Florian Larrue

The Use of Virtual Reality for Episodic Memory Assessment Effects of Active Navigation

Episodic memory was assessed using Virtual Reality (VR). Forty-four (44) subjects visualized a target virtual apartment containing specific objects in each room. Then they visualized a second virtual apartment comprised of specific objects and objects shared by the two apartments. Subjects navigated in the virtual apartments in one of the following two conditions: active and passive. Four main episodic memory components were scored from the VR exposures: (1) learning effect; (2) active forgetting effect; (3) strategies at encoding and at retrieval; and (4) false recognitions (FRs). The effect of navigation mode (active vs. passive) on each memory component was examined. Active subjects had better learning and retrieval (recognition hits) performances compared to passive subjects. A beneficial effect of active navigation was also observed on the source-based FR rates. Active subjects made fewer source-based FRs compared to passive subjects. These overall results for the effect of active navigation are discussed in terms of the distinction between item-specific and relational processing.

Virtual/Real Transfer of Spatial Knowledge: Benefit from Visual Fidelity Provided in a Virtual Environment and Impact of Active Navigation

The purpose of this study was to evaluate the effect the visual fidelity of a virtual environment (VE) (undetailed vs. detailed) has on the transfer of spatial knowledge based on the navigation mode (passive vs. active) for three different spatial recall tasks (wayfinding, sketch mapping, and picture sorting). Sixty-four subjects (32 men and 32 women) participated in the experiment. Spatial learning was evaluated by these three tasks in the context of the Bordeaux district. In the wayfinding task, the results indicated that the detailed VE helped subjects to transfer their spatial knowledge from the VE to the real world, irrespective of the navigation mode. In the sketch-mapping task, the detailed VE increased performances compared to the undetailed VE condition, and allowed subjects to benefit from the active navigation. In the sorting task, performances were better in the detailed VE; however, in the undetailed version of the VE, active learning either did not help the subjects or it even deteriorated their performances. These results are discussed in terms of appropriate perceptive-motor and/or spatial representations for each spatial recall task.

Executive and memory correlates of age-related differences in wayfinding performances using a virtual reality application

ABSTRACT The aim of this study was to evaluate in large-scale spaces wayfinding and spatial learning difficulties for older adults in relation to the executive and memory decline associated with aging. We compared virtual reality (VR)-based wayfinding and spatial memory performances between young and older adults. Wayfinding and spatial memory performances were correlated with classical measures of executive and visuo-spatial memory functions, but also with self-reported estimates of wayfinding difficulties. We obtained a significant effect of age on wayfinding performances but not on spatial memory performances. The overall correlations showed significant correlations between the wayfinding performances and the classical measures of both executive and visuo-spatial memory, but only when the age factor was not partialled out. Also, older adults underestimated their wayfinding difficulties. A significant relationship between the wayfinding performances and self-reported wayfinding difficulty estimates is found, but only when the age effect was partialled out. These results show that, even when older adults have an equivalent spatial knowledge to young adults, they had greater difficulties with the wayfinding task, supporting an executive decline view in age-related wayfinding difficulties. However, the correlation results are in favor of both the memory and executive decline views as mediators of age-related differences in wayfinding performances. This is discussed in terms of the relationships between memory and executive functioning in wayfinding task orchestration. Our results also favor the use of objective assessments of everyday navigation difficulties in virtual applications, instead of self-reported questionnaires, since older adults showed difficulties in estimating their everyday wayfinding problems.

Do patients with traumatic brain injury learn a route in the same way in real and virtual environments

An increasing number of studies address the use of virtual environments (VE) in the cognitive assessment of spatial abilities. However, the differences between learning in a VE and a real environment (RE) remain controversial. Purpose: To compare the topographical behavior and spatial representations of patients with traumatic brain injury navigating in a real environment and in a virtual reproduction of this environment. Methods: Twenty-seven subjects with moderate to severe traumatic brain injury were consecutively included and allocated to one of two groups. The subjects were taught the same route in either the virtual environment or the real environment and had to recall it twice immediately after learning the route and once after a delay. At the end of these sessions, the subjects were asked to complete three representational tests: a map test, a map recognition test recognition and a scene arrangement test. Results: No significant difference was found between the two groups with regards to demographics, severity of brain injury or episodic memory. As a main result, the number of error rates did not significantly differ between the real and virtual environment [F (1, 25) = 0.679; p = 0.4176)]. Scores on the scene arrangement test were higher in the real environment [U = 32.5; p = 0.01]. Conclusions: Although spatial representations probably differ between the real and virtual environment, virtual reality remains a trusty assessment tool for spatial abilities. Implications for Rehabilitation The transfer of cognitive skills and strategy acquired during rehabilitation programs into daily life situations remains a matter of debate. Virtual reality might provide ecological and rehabilitation scenarios that can be used to look at the daily functioning of patients. The route learning performance after traumatic brain injury shows no significant difference between the real environment and its virtual reproduction in this study.

