The Experts below are selected from a list of 38538 Experts worldwide ranked by ideXlab platform
Michel Cogne - One of the best experts on this subject based on the ideXlab platform.
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Association between prism adaptation and auditory cues on Spatial Navigation in individuals with unilateral neglect.
Annals of physical and rehabilitation medicine, 2019Co-Authors: Michel Cogne, Evelyne Klinger, Sophie Jacquin-courtois, Etienne Guillaud, Laurène Guillot, Bertrand Glize, Jean-rené Cazalets, Pierre-alain JosephAbstract:Abstract Background Unilateral neglect is common among right-hemispheric stroke individuals and also concerns the auditory modality. Prism adaptation can improve auditory extinction during a dichotic listening task, but its effect during an ecological task has not been studied. Objective The main objective was to evaluate whether lateralized cueing before and after prism adaptation improved virtual Spatial Navigation of stroke individuals with visual and auditory unilateral neglect. Secondary objectives were to assess Spatial memory and obtain a better understanding of the mechanism of the cueing treatment by using an eye-tracker. Methods We included 22 stroke individuals with left visual and auditory neglect, 14 individuals without neglect, and 12 healthy controls. After a familiarization task, participants underwent 3 evaluation sessions. Participants were first passively shown a path that they had then to actively reproduce by using a joystick. A path with lateralized beeping sounds indicating direction and a path without any sounds were followed in a randomized order. After prism adaptation, the participants followed a third path with lateralized beeping sounds. The time of Navigation and number of trajectory mistakes were recorded. After Navigation, Spatial memory was assessed. Additionally, an eye-tracker was used during the Navigation period. Results The Navigational performance of participants with neglect was significantly better with than without auditory cues, especially after prism adaptation. With auditory cues, participants without neglect reached the Navigational performance of healthy controls. The Spatial memory of individuals with neglect was significantly lower with auditory cues. Eye-tracking analyses showed that participants with neglect made more saccades and looked longer at the right-square angles in the absence of auditory cues. Conclusions This study demonstrates the positive effect of auditory cues in virtual Spatial Navigation of individuals with visual and auditory neglect and the potentiation of the help of cues after prism adaptation.
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the effect of the association between prism adaptation and auditory cues on virtual Spatial Navigation in patients with unilateral neglect
Annals of Physical and Rehabilitation Medicine, 2018Co-Authors: Michel Cogne, Evelyne Klinger, Etienne Guillaud, Laurène Guillot, Jean-rené Cazalets, S Jacquincourtois, P A JosephAbstract:Introduction/Background Spatial neglect is frequent among right-hemispheric stroke patients, and can concern the auditory modality. Some authors showed that a prism adaptation improved the auditory extinction during a dichotic listening task. However, this effect has not been studied yet during an ecological task. The aims of the study were to investigate whether right-hemispheric stroke patients with a contralesional visual and auditory neglect benefited from an auditory lateralized cueing during a Navigation task in virtual condition and to determine if a prism adaptation could potentiate this improvement. Material and method We included 32 right-hemispheric stroke patients, 22 with a visual and auditory neglect and10 without neglect; and 12 healthy controls. They all performed three paths including six intersections, at first passively and then actively with a joystick in two randomized conditions: (1) with lateralized beeping sounds indicating the directions; (2) without any sounds. After a prism adaptation, a third condition with lateralized beeping sounds was followed. Results There was a significant difference between the 3 groups concerning the number of trajectory mistakes in the 3 conditions (P Conclusion This study demonstrates the positive effect of auditory cues for Spatial Navigation in virtual condition on patients with visual and auditory neglect, and the potentiation of the help of auditory cues after a prism adaptation in this population.
