From allo- to egocentric spatial ability in early Alzheimer's disease: A study with virtual reality spatial tasks (original) (raw)
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Scientific Reports
Spatial navigation impairments in Alzheimer’s disease (AD) have been suggested to underlie patients experiencing spatial disorientation. Though many studies have highlighted navigation impairments for AD patients in virtual reality (VR) environments, the extent to which these impairments predict a patient’s risk for spatial disorientation in the real world is still poorly understood. The aims of this study were to (a) investigate the spatial navigation abilities of AD patients in VR environments as well as in a real world community setting and (b) explore whether we could predict patients at a high risk for spatial disorientation in the community based on their VR navigation. Sixteen community-dwelling AD patients and 21 age/gender matched controls were assessed on their egocentric and allocentric navigation abilities in VR environments using the Virtual Supermarket Test (VST) and Sea Hero Quest (SHQ) as well as in the community using the Detour Navigation Test (DNT). When compared ...
2014
Wayfinding ability has a high adaptive value, allowing humans to efficiently explore an environment in order to have a goal-oriented activity. This is done thanks to the capacity of individuals to actively acquire knowledge during interaction. Recently, different studies examined the wayfinding performances of older adults in Virtual Reality. While these studies underlined a greater difficulty with the wayfinding task in the elderly subjects, the effects of age on specific aspects of navigational tasks are less well specified. More, a recent study suggested that older people who use spatial navigational strategies (navigation is achieved by orientating oneself in relation to an allocentic landmark map) in their everyday lives may have increased gray matter in the hippocampus and enhance their probability of healthy and successful aging. To evaluate this hypothesis we tested 176 subjects (from 20 to 89 years old) in wayfinding ability by using an interactive computer-based evaluation tool -the VR Maze spatial task -that requires the translation of the allocentric spatial knowledge to the corresponding egocentric one and its organization to perform a goal directed wayfinding. More, the study explored the relationships of these abilites with traditional paper and pencil measures of memory, executive and attentive functions. Data show how some aspects of spatial ability impairment are not clearly detectable using classical tests, whereas they become evident using the VR Maze spatial task. This difference is even more marked in the wayfinding ability evaluation of the elderly population. Finally, the VR Maze spatial task appears to be correlated with classical neuropsychological tests.
Cortex, 2015
Alzheimer's disease Frontotemporal dementia a b s t r a c t Spatial disorientation is a prominent feature of early Alzheimer's disease (AD) attributed to degeneration of medial temporal and parietal brain regions, including the retrosplenial cortex (RSC). By contrast, frontotemporal dementia (FTD) syndromes show generally intact spatial orientation at presentation. However, currently no clinical tasks are routinely administered to objectively assess spatial orientation in these neurodegenerative conditions. In this study we investigated spatial orientation in 58 dementia patients and 23 healthy controls using a novel virtual supermarket task as well as voxel-based morphometry (VBM). We compared performance on this task with visual and verbal memory function, which has traditionally been used to discriminate between AD and FTD.
Frontiers in Aging Neuroscience, 2015
Several studies have pointed out that egocentric and allocentric spatial impairments are one of the earliest manifestations of Alzheimer's Disease (AD). It is less clear how a break in the continuous interaction between these two representations may be a crucial marker to detect patients who are at risk to develop dementia. The main objective of this study is to compare the performances of participants suffering from amnestic mild cognitive impairment (aMCI group), patients with AD (AD group) and a control group (CG), using a virtual reality (VR)-based procedure for assessing the abilities in encoding, storing and syncing different spatial representations. In the first task, participants were required to indicate on a real map the position of the object they had memorized, while in the second task they were invited to retrieve its position from an empty version of the same virtual room, starting from a different position. The entire procedure was repeated across three different trials, depending on the object location in the encoding phase. Our finding showed that aMCI patients performed significantly more poorly in the third trial of the first task, showing a deficit in the ability to encode and store an allocentric viewpoint independent representation. On the other hand, AD patients performed significantly more poorly when compared to the CG in the second task, indicating a specific impairment in storing an allocentric viewpoint independent representation and then syncing it with the allocentric viewpoint dependent representation. Furthermore, data suggested that these impairments are not a product of generalized cognitive decline or of general decay in spatial abilities, but instead may reflect a selective deficit in the spatial organization Overall, these findings provide an initial insight into the cognitive underpinnings of amnestic impairment in aMCI and AD patient exploiting the potentiality of VR.
