage, along with inflammation and neurodegeneration, have been described in retinas of patients with mild cognitive impairment and AD dementia. Histological, biochemical, and clinical studies have demonstrated that the nature and severity of AD pathologies in the retina and brain correspond. Proteomics analysis revealed a similar pattern of dysregulated proteins and biological pathways in the retina and brain of AD patients, with enhanced inflammatory and neurodegenerative processes, impaired oxidative-phosphorylation, and mitochondrial dysfunction. Notably, investigational imaging technologies can now detect AD-specific amyloid deposits, as well as vasculopathy and neurodegeneration in the retina of living AD patients, suggesting alterations at different disease stages and links to brain pathology. Current and exploratory ophthalmic imaging modalities, such as optical coherence tomography (OCT), OCT-angiography, confocal scanning laser ophthalmoscopy, and hyperspectral imaging, may offer promise in the clinical assessment of AD. However, further research is needed to deepen our understanding of AD's impact on the retina and its progression. To advance this field, future studies require replication in larger and diverse cohorts with confirmed AD biomarkers and standardized retinal imaging techniques. This will validate potential retinal biomarkers for AD, aiding in early screening and monitoring.
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Affiliation(s)
- Bhakta Prasad Gaire
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Haoshen Shi
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Altan Rentsendorj
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Ron Danziger
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jean-Philippe S Vit
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Nazanin Mirzaei
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Jonah Doustar
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Julia Sheyn
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Harald Hampel
- Sorbonne University, Alzheimer Precision Medicine (APM), Boulevard de l'hôpital, Paris, France
| | - Andrea Vergallo
- Sorbonne University, Alzheimer Precision Medicine (APM), Boulevard de l'hôpital, Paris, France
| | - Miyah R Davis
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Ousman Jallow
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Filippo Baldacci
- Sorbonne University, Alzheimer Precision Medicine (APM), Boulevard de l'hôpital, Paris, France; Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | - Ernesto Barron
- Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Mehdi Mirzaei
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Vivek K Gupta
- Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Stuart L Graham
- Department of Clinical Medicine, Macquarie University, Sydney, NSW, Australia
| | - Mourad Tayebi
- School of Medicine, Western Sydney University Campbelltown, New South Wales, Australia
| | | | - Alfredo A Sadun
- Department of Ophthalmology, Doheny Eye Institute, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Carol A Miller
- Department of Pathology Program in Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Shouri Lahiri
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Liang Gao
- Department of Bioengineering, University of California, Los Angeles, CA, USA
| | - Keith L Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States; Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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2
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Rehan S, Giroud N, Al-Yawer F, Wittich W, Phillips N. Visual Performance and Cortical Atrophy in Vision-Related Brain Regions Differ Between Older Adults with (or at Risk for) Alzheimer's Disease. J Alzheimers Dis 2021; 83:1125-1148. [PMID: 34397410 DOI: 10.3233/jad-201521] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Visual impairment is associated with deficits in cognitive function and risk for cognitive decline and Alzheimer's disease (AD). OBJECTIVE The purpose of this study was to characterize the degree of visual impairment and explore the association thereof with cortical atrophy in brain regions associated with visual processing in individuals with (or at risk for) AD. METHODS Using the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS-ND) dataset, we analyzed vision and brain imaging data from three diagnostic groups: individuals with subjective cognitive decline (SCD; N = 35), mild cognitive impairment (MCI; N = 74), and mild AD (N = 30). We used ANCOVAs to determine whether performance on reading acuity and contrast sensitivity tests differed across diagnostic groups. Hierarchical regression analyses were applied to determine whether visual performance predicted gray matter volume for vision-related regions of interest above and beyond group membership. RESULTS The AD group performed significantly worse on reading acuity (F(2,138) = 4.12, p < 0.01, ω 2 = 0.04) compared to the SCD group and on contrast sensitivity (F(2,138) = 7.6, p < 0.01, ω 2 = 0.09) compared to the SCD and MCI groups, which did not differ from each other. Visual performance was associated with volume in some vision-related structures beyond clinical diagnosis. CONCLUSION Our findings demonstrate poor visual performance in AD and that both group membership and visual performance are predictors of cortical pathology, consistent with the idea that atrophy in visual areas and pathways contributes to the functional vision deficits observed in AD.
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Affiliation(s)
- Sana Rehan
- Department of Psychology, Centre for Research in Human Development>, Concordia University, Montréal, Québec, Canada.,Centre for Research on Brain, Language, and Music, Montréal, Québec, Canada
| | - Nathalie Giroud
- Institute of Computational Linguistics, University of Zurich, Zurich, Switzerland
| | - Faisal Al-Yawer
- Department of Psychology, Centre for Research in Human Development>, Concordia University, Montréal, Québec, Canada.,Centre for Research on Brain, Language, and Music, Montréal, Québec, Canada
| | - Walter Wittich
- School of Optometry, Université de Montréal, Montreal, Quebec, Canada
| | - Natalie Phillips
- Department of Psychology, Centre for Research in Human Development>, Concordia University, Montréal, Québec, Canada.,Centre for Research on Brain, Language, and Music, Montréal, Québec, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
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3
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Kim NG, Lee HW. Stereoscopic Depth Perception and Visuospatial Dysfunction in Alzheimer's Disease. Healthcare (Basel) 2021; 9:healthcare9020157. [PMID: 33546119 PMCID: PMC7913121 DOI: 10.3390/healthcare9020157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 11/16/2022] Open
Abstract
With visuospatial dysfunction emerging as a potential marker that can detect Alzheimer's disease (AD) even in its earliest stages and with disturbance in stereopsis suspected to be the prime contributor to visuospatial deficits in AD, we assessed stereoscopic abilities of patients with AD and mild cognitive impairment (MCI). Whereas previous research assessing patients' stereoacuity has yielded mixed results, we assessed patients' capacity to process coarse disparities that can convey adequate depth information about objects in the environment. We produced two virtual cubes at two different distances from the observer by manipulating disparity type (absolute vs. relative), disparity direction (crossed vs. uncrossed) and disparity magnitude, then had participants judge the object that appeared closer to them. Two patient groups performed as well as, or even better than elderly controls, suggesting that AD patients' coarse disparity processing capacity is capable of supporting common tasks involving reaching, grasping, driving, and navigation. Results may help researchers narrow down the exact cause(s) of visuospatial deficits in AD and develop and validate measures to assess visuospatial dysfunction in clinical trials and disease diagnosis.
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Affiliation(s)
- Nam-Gyoon Kim
- Department of Psychology, Keimyung University, Daegu 42601, Korea
- Correspondence: ; Tel.: +82-53-580-5415
| | - Ho-Won Lee
- Department of Neurology, School of Medicine & Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
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Marquié M, Castilla-Martí M, Valero S, Martínez J, Sánchez D, Hernández I, Rosende-Roca M, Vargas L, Mauleón A, Rodríguez-Gómez O, Abdelnour C, Gil S, Santos-Santos MA, Alegret M, Espinosa A, Ortega G, Pérez-Cordón A, Sanabria Á, Roberto N, Moreno-Grau S, de Rojas I, Simó R, Ciudin A, Hernández C, Orellana A, Monté-Rubio G, Benaque A, Ruiz A, Tárraga L, Boada M. Visual impairment in aging and cognitive decline: experience in a Memory Clinic. Sci Rep 2019; 9:8698. [PMID: 31213626 PMCID: PMC6581941 DOI: 10.1038/s41598-019-45055-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 05/23/2019] [Indexed: 12/13/2022] Open
Abstract
Visual impairment is common in people living with dementia and regular ophthalmological exams may improve their quality of life. We evaluated visual function in a cohort of elderly individuals and analyzed its association with their degree of cognitive impairment. Participants underwent neurological and neuropsychological exams, neuro-ophthalmological assessment (visual acuity, intraocular pressure, rates of past ophthalmological pathologies, use of ocular correction, treatments and surgeries) and optical coherence tomography (OCT) scan. We analyzed differences in ophthalmological characteristics among diagnostic groups. The final sample of 1746 study participants aged ≥ 50 comprised 229 individuals with Subjective Cognitive Decline (SCD), 695 with mild cognitive impairment (MCI) and 833 with Dementia (Alzheimer disease: n = 660; vascular dementia: n = 92, Lewy body dementia: n = 34; frontotemporal dementia: n = 19 and other: n = 28). Age, gender and education were used as covariates. Patients with Dementia, compared to those with SCD and MCI, presented worse visual acuity (p < 0.001), used less visual correction (p = 0.02 and p < 0.001, respectively) and fewer ophthalmological treatments (p = 0.004 and p < 0.001, respectively) and underwent fewer ocular surgeries (p = 0.009 and p < 0.001, respectively). OCT image quality worsened in parallel to cognitive decline (Dementia vs SCD: p = 0.008; Dementia vs MCI: p < 0.001). No group differences in past ophthalmological disorders or abnormal OCT findings were detected. Efforts should be made to ensure dementia patients undergo regular ophthalmological assessments to correct their visual function in order to improve their quality of life.