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the effect of contextual auditory stimuli on virtual Spatial Navigation in patients with focal hemispheric lesions
Neuropsychological Rehabilitation, 2018Co-Authors: Michel Cogne, Evelyne Klinger, P A Joseph, Jeanfrancois Knebel, Claire Bindschaedler, Pierreandre Rapin, Stephanie ClarkeAbstract:ABSTRACTTopographical disorientation is a frequent deficit among patients suffering from brain injury. Spatial Navigation can be explored in this population using virtual reality environments, even in the presence of motor or sensory disorders. Furthermore, the positive or negative impact of specific stimuli can be investigated. We studied how auditory stimuli influence the performance of brain-injured patients in a Navigational task, using the Virtual Action Planning–Supermarket (VAP-S) with the addition of contextual (“sonar effect” and “name of product”) and non-contextual (“periodic randomised noises”) auditory stimuli. The study included 22 patients with a first unilateral hemispheric brain lesion and 17 healthy age-matched control subjects. After a software familiarisation, all subjects were tested without auditory stimuli, with a sonar effect or periodic random sounds in a random order, and with the stimulus “name of product”. Contextual auditory stimuli improved patient performance more than contr...
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the contribution of virtual reality to the diagnosis of Spatial Navigation disorders and to the study of the role of Navigational aids a systematic literature review
Annals of Physical and Rehabilitation Medicine, 2017Co-Authors: Michel Cogne, Mathieu Taillade, Bernard Nkaoua, Annabelle Tarruella, Evelyne Klinger, Florian Larrue, Helene Sauzeon, P A Joseph, E SoritaAbstract:Spatial Navigation, which involves higher cognitive functions, is frequently implemented in daily activities, and is critical to the participation of human beings in mainstream environments. Virtual reality is an expanding tool, which enables on one hand the assessment of the cognitive functions involved in Spatial Navigation, and on the other the rehabilitation of patients with Spatial Navigation difficulties. Topographical disorientation is a frequent deficit among patients suffering from neurological diseases. The use of virtual environments enables the information incorporated into the virtual environment to be manipulated empirically. But the impact of manipulations seems differ according to their nature (quantity, occurrence, and characteristics of the stimuli) and the target population. We performed a systematic review of research on virtual Spatial Navigation covering the period from 2005 to 2015. We focused first on the contribution of virtual Spatial Navigation for patients with brain injury or schizophrenia, or in the context of ageing and dementia, and then on the impact of visual or auditory stimuli on virtual Spatial Navigation. On the basis of 6521 abstracts identified in 2 databases (Pubmed and Scopus) with the keywords « Navigation » and « virtual », 1103 abstracts were selected by adding the keywords "ageing", "dementia", "brain injury", "stroke", "schizophrenia", "aid", "help", "stimulus" and "cue"; Among these, 63 articles were included in the present qualitative analysis. Unlike pencil-and-paper tests, virtual reality is useful to assess large-scale Navigation strategies in patients with brain injury or schizophrenia, or in the context of ageing and dementia. Better knowledge about both the impact of the different aids and the cognitive processes involved is essential for the use of aids in neurorehabilitation.
Jakub Hort - One of the best experts on this subject based on the ideXlab platform.
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Spatial Navigation deficits overlooked cognitive marker for preclinical alzheimer disease
Nature Reviews Neurology, 2018Co-Authors: Gillian Coughlan, Jan Laczó, Jakub Hort, Anne-marie Minihane, Michael HornbergerAbstract:Detection of incipient Alzheimer disease (AD) pathophysiology is critical to identify preclinical individuals and target potentially disease-modifying therapies towards them. Current neuroimaging and biomarker research is strongly focused in this direction, with the aim of establishing AD fingerprints to identify individuals at high risk of developing this disease. By contrast, cognitive fingerprints for incipient AD are virtually non-existent as diagnostics and outcomes measures are still focused on episodic memory deficits as the gold standard for AD, despite their low sensitivity and specificity for identifying at-risk individuals. This Review highlights a novel feature of cognitive evaluation for incipient AD by focusing on Spatial Navigation and orientation deficits, which are increasingly shown to be present in at-risk individuals. Importantly, the Navigation system in the brain overlaps substantially with the regions affected by AD in both animal models and humans. Notably, Spatial Navigation has fewer verbal, cultural and educational biases than current cognitive tests and could enable a more uniform, global approach towards cognitive fingerprints of AD and better cognitive treatment outcome measures in future multicentre trials. The current Review appraises the available evidence for Spatial Navigation and/or orientation deficits in preclinical, prodromal and confirmed AD and identifies research gaps and future research priorities.
