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Xu Y, Aung HL, Hesam-Shariati N, Keay L, Sun X, Phu J, Honson V, Tully PJ, Booth A, Lewis E, Anderson CS, Anstey KJ, Peters R. Contrast Sensitivity, Visual Field, Color Vision, Motion Perception, and Cognitive Impairment: A Systematic Review. J Am Med Dir Assoc 2024; 25:105098. [PMID: 38908397 DOI: 10.1016/j.jamda.2024.105098] [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: 07/23/2023] [Revised: 02/07/2024] [Accepted: 05/12/2024] [Indexed: 06/24/2024]
Abstract
OBJECTIVES To examine relationships between visual function (ie, contrast sensitivity, visual field, color vision, and motion perception) and cognitive impairment, including any definition of "cognitive impairment," mild cognitive impairment, or dementia. DESIGN Systematic review and meta-analyses. SETTING AND PARTICIPANTS Any settings; participants with (cases) or without (controls) cognitive impairment. METHODS We searched 4 databases (to January 2024) and included published studies that compared visual function between cases and controls. Standardized mean differences (SMD) with 95% CIs were calculated where data were available. Data were sufficient for meta-analyses when cases were people with dementia. The Joanna Briggs Institute checklists were used for quality assessment. RESULTS Fifty-one studies/69 reports were included. Cross-sectional evidence shows that people with dementia had worse contrast sensitivity function and color vision than controls: measured by contrast sensitivity (log units) on letter charts, SMD -1.22 (95% CI -1.98, -0.47), or at varied spatial frequencies, -0.92 (-1.28, -0.57); and by pseudoisochromatic plates, -1.04 (-1.59, -0.49); color arrangement, -1.30 (-2.31, -0.29); or matching tests, -0.51 (-0.78, -0.24). They also performed more poorly on tests of motion perception, -1.20 (-1.73, -0.67), and visual field: mean deviation, -0.87 (-1.29, -0.46), and pattern standard deviation, -0.69 (-1.24, -0.15). Results were similar when cases were limited to participants with clinically diagnosed Alzheimer disease. Sources of bias included lack of clarity on study populations or settings and definitions of cognitive impairment. The 2 included longitudinal studies with follow-ups of approximately 10 years were of good quality but reported inconsistent results. CONCLUSIONS AND IMPLICATIONS In the lack of longitudinal data, cross-sectional studies indicate that individuals with cognitive impairment have poorer visual function than those with normal cognition. Additional longitudinal data are needed to understand whether poor visual function precedes cognitive impairment and the most relevant aspects of visual function, dementia pathologies, and domains of cognition.
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Affiliation(s)
- Ying Xu
- Neuroscience Research Australia, Sydney, Australia; School of Psychology, Faculty of Science, UNSW Sydney, Sydney, Australia; The George Institute for Global Health, UNSW Sydney, Sydney, Australia; Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Ageing Futures Institute, UNSW Sydney, Sydney, Australia; Centre for Health Systems and Safety Research, Australian Institute of Health Innovation, Macquarie University, Sydney, Australia.