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Affiliation(s)
- Marta Marquié
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.
| | - Miguel Castilla-Martí
- Clínica Oftalmológica Dr. Castilla, Barcelona, Spain.,Department of Ophthalmology, Hospital del Mar and Hospital de l'Esperança - Parc de Salut Mar, Barcelona, Spain
| | - Sergi Valero
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Joan Martínez
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Domingo Sánchez
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Isabel Hernández
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Maitée Rosende-Roca
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Liliana Vargas
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Ana Mauleón
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Octavio Rodríguez-Gómez
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Carla Abdelnour
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Silvia Gil
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Miguel A Santos-Santos
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Montserrat Alegret
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Espinosa
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Gemma Ortega
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Alba Pérez-Cordón
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Ángela Sanabria
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Natalia Roberto
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Sonia Moreno-Grau
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Itziar de Rojas
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Rafael Simó
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.,Institut de Recerca Vall d'Hebron, Universitat Autònoma de Barcelona (VHIR-UAB), Barcelona, Spain
| | - Andreea Ciudin
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.,Institut de Recerca Vall d'Hebron, Universitat Autònoma de Barcelona (VHIR-UAB), Barcelona, Spain
| | - Cristina Hernández
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.,Institut de Recerca Vall d'Hebron, Universitat Autònoma de Barcelona (VHIR-UAB), Barcelona, Spain
| | - Adelina Orellana
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Gemma Monté-Rubio
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Alba Benaque
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain
| | - Agustín Ruiz
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Lluís Tárraga
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercè Boada
- Alzheimer Research Center and Memory Clinic, Fundació ACE Institut Català de Neurociències Aplicades - Universitat Internacional de Catalunya (UIC), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
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Chiquita S, Rodrigues-Neves AC, Baptista FI, Carecho R, Moreira PI, Castelo-Branco M, Ambrósio AF. The Retina as a Window or Mirror of the Brain Changes Detected in Alzheimer's Disease: Critical Aspects to Unravel. Mol Neurobiol 2019; 56:5416-5435. [PMID: 30612332 DOI: 10.1007/s12035-018-1461-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/17/2018] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease is the most frequent cause of dementia worldwide, representing a global health challenge, with a massive impact on the quality of life of Alzheimer's disease patients and their relatives. The diagnosis of Alzheimer's disease constitutes a real challenge, because the symptoms manifest years after the first degenerative changes occurring in the brain and the diagnosis is based on invasive and/or expensive techniques. Therefore, there is an urgent need to identify new reliable biomarkers to detect Alzheimer's disease at an early stage. Taking into account the evidence for visual deficits in Alzheimer's disease patients, sometimes even before the appearance of the first disease symptoms, and that the retina is an extension of the brain, the concept of the retina as a window to look into the brain or a mirror of the brain has received increasing interest in recent years. However, only a few studies have assessed the changes occurring in the retina and the brain at the same time points. Unlike previous reviews on this subject, which are mainly focused on brain changes, we organized this review by comprehensively summarizing findings related with structural, functional, cellular, and molecular parameters in the retina reported in both Alzheimer's disease patients and animal models. Moreover, we separated the studies that assessed only the retina, and those that assessed both the retina and brain, which are few but allow establishing correlations between the retina and brain. This review also highlights some inconsistent results in the literature as well as relevant missing gaps in this field.
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Affiliation(s)
- Samuel Chiquita
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Ana C Rodrigues-Neves
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Filipa I Baptista
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Rafael Carecho
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Miguel Castelo-Branco
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal
- CIBIT, Coimbra Institute for Biomedical Imaging and Translational Research, ICNAS, Institute of Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal
| | - António F Ambrósio
- iCBR, Coimbra Institute for Clinical and Biomedical Research, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
- CNC.IBILI Consortium, University of Coimbra, Coimbra, Portugal.
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Cerquera-Jaramillo MA, Nava-Mesa MO, González-Reyes RE, Tellez-Conti C, de-la-Torre A. Visual Features in Alzheimer's Disease: From Basic Mechanisms to Clinical Overview. Neural Plast 2018; 2018:2941783. [PMID: 30405709 PMCID: PMC6204169 DOI: 10.1155/2018/2941783] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 08/07/2018] [Indexed: 12/16/2022] Open
Abstract
Alzheimer's disease (AD) is the leading cause of dementia worldwide. It compromises patients' daily activities owing to progressive cognitive deterioration, which has elevated direct and indirect costs. Although AD has several risk factors, aging is considered the most important. Unfortunately, clinical diagnosis is usually performed at an advanced disease stage when dementia is established, making implementation of successful therapeutic interventions difficult. Current biomarkers tend to be expensive, insufficient, or invasive, raising the need for novel, improved tools aimed at early disease detection. AD is characterized by brain atrophy due to neuronal and synaptic loss, extracellular amyloid plaques composed of amyloid-beta peptide (Aβ), and neurofibrillary tangles of hyperphosphorylated tau protein. The visual system and central nervous system share many functional components. Thus, it is plausible that damage induced by Aβ, tau, and neuroinflammation may be observed in visual components such as the retina, even at an early disease stage. This underscores the importance of implementing ophthalmological examinations, less invasive and expensive than other biomarkers, as useful measures to assess disease progression and severity in individuals with or at risk of AD. Here, we review functional and morphological changes of the retina and visual pathway in AD from pathophysiological and clinical perspectives.
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Affiliation(s)
| | - Mauricio O. Nava-Mesa
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Rodrigo E. González-Reyes
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - Carlos Tellez-Conti
- Escuela Superior de Oftalmología-Instituto Barraquer de América, Bogotá, Colombia
| | - Alejandra de-la-Torre
- Grupo de Investigación en Neurociencias (NeURos), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
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Oishi Y, Imamura T, Shimomura T, Suzuki K. Visual texture agnosia in dementia with Lewy bodies and Alzheimer's disease. Cortex 2018; 103:277-290. [DOI: 10.1016/j.cortex.2018.03.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/10/2017] [Accepted: 03/19/2018] [Indexed: 01/16/2023]
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Affiliation(s)
| | - Charles Maxner
- Departments of Ophthalmology and Medicine (Neurology), Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia, Canada
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Abstract
This chapter describes the visual problems likely to be encountered in Parkinson's disease (PD) and whether such signs are useful in differentiating the parkinsonian syndromes. Visual dysfunction in PD may involve visual acuity, contrast sensitivity, color discrimination, pupil reactivity, saccadic and pursuit eye movements, motion perception, visual fields, and visual processing speeds. In addition, disturbance of visuospatial orientation, facial recognition problems, rapid eye movement (REM) sleep behavior disorder, and chronic visual hallucinations may be present. Problems affecting pupil reactivity, stereopsis, pursuit eye movement, and visuomotor adaptation, when accompanied by REM sleep behavior disorder, could be early features of PD. Dementia associated with PD is associated with enhanced eye movement problems, visuospatial deficits, and visual hallucinations. Visual dysfunction may be a useful diagnostic feature in differentiating PD from other parkinsonian symptoms, visual hallucinations, visuospatial dysfunction, and variation in saccadic eye movement problems being particularly useful discriminating features.