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Spatial Navigation impairment is proportional to right hippocampal volume
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Zuzana Nedelska, Jan Laczó, Ross Andel, Kamil Vlcek, Katerina Sheardova, Daniel Horinek, Jiri Lisy, Jan Bures, Jakub HortAbstract:Abstract Cognitive deficits in older adults attributable to Alzheimer's disease (AD) pathology are featured early on by hippocampal impairment. Among these individuals, deterioration in Spatial Navigation, manifested by poor hippocampus-dependent allocentric Navigation, may occur well before the clinical onset of dementia. Our aim was to determine whether allocentric Spatial Navigation impairment would be proportional to right hippocampal volume loss irrespective of general brain atrophy. We also contrasted the respective Spatial Navigation scores of the real-space human Morris water maze with its corresponding 2D computer version. We included 42 cognitively impaired patients with either amnestic mild cognitive impairment (n = 23) or mild and moderate AD (n = 19), and 14 cognitively intact older controls. All participants underwent 1.5T MRI brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Allocentric Spatial Navigation was tested in the real-space version of the human Morris water maze and in its corresponding computer version. Participants used two Navigational cues to locate an invisible goal independent of the start position. We found that smaller right hippocampal volume was associated with poorer Navigation performance in both the real-space (β = −0.62, P 0.59) subjects. The respective real-space and virtual scores strongly correlated with each other. Our findings indicate that the right hippocampus plays a critical role in allocentric Navigation, particularly when cognitive impairment is present.
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Spatial Navigation testing discriminates two types of amnestic mild cognitive impairment.
Behavioural brain research, 2009Co-Authors: Jan Laczó, Ross Andel, Martin Vyhnalek, Kamil Vlcek, Martin Tolar, Martin Bojar, Olga Vajnerová, Michael Ort, Iva Holmerová, Jakub HortAbstract:The hippocampus is essential for consolidation of declarative information and Spatial Navigation. Alzheimer's disease (AD) diagnosis tends to be preceded by a long prodromal period and mild cognitive impairment (MCI). Our goal was to test whether amnestic MCI comprises two different subgroups, with hippocampal and non-hippocampal memory impairment, that vary with respect to Spatial Navigation ability. A total of 52 patients were classified into two subgroups: non-amnestic MCI (naMCI) (n=10) and amnestic MCI (aMCI) (n=42). The aMCI subgroup was further stratified into memory impairment of hippocampal type-hippocampal aMCI (HaMCI) (n=10) (potential preclinical AD) and isolated retrieval impairment-non-hippocampal (NHaMCI) (n=32). Results were compared to control (n=28) and AD (n=21) groups. We used the Hidden Goal Task, a human analogue of the Morris Water Maze, to examine Spatial Navigation either dependent (egocentric) or independent of individual's position (allocentric). Overall, the HaMCI group performed poorer on Spatial Navigation than the NHaMCI group, especially in the latter trials when the HaMCI group exhibited limited capacity to learn and the NHaMCI group exhibited a learning effect. Finally, the HaMCI group performed almost identically as the AD group. Spatial Navigation deficit is particularly pronounced in individuals with hippocampus-related memory impairment and may signal preclinical AD.
