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Wang J, Wang Y, Cai X, Xia W, Zhu J. A Review: Visuospatial Dysfunction in Patients with the Cerebral Small Vessel Disease. Neuroscience 2024; 552:47-53. [PMID: 38880241 DOI: 10.1016/j.neuroscience.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2024] [Revised: 06/06/2024] [Accepted: 06/10/2024] [Indexed: 06/18/2024]
Abstract
Cerebral small vessel disease (CSVD) impairs visuospatial function, and this is one of the most obvious areas of cognitive impairment in CSVD. So, recognizing, monitoring, and treating visuospatial dysfunction are all important to the prognosis of CSVD. This review discussed the anatomical and pathological mechanisms, clinical recognition (scales, imaging, and biomarkers), and treatment of cognitive impairment especially visuospatial dysfunction in CSVD.
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Affiliation(s)
- Jiaxing Wang
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Youmeng Wang
- Department of Neurology, Fuyang People's Hospital, Fuyang, China
| | - Xiuying Cai
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Wei Xia
- Department of Ophthalmology, The First Affiliated Hospital of Soochow University, Suzhou, China.
| | - Juehua Zhu
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, China.
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Wang Y, Li Q, Yao L, He N, Tang Y, Chen L, Long F, Chen Y, Kemp GJ, Lui S, Li F. Shared and differing functional connectivity abnormalities of the default mode network in mild cognitive impairment and Alzheimer's disease. Cereb Cortex 2024; 34:bhae094. [PMID: 38521993 DOI: 10.1093/cercor/bhae094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/25/2024] Open
Abstract
Alzheimer's disease (AD) and mild cognitive impairment (MCI) both show abnormal resting-state functional connectivity (rsFC) of default mode network (DMN), but it is unclear to what extent these abnormalities are shared. Therefore, we performed a comprehensive meta-analysis, including 31 MCI studies and 20 AD studies. MCI patients, compared to controls, showed decreased within-DMN rsFC in bilateral medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC), precuneus/posterior cingulate cortex (PCC), right temporal lobes, and left angular gyrus and increased rsFC between DMN and left inferior temporal gyrus. AD patients, compared to controls, showed decreased rsFC within DMN in bilateral mPFC/ACC and precuneus/PCC and between DMN and left inferior occipital gyrus and increased rsFC between DMN and right dorsolateral prefrontal cortex. Conjunction analysis showed shared decreased rsFC in mPFC/ACC and precuneus/PCC. Compared to MCI, AD had decreased rsFC in left precuneus/PCC and between DMN and left inferior occipital gyrus and increased rsFC in right temporal lobes. MCI and AD share a decreased within-DMN rsFC likely underpinning episodic memory deficits and neuropsychiatric symptoms, but differ in DMN rsFC alterations likely related to impairments in other cognitive domains such as language, vision, and execution. This may throw light on neuropathological mechanisms in these two stages of dementia.
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Affiliation(s)
- Yaxuan Wang
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Qian Li
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Li Yao
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Ning He
- Department of Psychiatry, West China Hospital of Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan, P.R. China
| | - Yingying Tang
- Department of Neurology, West China Hospital of Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan, P.R. China
| | - Lizhou Chen
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Fenghua Long
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Yufei Chen
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Graham J Kemp
- Institute of Life Course and Medical Sciences, University of Liverpool, 6 West Derby Street, Liverpool L7 8TX, United Kingdom
| | - Su Lui
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
| | - Fei Li
- Department of Radiology and Huaxi MR Research Center (HMRRC), Functional and Molecular lmaging Key Laboratory of Sichuan Province, West China Hospital, Sichuan University, No. 37 Guo Xue Alley, Wuhou District, Chengdu 610041, Sichuan Province, P.R. China
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Dang C, Wang Y, Li Q, Lu Y. Neuroimaging modalities in the detection of Alzheimer's disease-associated biomarkers. PSYCHORADIOLOGY 2023; 3:kkad009. [PMID: 38666112 PMCID: PMC11003434 DOI: 10.1093/psyrad/kkad009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/04/2023] [Accepted: 06/20/2023] [Indexed: 04/28/2024]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. Neuropathological changes in AD patients occur up to 10-20 years before the emergence of clinical symptoms. Specific diagnosis and appropriate intervention strategies are crucial during the phase of mild cognitive impairment (MCI) and AD. The detection of biomarkers has emerged as a promising tool for tracking the efficacy of potential therapies, making an early disease diagnosis, and prejudging treatment prognosis. Specifically, multiple neuroimaging modalities, including magnetic resonance imaging (MRI), positron emission tomography, optical imaging, and single photon emission-computed tomography, have provided a few potential biomarkers for clinical application. The MRI modalities described in this review include structural MRI, functional MRI, diffusion tensor imaging, magnetic resonance spectroscopy, and arterial spin labelling. These techniques allow the detection of presymptomatic diagnostic biomarkers in the brains of cognitively normal elderly people and might also be used to monitor AD disease progression after the onset of clinical symptoms. This review highlights potential biomarkers, merits, and demerits of different neuroimaging modalities and their clinical value in MCI and AD patients. Further studies are necessary to explore more biomarkers and overcome the limitations of multiple neuroimaging modalities for inclusion in diagnostic criteria for AD.
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Affiliation(s)
- Chun Dang
- Department of Periodical Press, West China Hospital, Sichuan University, Chengdu 610000, China
| | - Yanchao Wang
- Department of Neurology, Chifeng University of Affiliated Hospital, Chifeng 024000, China
| | - Qian Li
- Department of Neurology, the Second Affiliated Hospital of Harbin Medical University, Harbin 150081, China
| | - Yaoheng Lu
- Department of General Surgery, Chengdu Integrated Traditional Chinese Medicine and Western Medicine Hospital, Chengdu 610000, China
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Aramadaka S, Mannam R, Sankara Narayanan R, Bansal A, Yanamaladoddi VR, Sarvepalli SS, Vemula SL. Neuroimaging in Alzheimer's Disease for Early Diagnosis: A Comprehensive Review. Cureus 2023; 15:e38544. [PMID: 37273363 PMCID: PMC10239271 DOI: 10.7759/cureus.38544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2023] [Indexed: 06/06/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the elderly, affecting roughly half of those over the age of 85. We briefly discussed the risk factors, epidemiology, and treatment options for AD. The development of therapeutic therapies operating very early in the disease cascade has been spurred by the realization that the disease process begins at least a decade or more before the manifestation of symptoms. Thus, the clinical significance of early diagnosis was emphasized. Using various keywords, a literature search was carried out using PubMed and other databases. For inclusion, pertinent articles were chosen and reviewed. This article has reviewed different neuroimaging techniques that are considered advanced tools to aid in establishing a diagnosis and highlighted the advantages as well as disadvantages of those techniques. Besides, the prevalence of several in vivo biomarkers aided in discriminating affected individuals from healthy controls in the early stages of the disease. Each imaging method has its advantages and disadvantages, hence no single imaging approach can be the optimum modality for diagnosis. This article also commented on a better approach to using these techniques to increase the likelihood of an early diagnosis.
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Affiliation(s)
| | - Raam Mannam
- Research, Narayana Medical College, Nellore, IND
| | | | - Arpit Bansal
- Research, Narayana Medical College, Nellore, IND
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Meehan CE, Embury CM, Wiesman AI, Schantell M, Wolfson SL, O’Neill J, Swindells S, Johnson CM, May PE, Murman DL, Wilson TW. Convergent and divergent oscillatory aberrations during visuospatial processing in HIV-related cognitive impairment and Alzheimer's disease. Cereb Cortex 2023; 33:3181-3192. [PMID: 35855581 PMCID: PMC10016044 DOI: 10.1093/cercor/bhac268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/24/2022] [Accepted: 06/12/2022] [Indexed: 12/13/2022] Open
Abstract
Adults with HIV frequently develop a form of mild cognitive impairment known as HIV-associated neurocognitive disorder (HAND), but presumably cognitive decline in older persons with HIV could also be attributable to Alzheimer's disease (AD). However, distinguishing these two conditions in individual patients is exceedingly difficult, as the distinct neural and neuropsychological features are poorly understood and most studies to date have only investigated HAND or AD spectrum (ADS) disorders in isolation. The current study examined the neural dynamics underlying visuospatial processing using magnetoencephalography (MEG) in 31 biomarker-confirmed patients on the ADS, 26 older participants who met criteria for HAND, and 31 older cognitively normal controls. MEG data were examined in the time-frequency domain, and a data-driven approach was utilized to identify the neural dynamics underlying visuospatial processing. Both clinical groups (ADS/HAND) were significantly less accurate than controls on the task and exhibited stronger prefrontal theta oscillations compared to controls. Regarding disease-specific alterations, those with HAND exhibited stronger alpha oscillations than those on the ADS in frontoparietal and temporal cortices. These results indicate both common and unique neurophysiological alterations among those with ADS disorders and HAND in regions serving visuospatial processing and suggest the underlying neuropathological features are at least partially distinct.
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Affiliation(s)
- Chloe E Meehan
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
- Department of Psychology, University of Nebraska – Omaha, Omaha, NE 68182, USA
| | - Christine M Embury
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
| | - Alex I Wiesman
- Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Mikki Schantell
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
- College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sara L Wolfson
- Geriatrics Medicine Clinic, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Jennifer O’Neill
- Department of Internal Medicine, Division of Infectious Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Susan Swindells
- Department of Internal Medicine, Division of Infectious Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Craig M Johnson
- Department of Radiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Pamela E May
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Daniel L Murman
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Memory Disorders & Behavioral Neurology Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Tony W Wilson
- Corresponding author: Institute for Human Neuroscience, Boys Town National Research Hospital, 14090 Mother Teresa Ln., Boys Town, NE 68010, USA.