Influence of body-centered information on the transfer of spatial learning from a virtual to a real environment

This study investigated the effects of body-centred information on the transfer of spatial learning using a wayfinding task and tasks that specifically probe the route and survey strategies of navigation. The subject learned a route in either a real or a virtual environment (VE; 3D scale model of a Bordeaux neighbourhood) and then reproduced it in the real environment. The involvement of body-based information was manipulated across the spatial learning conditions in the VE: participants learned with full body-based information (treadmill with rotation), with the translational component only (treadmill without rotation) or without body-based information (joystick). In the wayfinding task, the results showed a significant effect of the learning environment with the best scores obtained in the real and treadmill with rotation conditions. There was no significant difference between these two conditions, but the real condition was significantly different from the treadmill without rotation and joystick conditions. Also, the visual flow was sufficient to successfully perform the two egocentric tasks used as well as a direction estimation task (a survey task), in so far as there is no significant difference between the joystick and the treadmill conditions. By contrast, the distance estimates were improved by the treadmill condition including the translational component (but not the rotational component). Finally, our results show that treadmill with rotation promotes the transfer of spatial learning from a virtual to a real environment (compared to joystick and treadmill without rotation). Moreover, body-centred informations are more involved in allocentric (distance estimates) than egocentric navigational strategies.

Virtual/real transfer in a large-scale environment: impact of active navigation as a function of the viewpoint displacement effect and recall tasks

The purpose of this study was to examine the effect of navigation mode (passive versus active) on the virtual/real transfer of spatial learning, according to viewpoint displacement (ground: 1m 75 versus aerial: 4m) and as a function of the recall tasks used. We hypothesize that active navigation during learning can enhance performances when route strategy is favored by egocentric match between learning (ground-level viewpoint) and recall (egocentric frame-based tasks). Sixty-four subjects (32 men and 32 women) participated in the experiment. Spatial learning consisted of route learning in a virtual district (four conditions: passive/ground, passive/aerial, active/ground, or active/aerial), evaluated by three tasks: wayfinding, sketch-mapping, and picture-sorting. In the wayfinding task, subjects who were assigned the ground-level viewpoint in the virtual environment (VE) performed better than those with the aerial-level viewpoint, especially in combination with active navigation. In the sketch-mapping task, aerial-level learning in the VE resulted in better performance than the ground-level condition, while active navigation was only beneficial in the ground-level condition. The best performance in the picture-sorting task was obtained with the ground-level viewpoint, especially with active navigation. This study confirmed the expected results that the benefit of active navigation was linked with egocentric frame-based situations.

Brain computer interface vs walking interface in VR: the impact of motor activity on spatial transfer

The goal of this study is to explore new navigation methods in Virtual Reality (VR) and to understand the impact of motor activity on spatial cognition, and more precisely the question of the spatial learning transfer. We present a user study comparing two interfaces with different motor activities: the first one, a walking interface (a treadmill with rotation) gives the user a high level of sensorimotor activity (especially body-based and vestibular information). The second one, a brain computer interface (BCI), enables the user to navigate in a virtual environment (VE) without any motor activity, by using brain activity only. The task consisted in learning a path in a virtual city built from a 3D model of a real city with either one of these two interfaces (named treadmill condition and BCI condition), or in the real city directly (the real condition). Then, participants had to recall spatial knowledge, according to six different tasks assessing spatial memory and transfer. We also evaluated the ergonomics of these two interfaces and the presence felt by participants. Surprisingly, contrary to expectations, our results showed similar performances whatever the spatial restitution tasks or the interfaces used, very close to that of the real condition, which tends to indicate that motor activity is not essential to learn and transfer spatial knowledge. Even if BCI seems to be less natural to use than the treadmill, our study suggests that BCI is a promising interface for studying spatial cognition.

Assessing the impact of automatic vs. controlled rotations on spatial transfer with a joystick and a walking interface in VR

We present a user study assessing spatial transfer in a 3D navigation task, with two different motor activities: a minimal (joystick) and an extensive motor activity (walking Interface), with rotations of the viewpoint either controlled by the user, or automatically managed by the system. The task consisted in learning a virtual path of a 3D model of a real city, with either one of these four conditions: Joystick / Treadmill Vs Manual Rotation / Automatic Rotation. We assessed spatial knowledge with six spatial restitution tasks. To assess the interfaces used, we analyzed also the interaction data acquired during the learning path. Our results show that the direct control of rotations has different effects, depending on the motor activity required by the input modality. The quality of spatial representation increases with the Treadmill when rotations are enabled. With the Joystick, controlling the rotations affect spatial representations. We discuss our findings in terms of cognitive, sensorimotor processes and human computer interaction issues.