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Abstract
As part of a broad evaluation of dementia that includes a medical and neurological examination, neuropsychological assessment provides standardized ways to understand the nature and extent of cognitive deficits, and is a powerful adjunct in establishing a diagnosis. Also, neuropsychological assessment is a quantitative measure of disease progression and an indicator of the efficacy of interventions, and consequently, directly hinges on crucial issues of treatment and behavior management. Administering tests to elderly demented patients requires special skills from an examiner Attention must be paid to the needs of elderly people as well as to those people with an insidious, emotionally charged illness. This paper proposes some guidelines for testing the demented person in ways that clarify interpretation of performance.
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Cai S, Chong T, Zhang Y, Li J, von Deneen KM, Ren J, Dong M, Huang L. Altered Functional Connectivity of Fusiform Gyrus in Subjects with Amnestic Mild Cognitive Impairment: A Resting-State fMRI Study. Front Hum Neurosci 2015; 9:471. [PMID: 26379534 PMCID: PMC4550786 DOI: 10.3389/fnhum.2015.00471] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/12/2015] [Indexed: 11/30/2022] Open
Abstract
Visual cognition such as face recognition requests a high degree of functional integration between distributed brain areas of a network. It has been reported that the fusiform gyrus (FG) is an important brain area involved in facial cognition; altered connectivity of FG to some other regions may lead to a deficit in visual cognition especially face recognition. However, whether functional connectivity between the FG and other brain areas changes remains unclear in the resting state in amnestic mild cognitive impairment (aMCI) subjects. Here, we employed a resting-state functional MRI (fMRI) to examine alterations in functional connectivity of left/right FG comparing aMCI patients with age-matched control subjects. Forty-eight aMCI and 38 control subjects from the Alzheimer’s disease Neuroimaging Initiative were analyzed. We concentrated on the correlation between low frequency fMRI time courses in the FG and those in all other brain regions. Relative to the control group, we found some discrepant regions in the aMCI group which presented increased or decreased connectivity with the left/right FG including the left precuneus, left lingual gyrus, right thalamus, supramarginal gyrus, left supplementary motor area, left inferior temporal gyrus, and left parahippocampus. More importantly, we also obtained that both left and right FG have increased functional connections with the left middle occipital gyrus (MOG) and right anterior cingulate gyrus (ACC) in aMCI patients. That was not a coincidence and might imply that the MOG and ACC also play a critical role in visual cognition, especially face recognition. These findings in a large part supported our hypothesis and provided a new insight in understanding the important subtype of MCI.
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Affiliation(s)
- Suping Cai
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Tao Chong
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Yun Zhang
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Jun Li
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Karen M von Deneen
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Junchan Ren
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Minghao Dong
- School of Life Science and Technology, Xidian University , Xi'an , China
| | - Liyu Huang
- School of Life Science and Technology, Xidian University , Xi'an , China
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12
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Armstrong R, Kergoat H. Oculo-visual changes and clinical considerations affecting older patients with dementia. Ophthalmic Physiol Opt 2015; 35:352-76. [DOI: 10.1111/opo.12220] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 05/19/2015] [Indexed: 12/18/2022]
Affiliation(s)
| | - Hélène Kergoat
- École d'optométrie; Université de Montréal; Montreal Canada
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13
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Abstract
This review describes the oculo-visual problems likely to be encountered in Parkinson's disease (PD) with special reference to three questions: (1) are there visual symptoms characteristic of the prodromal phase of PD, (2) is PD dementia associated with specific visual changes, and (3) can visual symptoms help in the differential diagnosis of the parkinsonian syndromes, viz. PD, progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and corticobasal degeneration (CBD)? Oculo-visual dysfunction in PD can involve visual acuity, dynamic contrast sensitivity, colour discrimination, pupil reactivity, eye movement, motion perception, and visual processing speeds. In addition, disturbance of visuo-spatial orientation, facial recognition problems, and chronic visual hallucinations may be present. Prodromal features of PD may include autonomic system dysfunction potentially affecting pupil reactivity, abnormal colour vision, abnormal stereopsis associated with postural instability, defects in smooth pursuit eye movements, and deficits in visuo-motor adaptation, especially when accompanied by idiopathic rapid eye movement (REM) sleep behaviour disorder. PD dementia is associated with the exacerbation of many oculo-visual problems but those involving eye movements, visuo-spatial function, and visual hallucinations are most characteristic. Useful diagnostic features in differentiating the parkinsonian symptoms are the presence of visual hallucinations, visuo-spatial problems, and variation in saccadic eye movement dysfunction.
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Albers MW, Gilmore GC, Kaye J, Murphy C, Wingfield A, Bennett DA, Boxer AL, Buchman AS, Cruickshanks KJ, Devanand DP, Duffy CJ, Gall CM, Gates GA, Granholm AC, Hensch T, Holtzer R, Hyman BT, Lin FR, McKee AC, Morris JC, Petersen RC, Silbert LC, Struble RG, Trojanowski JQ, Verghese J, Wilson DA, Xu S, Zhang LI. At the interface of sensory and motor dysfunctions and Alzheimer's disease. Alzheimers Dement 2015; 11:70-98. [PMID: 25022540 DOI: 10.1016/j.jalz.2014.04.514] [Citation(s) in RCA: 357] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/13/2014] [Accepted: 04/09/2014] [Indexed: 11/21/2022]
Abstract
Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses.
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15
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Armstrong RA. Visual signs and symptoms of multiple system atrophy. Clin Exp Optom 2014; 97:483-91. [PMID: 25256122 DOI: 10.1111/cxo.12206] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/24/2014] [Accepted: 06/05/2014] [Indexed: 11/26/2022] Open
Abstract
Multiple system atrophy (MSA) is a rare movement disorder and a member of the 'parkinsonian syndromes', which also include Parkinson's disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB) and corticobasal degeneration (CBD). Multiple system atrophy is a complex syndrome, in which patients exhibit a variety of signs and symptoms, including parkinsonism, ataxia and autonomic dysfunction. It can be difficult to separate MSA from the other parkinsonian syndromes but if ocular signs and symptoms are present, they may aid differential diagnosis. Typical ocular features of MSA include blepharospasm, excessive square-wave jerks, mild to moderate hypometria of saccades, impaired vestibular-ocular reflex (VOR), nystagmus and impaired event-related evoked potentials. Less typical features include slowing of saccadic eye movements, the presence of vertical gaze palsy, visual hallucinations and an impaired electroretinogram (ERG). Aspects of primary vision such as visual acuity, colour vision or visual fields are usually unaffected. Management of the disease to deal with problems of walking, movement, daily tasks and speech problems is important in MSA. Optometrists can work in collaboration with the patient and health-care providers to identify and manage the patient's visual deficits. A more specific role for the optometrist is to correct vision to prevent falls and to monitor the anterior eye to prevent dry eye and control blepharospasm.