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Canário NS, Jorge LP, Santana IJ, Castelo-Branco MS. Hemispheric Patterns of Recruitment of Object Processing Regions in Early Alzheimer's Disease: A Study Along the Entire Ventral Stream. J Alzheimers Dis 2023; 91:1151-1164. [PMID: 36565110 PMCID: PMC9912740 DOI: 10.3233/jad-220055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Investigation of neural response patterns along the entire network of functionally defined object recognition ventral stream regions in Alzheimer's disease (AD) is surprisingly lacking. OBJECTIVE We aimed to investigate putative functional reorganization along a wide-ranging network of known regions in the ventral visual stream in mild AD. METHODS Overall we investigated 6 regions of interest (5 of which were not investigated before), in 19 AD patients and 19 controls, in both hemispheres along the ventral visual stream: Fusiform Face Area, Fusiform Body Area, Extrastriate Body Area, Lateral Occipital Cortex, Parahippocampal Place Area, and Visual Word Form Area, while assessing object recognition performance. RESULTS We found group differences in dprime measures for all object categories, corroborating generalized deficits in object recognition. Concerning neural responses, we found region dependent group differences respecting a priori expected Hemispheric asymmetries. Patients showed significantly decreased BOLD responses in the right hemisphere-biased Fusiform Body Area, and lower left hemisphere responses in the Visual Word Form Area (with a priori known left hemispheric bias), consistent with deficits in body shape and word/pseudoword processing deficits. This hemispheric dominance related effects were preserved when controlling for performance differences. Whole brain analysis during the recognition task showed enhanced activity in AD group of left dorsolateral prefrontal cortex, left cingulate gyrus, and in the posterior cingulate cortex- a hotspot of amyloid-β accumulation. CONCLUSION These findings demonstrate region dependent respecting hemispheric dominance patterns activation changes in independently localized selective regions in mild AD, accompanied by putative compensatory activity of frontal and cingular networks.
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Affiliation(s)
- Nádia S. Canário
- Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal,
Institute for Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal
| | - Lília P. Jorge
- Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal,
Institute for Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal
| | - Isabel J. Santana
- Department of Neurology, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal,Faculty of Medicine, University of Coimbra, Coimbra, Portugal,
Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal
| | - Miguel S. Castelo-Branco
- Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal,
Institute for Nuclear Sciences Applied to Health, University of Coimbra, Coimbra, Portugal,Faculty of Medicine, University of Coimbra, Coimbra, Portugal,Correspondence to: M. Castelo-Branco, MD, PhD, Faculdade de Medicina, Polo de Ciências da Saúde da Universidade de Coimbra, Azinhaga de Santa Comba, Celas 3000-548, Coimbra, Portugal. Tel.: +351 239488514; E-mail:
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Meehan CE, Schantell M, Wiesman AI, Wolfson SL, O’Neill J, Bares SH, Johnson CM, May PE, Murman DL, Wilson TW. Oscillatory markers of neuroHIV-related cognitive impairment and Alzheimer's disease during attentional interference processing. Aging (Albany NY) 2023; 15:524-541. [PMID: 36656738 PMCID: PMC9925679 DOI: 10.18632/aging.204496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/03/2023] [Indexed: 01/20/2023]
Abstract
People with HIV (PWH) frequently experience mild cognitive decline, which is typically attributed to HIV-associated neurocognitive disorder (HAND). However, such declines could also be a sign of early Alzheimer's disease (AD) in older PWH. Distinguishing these two pathologies in PWH is exceedingly difficult, as there is a major knowledge gap regarding their neural and neuropsychological bases. In the current study, we begin to address this knowledge gap by recording magnetoencephalography (MEG) during a flanker interference task in 31 biomarker-confirmed patients on the AD spectrum (ADS), 25 older participants with HAND, and 31 cognitively-normal controls. MEG data was examined in the time-frequency domain using a data-driven approach. Our results indicated that the clinical groups (ADS/HAND) performed significantly worse than controls on the task and exhibited aberrations in interference-related theta and alpha oscillations, some of which were disease-specific. Specifically, patients (ADS/HAND) exhibited weaker interference activity in frontoparietal and cingulate cortices compared to controls, while the ADS group exhibited stronger theta interference than those with HAND in frontoparietal, occipital, and temporal cortices. These results reveal overlapping and distinct patterns of neurophysiological alterations among those with ADS and HAND in attentional processing centers and suggest the existence of unique oscillatory markers of each condition.
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Affiliation(s)
- Chloe E. Meehan
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
- Department of Psychology, University of Nebraska – Omaha, Omaha, NE 68182, USA
| | - Mikki Schantell
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
- College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Alex I. Wiesman
- Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, CA
| | | | - Jennifer O’Neill
- Department of Internal Medicine, Division of Infectious Diseases, UNMC, Omaha, NE 68198, USA
| | - Sara H. Bares
- Department of Internal Medicine, Division of Infectious Diseases, UNMC, Omaha, NE 68198, USA
| | | | - Pamela E. May
- Department of Neurological Sciences, UNMC, Omaha, NE 68198, USA
| | - Daniel L. Murman
- Department of Neurological Sciences, UNMC, Omaha, NE 68198, USA
- Memory Disorders and Behavioral Neurology Program, UNMC, Omaha, NE 68198, USA
| | - Tony W. Wilson
- Institute for Human Neuroscience, Boys Town National Research Hospital, Boys Town, NE 68010, USA
- Department of Psychology, University of Nebraska – Omaha, Omaha, NE 68182, USA
- College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68178, USA
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Papageorgiou E, Tsirelis D, Lazari K, Siokas V, Dardiotis E, Tsironi EE. Visual disorders and driving ability in persons with dementia: A mini review. Front Hum Neurosci 2022; 16:932820. [DOI: 10.3389/fnhum.2022.932820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 11/11/2022] [Indexed: 11/30/2022] Open
Abstract
BackgroundImpaired driving ability in patients with Alzheimer’s disease (AD) is associated with a decline in cognitive processes and a deterioration of their basic sensory visual functions. Although a variety of ocular abnormalities have been described in patients with AD, little is known about the impact of those visual disorders on their driving performance.AimAim of this mini-review is to provide an update on the driving ability of patients with dementia and summarize the primary visual disorders affecting their driving behavior.MethodsDatabases were screened for studies investigating dementia, associated visual abnormalities and driving ability.ResultsThere is consistent evidence that dementia affects driving ability. Patients with dementia present with a variety of visual disorders, such as visual acuity reduction, visual field defects, impaired contrast sensitivity, decline in color vision and age-related pathological changes, that may have a negative impact on their driving ability. However, there is a paucity in studies describing the impact of oculovisual decline on the driving ability of AD subjects. A bidirectional association between cognitive and visual impairment (VI) has been described.ConclusionGiven the bidirectional association between VI and dementia, vision screening and cognitive assessment of the older driver should aim to identify at-risk individuals and employ timely strategies for treatment of both cognitive and ocular problems. Future studies should characterize the basic visual sensory status of AD patients participating in driving studies, and investigate the impact of vision abnormalities on their driving performance.
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Zhang J, Xiao Y, Li ZM, Wei N, Lin L, Li K. Reach-to-grasp kinematics and kinetics with and without visual feedback in early-stage Alzheimer’s disease. J Neuroeng Rehabil 2022; 19:121. [DOI: 10.1186/s12984-022-01108-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 11/01/2022] [Indexed: 11/12/2022] Open
Abstract
AbstractThis study aimed to investigate the effects of early-stage Alzheimer’s disease (AD) on the reach-to-grasp kinematics and kinetics with and without visual supervision of the grasping arm and hand. Seventeen patients who had been diagnosed with early-stage AD and 17 age- and gender-matched, cognitive normal (CN) adults participated in the experiment. A mirror operating system was designed to block the visual feedback of their grasping hand and forearms but to virtually show grasped targets. The target for reach-to-grasp kinematics was a reflective marker installed on a base; and the target for reach-to-grasp kinetics was a custom-made apparatus installed with two six-component force/torque transducers. Kinematics and kinetic parameters were used to quantify the reach-to-grasp performances. Results showed that the early-stage AD remarkably decreased the reaching speed, reduced the grasping accuracy and increased the transportation variability for reach-to-grasp kinematics. For kinetic analysis, early-stage AD extended the preload duration, disturbed the grip and lift forces coordination, and increased the feedforward proportion in the grasping force control. The AD-related changes in the reach-to-grasp kinematic and kinetic parameters depended on visual feedback and were associated with nervous system function according to correlation analyses with the neuropsychological testing. These results suggest that the abnormal kinematic and kinetic characteristics may correlate with the neuropsychological status of early-stage AD, and that the reach-to-grasp kinematic and kinetic maneuver could potentially be used as a novel tool for non-invasive screening or evaluation of early-stage AD.
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Dion-Albert L, Bandeira Binder L, Daigle B, Hong-Minh A, Lebel M, Menard C. Sex differences in the blood-brain barrier: Implications for mental health. Front Neuroendocrinol 2022; 65:100989. [PMID: 35271863 DOI: 10.1016/j.yfrne.2022.100989] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/07/2022] [Accepted: 02/19/2022] [Indexed: 12/13/2022]
Abstract
Prevalence of mental disorders, including major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ) are increasing at alarming rates in our societies. Growing evidence points toward major sex differences in these conditions, and high rates of treatment resistance support the need to consider novel biological mechanisms outside of neuronal function to gain mechanistic insights that could lead to innovative therapies. Blood-brain barrier alterations have been reported in MDD, BD and SZ. Here, we provide an overview of sex-specific immune, endocrine, vascular and transcriptional-mediated changes that could affect neurovascular integrity and possibly contribute to the pathogenesis of mental disorders. We also identify pitfalls in current literature and highlight promising vascular biomarkers. Better understanding of how these adaptations can contribute to mental health status is essential not only in the context of MDD, BD and SZ but also cardiovascular diseases and stroke which are associated with higher prevalence of these conditions.
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Affiliation(s)
- Laurence Dion-Albert
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Luisa Bandeira Binder
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Beatrice Daigle
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Amandine Hong-Minh
- Smurfit Institute of Genetics, Trinity College Dublin, Lincoln Place Gate, Dublin 2, Ireland
| | - Manon Lebel
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada
| | - Caroline Menard
- Department of Psychiatry and Neuroscience, Faculty of Medicine and CERVO Brain Research Center, Université Laval, Quebec City, Canada.
