From allo- to egocentric spatial ability in early Alzheimer’s disease: A study with virtual reality spatial tasks

Abstract

The ability to orient in space constitutes a main sign of cognitive impairment in Alzheimer's disease (AD). Presently, a peculiar aspect of topographical disorientation in AD linked with spatial reference frame congruence appears to have been only minimally investigated. We aim to study whether there is a decline in performing the allo- to egocentric translation of spatial knowledge during different types of wayfinding in AD patients. We introduced two virtual reality tasks, the VR-Maze and VR-Road Map tasks, in which we compared 26 AD and 26 healthy, elderly subjects. The results emphasize that there is a specific reduction in performing allo- to egocentric spatial tasks in AD, whereas this reduction is not as evident in equivalent allocentric spatial tasks. The data are consistent with the neurological results regarding the early degeneration of the hippocampus and retrosplenial cortex in AD, which underlies the ability to translate between these two reference frames.

Path Integration Changes as a Cognitive Marker for Vascular Cognitive Impairment?—A Pilot Study

“…Videos were presented in a first-person perspective and participants are provided with optic flow cues from the moving shopping trolley and changing scenery as they followed different routes to reach a different endpoint in each trial. The task avoids the use of landmarks or salient features within the environment and limits the demand on episodic memory, reflecting similar tasks in the literature (see Cushman et al, 2008;Morganti et al, 2013;Wolbers et al, 2007) and taps into path integration processes via three core spatial processes: (i) egocentric self-reference navigation; (ii) allocentric map-based navigation; and (iii) heading direction. Once the video clip stops, participants indicate in real-life the direction of their starting point (egocentric orientation; Figure 1D).…”

“…Tasks that tap into path integration, therefore, provide a promising ecological, cognitive framework to detect medial temporal and medial parietal pathophysiology. Not surprisingly, path integration has been already explored in AD (Morganti et al, 2013;Serino et al, 2014;Vlček and Laczó, 2014;Ritchie et al, 2018) and the advent of VR based testing has allowed such tests to be clinically available (Plancher et al, 2012;Morganti et al, 2013;Parizkova et al, 2018). We have developed previously such a test, the Virtual Supermarket task, which is now used across many large cohorts and drug trials as it can reliably detect path integration differences in preclinical and clinical dementia populations (Tu et al, 2015(Tu et al, , 2017.…”

Cholinergic modulation of spatial learning, memory and navigation

“…In another study testing virtual as well as real navigation in a hospital lobby, AD but not MCI patients were impaired on a test of self‐orientation, requiring to indicate directions to scenes from the route (Cushman, Stein, & Duffy, ). Patients were also impaired on translating allocentric map representations to egocentric directions in a VR (Morganti, Stefanini, & Riva, ). In sum, anatomical and functional evidence points to an early involvement of the cholinergic system in learning deficits in Alzheimer's patients (Hampel et al., ).…”

Neural Correlates of Spatial Navigation Changes in Mild Cognitive Impairment and Alzheimer’s Disease

“…In another study on virtual as well as real navigation in a hospital lobby, AD patients, but again not MCI patients, were impaired in a test of self-orientation, requiring to indicate directions to scenes from the route (Cushman et al, 2008). The AD patients were also impaired in navigation in a virtual-reality maze using its map, which required translation of allocentric representation in the map to the egocentric direction in the maze (Morganti et al, 2013). Location of scenes on a map could possibly be also regarded as a behavioral measure of RSC function, requiring egocentric to allocentric translation.…”