| | - Htein Linn Aung
- Neuroscience Research Australia, Sydney, Australia; Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia
| | - Negin Hesam-Shariati
- Neuroscience Research Australia, Sydney, Australia; School of Psychology, Faculty of Science, UNSW Sydney, Sydney, Australia
| | - Lisa Keay
- The George Institute for Global Health, UNSW Sydney, Sydney, Australia; Ageing Futures Institute, UNSW Sydney, Sydney, Australia; School of Optometry and Vision Science, UNSW Sydney, Sydney, Australia
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Shanghai Key Laboratory of Fundus Diseases, Shanghai, China; Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China; National Clinical Research Center for Ophthalmic Diseases, Shanghai, China
| | - Jack Phu
- School of Optometry and Vision Science, UNSW Sydney, Sydney, Australia; Center for Eye Health, UNSW Sydney, Sydney, Australia; Faculty of Medicine and Health, University of Sydney, Sydney, Australia; Concord Clinical School, Concord Repatriation General Hospital, Sydney, Australia
| | - Vanessa Honson
- School of Optometry and Vision Science, UNSW Sydney, Sydney, Australia
| | - Phillip J Tully
- School of Psychology, The University of New England, Armidale, Australia
| | - Andrew Booth
- School of Health and Related Research, University of Sheffield, Sheffield, United Kingdom
| | - Ebony Lewis
- Neuroscience Research Australia, Sydney, Australia; School of Psychology, Faculty of Science, UNSW Sydney, Sydney, Australia; Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Ageing Futures Institute, UNSW Sydney, Sydney, Australia
| | - Craig S Anderson
- The George Institute for Global Health, UNSW Sydney, Sydney, Australia; Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; The George Institute China, Peking University Health Science Center, Beijing, China; Neurology Department, Royal Prince Alfred Hospital, Sydney, Australia
| | - Kaarin J Anstey
- Neuroscience Research Australia, Sydney, Australia; School of Psychology, Faculty of Science, UNSW Sydney, Sydney, Australia; Ageing Futures Institute, UNSW Sydney, Sydney, Australia
| | - Ruth Peters
- Neuroscience Research Australia, Sydney, Australia; School of Psychology, Faculty of Science, UNSW Sydney, Sydney, Australia; The George Institute for Global Health, UNSW Sydney, Sydney, Australia; Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Ageing Futures Institute, UNSW Sydney, Sydney, Australia; School of Public Health, Imperial College London, London, United Kingdom
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Noroozian M. Alzheimer's Disease: Prototype of Cognitive Deterioration, Valuable Lessons to Understand Human Cognition. Neurol Clin 2016; 34:69-131. [PMID: 26613996 DOI: 10.1016/j.ncl.2015.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It is important for neurologists to become more familiar with neuropsychological evaluation for Alzheimer disease. The growth of this method in research, as an available, inexpensive, and noninvasive diagnostic approach, which can be administered even by non-specialist-trained examiners, makes this knowledge more necessary than ever. Such knowledge has a basic role in planning national programs in primary health care systems for prevention and early detection of Alzheimer disease. This is more crucial in developing countries, which have higher rates of dementia prevalence along with cardiovascular risk factors, lack of public knowledge about dementia, and limited social support. In addition compared to the neurological hard signs which are tangible and measurable, the concept of cognition seems to be more difficult for the neurologists to evaluate and for the students to understand. Dementia in general and Alzheimer's disease as the prototype of cognitive disorders specifically, play an important role to explore all domains of human cognition through its symptomatology and neuropsychological deficits.
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Affiliation(s)
- Maryam Noroozian
- Memory and Behavioral Neurology Division, Department of Psychiatry, Roozbeh Hospital, Tehran University of Medical Sciences, 606 South Kargar Avenue, Tehran 1333795914, Iran.
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Lavallée MM, Gandini D, Rouleau I, Vallet GT, Joannette M, Kergoat MJ, Busigny T, Rossion B, Joubert S. A Qualitative Impairment in Face Perception in Alzheimer’s Disease: Evidence from a Reduced Face Inversion Effect. J Alzheimers Dis 2016; 51:1225-36. [DOI: 10.3233/jad-151027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Marie Maxime Lavallée
- Département de psychologie, Université de Montréal, Montréal, Canada
- Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Canada
| | - Delphine Gandini
- Département de psychologie, Université de Montréal, Montréal, Canada
- Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Canada
| | - Isabelle Rouleau
- Département de psychologie, Université du Québec à Montréal, Montréal, Canada
- Centre de recherche du Centre hospitalier universitaire de Montréal (CHUM), Montréal, Canada