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Mitchell AG, Rossit S, Pal S, Hornberger M, Warman A, Kenning E, Williamson L, Shapland R, McIntosh RD. Peripheral reaching in Alzheimer's disease and mild cognitive impairment. Cortex 2022; 149:29-43. [PMID: 35184013 PMCID: PMC9007170 DOI: 10.1016/j.cortex.2022.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 12/02/2021] [Accepted: 01/12/2022] [Indexed: 12/15/2022]
Abstract
Recent evidence has implicated areas within the posterior parietal cortex (PPC) as among the first to show pathophysiological changes in Alzheimer's disease (AD). Focal brain damage to the PPC can cause optic ataxia, a specific deficit in reaching to peripheral targets. The present study describes a novel investigation of peripheral reaching ability in AD and mild cognitive impairment (MCI), to assess whether this deficit is common among these patient groups. Individuals with a diagnosis of mild-to-moderate AD, or MCI, and healthy older adult controls were required to reach to targets presented in central vision or in peripheral vision using two reaching tasks; one in the lateral plane and another presented in radial depth. Pre-registered case–control comparisons identified 1/10 MCI and 3/17 AD patients with significant peripheral reaching deficits at the individual level, but group-level comparisons did not find significantly higher peripheral reaching error in either AD or MCI by comparison to controls. Exploratory analyses showed significantly increased reach duration in both AD and MCI groups relative to controls, accounted for by an extended Deceleration Time of the reach movement. These findings suggest that peripheral reaching deficits like those observed in optic ataxia are not a common feature of AD. However, we show that cognitive decline is associated with a generalised slowing of movement which may indicate a visuomotor deficit in reach planning or online guidance.
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Affiliation(s)
- Alexandra G Mitchell
- Department of Psychology, University of Edinburgh, Edinburgh, UK; Center for Functionally Integrative Neuroscience, Aarhus University, Denmark.
| | - Stephanie Rossit
- School of Psychology, Lawrence Stenhouse Building, University of East Anglia, Norwich, UK.
| | - Suvankar Pal
- Anne Rowling Regenerative Neurology Clinic, Chancellor's Building, The University of Edinburgh, Edinburgh, UK.
| | | | - Annie Warman
- School of Psychology, Lawrence Stenhouse Building, University of East Anglia, Norwich, UK.
| | - Elise Kenning
- School of Psychology, Lawrence Stenhouse Building, University of East Anglia, Norwich, UK
| | - Laura Williamson
- School of Psychology, Lawrence Stenhouse Building, University of East Anglia, Norwich, UK
| | - Rebecca Shapland
- School of Psychology, Lawrence Stenhouse Building, University of East Anglia, Norwich, UK
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12
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Almario G, Piñero DP. Impact of Alzheimer's Disease in Ocular Motility and Visual Perception: A Narrative Review. Semin Ophthalmol 2021; 37:436-446. [PMID: 34779338 DOI: 10.1080/08820538.2021.2002371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE Alzheimer's disease (AD) is a neurodegenerative disease generating a progressive neuronal loss as well as cognitive deficiencies. This disease can be accompanied by ocular manifestations, including alterations in ocular motility and visual perception. The aim of the current review article was to collect all the information about these alterations and to analyze if there is scientific evidence supporting the potential use of these changes as biomarkers of the disease. METHODS A bibliographic search was performed using two different databases, Pubmed and Google Scholar, as well as a search of material in non-peer reviewed journals about Alzheimer's and Neurology. A total of 227 articles were found in the initial search, but only 76 were included considering their relevance according to the purpose of the reviewResults: This narrative review describes the findings obtained in this area to this date, confirming that deficiencies in saccades is the most common condition among AD patients. Furthermore, other visual alterations have also been reported in these patients, including a compromise of visual acuity and contrast sensitivity, fluctuations of colour vision, stereopsis impairment and visual field losses. Likewise, other complex visuo-spatial and visuo-perceptual impairments can be present. More studies are still needed to understand better what type of changes occurs in ocular alignment, binocularity, and fixation pattern in AD patients. CONCLUSIONS AD is associated to visual perception and ocular motility alterations. All the scientific information found in this review should be considered as a guide for designing future studies and to define adequate clinical protocols for the visual evaluation of patients with AD, considering the cognitive limitations that are normally present in this type of patients.
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Affiliation(s)
- Gemma Almario
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain.,Punto Óptico, Elche, Alicante, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain.,Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain
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13
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Gupta S, Chan YH, Rajapakse JC. Obtaining leaner deep neural networks for decoding brain functional connectome in a single shot. Neurocomputing 2021. [DOI: 10.1016/j.neucom.2020.04.152] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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14
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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] [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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15
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Piano M, Nilforooshan R, Evans S. Binocular Vision, Visual Function, and Pupil Dynamics in People Living With Dementia and Their Relation to the Rate of Cognitive Decline and Structural Changes Within the Brain: Protocol for an Observational Study. JMIR Res Protoc 2020; 9:e16089. [PMID: 32773379 PMCID: PMC7445601 DOI: 10.2196/16089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 04/24/2020] [Accepted: 05/12/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Visual impairment is a common comorbidity in people living with dementia. Addressing sources of visual difficulties can have a significant impact on the quality of life for people living with dementia and their caregivers. Depth perception problems are purportedly common in dementia and also contribute to falls, visuomotor task difficulties, and poorer psychosocial well-being. However, depth perception and binocular vision are rarely assessed in dementia research. Sleep fragmentation is also common for people living with dementia, and binocular cooperation for depth perception can be affected by fatigue. Pupillary responses under cognitive load also have the potential to be a risk marker for cognitive decline in people living with dementia and can be combined with the above measures for a comprehensive evaluation of clinical visual changes in people living with dementia and their relation to changes in cognitive status, sleep quality, and cortical structure or function. OBJECTIVE This study aims to characterize the nature of clinical visual changes and altered task-evoked pupillary responses that may occur in people living with dementia and evaluate whether these responses relate to changes in cognitive status (standardized Mini Mental State Examination [MMSE] score), Pittsburgh sleep quality index, and cortical structure or function. METHODS This proposed exploratory observational study will enroll ≤210 people with recently diagnosed dementia (within the last 24 months). The following parameters will be assessed on 3 occasions, 4 months apart (plus or minus 2 weeks): visual function (visual acuity and contrast sensitivity), binocular function (motor fusion and stereopsis), task-evoked pupillary responses (minimum and maximum pupil size, time to maximum dilation, and dilation velocity), cognitive status (MMSE score), and sleep quality (Pittsburgh Sleep Quality Index). A subset of patients (n=30) with Alzheimer disease will undergo structural and functional magnetic resonance imaging at first and third visits, completing a 10-day consensus sleep diary to monitor sleep quality, verified by sleep actimetry. RESULTS This research was funded in February 2018 and received National Health Service Research Ethics Committee approval in September 2018. The data collection period was from October 1, 2018, to November 30, 2019. A total of 24 participants were recruited for the study. The data analysis is complete, with results expected to be published before the end of 2020. CONCLUSIONS Findings will demonstrate how often people with dementia experience binocular vision problems. If frequent, diagnosing and treating them could improve quality of life by reducing the risk of falls and fine visuomotor task impairment and by relieving psychosocial anxiety. This research will also demonstrate whether changes in depth perception, pupillary responses, and quality of vision relate to changes in memory or sleep quality and brain structure or function. If related, these quick and noninvasive eye tests help monitor dementia. This would help justify whether binocular vision and pupillary response testing should be included in dementia-friendly eye-testing guidelines. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) RR1-10.2196/16089.
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Affiliation(s)
- Marianne Piano
- School of Health Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Australia
- National Vision Research Institute, Australian College of Optometry, Melbourne, Australia
| | | | - Simon Evans
- School of Psychology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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16
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Oishi Y, Imamura T, Shimomura T, Suzuki K. Vegetable Freshness Perception in Dementia with Lewy Bodies and Alzheimer's Disease. Dement Geriatr Cogn Dis Extra 2020; 10:74-85. [PMID: 33082771 PMCID: PMC7548879 DOI: 10.1159/000508282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 11/19/2022] Open
Abstract
Introduction Although various visual function deficits have been reported in patients with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), vegetable freshness perception has not been thoroughly examined. Objective To investigate vegetable freshness perception in patients with AD and DLB and to clarify the relationship between vegetable freshness perception and various visuoperceptual functions. Methods We enrolled 37 patients with probable DLB, 58 patients with probable AD, and 32 age-matched healthy controls. We assessed vegetable freshness perception and visuoperceptual functions, including vegetable brightness perception, contrast sensitivity, color perception, and stereopsis. Patients with DLB showed disproportionate deficits in vegetable freshness perception and vegetable luminance perception compared to patients with AD and controls. Analyses of the groups with higher and lower vegetable freshness perceptions revealed significant differences in contrast sensitivity and visual texture recognition. Results In the vegetable freshness test, we found significant differences among the 3 groups (F = 30.029, p < 0.0001); the extent of impairment in patients with DLB was greater than that in patients with AD. In patients with DLB, the vegetable freshness judgments were significantly correlated with texture judgment scores and contrast sensitivity. Conclusion Our findings revealed significantly impaired vegetable freshness perception in patients with DLB. Vegetable freshness perception may be related to visual texture recognition in patients with DLB.
