ARIADE : Augmented Reality for Improving Autonomy in Dementia. Creation, Implementation and Testing of an Augmented Reality Tool to Help People With Alzheimer's Type Dementia in Their Travels.

Navigating according to a specific goal is a common activity of everyday life. Spatial navigation requires the implementation of motor and perceptual functions (sight, walking, proprioception), but also various cognitive functions (executive functions, memory, spatial orientation skills). Many people affected by a neurodegenerative disease have topographical difficulties which have a major impact on their autonomy in daily life, by gradually limiting their movements outside their home, then inside their home, and which are the main factor leading to the institutionalization of this population. People with dementia or MCI (Mild Cognitive Impairment) of the Alzheimer type, according to the definition of the NIAA (National Institute on Aging-Alzheimer's Association) have navigation and spatial memory disorders, with difficulty in acquiring mental spatial representations of their environment. These topographical difficulties have been shown to be related to the reduction in volume of the temporal cortex, in particular the hippocampal regions, as well as to atrophy of the retrosplenial cortex.

Augmented Reality (AR), often defined as an intermediary between the totally artificial world of VR and the real world in which we operate, makes it possible in particular to add summary information to the natural environment in which a participant operates. Even if, in particular in outside environment, AR must solve many challenges, such as the integration of the real and virtual worlds in real time, the selection of the modalities of restitution of information, its use is exponential in the medical field, in particular in surgery for the assistance of the practitioner, but also in the field of sensory substitution, in particular to facilitate the movements of people with visual impairment. Other works focused in helping people with dementia of the Alzheimer type, such as those of Quintana and Favela (2012) who proposed preliminary systems of annotations in AR. Hervás et al. were the first in 2014 to test the use of augmented reality to provide navigation assistance to people with dementia. In 2017, Firouzian et al. as well as Sejunaite et al. implemented related systems. Firouzian et al. have developed spectacle frames comprising around ten LED lights in order to provide directional indications to people who moved outdoor. However, the influence of this system on navigation performance has not been tested yet. On the other hand, although simple to develop, this system requires training on the part of the users and only makes it possible to provide directional information, which is not recommended for the implementation of a tool for this population. Finally, Sejunaite et al. used an environmentally tested smart glasses to allow users to display information in the form of a map to help older people navigate independently. However, the literature review indicates that even increased card use does not seem to be suitable for people with dementia or Alzheimer's-type MCI. Finally, these two tools do not allow navigational information to be co-located in the field of vision of people, which represents one of the major advantages of augmented reality. To our knowledge, there is not yet an AR device providing co-located information in the environment dedicated to outdoor navigation of people with dementia or Alzheimer's type MCI.