| | - Guillaume T. Vallet
- Département de psychologie, Université de Montréal, Montréal, Canada
- Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Canada
| | - Maude Joannette
- Département de psychologie, Université de Montréal, Montréal, Canada
- Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Canada
| | - Marie-Jeanne Kergoat
- Département de médecine, Université de Montréal, Montréal, Canada
- Clinique de cognition, Institut universitaire de gériatrie de Montréal, Montréal, Canada
| | - Thomas Busigny
- CHU Purpan, Toulouse, France
- Institut de Recherche en Sciences Psychologique et institut de Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Bruno Rossion
- Institut de Recherche en Sciences Psychologique et institut de Neuroscience, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Sven Joubert
- Département de psychologie, Université de Montréal, Montréal, Canada
- Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Canada
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Yang Y, Shiao C, Hemingway JF, Jorstad NL, Shalloway BR, Chang R, Keene CD. Suppressed retinal degeneration in aged wild type and APPswe/PS1ΔE9 mice by bone marrow transplantation. PLoS One 2013; 8:e64246. [PMID: 23750207 PMCID: PMC3672108 DOI: 10.1371/journal.pone.0064246] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/10/2013] [Indexed: 11/18/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related condition characterized by accumulation of neurotoxic amyloid β peptides (Aβ) in brain and retina. Because bone marrow transplantation (BMT) results in decreased cerebral Aβ in experimental AD, we hypothesized that BMT would mitigate retinal neurotoxicity through decreased retinal Aβ. To test this, we performed BMT in APPswe/PS1ΔE9 double transgenic mice using green fluorescent protein expressing wild type (wt) mice as marrow donors. We first examined retinas from control, non-transplanted, aged AD mice and found a two-fold increase in microglia compared with wt mice, prominent inner retinal Aβ and paired helical filament-tau, and decreased retinal ganglion cell layer neurons. BMT resulted in near complete replacement of host retinal microglia with BMT-derived cells and normalized total AD retinal microglia to non-transplanted wt levels. Aβ and paired helical filament-tau were reduced (61.0% and 44.1% respectively) in BMT-recipient AD mice, which had 20.8% more retinal ganglion cell layer neurons than non-transplanted AD controls. Interestingly, aged wt BMT recipients also had significantly more neurons (25.4%) compared with non-transplanted aged wt controls. Quantitation of retinal ganglion cell layer neurons in young mice confirmed age-related retinal degeneration was mitigated by BMT. We found increased MHC class II expression in BMT-derived microglia and decreased oxidative damage in retinal ganglion cell layer neurons. Thus, BMT is neuroprotective in age-related as well as AD-related retinal degeneration, and may be a result of alterations in innate immune function and oxidative stress in BMT recipient mice.
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Affiliation(s)
- Yue Yang
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Christine Shiao
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Jake Frederick Hemingway
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Nikolas L. Jorstad
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Bryan Richard Shalloway
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - Rubens Chang
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
| | - C. Dirk Keene
- Department of Pathology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Goudour A, Samson S, Bakchine S, Ehrle N. Agnosic or semantic impairment in very mild Alzheimer's disease? NEUROPSYCHOLOGY, DEVELOPMENT, AND COGNITION. SECTION B, AGING, NEUROPSYCHOLOGY AND COGNITION 2011; 18:230-253. [PMID: 21360357 DOI: 10.1080/13825585.2010.540643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The present study investigated object recognition impairment and the existence of category effects in patients with mild Alzheimer's disease. A battery of tests was designed to assess the deterioration of semantic memory and/or the existence of agnosia by evaluating visual and auditory naming, knowledge of structural descriptions (pre-semantic representation of an object within each perceptual system) and conceptual knowledge. The group of Alzheimer's patients were impaired in all experimental tests as compared to healthy participants. This result suggests an impairment of multiple levels of object integration processing even at an early stage of the disease. The patients also demonstrated a category effect with massive difficulties in recognizing human actions and musical instruments as compared to the other categories. This study provides an innovative clinical tool for exploring the recognition of visual and auditory objects at different levels of representation, allowing for the description of early signs of Alzheimer disease.