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Affiliation(s)
- Yuka Oishi
- Department of Speech, Language, and Hearing Sciences, Niigata University of Health and Welfare, Niigata, Japan.,Graduate School of Health and Welfare, Niigata University of Health and Welfare, Niigata, Japan.,Department of Neurology, Niigata Rehabilitation Hospital, Niigata, Japan
| | - Toru Imamura
- Department of Speech, Language, and Hearing Sciences, Niigata University of Health and Welfare, Niigata, Japan.,Graduate School of Health and Welfare, Niigata University of Health and Welfare, Niigata, Japan.,Department of Neurology, Niigata Rehabilitation Hospital, Niigata, Japan
| | - Tatsuo Shimomura
- Department of Rehabilitation Medicine, Akita Prefectural Center for Rehabilitation and Psychiatric Medicine, Daisen, Japan
| | - Kyoko Suzuki
- Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan
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17
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Sun X, Nie B, Zhao S, Chen Q, Li P, Zhang T, Pan T, Feng T, Wang L, Yin X, Zhang W, Zhao S, Shan B, Liu H, Liang S, Ai L, Wang G. Tau PET Distributional Pattern in AD Patients with Visuospatial Dysfunction. Curr Alzheimer Res 2019; 16:1055-1062. [PMID: 31724513 DOI: 10.2174/1567205016666191113152434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 09/25/2019] [Accepted: 10/21/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Visuospatial dysfunction is one predominant symptom in many atypical Alzheimer's disease (AD) patients, however, until now its neural correlates still remain unclear. For the accumulation of intracellular hyperphosphorylated tau proteins is a major pathogenic factor in neurodegeneration of AD, the distributional pattern of tau could highlight the affected brain regions associated with specific cognitive deficits. OBJECTIVE We investigated the brain regions particularly affected by tau accumulation in patients with visuospatial dysfunction to explore its neural correlates. METHODS Using 18F-AV-1451 tau positron emission tomography (PET), voxel-wise two-sample t-tests were performed between AD patients with obvious visuospatial dysfunction (VS-AD) and cognitively normal subjects, AD patients with little-to-no visuospatial dysfunction (non VS-AD) and cognitively normal subjects, respectively. RESULTS Results showed increased tau accumulations mainly located in occipitoparietal cortex, posterior cingulate cortex, precuneus, inferior and medial temporal cortex in VS-AD patients, while increased tau accumulations mainly occurred in the inferior and medial temporal cortex in non VS-AD patients. CONCLUSION These findings suggested that occipitoparietal cortex, posterior cingulate cortex and precuneus, which were particularly affected by increased tau accumulation in VS-AD patients, may associate with visuospatial dysfunction of AD.
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Affiliation(s)
- Xi Sun
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Binbin Nie
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Shujun Zhao
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China
| | - Qian Chen
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100071, China
| | - Panlong Li
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Tianhao Zhang
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tingting Pan
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Ting Feng
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Luying Wang
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaolong Yin
- College of Physical Science and Technology, Zhengzhou University, Zhengzhou 450001, China.,Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Zhang
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shilun Zhao
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoci Shan
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Hua Liu
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.,School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shengxiang Liang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, Fujian 350122, China.,Traditional Chinese Medicine Rehabilitation Research Center of State Administration of Traditional Chinese Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - Lin Ai
- Department of Nuclear Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing 100071, China
| | - Guihong Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100071, China
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18
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Distinct forms of motion sensitivity impairments in Alzheimer's disease. Sci Rep 2019; 9:12931. [PMID: 31506450 PMCID: PMC6736838 DOI: 10.1038/s41598-019-48942-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/31/2019] [Indexed: 11/21/2022] Open
Abstract
Motion sensitivity impairment in Alzheimer’s disease (AD) is often characterized as elevated coherence threshold. An alternative way to measure motion sensitivity is the direction threshold, i.e., the minimal angle of motion direction that can be discriminated. So far, it is less clear whether and how the direction threshold is altered in AD. Here we asked a group of AD patients and two control groups of healthy participants (young and elderly adults) to judge their perceived heading direction based on a field of optic flow stimuli simulating a forward translation in the environment. We manipulated the heading direction and the coherence of the optic flow independently and measured the direction and coherence thresholds from each participant. We found that the direction threshold increased significantly in AD patients as compared to healthy controls, like the coherence threshold. Yet, the elevation in the direction threshold was less pronounced than the coherence threshold. Moreover, the magnitudes of the direction and coherence thresholds in AD patients were not correlated. Our results suggest that coherence and direction impairments are two distinct forms of motion deficits in AD patients which might be associated with independent neural mechanisms.
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19
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Song Y, Wang H. Motion-induced position mis-localization predicts the severity of Alzheimer's disease. J Neuropsychol 2019; 14:333-345. [PMID: 30859737 DOI: 10.1111/jnp.12181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/31/2019] [Indexed: 01/16/2023]
Abstract
Patients with Alzheimer's disease (AD) often exhibit motion processing deficits. It is unclear whether the localization of moving objects - a perceptual process tightly linked to motion - is impaired or intact in AD. In this study, we used the phenomenon of illusory shift of position induced by motion as a behavioural paradigm to probe how the spatial representation differs between AD patients and healthy elderly controls. We measured the magnitudes of motion-induced position shift in a group of AD participants (N = 24) and age-matched elderly observers (N = 24). We found that AD patients showed weakened position mis-localization, but only for motion stimuli of slow speeds. For fast motion, the position mis-localization did not differ significantly between groups. Furthermore, we showed that the magnitudes of position mis-localization can predict the severity of AD; that is, patients with more severe symptoms had less preserved position mis-localization. Our results suggest that AD pathology impacts not only motion processing per se, but also the perceptual process related to motion such as the localization of moving objects.
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Affiliation(s)
- Yamin Song
- Department of Neurology, Liaocheng People's Hospital, China
| | - Huiting Wang
- Department of Neurology, Liaocheng People's Hospital, China
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20
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Magnetic resonance imaging in Alzheimer's disease and mild cognitive impairment. J Neurol 2018; 266:1293-1302. [PMID: 30120563 PMCID: PMC6517561 DOI: 10.1007/s00415-018-9016-3] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/07/2018] [Accepted: 08/11/2018] [Indexed: 11/25/2022]
Abstract
Research utilizing magnetic resonance imaging (MRI) has been crucial to the understanding of the neuropathological mechanisms behind and clinical identification of Alzheimer’s disease (AD) and mild cognitive impairment (MCI). MRI modalities show patterns of brain damage that discriminate AD from other brain illnesses and brain abnormalities that are associated with risk of conversion to AD from MCI and other behavioural outcomes. This review discusses the application of various MRI techniques to and their clinical usefulness in AD and MCI. MRI modalities covered include structural MRI, diffusion tensor imaging (DTI), arterial spin labelling (ASL), magnetic resonance spectroscopy (MRS), and functional MRI (fMRI). There is much evidence supporting the validity of MRI as a biomarker for these disorders; however, only traditional structural imaging is currently recommended for routine use in clinical settings. Future research is needed to warrant the inclusion for more advanced MRI methodology in forthcoming revisions to diagnostic criteria for AD and MCI.
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21
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Colligris P, Perez de Lara MJ, Colligris B, Pintor J. Ocular Manifestations of Alzheimer's and Other Neurodegenerative Diseases: The Prospect of the Eye as a Tool for the Early Diagnosis of Alzheimer's Disease. J Ophthalmol 2018; 2018:8538573. [PMID: 30151279 PMCID: PMC6091327 DOI: 10.1155/2018/8538573] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/07/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022] Open
Abstract
Dementia, including Alzheimer's disease (AD), is a major disorder, leading to several ocular manifestations amongst the elderly population. These visual disorders may be due to retinal nerve degenerative changes, including nerve fibre layer thinning, degeneration of retinal ganglion cells, and changes to vascular parameters. There is no cure for Alzheimer's, but medicines can slow down the development of many of the classic symptoms, such as loss of memory and communication skills, mood swings, and depression. The disease diagnosis is difficult, and it is only possible through PET scans of the brain, detecting evidence of the accumulation of amyloid and tau. PET is expensive and invasive, requiring the injection of radioactive tracers, which bind with these proteins and glow during scanning. Recently, scientists developed promising eye-scan techniques that may detect Alzheimer's disease at its earliest stage, before major symptoms appear, leading to improved management of the disease symptoms. In this review, we are discussing the visual abnormalities of Alzheimer's and other neurodegenerative diseases, focused on ocular functional-visual-structural biomarkers, retinal pathology, and potential novel diagnostic tools.
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Affiliation(s)
- Pade Colligris
- Universidad Alfonso X, Madrid, Spain
- Ocupharm Diagnostics SL, Madrid, Spain
| | | | - Basilio Colligris
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
| | - Jesus Pintor
- Ocupharm Diagnostics SL, Madrid, Spain
- Universidad Complutense de Madrid, Madrid, Spain
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22
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Ward LM, Morison G, Simmers AJ, Shahani U. Age-Related Changes in Global Motion Coherence: Conflicting Haemodynamic and Perceptual Responses. Sci Rep 2018; 8:10013. [PMID: 29968729 PMCID: PMC6030110 DOI: 10.1038/s41598-018-27803-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/08/2018] [Indexed: 11/22/2022] Open
Abstract
Our aim was to use both behavioural and neuroimaging data to identify indicators of perceptual decline in motion processing. We employed a global motion coherence task and functional Near Infrared Spectroscopy (fNIRS). Healthy adults (n = 72, 18-85) were recruited into the following groups: young (n = 28, mean age = 28), middle-aged (n = 22, mean age = 50), and older adults (n = 23, mean age = 70). Participants were assessed on their motion coherence thresholds at 3 different speeds using a psychophysical design. As expected, we report age group differences in motion processing as demonstrated by higher motion coherence thresholds in older adults. Crucially, we add correlational data showing that global motion perception declines linearly as a function of age. The associated fNIRS recordings provide a clear physiological correlate of global motion perception. The crux of this study lies in the robust linear correlation between age and haemodynamic response for both measures of oxygenation. We hypothesise that there is an increase in neural recruitment, necessitating an increase in metabolic need and blood flow, which presents as a higher oxygenated haemoglobin response. We report age-related changes in motion perception with poorer behavioural performance (high motion coherence thresholds) associated with an increased haemodynamic response.
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Affiliation(s)
- Laura McKernan Ward
- Department of Vision Science, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, United Kingdom.
| | - Gordon Morison
- Department of Engineering, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, United Kingdom
| | - Anita Jane Simmers
- Department of Vision Science, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, United Kingdom
| | - Uma Shahani
- Department of Vision Science, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, United Kingdom
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23
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Abstract
The localization of object position in space is one of the most important visual abilities in humans. Motion-induced position shift is a perceptual illusion in which the position of a moving object is perceived to be shifted in the direction of motion. In this study, we wanted to explore whether and how Alzheimer’s disease (AD) affects this illusion. We recruited a group of patients with early AD and a group of age-matched healthy controls. In our experiments, two drifting Gabor patches moving in opposite directions were presented and participants were asked to report whether the upper Gabor appeared rightwards or leftwards of the lower one. We measured the psychometric functions, of which the point of subjective alignment was taken as the magnitude of motion-induced position shift. We compared the position shift across the two groups at three different retinal eccentricities. We found that position shifts were systematically smaller in the AD group as comparing to the elderly control group. Our data demonstrated that AD patients were less prone to motion-induced position shift. The results add to the existing knowledge of perceptual deficits in AD patients. We suggest that motion induced position shift may be effective as a new behavioral indicator for AD identification.