Frontiers in Aging Neuroscience, 2015
Several studies have pointed out that egocentric and allocentric spatial impairments are one of the earliest manifestations of Alzheimer's Disease (AD). It is less clear how a break in the continuous interaction between these two representations may be a crucial marker to detect patients who are at risk to develop dementia. The main objective of this study is to compare the performances of participants suffering from amnestic mild cognitive impairment (aMCI group), patients with AD (AD group) and a control group (CG), using a virtual reality (VR)-based procedure for assessing the abilities in encoding, storing and syncing different spatial representations. In the first task, participants were required to indicate on a real map the position of the object they had memorized, while in the second task they were invited to retrieve its position from an empty version of the same virtual room, starting from a different position. The entire procedure was repeated across three different trials, depending on the object location in the encoding phase. Our finding showed that aMCI patients performed significantly more poorly in the third trial of the first task, showing a deficit in the ability to encode and store an allocentric viewpoint independent representation. On the other hand, AD patients performed significantly more poorly when compared to the CG in the second task, indicating a specific impairment in storing an allocentric viewpoint independent representation and then syncing it with the allocentric viewpoint dependent representation. Furthermore, data suggested that these impairments are not a product of generalized cognitive decline or of general decay in spatial abilities, but instead may reflect a selective deficit in the spatial organization Overall, these findings provide an initial insight into the cognitive underpinnings of amnestic impairment in aMCI and AD patient exploiting the potentiality of VR.
Spatial Navigation in the Elderly with Alzheimer’s Disease: A Cross-Sectional Study
Journal of Alzheimer's Disease, 2018
Background: Spatial navigation is a fundamental cognitive ability that allows an individual to maintain independence by facilitating the safe movement from one place to another. It emerges as one of the first deficits in patients with Alzheimer's disease (AD). Objective: To compare spatial navigation performance in the healthy elderly and AD patients through use of the Floor Maze Test (FMT)-an easy-to-apply two-dimensional (2D) maze-and determine which cognitive and functional capacities were associated with performance in this task. Methods: The FMT was administered to 24 AD patients and 36 healthy controls. Spatial navigation was evaluated through the FMT. Functional capacity was evaluated through the Senior Fitness Test battery of tests. Cognitive functions were evaluated through the Mini-Mental State Examination (MMSE), verbal fluency, digit span test, and the Rey Auditory Verbal Learning Test (RAVLT). Results: The group with AD was significantly slower and presented more errors at all stages of the FMT. Planning Time (PT) performance was associated with cardiorespiratory resistance (Step test) and delayed memory according to the RAVLT (R 2 = 0.395, p < 0.001). Performance in the Immediate Maze Time (IMT) and Delayed Maze Time (DMT) was associated with global cognitive status (MMSE) (R 2 = 0.509) and delayed memory (R 2 = 0.540). Conclusion: Patients with AD present significant spatial navigation deficits. Their performance on the FMT is influenced by cardiorespiratory capacity, memory, and global cognitive function. As exercise helps to improve executive function and functional capacity, future intervention studies should be carried out to analyze the possible effects of physical exercise on spatial navigation.
Spatial disorientation in Alzheimer's disease: The remembrance of things passed
Neurology, 2003
Background: Patients with Alzheimer's disease (AD) and many older adults become lost even in familiar surroundings. This is commonly attributed to memory impairment, but it may reflect impaired spatial cognition. Methods: The authors examined the role of memory, perceptual, and cognitive mechanisms in spatial disorientation by comparing the performance of normal young (YN), middle-aged (MA), older adult (OA), and AD subjects on neuropsychological and spatial orientation tests. Results: The tendency to become lost is shared by almost all patients with AD (93%) and some OA subjects (38%). This impairment is not related to memory impairment. Instead, it reflects an inability to link recognized scenes with locations in the environment. Conclusions: Spatial disorientation reflects the impaired linking of landmarks and routes that should be assessed in conjunction with routine memory testing in elderly patients.
Spatial Navigation and Visuospatial Strategies in Typical and Atypical Aging
Brain Sciences, 2021
Age-related spatial navigation decline is more pronounced in patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) dementia. We used a realistic-looking virtual navigation test suite to analyze different aspects of visuospatial processing in typical and atypical aging. A total of 219 older adults were recruited from the Czech Brain Aging Study cohort. Cognitively normal older adults (CN; n = 78), patients with amnestic MCI (n = 75), and those with mild AD dementia (n = 66) underwent three navigational tasks, cognitive assessment, and brain MRI. Route learning and wayfinding/perspective-taking tasks distinguished the groups as performance and learning declined and specific visuospatial strategies were less utilized with increasing cognitive impairment. Increased perspective shift and utilization of non-specific strategies were associated with worse task performance across the groups. Primacy and recency effects were observed across the groups in the route learnin...
Getting lost in Alzheimer's disease: A break in the mental frame syncing
Medical hypotheses, 2013
Despite the clinical significance of topographical disorientation in Alzheimer's disease, it is not clear which cognitive spatial processes are primarily impaired. Here, we argue that a deficit in ''mental frame syncing'' between egocentric and allocentric spatial representations causes early manifestations of topographical disorientation in AD. Specifically, patients show impairment in translating from an allocentric hippocampal representation to an egocentric parietal one for the purpose of effective spatial orientation and navigation. We suggest that a break in ''mental frame syncing'', underpinned by damage to the hippocampus and retrosplenial cortex, may be a crucial cognitive marker both for early and differential diagnosis of AD. Identification of these spatial deficits could facilitate the development of early cognitive rehabilitation interventions and the possibility of identifying individuals most at risk for progression to AD during the preclinical stages.