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16
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Tzekov R, Mullan M. Vision function abnormalities in Alzheimer disease. Surv Ophthalmol 2014; 59:414-33. [DOI: 10.1016/j.survophthal.2013.10.002] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 09/28/2013] [Accepted: 10/01/2013] [Indexed: 12/16/2022]
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17
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Petrus E, Lee HK. BACE1 is necessary for experience-dependent homeostatic synaptic plasticity in visual cortex. Neural Plast 2014; 2014:128631. [PMID: 24963413 DOI: 10.1155/2014/128631] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/22/2014] [Indexed: 01/18/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of age-related dementia, which is thought to result from overproduction and/or reduced clearance of amyloid-beta (Aβ) peptides. Studies over the past few decades suggest that Aβ is produced in an activity-dependent manner and has physiological relevance to normal brain functions. Similarly, physiological functions for β- and γ-secretases, the two key enzymes that produce Aβ by sequentially processing the amyloid precursor protein (APP), have been discovered over recent years. In particular, activity-dependent production of Aβ has been suggested to play a role in homeostatic regulation of excitatory synaptic function. There is accumulating evidence that activity-dependent immediate early gene Arc is an activity “sensor,” which acts upstream of Aβ production and triggers AMPA receptor endocytosis to homeostatically downregulate the strength of excitatory synaptic transmission. We previously reported that Arc is critical for sensory experience-dependent homeostatic reduction of excitatory synaptic transmission in the superficial layers of visual cortex. Here we demonstrate that mice lacking the major neuronal β-secretase, BACE1, exhibit a similar phenotype: stronger basal excitatory synaptic transmission and failure to adapt to changes in visual experience. Our results indicate that BACE1 plays an essential role in sensory experience-dependent homeostatic synaptic plasticity in the neocortex.
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Viskontas IV, Boxer AL, Fesenko J, Matlin A, Heuer HW, Mirsky J, Miller BL. Visual search patterns in semantic dementia show paradoxical facilitation of binding processes. Neuropsychologia 2011; 49:468-78. [PMID: 21215762 DOI: 10.1016/j.neuropsychologia.2010.12.039] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 11/24/2010] [Accepted: 12/23/2010] [Indexed: 11/19/2022]
Abstract
While patients with Alzheimer's disease (AD) show deficits in attention, manifested by inefficient performance on visual search, new visual talents can emerge in patients with frontotemporal lobar degeneration (FTLD), suggesting that, at least in some of the patients, visual attention is spared, if not enhanced. To investigate the underlying mechanisms for visual talent in FTLD (behavioral variant FTD [bvFTD] and semantic dementia [SD]) patients, we measured performance on a visual search paradigm that includes both feature and conjunction search, while simultaneously monitoring saccadic eye movements. AD patients were impaired relative to healthy controls (NC) and FTLD patients on both feature and conjunction search. BvFTD patients showed less accurate performance only on the conjunction search task, but slower response times than NC on all three tasks. In contrast, SD patients were as accurate as controls and had faster response times when faced with the largest number of distracters in the conjunction search task. Measurement of saccades during visual search showed that AD patients explored more of the image, whereas SD patients explored less of the image before making a decision as to whether the target was present. Performance on the conjunction search task positively correlated with gray matter volume in the superior parietal lobe, precuneus, middle frontal gyrus and superior temporal gyrus. These data suggest that despite the presence of extensive temporal lobe degeneration, visual talent in SD may be facilitated by more efficient visual search under distracting conditions due to enhanced function in the dorsal frontoparietal attention network.
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Affiliation(s)
- Indre V Viskontas
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, 350 Parnassus Ave., Ste. 905, San Francisco, CA 94143, USA.
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20
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Abstract
The optic disc represents the anterior end of the optic nerve, the most forward extension of the central nervous system (CNS). The optic disc gives a rare glimpse into the CNS. Hence, diseases of the CNS are often manifested on fundus examination. Abnormalities of the optic disc may reflect eye disease (such as glaucoma), problems in development (as in various syndromes), or CNS disease (such as increased intracranial pressure). Each optic nerve is composed of about 1.2 million axons deriving from the retinal ganglion cells of one eye. Optic atrophy is a morphological sequela reflecting the loss of many or all of these axons. Myriad diseases such as hereditary, metabolic, tumor, and increased intracranial pressure can lead to optic atrophy. Some diseases, such as optic disc drusen, intracranial masses, orbital tumors, ischemic optic neuropathies, inflammations, and infiltrations, can produce optic disc edema before leading to optic atrophy. A number of new imaging modalities, such as optical coherence tomography (OCT), quantitate the thickness of the peripapillary retinal nerve fiber layer as an indirect measure of axonal loss or swelling. OCT can therefore be used to quantitate pathology or the response to therapy in various generalized CNS conditions, such as multiple sclerosis.
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Affiliation(s)
- Alfredo A Sadun
- Departments of Ophthalmology and Neurosurgery, Doheny Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA.
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21
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Abstract
Acquired cataract and cognitive impairment are both common age-related problems, and ophthalmologists are increasingly likely to encounter patients who have both. Patients with dementia types who display early visuoperceptual impairment may present first to ophthalmology services. When these patients have coexisting cataract, it may be difficult to distinguish visual complaints due to cataract from those due to dementia. The interaction between visual impairment due to cataract and neurodegenerative disorders affecting the central visual pathways, is not fully understood. Visual impairment due to cataract may stress impaired attentional mechanisms and cataract extraction may improve cognitive performance in some patients with early cognitive impairment; however, the benefits of cataract surgery in established dementia are less clear. In this study, the literature on this subject was reviewed and the implications for practice were considered.
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Affiliation(s)
- J M Jefferis
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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22
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Gadani S, Truwit C, McKinney AM. Recent advances and future directions in ophthalmologic neuroimaging. Expert Review of Ophthalmology 2009. [DOI: 10.1586/eop.09.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Meilandt WJ, Yu GQ, Chin J, Roberson ED, Palop JJ, Wu T, Scearce-Levie K, Mucke L. Enkephalin elevations contribute to neuronal and behavioral impairments in a transgenic mouse model of Alzheimer's disease. J Neurosci 2008; 28:5007-17. [PMID: 18463254 DOI: 10.1523/JNEUROSCI.0590-08.2008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The enkephalin signaling pathway regulates various neural functions and can be altered by neurodegenerative disorders. In Alzheimer's disease (AD), elevated enkephalin levels may reflect compensatory processes or contribute to cognitive impairments. To differentiate between these possibilities, we studied transgenic mice that express human amyloid precursor protein (hAPP) and amyloid-beta (Abeta) peptides in neurons and exhibit key aspects of AD. Met-enkephalin levels in neuronal projections from the entorhinal cortex and dentate gyrus (brain regions important for memory that are affected in early stages of AD) were increased in hAPP mice, as were preproenkephalin mRNA levels. Genetic manipulations that exacerbate or prevent excitotoxicity also exacerbated or prevented the enkephalin alterations. In human AD brains, enkephalin levels in the dentate gyrus were also increased. In hAPP mice, enkephalin elevations correlated with the extent of Abeta-dependent neuronal and behavioral alterations, and memory deficits were reduced by irreversible blockade of mu-opioid receptors with the antagonist beta-funaltrexamine. We conclude that enkephalin elevations may contribute to cognitive impairments in hAPP mice and possibly in humans with AD. The therapeutic potential of reducing enkephalin production or signaling merits further exploration.
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Salmon E, Kerrouche N, Perani D, Lekeu F, Holthoff V, Beuthien-Baumann B, Sorbi S, Lemaire C, Collette F, Herholz K. On the multivariate nature of brain metabolic impairment in Alzheimer's disease. Neurobiol Aging 2007; 30:186-97. [PMID: 17651869 DOI: 10.1016/j.neurobiolaging.2007.06.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2006] [Revised: 06/10/2007] [Accepted: 06/18/2007] [Indexed: 01/18/2023]
Abstract
We used principal component analysis to decompose functional images of patients with AD in orthogonal ensembles of brain regions with maximal metabolic covariance. Three principal components explained 38% of the total variance in a large sample of FDG-PET images obtained in 225 AD patients. One functional ensemble (PC2) included limbic structures from Papez's circuit (medial temporal regions, posterior and anterior cingulate cortex, thalamus); its disruption in AD patients was related to episodic memory impairment. Another principal component (PC1) illustrated major metabolic variance in posterior cerebral cortices, and patients' scores were correlated to instrumental functions (language and visuospatial abilities). PC3 comprised frontal, parietal, temporal and posteromedial (posterior cingulate and precuneus) cortices, and patients' scores were related to executive dysfunction and global cognitive impairment. The three main metabolic covariance networks converged in the posterior cingulate area that showed complex relationships with medial temporal structures within each PC. Individual AD scores were distributed as a continuum along PC axes: an individual combination of scores would determine specific clinical symptoms in each patient.