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24
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Balachandar R, Bharath S, John JP, Joshi H, Sadanand S, Saini J, Kumar KJ, Varghese M. Resting-State Functional Connectivity Changes Associated with Visuospatial Cognitive Deficits in Patients with Mild Alzheimer Disease. Dement Geriatr Cogn Disord 2018; 43:229-236. [PMID: 28351035 DOI: 10.1159/000457118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Alzheimer disease (AD) is a neurodegenerative disorder characterized by progressive disconnection of various brain networks leading to neuropsychological impairment. Pathology in the visual association areas has been documented in presymptomatic AD and therefore we aimed at examining the relationship between brain connectivity and visuospatial (VS) cognitive deficits in early AD. METHODS Tests for VS working memory, episodic memory and construction were used to classify patients with AD (n = 48) as having severe VS deficits (n = 12, female = 4) or mild deficits (n = 11, female = 4). Resting-state functional magnetic resonance imaging and structural images were acquired as per the standard protocols. Between-group differences in resting-state functional connectivity (rsFC) were examined by dual regression analysis correcting for age, gender, and total brain volume. RESULTS Patients with AD having severe VS deficits exhibited significantly reduced rsFC in bilateral lingual gyri of the visual network compared to patients with mild VS deficits. CONCLUSION Reduced rsFC in the visual network in patients with more severe VS deficits may be a functional neuroimaging biomarker reflecting hypoconnectivity of the brain with progressive VS deficits during early AD.
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Affiliation(s)
- Rakesh Balachandar
- Department of Clinical Neuroscience, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, India
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25
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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] [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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26
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Cho H, Lee HS, Choi JY, Lee JH, Ryu YH, Lee MS, Lyoo CH. Predicted sequence of cortical tau and amyloid-β deposition in Alzheimer disease spectrum. Neurobiol Aging 2018; 68:76-84. [PMID: 29751288 DOI: 10.1016/j.neurobiolaging.2018.04.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 12/23/2022]
Abstract
We investigated sequential order between tau and amyloid-β (Aβ) deposition in Alzheimer disease spectrum using a conditional probability method. Two hundred twenty participants underwent 18F-flortaucipir and 18F-florbetaben positron emission tomography scans and neuropsychological tests. The presence of tau and Aβ in each region and impairment in each cognitive domain were determined by Z-score cutoffs. By comparing pairs of conditional probabilities, the sequential order of tau and Aβ deposition were determined. Probability for the presence of tau in the entorhinal cortex was higher than that of Aβ in all cortical regions, and in the medial temporal cortices, probability for the presence of tau was higher than that of Aβ. Conversely, in the remaining neocortex above the inferior temporal cortex, probability for the presence of Aβ was always higher than that of tau. Tau pathology in the entorhinal cortex may appear earlier than neocortical Aβ and may spread in the absence of Aβ within the neighboring medial temporal regions. However, Aβ may be required for massive tau deposition in the distant cortical areas.
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Affiliation(s)
- Hanna Cho
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hye Sun Lee
- Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, South Korea
| | - Jae Yong Choi
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea; Division of RI-Convergence Research, Korea Institute Radiological and Medical Sciences, Seoul, South Korea
| | - Jae Hoon Lee
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Myung Sik Lee
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
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Zhuang X, Chen Y, Zhuang X, Xing T, Chen T, Jiang G, Yang X. Impaired Center-Surround Suppression in Patients with Alzheimer's Disease. J Alzheimers Dis 2018; 55:1101-1108. [PMID: 27767987 DOI: 10.3233/jad-160603] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is often associated with declined visual processing abilities. Here we tested whether the functions of center-surround suppression- a hallmark property in the visual system- are altered by AD. To this end, we recruited three groups of participants (AD, elderly, and young) in a motion direction discrimination task, in which we measured the temporal duration threshold of a drifting Gabor with varying stimulus sizes. We first replicated the phenomena of center-surround suppression that the required duration for discriminating a high contrast grating decreases with increasing stimulus size. We then showed that the magnitudes of suppression varied among the three groups. There was progressive reduction of suppression in the elderly and AD groups compared with the young group. Interestingly, we found that the levels of suppression can predict the severity of dementia in the AD group. Our results suggest that AD is associated with impaired center-surround functions in the visual motion processing pathway.
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Affiliation(s)
- Xianbo Zhuang
- Department of Neurology, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
| | - Yanxiu Chen
- Department of Neurology, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
| | - Xianpeng Zhuang
- Department of CT room, Liaocheng Fourth People's Hospital, Liaocheng city, Shandong Province, China
| | - Tao Xing
- Department of Neurosurgery, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
| | - Tuanzhi Chen
- Department of Neurology, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
| | - Guisheng Jiang
- Department of Neurology, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
| | - Xiafeng Yang
- Department of Neurology, Liaocheng People's Hospital, Liaocheng city, Shandong Province, China
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Ansai JH, Andrade LPD, Rossi PG, Almeida ML, Carvalho Vale FA, Rebelatto JR. Association Between Gait and Dual Task With Cognitive Domains in Older People With Cognitive Impairment. J Mot Behav 2017; 50:409-415. [PMID: 28901834 DOI: 10.1080/00222895.2017.1363702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The authors investigated whether impaired gait and dual-task performances are associated with specific cognitive domains among older people with preserved cognition (PC), mild cognitive impairment (MCI), and mild Alzheimer's disease (AD). The sample comprised 40 older adults with PC, 40 with MCI, and 38 with mild AD. The assessment consisted of gait (measured by 10-m walk test and Timed Up and Go Test [TUGT]), dual task (measured by TUGT associated with a cognitive-motor task of calling a phone number), and cognition (domains of the Addenbrooke Cognitive Examination-Revised and Frontal Assessment Battery [FAB]). For data analysis, the Pearson product-moment correlation and the backward stepwise linear regression were conducted. Language, fluency, and visuospatial domains predicted the 10-m walk test measure specifically in PC, MCI, and AD groups. Only the visuospatial domain was independently associated with the TUGT measure in the MCI and AD groups. FAB score, language domain, and FAB score and fluency domain were the strongest predictors for the isolated cognitive-motor task measure in the PC, MCI, and AD groups, respectively. The visuospatial domain was independently associated with the dual-task test measure in all 3 groups. The study findings demonstrate the influence of specific cognitive domains in daily mobility tasks in people with different cognitive profiles.
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Affiliation(s)
| | | | - Paulo Giusti Rossi
- a Department of Physiotherapy , Federal University of São Carlos , Brazil
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Wang J, Guo X, Zhuang X, Chen T, Yan W. Disrupted pursuit compensation during self-motion perception in early Alzheimer's disease. Sci Rep 2017. [PMID: 28642572 PMCID: PMC5481347 DOI: 10.1038/s41598-017-04377-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Our perception of the world is remarkably stable despite of distorted retinal input due to frequent eye movements. It is considered that the brain uses corollary discharge, efference copies of signals sent from motor to visual regions, to compensate for distortions and stabilize visual perception. In this study, we tested whether patients with Alzheimer’s disease (AD) have impaired corollary discharge functions as evidenced by reduced compensation during the perception of optic flow that mimics self-motion in the environment. We asked a group of early-stage AD patients and age-matched healthy controls to indicate the perceived direction of self-motion based on optic flow while tracking a moving target with smooth pursuit eye movement, or keeping eye fixation at a stationary target. We first replicated the previous findings that healthy participants were able to compensate for distorted optic flow in the presence of eye movements, as indicated by similar performance of self-motion perception between pursuit and fixation conditions. In stark contrast, AD patients showed impaired self-motion perception when the optic flow was distorted by eye movements. Our results suggest that early-stage AD pathology is associated with disrupted eye movement compensation during self-motion perception.
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Affiliation(s)
- Jingru Wang
- Department of Neurology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng city, Shandong Province, 252000, China
| | - Xiaojun Guo
- Department of Neurology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng city, Shandong Province, 252000, China
| | - Xianbo Zhuang
- Department of Neurology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng city, Shandong Province, 252000, China
| | - Tuanzhi Chen
- Department of Neurology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng city, Shandong Province, 252000, China
| | - Wei Yan
- Department of Neurology, Liaocheng People's Hospital and Liaocheng Clinical School of Taishan Medical University, Liaocheng city, Shandong Province, 252000, China.
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Jones DJW, Harris JP, Butler LT, Vaux EC. Stereopsis in end-stage renal disease (ESRD). Physiol Behav 2017; 171:1-6. [PMID: 28025091 DOI: 10.1016/j.physbeh.2016.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 12/02/2016] [Accepted: 12/21/2016] [Indexed: 11/17/2022]
Abstract
We investigated an effect of end-stage renal disease (ESRD) on the visual system by measuring the ability of 21 patients to perceive depth in the random dot stereograms and circles of the Randot Test. To control for other factors which might influence performance on the tests of stereopsis, patients were compared with healthy controls matched for age, years of education, IQ, and general cognitive ability. Vernier acuity (thought to reflect mainly central processing) and Landolt acuity (more sensitive to retinal and optical abnormalities) were also measured, but the study did not include a formal ophthalmological examination. All controls could perceive depth in random dot stereograms, whereas 9/21 patients could not. Patients who could perceive depth had worse stereoacuity than did their matched controls. The patient group as a whole had worse Vernier and Landolt acuities than the controls. The stereoblind patient subgroup had similar Vernier acuity to the stereoscopic subgroup, but worse Landolt acuity, and was more likely to have peripheral vascular disease. We conclude that ESRD had affected structures both within the eye, and within the visual brain. However, the similarity of Vernier acuity and difference of Landolt acuity in the stereoblind and stereoscopic patient subgroups suggest that the differences in stereoscopic ability arise from abnormalities in the eyes rather than in the brain.