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Spatial Navigation deficit in amnestic mild cognitive impairment
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Jakub Hort, Jan Laczó, Martin Vyhnalek, Martin Bojar, Jan Bures, Kamil VlcekAbstract:Patients with Alzheimer's disease (AD) frequently have difficulties with Spatial orientation in their day-to-day life. Although AD is typically preceded by amnestic mild cognitive impairment (MCI), Spatial Navigation has not yet been studied in MCI. Sixty-five patients were divided into five groups: probable AD (n = 21); MCI, further classified as amnestic MCI single domain (n = 11); amnestic MCI multiple domain (n = 18), or nonamnestic MCI (n = 7), and subjective memory complaints (n = 8). These patients, together with a group of healthy control subjects (n = 26), were tested by using a four-subtests task that required them to locate an invisible goal inside a circular arena. Each subtest began with an overhead view of the arena showed on a computer monitor. This was followed by a real Navigation inside of the actual space, an enclosed arena 2.9 m in diameter. Depending on the subtest, the subjects could use the starting position and/or cues on the wall for Navigation. The subtests thus were focused on allocentric and egocentric Navigation. The AD group and amnestic MCI multiple-domain group were impaired in all subtests. The amnestic MCI single-domain group was impaired significantly in subtests focused on allocentric orientation and at the beginning of the real space egocentric subtest, suggesting impaired memory for allocentric and real space configurations. Our results suggest that Spatial Navigation impairment occurs early in the development of AD and can be used for monitoring of the disease progression or for evaluation of presymptomiatic AD.
Evelyne Klinger - One of the best experts on this subject based on the ideXlab platform.
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Association between prism adaptation and auditory cues on Spatial Navigation in individuals with unilateral neglect.
Annals of physical and rehabilitation medicine, 2019Co-Authors: Michel Cogne, Evelyne Klinger, Sophie Jacquin-courtois, Etienne Guillaud, Laurène Guillot, Bertrand Glize, Jean-rené Cazalets, Pierre-alain JosephAbstract:Abstract Background Unilateral neglect is common among right-hemispheric stroke individuals and also concerns the auditory modality. Prism adaptation can improve auditory extinction during a dichotic listening task, but its effect during an ecological task has not been studied. Objective The main objective was to evaluate whether lateralized cueing before and after prism adaptation improved virtual Spatial Navigation of stroke individuals with visual and auditory unilateral neglect. Secondary objectives were to assess Spatial memory and obtain a better understanding of the mechanism of the cueing treatment by using an eye-tracker. Methods We included 22 stroke individuals with left visual and auditory neglect, 14 individuals without neglect, and 12 healthy controls. After a familiarization task, participants underwent 3 evaluation sessions. Participants were first passively shown a path that they had then to actively reproduce by using a joystick. A path with lateralized beeping sounds indicating direction and a path without any sounds were followed in a randomized order. After prism adaptation, the participants followed a third path with lateralized beeping sounds. The time of Navigation and number of trajectory mistakes were recorded. After Navigation, Spatial memory was assessed. Additionally, an eye-tracker was used during the Navigation period. Results The Navigational performance of participants with neglect was significantly better with than without auditory cues, especially after prism adaptation. With auditory cues, participants without neglect reached the Navigational performance of healthy controls. The Spatial memory of individuals with neglect was significantly lower with auditory cues. Eye-tracking analyses showed that participants with neglect made more saccades and looked longer at the right-square angles in the absence of auditory cues. Conclusions This study demonstrates the positive effect of auditory cues in virtual Spatial Navigation of individuals with visual and auditory neglect and the potentiation of the help of cues after prism adaptation.
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the effect of the association between prism adaptation and auditory cues on virtual Spatial Navigation in patients with unilateral neglect
Annals of Physical and Rehabilitation Medicine, 2018Co-Authors: Michel Cogne, Evelyne Klinger, Etienne Guillaud, Laurène Guillot, Jean-rené Cazalets, S Jacquincourtois, P A JosephAbstract:Introduction/Background Spatial neglect is frequent among right-hemispheric stroke patients, and can concern the auditory modality. Some authors showed that a prism adaptation improved the auditory extinction during a dichotic listening task. However, this effect has not been studied yet during an ecological task. The aims of the study were to investigate whether right-hemispheric stroke patients with a contralesional visual and auditory neglect benefited from an auditory lateralized cueing during a Navigation task in virtual condition and to determine if a prism adaptation could potentiate this improvement. Material and method We included 32 right-hemispheric stroke patients, 22 with a visual and auditory neglect and10 without neglect; and 12 healthy controls. They all performed three paths including six intersections, at first passively and then actively with a joystick in two randomized conditions: (1) with lateralized beeping sounds indicating the directions; (2) without any sounds. After a prism adaptation, a third condition with lateralized beeping sounds was followed. Results There was a significant difference between the 3 groups concerning the number of trajectory mistakes in the 3 conditions (P Conclusion This study demonstrates the positive effect of auditory cues for Spatial Navigation in virtual condition on patients with visual and auditory neglect, and the potentiation of the help of auditory cues after a prism adaptation in this population.