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Affiliation(s)
- Eric Salmon
- Cyclotron Research Center, University of Liège, B30 Sart Tilman, 4000 Liège, Belgium.
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25
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Leocani L, Comi E, Annovazzi P, Rovaris M, Rossi P, Cursi M, Comola M, Martinelli V, Comi G. Impaired short-term motor learning in multiple sclerosis: evidence from virtual reality. Neurorehabil Neural Repair 2007; 21:273-8. [PMID: 17351084 DOI: 10.1177/1545968306294913] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Virtual reality (VR) has been proposed as a potentially useful tool for motor assessment and rehabilitation. The objective of this study was to investigate the usefulness of VR in the assessment of short-term motor learning in multiple sclerosis (MS). METHODS Twelve right-handed MS patients and 12 control individuals performed a motor-tracking task with their right upper limb, following the trajectory of an object projected on a screen along with online visual feedback on hand position from a sensor on the index finger. A pretraining test (3 trials), a training phase (12 trials), and a posttraining test (3 trials) were administered. Distances between performed and required trajectory were computed. RESULTS Both groups performed worse in depth planes compared to the frontal (x,z) plane (P < .006). MS patients performed worse than control individuals in the frontal plane at both evaluations (P < .015), whereas they had lower percent posttraining improvement in the depth planes only (P = .03). CONCLUSIONS The authors' VR system detected impaired motor learning in MS patients, especially for task features requiring a complex integration of sensory information (movement in the depth planes). These findings stress the need for careful customization of rehabilitation strategies, which must take into account the patients' motor, sensory, and cognitive limitations.
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Affiliation(s)
- Letizia Leocani
- Department of Neurology, Clinical Neurophysiology and Neurorehabilitation, University Vita-Salute, Scientific Institute Hospital San Raffaele, Milan, Italy.
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Abstract
Posterior cortical atrophy is a striking clinical syndrome in which a dementing illness begins with visual symptoms. Initially, the problem may seem to be loss of elementary vision, but over time the patient develops features of visual agnosia, topographical difficulty, optic ataxia, simultanagnosia, ocular apraxia (Balint's syndrome), alexia, acalculia, right-left confusion, and agraphia (Gerstmann's syndrome), and later a more generalized dementia. Occasional patients have visual hallucinations and signs of Parkinson's disease or Lewy body dementia. A number of different neuropathologic disorders are associated with posterior cortical atrophy.
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Affiliation(s)
- Howard S Kirshner
- Department of Neurology, Vanderbilt University School of Medicine, 2311 Pierce Avenue, Nashville, TN 37232-3375, USA.
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von Gunten A, Bouras C, Kövari E, Giannakopoulos P, Hof PR. Neural substrates of cognitive and behavioral deficits in atypical Alzheimer's disease. ACTA ACUST UNITED AC 2006; 51:176-211. [PMID: 16413610 DOI: 10.1016/j.brainresrev.2005.11.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 11/04/2005] [Accepted: 11/11/2005] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by a progressive cognitive decline that typically affects first memory and later executive functions, language, and visuospatial skills. This sequence of cognitive deterioration is thought to reflect the progressive invasion of the cerebral cortex by the two major pathological hallmarks of AD, neurofibrillary tangles (NFT) and senile plaques (SP), as well as degree of neuronal and synaptic loss. In atypical AD, prominent and early deficits are found in language, motor abilities, frontal and executive capacities, or visuospatial skills. These atypical clinical features are associated with an unusual pattern of NFT or SP formation that predominantly involves cortical areas usually spared in the course of the degenerative process. In an attempt to classify this highly heterogeneous subgroup, the present article provides an overview of clinicopathological analyses in patients with atypical progression of AD symptomatology with special reference to the relationship between specific cognitive and behavioral deficits and hierarchical patterns of AD lesion distribution within the cerebral cortex. On the basis of these representative examples of a cortical circuit-based approach to explore the mechanisms giving rise to AD neuropsychological expression, we also critically discuss the possibility to develop a matrix linking clinical presentations to degeneration of forward and backward long corticocortical pathways in this disorder.
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Affiliation(s)
- Armin von Gunten
- Division of Old Age Psychiatry, Department of Psychiatry-CHUV, Prilly-Lausanne, Switzerland.
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28
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Abstract
PURPOSE Stereopsis in normal subjects aged between 7 and 76 years was compared to examine changes in stereopsis with age. METHODS Eighty subjects with no ocular disease were divided into 8 groups by age. Near stereopsis was evaluated with the TNO, Titmus, and Randot tests; distance stereopsis with the Mentor B-VAT II video acuity tester. RESULTS The results of all 4 tests showed decreased stereopsis with increasing age (p<0.05). Compared to the stereoacuity of 7 to 10-year-old group, both the TNO and distance stereopsis test results were significantly decreased for the 6th, 7th, and 8th decade groups, while both the Titmus and Randot test results were significantly decreased for the 8th decade group (p<0.05). CONCLUSIONS Overall, both near and distance stereopsis decreased with increasing age. Thus, decreased stereopsis should be taken into account when performing the stereopsis test.
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Affiliation(s)
- Se-Youp Lee
- Department of Ophthalmology, Keimyung University School of Medicine, Dongsan Medical Center, Daegu, Korea.
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29
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Polidori C, Zeng YC, Zaccheo D, Amenta F. Age-related changes in the visual cortex: a review. Arch Gerontol Geriatr 2005; 17:145-64. [PMID: 15374315 DOI: 10.1016/0167-4943(93)90047-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/1993] [Revised: 09/16/1993] [Accepted: 09/17/1993] [Indexed: 11/26/2022]
Abstract
The main age related changes in visual cortex are reviewed. The visual cortex (occipital cortex, areas 17-19) undergoes a variety of anatomical, biochemical and functional changes with aging. From a morphological point of view the visual cortex loses nerve cells mainly in the last period of life. From a biochemical point of view cholinergic, serotonergic, and GABAergic neurotransmissions seem to be the most remarkably affected. In terms of functional correlates, a decline of several activities of the visual cortex has been documented in the elderly. Due to the importance of visual cortex in the realization of visual function, the influence of aging on this cerebrocortical area requires a more detailed analysis.
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Affiliation(s)
- C Polidori
- Sezione di Anatomia Umana, Istituto di Farmacologia, Università di Camerino, Via Scalzino 5, 62032 Camerino, Italy
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30
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Abstract
The past three decades have seen an accumulation of reports of neurodegenerative disease with disruption to visual processing. Disorders of both visuospatial processing and visual recognition have been described, though the former predominate. But the conundrum of posterior cortical atrophy (PCA) is that while the clinical presentation is relatively homogeneous, the nosological status remains something of a puzzle. Many cases coming to pathology have had Alzheimer's Disease (AD) but in a different distribution from that seen in typical AD (tAD). Patients with non-specific subcortical gliosis and, more occasionally, Creutzfeldt Jacob disease, neither of which have an obvious affinity with PCA, have also been described. On the other hand, no case of PCA has been reported with the pathology of either corticobasal degeneration or dementia with Lewy Bodies, both of which do commonly present with prominent parietal symptomatology.