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Affiliation(s)
- Daniel J W Jones
- School of Psychology and Clinical Language Sciences, University of Reading Malaysia, Malaysia.
| | - John P Harris
- School of Psychology and Clinical Language Sciences, University of Reading, UK
| | - Laurie T Butler
- School of Psychology and Clinical Language Sciences, University of Reading, UK
| | - Emma C Vaux
- Department of Renal Medicine, Royal Berkshire NHS Foundation Trust, UK
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Porter G, Wattam-Bell J, Bayer A, Haworth J, Braddick O, Atkinson J, Tales A. Different trajectories of decline for global form and global motion processing in aging, mild cognitive impairment and Alzheimer's disease. Neurobiol Aging 2017; 56:17-24. [PMID: 28482210 DOI: 10.1016/j.neurobiolaging.2017.03.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 02/06/2017] [Accepted: 03/05/2017] [Indexed: 12/23/2022]
Abstract
The visual processing of complex motion is impaired in Alzheimer's disease (AD). However, it is unclear whether these impairments are biased toward the motion stream or part of a general disruption of global visual processing, given some reports of impaired static form processing in AD. Here, for the first time, we directly compared the relative preservation of motion and form systems in AD, mild cognitive impairment, and healthy aging, by measuring coherence thresholds for well-established global rotational motion and static form stimuli known to be of equivalent complexity. Our data confirm a marked motion-processing deficit specific to some AD patients, and greater than any form-processing deficit for this group. In parallel, we identified a more gradual decline in static form recognition, with thresholds raised in mild cognitive impairment patients and slightly further in the AD group compared with controls. We conclude that complex motion processing is more vulnerable to decline in dementia than complex form processing, perhaps owing to greater reliance on long-range neural connections heavily targeted by AD pathology.
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Affiliation(s)
- Gillian Porter
- School of Psychology, University of Bristol, Bristol, UK.
| | - John Wattam-Bell
- Division of Psychology and Language Sciences, Faculty of Brain Sciences, University College London, London, UK
| | - Antony Bayer
- Department of Geriatric Medicine, Cardiff University, Cardiff, UK
| | - Judy Haworth
- South Glos Memory Services, Avon and Wiltshire Mental Health Partnership, Bristol, UK
| | - Oliver Braddick
- Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Janette Atkinson
- Division of Psychology and Language Sciences, Faculty of Brain Sciences, University College London, London, UK
| | - Andrea Tales
- School of Psychology, University of Bristol, Bristol, UK; Department of Psychology, University of Swansea, Swansea, UK
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Visual dysfunction and its correlation with retinal changes in patients with Alzheimer's disease. Eye (Lond) 2017; 31:1034-1041. [PMID: 28282060 DOI: 10.1038/eye.2017.23] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/24/2017] [Indexed: 12/23/2022] Open
Abstract
AimTo evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Alzheimer's disease (AD).MethodsPatients with AD (n=24) and controls (n=24) underwent evaluation of visual acuity (VA), color vision (using the Farnsworth and L'Anthony desaturated (D) 15 color tests), and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV-1000E test) to measure visual dysfunction. Structural measurements of the retinal nerve fiber layer (RNFL) and macular thickness were obtained using spectral domain-optical coherence tomography (SD-OCT).ResultsCSV at three of the four spatial frequencies was significantly worse in AD patients than in controls. Color vision was significantly affected in AD patients based on the Farnsworth color test. Compared with controls, macular thinning was detected in all sectors except the fovea, and the RNFL exhibited significant thinning in the superior quadrant and lower average thickness (P<0.05). CSV was the functional parameter most strongly correlated with structural measurements in patients with AD. Color vision was strongly associated with macular volume (r>0.70, P<0.05). VA at different levels of contrast was associated with macular and RNFL thickness.ConclusionsPatients with AD had visual dysfunction that correlated with structural changes evaluated by SD-OCT. Macular measurements may be reliable indicators of visual impairment in AD patients.
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Abstract
Recent research in Alzheimer’s disease (AD) indicates that perceptual impairments may occur before the onset of cognitive declines, and can thus serve as an early noninvasive indicator for AD. In this study, we focused on visual motion processing and explored whether AD induces changes in the properties of direction repulsion between two competing motions. We used random dot kinematograms (RDKs) and measured the magnitudes of direction repulsion between two overlapping RDKs moving different directions in three groups of participants: an AD group, an age-matched old control group, and a young control group. We showed that motion direction repulsion was significantly weaker in AD patients as comparing to both healthy controls. More importantly, we found that the magnitude of motion repulsion was predictive of the assessment of clinical severity in the AD group. Our results implicate that AD pathology is associated with altered neural functions in visual cortical areas and that motion repulsion deficit is a behavioral biomarker for the tracking of AD development.
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Kaubrys G, Bukina V, Bingelytė I, Taluntis V. Perception of Fechner Illusory Colors in Alzheimer Disease Patients. Med Sci Monit 2016; 22:4670-4678. [PMID: 27902677 PMCID: PMC5134362 DOI: 10.12659/msm.902061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 11/22/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Alzheimer disease (AD) primarily affects cognition. A variety of visual disorders was established in AD. Fechner illusory colors are produced by a rotating disk with a black and white pattern. The purpose of our research was to explore the perception of illusory colors in AD. MATERIAL AND METHODS W recruited 40 AD patients (MMSE ≥14) and 40 normal controls (CG group) matched by age, education, gender in this prospective, cross-sectional, case-control study. An achromatic Benham's disk attached to a device to control the speed and direction of rotation was used to produce illusory colors. Primary, secondary, and tertiary RGB system colors were used for matching of illusory and physical colors. RESULTS Subjects in the AD group perceived less illusory colors in 5 arcs (p<0.05) of the 8 arcs assessed. The biggest difference was found between AD and CG groups for pure blue (χ²=26.87, p<0.001 clockwise, χ²=22.75, p<0.001 counter-clockwise). Groups did not differ in perception of pure yellow opponent colors (p>0.05). Mixed colors of the blue-yellow axis were perceived less often in AD, but more frequently than pure blue (#0000FF). The sequence of colors on Benham's disk followed a complex pattern, different from the order of physical spectral colors and opponent processes-based colors. CONCLUSIONS AD patients retained reduced perception of illusory colors. The perception of pure blue illusory color is almost absent in AD. The asymmetrical shift to the yellow opponent is observed in AD with red prevailing over green constituent. This may indicate cortical rather than retinal impairment.
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Affiliation(s)
- Gintaras Kaubrys
- Department of Neurology and Neurosurgery, Center for Neurology, Vilnius University, Vilnius, Lithuania
| | - Vera Bukina
- Department of Neurology and Neurosurgery, Center for Neurology, Vilnius University, Vilnius, Lithuania
| | - Ieva Bingelytė
- Department of Internal Diseases, Family Medicine and Oncology, Center of Family Medicine, Vilnius University, Vilnius, Lithuania
| | - Vladas Taluntis
- Department of Electronic Systems, Faculty of Electronics, Vilnius Gediminas Technical University, Vilnius, Lithuania
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Sanfilippo C, Malaguarnera L, Di Rosa M. Chitinase expression in Alzheimer's disease and non-demented brains regions. J Neurol Sci 2016; 369:242-249. [DOI: 10.1016/j.jns.2016.08.029] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/03/2016] [Accepted: 08/12/2016] [Indexed: 12/20/2022]
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Barzegaran E, van Damme B, Meuli R, Knyazeva MG. Perception-related EEG is more sensitive to Alzheimer's disease effects than resting EEG. Neurobiol Aging 2016; 43:129-39. [DOI: 10.1016/j.neurobiolaging.2016.03.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/28/2016] [Accepted: 03/30/2016] [Indexed: 01/06/2023]
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Ma X, Wang D, Zhou Y, Zhuo C, Qin W, Zhu J, Yu C. Sex-dependent alterations in resting-state cerebral blood flow, amplitude of low-frequency fluctuations and their coupling relationship in schizophrenia. Aust N Z J Psychiatry 2016; 50:334-44. [PMID: 26384367 DOI: 10.1177/0004867415601728] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE We aimed to investigate sex-dependent alterations in resting-state relative cerebral blood flow, amplitude of low-frequency fluctuations and relative cerebral blood flow-amplitude of low-frequency fluctuations coupling in patients with schizophrenia. METHOD Resting-state functional magnetic resonance imaging and three-dimensional pseudo-continuous arterial spin labeling imaging were performed to obtain resting-state amplitude of low-frequency fluctuations and relative cerebral blood flow in 95 schizophrenia patients and 99 healthy controls. Sex differences in relative cerebral blood flow and amplitude of low-frequency fluctuations were compared in both groups. Diagnostic group differences in relative cerebral blood flow, amplitude of low-frequency fluctuations and relative cerebral blood flow-amplitude of low-frequency fluctuations coupling were compared in male and female subjects, respectively. RESULTS In both healthy controls and schizophrenia patients, the males had higher relative cerebral blood flow in anterior brain regions and lower relative cerebral blood flow in posterior brain regions than did the females. Compared with multiple regions exhibiting sex differences in relative cerebral blood flow, only the left middle frontal gyrus had a significant sex difference in amplitude of low-frequency fluctuations. In the females, schizophrenia patients exhibited increased relative cerebral blood flow and amplitude of low-frequency fluctuations in the basal ganglia, thalamus and hippocampus and reduced relative cerebral blood flow and amplitude of low-frequency fluctuations in the frontal, parietal and occipital regions compared with those of healthy controls. However, there were fewer brain regions with diagnostic group differences in the males than in the females. Brain regions with diagnostic group differences in relative cerebral blood flow and amplitude of low-frequency fluctuations only partially overlapped. Only the female patients exhibited increased relative cerebral blood flow-amplitude of low-frequency fluctuations couplings compared with those of healthy females. CONCLUSION The alterations in the relative cerebral blood flow and amplitude of low-frequency fluctuations in schizophrenia are sex-specific, which should be considered in future neuroimaging studies. The relative cerebral blood flow and amplitude of low-frequency fluctuations have different sensitivity in detecting changes in neuronal activity in schizophrenia and can provide complementary information.