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Affiliation(s)
- Amandine Goudour
- Service de Neurologie & CMRR Champagne-Ardenne, Centre Hospitalier Universitaire de Reims, France
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Liu B, Rasool S, Yang Z, Glabe CG, Schreiber SS, Ge J, Tan Z. Amyloid-peptide vaccinations reduce {beta}-amyloid plaques but exacerbate vascular deposition and inflammation in the retina of Alzheimer's transgenic mice. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:2099-110. [PMID: 19834067 DOI: 10.2353/ajpath.2009.090159] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alzheimer's disease (AD) is pathologically characterized by accumulation of beta-amyloid (Abeta) protein deposits and/or neurofibrillary tangles in association with progressive cognitive deficits. Although numerous studies have demonstrated a relationship between brain pathology and AD progression, the Alzheimer's pathological hallmarks have not been found in the AD retina. A recent report showed Abeta plaques in the retinas of APPswe/PS1DeltaE9 transgenic mice. We now report the detection of Abeta plaques with increased retinal microvascular deposition of Abeta and neuroinflammation in Tg2576 mouse retinas. The majority of Abeta-immunoreactive plaques were detected from the ganglion cell layer to the inner plexiform layer, and some plaques were observed in the outer nuclear layer, photoreceptor outer segment, and optic nerve. Hyperphosphorylated tau was labeled in the corresponding areas of the Abeta plaques in adjacent sections. Although Abeta vaccinations reduced retinal Abeta deposits, there was a marked increase in retinal microvascular Abeta deposition as well as local neuroinflammation manifested by microglial infiltration and astrogliosis linked with disruption of the retinal organization. These results provide evidence to support further investigation of the use of retinal imaging to diagnose AD and to monitor disease activity.
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Affiliation(s)
- Bingqian Liu
- Department of Neurology, University of California Irvine School of Medicine, USA
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7
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Bush ALH, Allen PA, Kaut KP, Ogrocki PK. Influence of mild cognitive impairment on visual word recognition. AGING NEUROPSYCHOLOGY AND COGNITION 2007; 14:329-52. [PMID: 17612812 DOI: 10.1080/13825580600630278] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The present study examined the effects of normal aging and mild cognitive impairment (MCI) on visual word recognition. Madden et al. (1999) reported evidence of general slowing of cognitive processes in Alzheimer's disease (AD) patients relative to younger adults and healthy older adults using a lexical decision task. It was of interest to determine whether similar effects would be observed in MCI patients relative to healthy younger and older adults. We extended the lexical decision task paradigm developed by Allen et al. (2004b) on younger adults to an examination of the effect(s) of MCI on visual word recognition. Results from the present study showed that healthy older adults and MCI patients performed similarly. That is, both groups took longer than younger adults to process words presented in mixed-case than in consistent-case letters. Mild cognitive impairment patients, however, responded significantly more slowly than healthy older adults across all lexical decision task conditions and showed a trend toward larger case-mixing effects than healthy older adults, which suggests that MCI may result in poorer analytic processing ability. Based on the current findings, evidence of a generalized slowing of cognitive processes using a standard lexical decision task can be expanded to include not only AD patients, but also the preclinical stages of the disease as well.
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Affiliation(s)
- Aryn L H Bush
- University of Akron, Department of Psychology, OH 44325-4301, USA
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8
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Turner TH. The pointillism method for creating stimuli suitable for use in computer-based visual contrast sensitivity testing. J Neurosci Methods 2005; 142:219-29. [PMID: 15698662 DOI: 10.1016/j.jneumeth.2004.08.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Revised: 08/12/2004] [Accepted: 08/19/2004] [Indexed: 11/19/2022]
Abstract
An increasingly large corpus of clinical and experimental neuropsychological research has demonstrated the utility of measuring visual contrast sensitivity. Unfortunately, existing means of measuring contrast sensitivity can be prohibitively expensive, difficult to standardize, or lack reliability. Additionally, most existing tests do not allow full control over important characteristics, such as off-angle rotations, waveform, contrast, and spatial frequency. Ideally, researchers could manipulate characteristics and display stimuli in a computerized task designed to meet experimental needs. Thus far, 256-bit color limitation in standard cathode ray tube (CRT) monitors has been preclusive. To this end, the pointillism method (PM) was developed. Using MATLAB software, stimuli are created based on both mathematical and stochastic components, such that differences in regional luminance values of the gradient field closely approximate the desired contrast. This paper describes the method and examines its performance in sine and square-wave image sets from a range of contrast values. Results suggest the utility of the method for most experimental applications. Weaknesses in the current version, the need for validation and reliability studies, and considerations regarding applications are discussed. Syntax for the program is provided in an appendix, and a version of the program independent of MATLAB is available from the author.
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Affiliation(s)
- Travis H Turner
- Joint Doctoral Program in Clinical Psychology, San Diego State University, San Diego, CA, USA.