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Affiliation(s)
- Diana Caine
- School of Psychology, University of Sydney, NSW, Australia.
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31
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Lee AG, Martin CO. Neuro-ophthalmic findings in the visual variant of Alzheimer's disease. Ophthalmology 2004; 111:376-80; discussion 380-1. [PMID: 15019393 DOI: 10.1016/s0161-6420(03)00732-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2002] [Accepted: 03/21/2003] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To describe the clinical features of a visual variant Alzheimer's disease, a disorder that might be seen by the ophthalmologist with visual symptoms and signs. DESIGN Retrospective case series. PARTICIPANTS Eight patients with Alzheimer's disease presenting with predominantly visual complaints. METHODS A retrospective review of patients at a tertiary care academic center seen by the authors from 1999 to 2001 with Alzheimer's disease and predominantly visual complaints. RESULTS Eight patients with the visual variant of Alzheimer's disease were reviewed. All had seen eye care providers before referral to the neuro-ophthalmology clinic for visual complaints but without a diagnosis. Four patients had homonymous visual field loss, and two had presumed cortical visual impairment. Neuroimaging showed either normal brain (1 patient) or atrophy of the parietal or occipital areas but no structural lesions (7 patients). Fluoro-18-deoxyglucose positron emission tomography scans were performed in five of the cases, and all showed hypoperfusion in the parietooccipital areas. Neuropsychologic testing revealed visuospatial deficits in all 5 patients tested. CONCLUSIONS Visual symptoms might be the presenting (or rarely only) manifestation of Alzheimer's disease. Clinicians should be aware of the visual variant of Alzheimer's disease. Neuropsychological testing and magnetic resonance imaging (MRI) provide supporting evidence for the diagnosis. Positron emission tomography scans might be helpful in selected cases, especially those with a normal MRI.
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Affiliation(s)
- Andrew G Lee
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA.
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32
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Abstract
A case of a 50-year-old, right-handed female, mono-lingual native Spanish-speaker with a university-level education and cognitive changes is reported. Over approximately 2 years, she presented with a progressive deterioration of writing abilities associated with acalculia and anomia. An MRI disclosed a left parietal temporal atrophy. Two years later, further significant cognitive decline consistent with a dementia of the Alzheimer's type was observed. Amnesia, executive dysfunction, and ideomotor apraxia were found. Writing was severely impaired, and some difficulties in reading were observed. Copying abilities, however, were relatively well preserved, and the patient could drive and go to different city locations without significant spatial orientation difficulties. A second MRI approximately 2 years later showed that brain atrophy had progressed significantly. Spontaneous writing and writing to dictation were impossible. The ability to read words was preserved, but the ability to read pseudowords was lost. Changes in calligraphy were noted. This case clearly illustrates the progression of focal cognitive defects over time and the spread of abnormalities to other domains.
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Affiliation(s)
- Alfredo Ardila
- Communication Sciences and Disorders, Florida International University, Miami, Florida 33182, USA.
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33
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Abstract
The four most common sight-threatening conditions in older adults in North America are cataract, ARM, glaucoma, and diabetic retinopathy. Even in their moderate stages, these conditions cause visual sensory impairments and reductions in health-related quality of life, including difficulties in daily tasks and psychosocial problems. Many older adults are free from these conditions, yet still experience a variety of visual perceptual problems resulting from aging-related changes in the optics of the eye and degeneration of the visual neural pathways. These problems consist of impairments in visual acuity, contrast sensitivity, color discrimination, temporal sensitivity, motion perception, peripheral visual field sensitivity, and visual processing speed. PD causes a progressive loss of dopaminergic cells predominantly in the retina and possibly in other areas of the visual system. This retinal dopamine deficiency produces selective spatial-temporal abnormalities in retinal ganglion cell function, probably arising from altered receptive field organization in the PD retina. The cortical degeneration characteristics of AD, including neurofibrillary tangles and neuritic plaques, also are present in the visual cortical areas, especially in the visual association areas. The most prominent electrophysiologic change in AD is a delay in the P2 component of the flash VEP. Deficits in higher-order visual abilities typically are compromised in AD, including problems with visual attention, perceiving structure from motion, visual memory, visual learning, reading, and object and face perception. There have been reports of a visual variant of AD in which these types of visual problems are the initial and most prominent signs of the disease. Visual sensory impairments (e.g., contrast sensitivity or achromatopsia) also have been reported but are believed more reflective of cortical disturbances than of AD-associated optic neuropathy.
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Affiliation(s)
- Gregory R Jackson
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, 700 South 18th Street, Suite 609, Birmingham, AL 35294-0009, USA.
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Nestor PJ, Caine D, Fryer TD, Clarke J, Hodges JR. The topography of metabolic deficits in posterior cortical atrophy (the visual variant of Alzheimer's disease) with FDG-PET. J Neurol Neurosurg Psychiatry 2003; 74:1521-9. [PMID: 14617709 PMCID: PMC1738241 DOI: 10.1136/jnnp.74.11.1521] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The term "posterior cortical atrophy" (PCA) refers to a clinical syndrome in which higher order visual processing is disrupted owing to a neurodegenerative disorder, the most commonly associated pathology being Alzheimer's disease. OBJECTIVE To map the topography of hypometabolic brain regions in a group of subjects with PCA who had undergone detailed neuropsychological characterisation. METHODS Resting cerebral metabolism was measured with ((18)F)fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with PCA (n = 6), typical Alzheimer's disease (n = 10), and healthy controls (n = 10). The data were analysed using statistical parametric mapping (SPM99) and region of interest techniques. RESULTS Clinically, the PCA subjects showed predominant visuospatial deficits (including features of Balint's syndrome) consistent with damage to the dorsal stream of visual processing. Compared with the controls, the PCA group showed marked glucose hypometabolism primarily affecting the posterior cerebral hemispheres (right worse than left). In addition, the PCA group showed two symmetrical areas of hypometabolism in the region of the frontal eye fields. Compared with typical Alzheimer's disease, the PCA group had selective hypometabolism in the occipito-parietal region (right much worse than left). CONCLUSIONS The neuropsychological and PET findings are consistent with damage predominantly to the dorsal stream of visual processing. Frontal eye field hypometabolism secondary to loss of input from the occipito-parietal region may be the mechanism for the ocular apraxia seen in Balint's syndrome.
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Affiliation(s)
- P J Nestor
- University of Cambridge, Neurology Unit, Addenbrooke's Hospital, Cambridge, UK
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Newberg A, Cotter A, Udeshi M, Brinkman F, Glosser G, Alavi A, Clark C. Brain metabolism in the cerebellum and visual cortex correlates with neuropsychological testing in patients with Alzheimer's disease. Nucl Med Commun 2003; 24:785-90. [PMID: 12813197 DOI: 10.1097/01.mnm.0000080249.50447.99] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study was designed to measure glucose metabolic deficits in areas not typically recognized as abnormal on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans in patients with Alzheimer's disease (AD), and to correlate such findings with subtle neuropsychological impairment. FDG-PET scans on 38 AD patients with no clinical evidence of visual, spatial or motor deficits were acquired on the PET HEAD scanner 40 min following the intravenous administration of 115 microCi.kg-1 of FDG. All FDG-PET scans were analysed blindly using a region of interest (ROI) template with regions for the primary visual cortex (PVC), secondary visual cortex (SVC) and cerebellum. Counts from the ROIs of these regions were normalized to whole brain activity and the results were compared with psychometric and neuropsychological measures. A number of significant correlations were found between these structures and various neuropsychological measures (P<0.05). Specifically, there were significant correlations between clock drawing and the cerebellum activity; memory and activity in the PVC, SVC and cerebellum; social score and activity in the PVC and left cerebellum; judgement and activity in the right SVC and right PVC; and the overall Mini-Mental State Examination and activity in the PVC, SVC and cerebellum. The results of this study suggest that metabolism in areas not typically recognized as abnormal on FDG-PET scans in AD, such as the PVC, SVC and cerebellum, is correlated with deficits in neuropsychological function. This may have important clinical and pathophysiological implications in the study of AD and other illnesses of dementia.