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Affiliation(s)
- Xiaomei Ma
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Di Wang
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Yujing Zhou
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Chuanjun Zhuo
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Wen Qin
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Jiajia Zhu
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Chunshui Yu
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
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Pal A, Biswas A, Pandit A, Roy A, Guin D, Gangopadhyay G, Senapati AK. Study of visuospatial skill in patients with dementia. Ann Indian Acad Neurol 2016; 19:83-8. [PMID: 27011635 PMCID: PMC4782559 DOI: 10.4103/0972-2327.168636] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To assess the visuospatial function in different types of dementia with the visual object and space perception (VOSP) battery and to relate the degree of visuospatial dysfunction with different types and stages of dementia. MATERIALS AND METHODS A sample of 53 participants with dementia and equal number of age-, sex-, and education-matched controls were recruited for the study. Participants were evaluated for visuospatial skill using VOSP test battery. The scores of dementia patients were compared with controls and within dementia cohort scores were compared based on stage of dementia. RESULTS The dementia group scored low in all of the subtests of the VOSP battery in comparison to controls. Alzheimer's disease (AD), dementia of Lewy bodies (DLB), and vascular dementia (VaD) patients performed more poorly than controls in all subtests examining object perception and space perception. The three semantic variants of frontotemporal dementia (FTD) patients scored low in all four subtests of object perception, whereas behavioral variant FTD (bvFTD) patients performed normally. The scores deteriorated with the advancement of dementia in all patients from the dementia groups. CONCLUSIONS Visuospatial function is significantly impaired in dementia patients particularly in AD, DLB, and VaD patients from the beginning, and the impairment is severe in advanced disease stages.
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Affiliation(s)
- Asutosh Pal
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Atanu Biswas
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Alak Pandit
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Arijit Roy
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Debsankar Guin
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Goutam Gangopadhyay
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
| | - Asit Kumar Senapati
- Department of Neurology, Bangur Institute of Neurosciences, Kolkata, West Bengal, India
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Ward LM, Morison G, Simpson WA, Simmers AJ, Shahani U. Using Functional Near Infrared Spectroscopy (fNIRS) to Study Dynamic Stereoscopic Depth Perception. Brain Topogr 2016; 29:515-23. [PMID: 26900069 PMCID: PMC4899499 DOI: 10.1007/s10548-016-0476-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 02/08/2016] [Indexed: 11/28/2022]
Abstract
The parietal cortex has been widely implicated in the processing of depth perception by many neuroimaging studies, yet functional near infrared spectroscopy (fNIRS) has been an under-utilised tool to examine the relationship of oxy- ([HbO]) and de-oxyhaemoglobin ([HbR]) in perception. Here we examine the haemodynamic response (HDR) to the processing of induced depth stimulation using dynamic random-dot-stereograms (RDS). We used fNIRS to measure the HDR associated with depth perception in healthy young adults (n = 13, mean age 24). Using a blocked design, absolute values of [HbO] and [HbR] were recorded across parieto-occipital and occipital cortices, in response to dynamic RDS. Control and test images were identical except for the horizontal shift in pixels in the RDS that resulted in binocular disparity and induced the percept of a 3D sine wave that ‘popped out’ of the test stimulus. The control stimulus had zero disparity and induced a ‘flat’ percept. All participants had stereoacuity within normal clinical limits and successfully perceived the depth in the dynamic RDS. Results showed a significant effect of this complex visual stimulation in the right parieto-occipital cortex (p < 0.01, η2 = 0.54). The test stimulus elicited a significant increase in [HbO] during depth perception compared to the control image (p < 0.001, 99.99 % CI [0.008–0.294]). The similarity between the two stimuli may have resulted in the HDR of the occipital cortex showing no significant increase or decrease of cerebral oxygenation levels during depth stimulation. Cerebral oxygenation measures of [HbO] confirmed the strong association of the right parieto-occipital cortex with processing depth perception. Our study demonstrates the validity of fNIRS to investigate [HbO] and [HbR] during high-level visual processing of complex stimuli.
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Affiliation(s)
- Laura M Ward
- Department of Vision Sciences, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, UK
| | - Gordon Morison
- Department of Engineering, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, UK
| | - William A Simpson
- School of Psychology, Plymouth University, Drake Circus, Plymouth, Devon, PL4 8AA, UK
| | - Anita J Simmers
- Department of Vision Sciences, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, UK
| | - Uma Shahani
- Department of Vision Sciences, Glasgow Caledonian University, 70 Cowcaddens Road, Glasgow, G4 0BA, UK.
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40
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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] [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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Li H, Hou X, Liu H, Yue C, He Y, Zuo X. Toward systems neuroscience in mild cognitive impairment and Alzheimer's disease: a meta-analysis of 75 fMRI studies. Hum Brain Mapp 2015; 36:1217-32. [PMID: 25411150 PMCID: PMC6869191 DOI: 10.1002/hbm.22689] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/03/2014] [Accepted: 11/03/2014] [Indexed: 11/11/2022] Open
Abstract
Most of the previous task functional magnetic resonance imaging (fMRI) studies found abnormalities in distributed brain regions in mild cognitive impairment (MCI) and Alzheimer's disease (AD), and few studies investigated the brain network dysfunction from the system level. In this meta-analysis, we aimed to examine brain network dysfunction in MCI and AD. We systematically searched task-based fMRI studies in MCI and AD published between January 1990 and January 2014. Activation likelihood estimation meta-analyses were conducted to compare the significant group differences in brain activation, the significant voxels were overlaid onto seven referenced neuronal cortical networks derived from the resting-state fMRI data of 1,000 healthy participants. Thirty-nine task-based fMRI studies (697 MCI patients and 628 healthy controls) were included in MCI-related meta-analysis while 36 task-based fMRI studies (421 AD patients and 512 healthy controls) were included in AD-related meta-analysis. The meta-analytic results revealed that MCI and AD showed abnormal regional brain activation as well as large-scale brain networks. MCI patients showed hypoactivation in default, frontoparietal, and visual networks relative to healthy controls, whereas AD-related hypoactivation mainly located in visual, default, and ventral attention networks relative to healthy controls. Both MCI-related and AD-related hyperactivation fell in frontoparietal, ventral attention, default, and somatomotor networks relative to healthy controls. MCI and AD presented different pathological while shared similar compensatory large-scale networks in fulfilling the cognitive tasks. These system-level findings are helpful to link the fundamental declines of cognitive tasks to brain networks in MCI and AD.
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Affiliation(s)
- Hui‐Jie Li
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
| | - Xiao‐Hui Hou
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
- University of Chinese Academy of SciencesBeijing100049China
| | - Han‐Hui Liu
- Youth Work DepartmentChina Youth University of Political StudiesBeijing100089China
| | - Chun‐Lin Yue
- Institute of Sports MedicineSoochow UniversitySuzhou215006China
| | - Yong He
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain ResearchBeijing Normal UniversityBeijing100875China
- Center for Collaboration and Innovation in Brain and Learning SciencesBeijing Normal UniversityBeijing100875China
| | - Xi‐Nian Zuo
- Key Laboratory of Behavioral ScienceInstitute of PsychologyChinese Academy of SciencesBeijing100101China
- Center for Collaboration and Innovation in Brain and Learning SciencesBeijing Normal UniversityBeijing100875China
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Meusel LAC, Kansal N, Tchistiakova E, Yuen W, MacIntosh BJ, Greenwood CE, Anderson ND. A systematic review of type 2 diabetes mellitus and hypertension in imaging studies of cognitive aging: time to establish new norms. Front Aging Neurosci 2014; 6:148. [PMID: 25071557 PMCID: PMC4085499 DOI: 10.3389/fnagi.2014.00148] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 06/17/2014] [Indexed: 12/19/2022] Open
Abstract
The rising prevalence of type 2 diabetes (T2DM) and hypertension in older adults, and the deleterious effect of these conditions on cerebrovascular and brain health, is creating a growing discrepancy between the "typical" cognitive aging trajectory and a "healthy" cognitive aging trajectory. These changing health demographics make T2DM and hypertension important topics of study in their own right, and warrant attention from the perspective of cognitive aging neuroimaging research. Specifically, interpretation of individual or group differences in blood oxygenation level dependent magnetic resonance imaging (BOLD MRI) or positron emission tomography (PET H2O(15)) signals as reflective of differences in neural activation underlying a cognitive operation of interest requires assumptions of intact vascular health amongst the study participants. Without adequate screening, inclusion of individuals with T2DM or hypertension in "healthy" samples may introduce unwanted variability and bias to brain and/or cognitive measures, and increase potential for error. We conducted a systematic review of the cognitive aging neuroimaging literature to document the extent to which researchers account for these conditions. Of the 232 studies selected for review, few explicitly excluded individuals with T2DM (9%) or hypertension (13%). A large portion had exclusion criteria that made it difficult to determine whether T2DM or hypertension were excluded (44 and 37%), and many did not mention any selection criteria related to T2DM or hypertension (34 and 22%). Of all the surveyed studies, only 29% acknowledged or addressed the potential influence of intersubject vascular variability on the measured BOLD or PET signals. To reinforce the notion that individuals with T2DM and hypertension should not be overlooked as a potential source of bias, we also provide an overview of metabolic and vascular changes associated with T2DM and hypertension, as they relate to cerebrovascular and brain health.
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Affiliation(s)
| | - Nisha Kansal
- Baycrest Centre, Rotman Research Institute Toronto, ON, Canada
| | - Ekaterina Tchistiakova
- Sunnybrook Research Institute, Heart and Stroke Foundation Canadian Partnership for Stroke Recovery Toronto, ON, Canada ; Department of Medical Biophysics, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - William Yuen
- Baycrest Centre, Rotman Research Institute Toronto, ON, Canada ; Department of Nutritional Sciences, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Bradley J MacIntosh
- Sunnybrook Research Institute, Heart and Stroke Foundation Canadian Partnership for Stroke Recovery Toronto, ON, Canada ; Department of Medical Biophysics, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Carol E Greenwood
- Baycrest Centre, Rotman Research Institute Toronto, ON, Canada ; Department of Nutritional Sciences, Faculty of Medicine, University of Toronto Toronto, ON, Canada
| | - Nicole D Anderson
- Baycrest Centre, Rotman Research Institute Toronto, ON, Canada ; Departments of Psychology and Psychiatry, University of Toronto Toronto, ON, Canada
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43
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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] [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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Brewer AA, Barton B. Visual cortex in aging and Alzheimer's disease: changes in visual field maps and population receptive fields. Front Psychol 2014; 5:74. [PMID: 24570669 PMCID: PMC3916727 DOI: 10.3389/fpsyg.2014.00074] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 01/20/2014] [Indexed: 11/20/2022] Open
Abstract
Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1) during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer's disease (AD), the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM) organization and population receptive fields (pRFs) between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD.