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Dutton GN. Cognitive vision, its disorders and differential diagnosis in adults and children: knowing where and what things are. Eye (Lond) 2003; 17:289-304. [PMID: 12724689 DOI: 10.1038/sj.eye.6700344] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
As ophthalmologists we need a basic model of how the higher visual system works and its common disorders. This presentation aims to provide an outline of such a model. Our ability to survey a visual scene, locate and recognise an object of interest, move towards it and pick it up, recruits a number of complex cognitive higher visual pathways, all of which are susceptible to damage. The visual map in the mind needs to be co-located with reality and is primarily plotted by the posterior parietal lobes, which interact with the frontal lobes to choose the object of interest. Neck and extraocular muscle proprioceptors are probably responsible for maintaining this co-location when the head and eyes move with respect to the body, and synchronous input from both eyes is needed for correct localisation of moving targets. Recognition of what is being looked at is brought about by comparing the visual input with the "image libraries" in the temporal lobes. Once an object is recognised, its choice is mediated by parietal and frontal lobe tissue. The parietal lobes determine the visual coordinates and plan the visually guided movement of the limbs to pick it up, and the frontal lobes participate in making the choice. The connection between the occipital lobes and the parietal lobes is known as the dorsal stream, and the connection between the occipital lobes and the temporal lobes, comprises the ventral stream. Both disorders of neck and extraocular muscle proprioception, and disorders leading to asynchronous input along the two optic nerves are "peripheral" causes of impaired visually guided movement, while bilateral damage to the parietal lobes can result in central impairment of visually guided movement, or optic ataxia. Damage to the temporal lobes can result in impaired recognition, problems with route finding and poor visual memory. Spontaneous activity in the temporal lobes can result in formed visual hallucinations, in patients with impaired central visual function, particularly the elderly. Deficits in cognitive visual function can occur in different combinations in both children and adults depending on the nature and distribution of the underlying brain damage. In young children the potential for recovery can lead to significant improvement in parietal lobe function with time. Patients with these disorders need an understanding of their deficits and a structured positive approach to their rehabilitation.
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Affiliation(s)
- G N Dutton
- Tennent Institute of Ophthalmology, Gartnavel General Hospital, Great Western Road, Glasgow G12 0YN, Scotland, UK
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Benedek K, Kéri S, Grósz A, Tótka Z, Tóth E, Benedek G. Short-term hypobaric hypoxia enhances visual contrast sensitivity. Neuroreport 2002; 13:1063-6. [PMID: 12060809 DOI: 10.1097/00001756-200206120-00017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of hypoxia on early visual functions remains a controversial area of research. To explore this question, we measured static and dynamic visual contrast sensitivity in 14 healthy volunteers at a simulated altitude of 5500 m. In comparison with the baseline condition (mean arterial oxygen saturation: 98.4%), contrast sensitivity significantly increased after 5, 10 and 15 min of hypoxic exposure (saturation: 82.9%, 77.0%, 74.3%, respectively). After 10 min, this enhancement was markedly pronounced under dynamic conditions. Returning to the baseline altitude (saturation: 97.7%), contrast sensitivity recovered, mostly at the lower spatial frequencies. There was a significant negative relationship between arterial oxygen saturation and contrast sensitivity values at low and medium spatial frequencies (0.5-4.8 c/deg). These results suggest that early visual processing may be enhanced during short-term hypoxic challenge.
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Affiliation(s)
- Krisztina Benedek
- University of Szeged, Department of Neurology, Aeromedical Hospital, Hungarian Defense Forces, H-6725, Semmelweis u. 6., Szeged, Hungary
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Karlsson T, Börjesson A, Adolfsson R, Nilsson LG. Successive memory test performance and priming in Alzheimer's disease: evidence from the word-fragment completion task. Cortex 2002; 38:341-55. [PMID: 12146660 DOI: 10.1016/s0010-9452(08)70664-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study assessed the performance of patients with Alzheimer's disease and healthy controls in a successive memory test paradigm. Subjects studied lists of words. Following study, tests of recognition (an explicit memory task) and primed word fragment completion (an implicit memory task) were administered. Since the same words were used in the two tasks, we were able to calculate the degree of dependence between recognition performance and primed word fragment completion. AD patients evidenced impaired recognition memory. In contrast, priming was intact. The pattern of correlation between the two tasks was similar in healthy controls and in AD. Independence between recognition and fragment completion was obtained when recognition preceded the fragment completion task, but not when fragment completion preceded recognition.