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the effect of contextual auditory stimuli on virtual Spatial Navigation in patients with focal hemispheric lesions
Neuropsychological Rehabilitation, 2018Co-Authors: Michel Cogne, Evelyne Klinger, P A Joseph, Jeanfrancois Knebel, Claire Bindschaedler, Pierreandre Rapin, Stephanie ClarkeAbstract:ABSTRACTTopographical disorientation is a frequent deficit among patients suffering from brain injury. Spatial Navigation can be explored in this population using virtual reality environments, even in the presence of motor or sensory disorders. Furthermore, the positive or negative impact of specific stimuli can be investigated. We studied how auditory stimuli influence the performance of brain-injured patients in a Navigational task, using the Virtual Action Planning–Supermarket (VAP-S) with the addition of contextual (“sonar effect” and “name of product”) and non-contextual (“periodic randomised noises”) auditory stimuli. The study included 22 patients with a first unilateral hemispheric brain lesion and 17 healthy age-matched control subjects. After a software familiarisation, all subjects were tested without auditory stimuli, with a sonar effect or periodic random sounds in a random order, and with the stimulus “name of product”. Contextual auditory stimuli improved patient performance more than contr...
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the contribution of virtual reality to the diagnosis of Spatial Navigation disorders and to the study of the role of Navigational aids a systematic literature review
Annals of Physical and Rehabilitation Medicine, 2017Co-Authors: Michel Cogne, Mathieu Taillade, Bernard Nkaoua, Annabelle Tarruella, Evelyne Klinger, Florian Larrue, Helene Sauzeon, P A Joseph, E SoritaAbstract:Spatial Navigation, which involves higher cognitive functions, is frequently implemented in daily activities, and is critical to the participation of human beings in mainstream environments. Virtual reality is an expanding tool, which enables on one hand the assessment of the cognitive functions involved in Spatial Navigation, and on the other the rehabilitation of patients with Spatial Navigation difficulties. Topographical disorientation is a frequent deficit among patients suffering from neurological diseases. The use of virtual environments enables the information incorporated into the virtual environment to be manipulated empirically. But the impact of manipulations seems differ according to their nature (quantity, occurrence, and characteristics of the stimuli) and the target population. We performed a systematic review of research on virtual Spatial Navigation covering the period from 2005 to 2015. We focused first on the contribution of virtual Spatial Navigation for patients with brain injury or schizophrenia, or in the context of ageing and dementia, and then on the impact of visual or auditory stimuli on virtual Spatial Navigation. On the basis of 6521 abstracts identified in 2 databases (Pubmed and Scopus) with the keywords « Navigation » and « virtual », 1103 abstracts were selected by adding the keywords "ageing", "dementia", "brain injury", "stroke", "schizophrenia", "aid", "help", "stimulus" and "cue"; Among these, 63 articles were included in the present qualitative analysis. Unlike pencil-and-paper tests, virtual reality is useful to assess large-scale Navigation strategies in patients with brain injury or schizophrenia, or in the context of ageing and dementia. Better knowledge about both the impact of the different aids and the cognitive processes involved is essential for the use of aids in neurorehabilitation.
P A Joseph - One of the best experts on this subject based on the ideXlab platform.