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Affiliation(s)
- Alyssa A Brewer
- Laboratory of Visual Neuroscience, Department of Cognitive Sciences, Center for Cognitive Neuroscience, University of California Irvine, CA, USA
| | - Brian Barton
- Laboratory of Visual Neuroscience, Department of Cognitive Sciences, Center for Cognitive Neuroscience, University of California Irvine, CA, USA
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Chang LYL, Lowe J, Ardiles A, Lim J, Grey AC, Robertson K, Danesh-Meyer H, Palacios AG, Acosta ML. Alzheimer's disease in the human eye. Clinical tests that identify ocular and visual information processing deficit as biomarkers. Alzheimers Dement 2013; 10:251-61. [PMID: 24011928 DOI: 10.1016/j.jalz.2013.06.004] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/21/2013] [Accepted: 06/03/2013] [Indexed: 12/19/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia with progressive deterioration of memory and cognition. Complaints related to vision are common among AD patients. Several changes in the retina, lens, and in the vasculature have been noted in the AD eye that may be the cause of visual symptoms experienced by the AD patient. Anatomical changes have been detected within the eye before signs of cognitive impairment and memory loss are apparent. Unlike the brain, the eye is a unique organ that can be visualized noninvasively at the cellular level because of its transparent nature, which allows for inexpensive testing of biomarkers in a clinical setting. In this review, we have searched for candidate biomarkers that could enable diagnosis of AD, covering ocular neurodegeneration associated with functional tests. We explore the evidence that suggests that inexpensive, noninvasive clinical tests could be used to detect AD ocular biomarkers.
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Affiliation(s)
- Lily Y L Chang
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Jennifer Lowe
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand
| | - Alvaro Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Julie Lim
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Angus C Grey
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Ken Robertson
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand
| | - Helen Danesh-Meyer
- New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand; Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Adrian G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Monica L Acosta
- Department of Optometry and Vision Science, The University of Auckland, Auckland, New Zealand; New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
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Quental NBM, Brucki SMD, Bueno OFA. Visuospatial function in early Alzheimer's disease--the use of the Visual Object and Space Perception (VOSP) battery. PLoS One 2013; 8:e68398. [PMID: 23874610 PMCID: PMC3713013 DOI: 10.1371/journal.pone.0068398] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 05/31/2013] [Indexed: 12/04/2022] Open
Abstract
Alzheimer’s disease (AD) is the most frequent cause of dementia. The clinical symptoms of AD begin with impairment of memory and executive function followed by the gradual involvement of other functions, such as language, semantic knowledge, abstract thinking, attention, and visuospatial abilities. Visuospatial function involves the identification of a stimulus and its location and can be impaired at the beginning of AD. The Visual Object and Space Perception (VOSP) battery evaluates visuospatial function, while minimizing the interference of other cognitive functions. Objectives To evaluate visuospatial function in early AD patients using the VOSP and determine cutoff scores to differentiate between cognitively healthy individuals and AD patients. Methods Thirty-one patients with mild AD and forty-four healthy elderly were evaluated using a neuropsychological battery and the VOSP. Results In the VOSP, the AD patients performed more poorly in all subtests examining object perception and in two subtests examining space perception (Number Location and Cube Analysis). The VOSP showed good accuracy and good correlation with tests measuring visuospatial function. Conclusion Visuospatial function is impaired in the early stages of AD. The VOSP battery is a sensitive battery test for visuospatial deficits with minimal interference by other cognitive functions.
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Graewe B, Lemos R, Ferreira C, Santana I, Farivar R, De Weerd P, Castelo-Branco M. Impaired processing of 3D motion-defined faces in mild cognitive impairment and healthy aging: an fMRI study. Cereb Cortex 2012; 23:2489-99. [PMID: 22879351 DOI: 10.1093/cercor/bhs246] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mild cognitive impairment (MCI), which shows high risk for conversion to Alzheimer's disease (AD), is accompanied by progressive visual deteriorations that so far are poorly understood. Here, we compared dorsal and ventral visual stream functional magnetic resonance imaging (fMRI) activity among amnestic MCI, healthy elderly, and young participants during structure-from-motion (SFM) face categorization performance. Task performance varied with stimulus depth and duration levels and differences among groups were highly correlated with face-related fMRI activation patterns. Young participants showed larger activation to faces than scrambled faces (face sensitivity) in the right fusiform face area (FFA) and right occipital face area (OFA) whereas in elderly, this difference was reduced. Surprisingly, in MCI, scrambled faces elicited larger activation in right FFA/OFA than faces. The latter observation may be related to the additional finding of elevated depth sensitivity in left FFA/OFA of MCI, suggesting that an increased representation of low-level stimulus aspects may impair face perception in MCI. Discriminant function analysis using face and depth sensitivity indices in FFA/OFA classified MCI and healthy elderly with 88.2% accuracy, marking a fundamental distinction between groups. Potentially related findings include altered activation patterns in dorsal-ventral stream integration regions and attention-related networks of MCI patients. Our results highlight aberrant visual and additional potentially compensatory processes that identify dispositions of (preclinical) AD.
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Affiliation(s)
- Britta Graewe
- Department of Cognitive Neuroscience, Faculty of Psychology & Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
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Browndyke JN, Giovanello K, Petrella J, Hayden K, Chiba-Falek O, Tucker KA, Burke JR, Welsh-Bohmer KA. Phenotypic regional functional imaging patterns during memory encoding in mild cognitive impairment and Alzheimer's disease. Alzheimers Dement 2012; 9:284-94. [PMID: 22841497 DOI: 10.1016/j.jalz.2011.12.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 12/10/2011] [Accepted: 12/28/2011] [Indexed: 10/28/2022]
Abstract
BACKGROUND Reliable blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) phenotypic biomarkers of Alzheimer's disease (AD) or mild cognitive impairment (MCI) are likely to emerge only from a systematic, quantitative, and aggregate examination of the functional neuroimaging research literature. METHODS A series of random-effects activation likelihood estimation (ALE) meta-analyses were conducted on studies of episodic memory encoding operations in AD and MCI samples relative to normal controls. ALE analyses were based on a thorough literature search for all task-based functional neuroimaging studies in AD and MCI published up to January 2010. Analyses covered 16 fMRI studies, which yielded 144 distinct foci for ALE meta-analysis. RESULTS ALE results indicated several regional task-based BOLD consistencies in MCI and AD patients relative to normal control subjects across the aggregate BOLD functional neuroimaging research literature. Patients with AD and those at significant risk (MCI) showed statistically significant consistent activation differences during episodic memory encoding in the medial temporal lobe, specifically parahippocampal gyrus, as well superior frontal gyrus, precuneus, and cuneus, relative to normal control subjects. CONCLUSIONS ALE consistencies broadly support the presence of frontal compensatory activity, medial temporal lobe activity alteration, and posterior midline "default mode" hyperactivation during episodic memory encoding attempts in the diseased or prospective predisease condition. Taken together, these robust commonalities may form the foundation for a task-based fMRI phenotype of memory encoding in AD.
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Affiliation(s)
- Jeffrey N Browndyke
- Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Duke University, Durham, NC, USA.
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Ginani GE, Tufik S, Bueno OFA, Pradella-Hallinan M, Rusted J, Pompéia S. Acute effects of donepezil in healthy young adults underline the fractionation of executive functioning. J Psychopharmacol 2011; 25:1508-16. [PMID: 21262858 DOI: 10.1177/0269881110391832] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The cholinergic system is involved in the modulation of both bottom-up and top-down attentional control. Top-down attention engages multiple executive control processes, but few studies have investigated whether all or selective elements of executive functions are modulated by the cholinergic system. To investigate the acute effects of the pro-cholinergic donepezil in young, healthy volunteers on distinct components of executive functions we conducted a double-blind, placebo-controlled, independent-groups design study including 42 young healthy male participants who were randomly assigned to one of three oral treatments: glucose (placebo), donepezil 5 mg or donepezil 7.5 mg. The test battery included measures of different executive components (shifting, updating, inhibition, dual-task performance, planning, access to long-term memory), tasks that evaluated arousal/vigilance/visuomotor performance, as well as functioning of working memory subsidiary systems. Donepezil improved sustained attention, reaction times, dual-task performance and the executive component of digit span. The positive effects in these executive tasks did not correlate with arousal/visuomotor/vigilance measures. Among the various executive domains investigated donepezil selectively increased dual-task performance in a manner that could not be ascribed to improvement in arousal/vigilance/visuomotor performance nor working memory slave systems. Other executive tasks that rely heavily on visuospatial processing may also be modulated by the cholinergic system.
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Affiliation(s)
- G E Ginani
- Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil
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Understanding the Pathophysiology of Alzheimer's Disease and Mild Cognitive Impairment: A Mini Review on fMRI and ERP Studies. Neurol Res Int 2011; 2012:719056. [PMID: 21773027 PMCID: PMC3135099 DOI: 10.1155/2012/719056] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/11/2011] [Accepted: 05/15/2011] [Indexed: 01/02/2023] Open
Abstract
The prevalence of Alzheimer's disease (AD) is predicted to increase rapidly in the coming decade, highlighting the importance of early detection and intervention in patients with AD and mild cognitive impairment (MCI). Recently, remarkable advances have been made in the application of neuroimaging techniques in investigations of AD and MCI. Among the various neuroimaging techniques, functional magnetic resonance imaging (fMRI) has many potential advantages, noninvasively detecting alterations in brain function that may be present very early in the course of AD and MCI. In this paper, we first review task-related and resting-state fMRI studies on AD and MCI. We then present our recent fMRI studies with additional event-related potential (ERP) experiments during a motion perception task in MCI. Our results indicate that fMRI, especially when combined with ERP recording, can be useful for detecting spatiotemporal functional changes in AD and MCI patients.
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