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Affiliation(s)
- A Newberg
- Department of Radiology and Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
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Abstract
Dementia with Lewy bodies (DLB) is recognized as one of the most common forms of neurodegenerative dementia. Neuroimaging contributes to a better understanding of the pathophysiology of DLB by examining alterations in brain metabolism, neurochemisty, and morphology in living patients. Neuroimaging can provide objective and quantifiable antemortem markers for the presence of and the progression of DLB and permits differentiation from other dementias. This article reviews current neuroimaging findings in DLB with particular attention to occipital hypometabolism, dopaminergic and cholinergic deficits, and medial temporal lobe atrophy as measured by positron emission tomography, single-photon emission computed tomography, and magnetic resonance imaging.
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Affiliation(s)
- Satoshi Minoshima
- Departments of Radiology, University of Washington School of Medicine, Seattle, Washington 98195-6004, USA
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Abstract
PURPOSE To determine whether subjects with early Alzheimer Disease (AD) or Mild Cognitive Impairment (MCI) would demonstrate significant abnormalities on tests of word reading threshold (WRT), spatial contrast sensitivity (SCS), and color discrimination (CD). METHODS Prospective cohort study of 13 AD subjects, 13 subjects with Mild Cognitive Impairment (MCI), and 12 healthy elderly normal controls (ENC). CD was determined using the Farnsworth D-15 method. SCS was tested using a Vistech photographic chart. For WRT determination, pattern-masked words were presented successively at increasing target durations. The threshold was determined as the target duration at which 50% of the words were read. RESULTS The mean number of errors in Color Discrimination and Spatial Contrast Sensitivity did not differ significantly among the three groups. WRT was significantly longer in the AD group (122.6 +/- 70.8 ms) in comparison with ENC group (53.8 +/- 15.9 ms) (p < 0.001). A WRT threshold limit of 85 msec correctly classified 11/12 ENC subjects and 10/13 AD subjects. Four of the 13 MCI subjects also exceeded this threshold and all four progressed to AD within 2 year follow-up. CONCLUSION Word Reading Threshold determination discriminates mild AD subjects from ENC, and correlates with severity of cognitive impairment. It may have diagnostic and prognostic utility in early AD and MCI subjects.
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Affiliation(s)
- Fadi Massoud
- Division of Geriatric Medicine, Centre Hospitalier de l'Université de Montréal, University of Montreal, Montreal, Québec, Canada
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Nagaratnam N, Nagaratnam K, Jolley D, Ting A. Dementia following posterior cortical atrophy—a descriptive clinical case report. Arch Gerontol Geriatr 2001; 33:179-90. [PMID: 15374033 DOI: 10.1016/s0167-4943(01)00179-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2000] [Revised: 06/04/2001] [Accepted: 06/06/2001] [Indexed: 10/18/2022]
Abstract
Whether posterior cortical atrophy is a distinct entity or a variant of one of the other degenerative processes continues to be debated. We describe five patients four of whom had bilateral changes of posterior cortical atrophy on the CT scan. These four had a cluster of symptoms consistent with parieto-occiptial dysfunction together with a spectrum of dementia. The fifth patient with unilateral changes had optic ataxia, apraxia of gait and dementia. Three of the five patients were heavy drinkers of alcohol but any direct causal link between alcohol and posterior cortical atrophy is tenuous but alcohol could be a consideration in lowering the threshold for dementia in conjunction with other determinants. The study revealed there is little or no difficulty in recognizing posterior cortical atrophy in the early stages and the end stages are sufficiently uniform to reduce the diagnostic uncertainty.
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Affiliation(s)
- N Nagaratnam
- Blacktown-Mount Druitt Health, Blacktown, NSW 2148, Australia
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40
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Abstract
Alzheimer's disease is the most prevalent dementia. Definitive diagnosis is made only at autopsy, although "probable" diagnoses are made using clinical criteria. Patients with Alzheimer's disease demonstrate severe deficits in memory with cortical features of language difficulty and visuomotor spatial deficits. They also may present with psychotic symptoms of delusions and hallucinations, and personality and behavioral changes. Advancing age, genetics, and environmental risk factors are important in the development of Alzheimer's disease. Visual abnormalities have been described in Alzheimer's disease and may be related to the development of visual hallucinations. Although palliative treatments exist for the cognitive loss and behavioral symptoms, future treatments will focus on both delay of onset and slowing of progression of the disease. Continued research is needed to further understand this devastating disorder, which may in turn lead to more successful treatments.
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Affiliation(s)
- S Holroyd
- University of Virginia Health Sciences Center, Department of Psychiatric Medicine, Charlottesville, VA 22908, USA
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41
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Abstract
Visual impairments that are not related to optical changes are not uncommon during aging, and a number of psychophysical investigations have documented deficits in motion detection as well as in spatiotemporal contrast sensitivity in elderly people. However, little is known about the extent and nature of age-related changes in neural structure and how they may affect visual function in aging. To address this question, the authors analyzed the effect of aging on two well-characterized neuronal populations in the primary visual cortex (area V1) of macaque monkeys. Four young adult (ages, 7-11 years) and four aged (ages, 26-32 years) rhesus monkeys were analyzed. The animals were perfused, and their brains were prepared for immunohistochemistry with an antibody to neurofilament protein. Unbiased stereologic estimates of the total numbers of neurofilament protein-containing layer IVB cells and Meynert cells were obtained by using the optical fractionator method for the calcarine cortex and the opercular cortex separately. Stereologic estimates of the volume of these parts of area V1 also were calculated by using the Cavalieri principle. A considerable degree of interindividual variability in neuron numbers and cortical volume was observed among animals of both groups. However, there were no differences in either Meynert cell numbers or layer IVB cell numbers between the aged group and the young group. It is noteworthy that the oldest animal in the sample had the lowest numbers of Meynert cells, indicating that, despite the small size of the available sample, it is possible that some animals have a certain degree of neuronal loss in area V1 during aging. No change in the volume of area V1 was observed as a function of aging. These data suggest that the deficits that occur during aging in the visual system are not due to the loss of highly specific neocortical neuronal populations, such as those analyzed in this study. Rather, it is possible that more subtle alterations in the neurochemical characteristics or synaptic organization of the functional pathways subserving the different visual modalities are responsible for these deficits.
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Affiliation(s)
- P R Hof
- Kastor Neurobiology of Aging Laboratories and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Vogt BA, Martin A, Vrana KE, Absher JR, Vogt LJ, Hof PR. Multifocal Cortical Neurodegeneration in Alzheimer’s Disease. In: Peters A, Morrison JH, editors. Cerebral Cortex. Boston: Springer US; 1999. pp. 553-601. [DOI: 10.1007/978-1-4615-4885-0_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
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Vogt BA, Vogt LJ, Vrana KE, Gioia L, Meadows RS, Challa VR, Hof PR, Van Hoesen GW. Multivariate analysis of laminar patterns of neurodegeneration in posterior cingulate cortex in Alzheimer's disease. Exp Neurol 1998; 153:8-22. [PMID: 9743563 DOI: 10.1006/exnr.1998.6852] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Posterior cingulate cortex is the site of earliest reductions in glucose metabolism and qualitatively different laminar patterns of neurodegeneration in Alzheimer's disease (AD). This study used multivariate analyses of area 23 in 72 cases of definite AD to assess relationships between laminar patterns of neurodegeneration, neurofibrillary tangle (NFT) and senile plaque (SP) densities, age of disease onset and duration, and apolipoprotein E (ApoE) genotype. No age-related changes in neurons occurred over four decades in 17 controls and regression analysis of all AD cases showed no relationships between neuron, SP, and tau-immunoreactive NFT densities. Principal components analysis of neurons in layers III-Va and eigenvector projections showed five subgroups. The subgroups were independent because each had a full range of disease durations and qualitatively different laminar patterns in degeneration suggested disease subtypes (ST). Cases with most severe neuron losses (STSevere) had an early onset, most SP, and highest proportion of ApoE epsilon4 homozygotes. Changes in the distribution of NFT were similar over disease course in two subtypes and NFT did not account for most neurodegeneration. In STII-V with moderate neuron loss in most layers, cases with no NFT had a disease duration of 3.5 +/- 0.9 years (mean +/- SEM), those with most in layers IIIc or Va had a duration of 7.3 +/- 1 years, and those with most in layers II-IIIab had a duration of 12.1 +/- 1 years. In STSevere, cases with highest NFT densities in layers II-IIIab also were late stage. Finally, epsilon4 homozygotes were most frequent in STSevere, but four statistical tests showed that this risk is not directly involved in neurodegeneration. In conclusion, multivariate pattern recognition shows that AD is composed of independent neuropathological subtypes and NFT in area 23 do not account for most neuron losses.