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the effect of the association between prism adaptation and auditory cues on virtual Spatial Navigation in patients with unilateral neglect
Annals of Physical and Rehabilitation Medicine, 2018Co-Authors: Michel Cogne, Evelyne Klinger, Etienne Guillaud, Laurène Guillot, Jean-rené Cazalets, S Jacquincourtois, P A JosephAbstract:Introduction/Background Spatial neglect is frequent among right-hemispheric stroke patients, and can concern the auditory modality. Some authors showed that a prism adaptation improved the auditory extinction during a dichotic listening task. However, this effect has not been studied yet during an ecological task. The aims of the study were to investigate whether right-hemispheric stroke patients with a contralesional visual and auditory neglect benefited from an auditory lateralized cueing during a Navigation task in virtual condition and to determine if a prism adaptation could potentiate this improvement. Material and method We included 32 right-hemispheric stroke patients, 22 with a visual and auditory neglect and10 without neglect; and 12 healthy controls. They all performed three paths including six intersections, at first passively and then actively with a joystick in two randomized conditions: (1) with lateralized beeping sounds indicating the directions; (2) without any sounds. After a prism adaptation, a third condition with lateralized beeping sounds was followed. Results There was a significant difference between the 3 groups concerning the number of trajectory mistakes in the 3 conditions (P Conclusion This study demonstrates the positive effect of auditory cues for Spatial Navigation in virtual condition on patients with visual and auditory neglect, and the potentiation of the help of auditory cues after a prism adaptation in this population.
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the effect of contextual auditory stimuli on virtual Spatial Navigation in patients with focal hemispheric lesions
Neuropsychological Rehabilitation, 2018Co-Authors: Michel Cogne, Evelyne Klinger, P A Joseph, Jeanfrancois Knebel, Claire Bindschaedler, Pierreandre Rapin, Stephanie ClarkeAbstract:ABSTRACTTopographical disorientation is a frequent deficit among patients suffering from brain injury. Spatial Navigation can be explored in this population using virtual reality environments, even in the presence of motor or sensory disorders. Furthermore, the positive or negative impact of specific stimuli can be investigated. We studied how auditory stimuli influence the performance of brain-injured patients in a Navigational task, using the Virtual Action Planning–Supermarket (VAP-S) with the addition of contextual (“sonar effect” and “name of product”) and non-contextual (“periodic randomised noises”) auditory stimuli. The study included 22 patients with a first unilateral hemispheric brain lesion and 17 healthy age-matched control subjects. After a software familiarisation, all subjects were tested without auditory stimuli, with a sonar effect or periodic random sounds in a random order, and with the stimulus “name of product”. Contextual auditory stimuli improved patient performance more than contr...
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the contribution of virtual reality to the diagnosis of Spatial Navigation disorders and to the study of the role of Navigational aids a systematic literature review
Annals of Physical and Rehabilitation Medicine, 2017Co-Authors: Michel Cogne, Mathieu Taillade, Bernard Nkaoua, Annabelle Tarruella, Evelyne Klinger, Florian Larrue, Helene Sauzeon, P A Joseph, E SoritaAbstract:Spatial Navigation, which involves higher cognitive functions, is frequently implemented in daily activities, and is critical to the participation of human beings in mainstream environments. Virtual reality is an expanding tool, which enables on one hand the assessment of the cognitive functions involved in Spatial Navigation, and on the other the rehabilitation of patients with Spatial Navigation difficulties. Topographical disorientation is a frequent deficit among patients suffering from neurological diseases. The use of virtual environments enables the information incorporated into the virtual environment to be manipulated empirically. But the impact of manipulations seems differ according to their nature (quantity, occurrence, and characteristics of the stimuli) and the target population. We performed a systematic review of research on virtual Spatial Navigation covering the period from 2005 to 2015. We focused first on the contribution of virtual Spatial Navigation for patients with brain injury or schizophrenia, or in the context of ageing and dementia, and then on the impact of visual or auditory stimuli on virtual Spatial Navigation. On the basis of 6521 abstracts identified in 2 databases (Pubmed and Scopus) with the keywords « Navigation » and « virtual », 1103 abstracts were selected by adding the keywords "ageing", "dementia", "brain injury", "stroke", "schizophrenia", "aid", "help", "stimulus" and "cue"; Among these, 63 articles were included in the present qualitative analysis. Unlike pencil-and-paper tests, virtual reality is useful to assess large-scale Navigation strategies in patients with brain injury or schizophrenia, or in the context of ageing and dementia. Better knowledge about both the impact of the different aids and the cognitive processes involved is essential for the use of aids in neurorehabilitation.