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Affiliation(s)
- Thomas Karlsson
- Department of Behavioral Sciences, Linköping University, Sweden.
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Kéri S, Janka Z, Benedek G, Aszalós P, Szatmáry B, Szirtes G, Lörincz A. Categories, prototypes and memory systems in Alzheimer's disease. Trends Cogn Sci 2002; 6:132-136. [PMID: 11861191 DOI: 10.1016/s1364-6613(00)01859-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent studies indicate that category learning is mediated by multiple neuronal systems. It has been shown that patients with marked impairments in executive functions, explicit memory and procedural learning can categorize the exemplars and prototype of a previously trained category. Simple, self-organizing neuronal networks can explain prototype learning and related dysfunctions in Alzheimer's disease, and provide a model of how prototype learning is mediated by circumscribed mechanisms in the visual cortex.
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Affiliation(s)
- Szabolcs Kéri
- Dept of Psychiatry and Physiology, University of Szeged, Semmelweis u. 6, H-6725, Szeged, Hungary
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Kéri S, Kálmán J, Kelemen O, Benedek G, Janka Z. Are Alzheimer's disease patients able to learn visual prototypes? Neuropsychologia 2001; 39:1218-23. [PMID: 11527559 DOI: 10.1016/s0028-3932(01)00046-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recently, controversial results emerged regarding visual prototype learning in Alzheimer's disease (AD). The aim of this study was to elucidate this issue in a larger population of AD patients. The AD patients (N=72) and age-matched healthy control subjects (N=25) learned to recognize and to categorize visual dot patterns. In comparison with the control subjects, the AD patients as a group showed dysfunctions in the recognition task, whereas categorization was relatively spared in their case. Recognition was impaired in patients with mild AD (Mini-Mental score: 18-23) and moderate AD (Mini-Mental score<18), whereas categorization was impaired only in patients with moderate AD. These results suggest that while the medio-temporal/diencephalic explicit memory system is markedly affected even in early AD, the sensory neocortical areas mediating implicit category learning display a sufficient degree of functional capacity until later stages of the disease.
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Affiliation(s)
- S Kéri
- Department of Psychiatry, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary.
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De Vreese LP, Neri M, Fioravanti M, Belloi L, Zanetti O. Memory rehabilitation in Alzheimer's disease: a review of progress. Int J Geriatr Psychiatry 2001; 16:794-809. [PMID: 11536347 DOI: 10.1002/gps.428] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Memory rehabilitation is a sadly misrepresented area of applied research in Alzheimer's disease. OBJECTIVES To gather and evaluate recent evidence for the clinical effectiveness or ecologically validity of memory rehabilitation for mild to moderate Alzheimer's patients. METHODS Computerised searches and some handsearching were conducted spanning the last five years, from 1995 to 2000, inclusively. Criteria for inclusion in this overview involved the use of a precise memory rehabilitation technique within an experimental study design applied to Alzheimer's patients with pre- and post-treatment evaluation. FINDINGS Three potential levels of memory rehabilitation procedures with proven clinical or pragmatic efficacy were identified. The first level bears on the facilitation of residual explicit memory with structured support both at encoding and at subsequent recall; the second level of memory rehabilitation exploits the relatively intact implicit memory system (priming and procedural memory); the last deals with finding ways of coping with the patient's limited explicit memory capacities through the use of external memory aids. A proposal of suggestions for good practice and future research in memory rehabilitation is also offered with the hope to spur further development in this rapidly expanding area of applied research. CONCLUSION The available evidence shows that alternative and innovative ways of memory rehabilitation for Alzheimer's patients can indeed be clinically effective or pragmatically useful with a great potential for use within the new culture of a more graded and proactive type of Alzheimer's disease care.
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Affiliation(s)
- L P De Vreese
- Special Care Unit for Dementia Patients, Health Care Facility for Elderly, Via Paul Harris 165, 41100 Modena, Italy.
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