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Affiliation(s)
- B A Vogt
- Cingulum NeuroSciences Institute, 101 North Chestnut Street, Winston-Salem, North Carolina 27101, USA
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46
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Abstract
Abstract Posterior cortical atrophy (PCA) is a visual-cognitive syndrome caused by Creutzfeldt-Jakob disease (CJD), Alzheimer's disease (AD), or subcortical gliosis. We report a case of posterior cortical atrophy unique in (1) comprehensive documentation of clinical, radiologic, electroencephalograph, metabolic and histopathologic findings, (2) repeated clinical and laboratory assessment, and (3) establishment of unique occipital subcortical gliosis in a patient with AD. Clinical manifestations of PCA caused by AD included visual agnosia, cortical blindness, optic apraxla, delusions, hallucinations, agitation, depression, amnestic deficit, Wernicke's aphasia, acalculia, and left/right disorientation. Posterior cortical atrophy produced by AD can be demonstrated on magnetic resonance imaging, positron emission tomography, and electroencephalography; determination of the etiology requires tissue examination. Autopsy-diagnosed cases in the literature document PCA due to CJD and AD with equal frequency.
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Affiliation(s)
- T Tom
- a Department of Neurology , Los Angeles , CA , 90095-1769 , USA
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47
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Hof PR, Vogt BA, Bouras C, Morrison JH. Atypical form of Alzheimer's disease with prominent posterior cortical atrophy: a review of lesion distribution and circuit disconnection in cortical visual pathways. Vision Res 1997; 37:3609-25. [PMID: 9425534 DOI: 10.1016/s0042-6989(96)00240-4] [Citation(s) in RCA: 170] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In recent years, the existence of visual variants of Alzheimer's disease characterized by atypical clinical presentation at onset has been increasingly recognized. In many of these cases post-mortem neuropathological assessment revealed that correlations could be established between clinical symptoms and the distribution of neurodegenerative lesions. We have analyzed a series of Alzheimer's disease patients presenting with prominent visual symptomatology as a cardinal sign of the disease. In these cases, a shift in the distribution of pathological lesions was observed such that the primary visual areas and certain visual association areas within the occipito-parieto-temporal junction and posterior cingulate cortex had very high densities of lesions, whereas the prefrontal cortex had fewer lesions than usually observed in Alzheimer's disease. Previous quantitative analyses have demonstrated that in Alzheimer's disease, primary sensory and motor cortical areas are less damaged than the multimodal association areas of the frontal and temporal lobes, as indicated by the laminar and regional distribution patterns of neurofibrillary tangles and senile plaques. The distribution of pathological lesions in the cerebral cortex of Alzheimer's disease cases with visual symptomatology revealed that specific visual association pathways were disrupted, whereas these particular connections are likely to be affected to a less severe degree in the more common form of Alzheimer's disease. These data suggest that in some cases with visual variants of Alzheimer's disease, the neurological symptomatology may be related to the loss of certain components of the cortical visual pathways, as reflected by the particular distribution of the neuropathological markers of the disease.
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Affiliation(s)
- P R Hof
- Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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48
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Abstract
This review of the literature has shown that a delayed flash P2, in the presence of a normal flash P1 and pattern-reversal P100, can distinguish groups of Alzheimer's patients from groups who are healthy, psychiatrically ill, or suffering from other types of dementia. The VER's usefulness in the individual patient remains undetermined. With today's techniques, too many patients are misclassified. False negatives may result if Alzheimer's patients with visual symptoms are a distinct subgroup. Those with a normal flash VER may have cortical dysfunction outside the visual association areas. This would most likely be in the earliest stages of the disease before the atrophy becomes widespread. It may be that a VER test would only be valid in established disease. Future research should use adequate numbers of patients who are in a single category of mild, moderate or severe, so that the applicability of a VER test in the early stages of the disease can be determined. Strict diagnostic criteria such as the NINCDS-ADRDA guidelines should be used. Patients should be drug free, or at least not taking medications with anticholinergic properties. Flash VER should be obtained using a strobe light with eyes closed, and the pattern VER using a black and white television with a large pattern and high contrast.
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Affiliation(s)
- N C Moore
- Mercer University School of Medicine, Macon, Georgia, USA
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49
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Abstract
Previous efforts aimed at attributing discrete behavioral functions to cortical cholinergic afferents have not resulted in a generally accepted hypothesis about the behavioral functions mediated by this system. Moreover, attempts to develop such a unifying hypothesis have been presumed to be unproductive considering the widespread innervation of the cortex by basal forebrain cholinergic neurons. In contrast to previous descriptions of the role of cortical acetylcholine (ACh) in specific behavioral phenomena (e.g., mediation of the behavioral effects of reward loss) or mnemonic entities (e.g., working or reference memory), cortical ACh is hypothesized to modulate the general efficacy of the cortical processing of sensory or associational information. Specifically, cortical cholinergic inputs mediate the subjects' abilities to detect and select stimuli and associations for extended processing and to allocate the appropriate processing resources to these functions. In addition to evidence from electrophysiological and behavioral studies on the role of cortical ACh in sensory information processing and attention, this hypothesis is consistent with proposed functions of the limbic and paralimbic networks in regulating the activity of the basal forebrain cholinergic neurons. Finally, while the proposed hypothesis implies that changes in activity in cortical ACh simultaneously occur throughout the cortex, the selectivity and precision of the functions of cholinergic function is due to its coordinated interactions with the activity of converging sensory or associational inputs. Finally, the dynamic, escalating consequences of alterations in the activity of cortical ACh (hypo- and hyperactivity) on cognitive functions are evaluated.
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Affiliation(s)
- M Sarter
- Department of Psychology, Ohio State University, Columbus 43210, USA.
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50
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Abstract
Abnormal depth perception contributes to visuospatial deficits in Alzheimer's disease. Disturbances in stereopsis, motion parallax, and the interpretation of static monocular depth cues may result from neuropathology in the visual cortex. We evaluated 15 patients with mild Alzheimer's disease and 15 controls matched for age, sex, and education on measures of local stereopsis (stereoscopic testing), global stereopsis (random dots), motion parallax (Howard-Dolman apparatus), and monocular depth perception by relative size, interposition, and perspective. Compared to controls, the patients were significantly impaired in over-all depth perception. This impairment was largely due to disturbances in local stereopsis and in the interpretation of depth from perspective, independent of other visuospatial functions. Patients with Alzheimer's disease have disturbed interpretation of monocular as well as binocular depth cues. This information could lead to optic interventions to improve their visual depth perception.
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Affiliation(s)
- M F Mendez
- University of California at Los Angeles, USA
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