Jan Laczó - One of the best experts on this subject based on the ideXlab platform.
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Spatial Navigation deficits overlooked cognitive marker for preclinical alzheimer disease
Nature Reviews Neurology, 2018Co-Authors: Gillian Coughlan, Jan Laczó, Jakub Hort, Anne-marie Minihane, Michael HornbergerAbstract:Detection of incipient Alzheimer disease (AD) pathophysiology is critical to identify preclinical individuals and target potentially disease-modifying therapies towards them. Current neuroimaging and biomarker research is strongly focused in this direction, with the aim of establishing AD fingerprints to identify individuals at high risk of developing this disease. By contrast, cognitive fingerprints for incipient AD are virtually non-existent as diagnostics and outcomes measures are still focused on episodic memory deficits as the gold standard for AD, despite their low sensitivity and specificity for identifying at-risk individuals. This Review highlights a novel feature of cognitive evaluation for incipient AD by focusing on Spatial Navigation and orientation deficits, which are increasingly shown to be present in at-risk individuals. Importantly, the Navigation system in the brain overlaps substantially with the regions affected by AD in both animal models and humans. Notably, Spatial Navigation has fewer verbal, cultural and educational biases than current cognitive tests and could enable a more uniform, global approach towards cognitive fingerprints of AD and better cognitive treatment outcome measures in future multicentre trials. The current Review appraises the available evidence for Spatial Navigation and/or orientation deficits in preclinical, prodromal and confirmed AD and identifies research gaps and future research priorities.
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neural correlates of Spatial Navigation changes in mild cognitive impairment and alzheimer s disease
Frontiers in Behavioral Neuroscience, 2014Co-Authors: Kamil Vlcek, Jan LaczóAbstract:Although the memory impairment is a hallmark of Alzheimer’s disease (AD), AD has also been characterized by Spatial disorientation, which is present from its early stages. Spatial disorientation in AD manifests itself in getting lost in familiar and unfamiliar places and have been characterized more specifically using Spatial Navigation tests in both real space and virtual environments as an impairment in multiple Spatial abilities, including allocentric and egocentric Navigation strategies, visuo-Spatial perception, or selection of relevant information for successful Navigation. Patients suffering mild cognitive impairment (MCI), who are at a high risk of development of dementia, show impairment in a subset of these abilities, mainly connected with allocentric and egocentric processing. While Spatial disorientation in typical AD patients probably reflects neurodegenerative changes in medial and posterior temporal, parietal, and frontal lobes, and retrosplenial cortex, the impairment of Spatial Navigation in MCI seem to be connected mainly with the medial temporal and also parietal brain changes. In this review, we will summarize the signs of brain disease in most MCI and AD patients showing in various tasks of Spatial memory and Navigation.
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Spatial Navigation impairment is proportional to right hippocampal volume
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Zuzana Nedelska, Jan Laczó, Ross Andel, Kamil Vlcek, Katerina Sheardova, Daniel Horinek, Jiri Lisy, Jan Bures, Jakub HortAbstract:Abstract Cognitive deficits in older adults attributable to Alzheimer's disease (AD) pathology are featured early on by hippocampal impairment. Among these individuals, deterioration in Spatial Navigation, manifested by poor hippocampus-dependent allocentric Navigation, may occur well before the clinical onset of dementia. Our aim was to determine whether allocentric Spatial Navigation impairment would be proportional to right hippocampal volume loss irrespective of general brain atrophy. We also contrasted the respective Spatial Navigation scores of the real-space human Morris water maze with its corresponding 2D computer version. We included 42 cognitively impaired patients with either amnestic mild cognitive impairment (n = 23) or mild and moderate AD (n = 19), and 14 cognitively intact older controls. All participants underwent 1.5T MRI brain scanning with subsequent automatic measurement of the total brain and hippocampal (right and left) volumes. Allocentric Spatial Navigation was tested in the real-space version of the human Morris water maze and in its corresponding computer version. Participants used two Navigational cues to locate an invisible goal independent of the start position. We found that smaller right hippocampal volume was associated with poorer Navigation performance in both the real-space (β = −0.62, P 0.59) subjects. The respective real-space and virtual scores strongly correlated with each other. Our findings indicate that the right hippocampus plays a critical role in allocentric Navigation, particularly when cognitive impairment is present.
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Spatial Navigation testing discriminates two types of amnestic mild cognitive impairment.
Behavioural brain research, 2009Co-Authors: Jan Laczó, Ross Andel, Martin Vyhnalek, Kamil Vlcek, Martin Tolar, Martin Bojar, Olga Vajnerová, Michael Ort, Iva Holmerová, Jakub HortAbstract:The hippocampus is essential for consolidation of declarative information and Spatial Navigation. Alzheimer's disease (AD) diagnosis tends to be preceded by a long prodromal period and mild cognitive impairment (MCI). Our goal was to test whether amnestic MCI comprises two different subgroups, with hippocampal and non-hippocampal memory impairment, that vary with respect to Spatial Navigation ability. A total of 52 patients were classified into two subgroups: non-amnestic MCI (naMCI) (n=10) and amnestic MCI (aMCI) (n=42). The aMCI subgroup was further stratified into memory impairment of hippocampal type-hippocampal aMCI (HaMCI) (n=10) (potential preclinical AD) and isolated retrieval impairment-non-hippocampal (NHaMCI) (n=32). Results were compared to control (n=28) and AD (n=21) groups. We used the Hidden Goal Task, a human analogue of the Morris Water Maze, to examine Spatial Navigation either dependent (egocentric) or independent of individual's position (allocentric). Overall, the HaMCI group performed poorer on Spatial Navigation than the NHaMCI group, especially in the latter trials when the HaMCI group exhibited limited capacity to learn and the NHaMCI group exhibited a learning effect. Finally, the HaMCI group performed almost identically as the AD group. Spatial Navigation deficit is particularly pronounced in individuals with hippocampus-related memory impairment and may signal preclinical AD.
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Spatial Navigation deficit in amnestic mild cognitive impairment
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Jakub Hort, Jan Laczó, Martin Vyhnalek, Martin Bojar, Jan Bures, Kamil VlcekAbstract:Patients with Alzheimer's disease (AD) frequently have difficulties with Spatial orientation in their day-to-day life. Although AD is typically preceded by amnestic mild cognitive impairment (MCI), Spatial Navigation has not yet been studied in MCI. Sixty-five patients were divided into five groups: probable AD (n = 21); MCI, further classified as amnestic MCI single domain (n = 11); amnestic MCI multiple domain (n = 18), or nonamnestic MCI (n = 7), and subjective memory complaints (n = 8). These patients, together with a group of healthy control subjects (n = 26), were tested by using a four-subtests task that required them to locate an invisible goal inside a circular arena. Each subtest began with an overhead view of the arena showed on a computer monitor. This was followed by a real Navigation inside of the actual space, an enclosed arena 2.9 m in diameter. Depending on the subtest, the subjects could use the starting position and/or cues on the wall for Navigation. The subtests thus were focused on allocentric and egocentric Navigation. The AD group and amnestic MCI multiple-domain group were impaired in all subtests. The amnestic MCI single-domain group was impaired significantly in subtests focused on allocentric orientation and at the beginning of the real space egocentric subtest, suggesting impaired memory for allocentric and real space configurations. Our results suggest that Spatial Navigation impairment occurs early in the development of AD and can be used for monitoring of the disease progression or for evaluation of presymptomiatic AD.
