Design of an adaptive wayfinding system for individuals with cognitive impairments

Many individuals with cognitive impairments experience difficulty with wayfinding, that is, the process of traveling from one place to another. This functional limitation decreases their opportunity to live independently, maintain employment, and participate in their community. This dissertation addresses the design of a system to help such individuals in wayfinding by presenting personalized, multi-modal directions to users by mobile phone. By creating prototypes that present directions to individuals with cognitive impairments in real indoor and outdoor environments, I have observed a wide range of potential users' reactions to different types of directions, both turn-based directions common in current navigation aids and landmark-based directions that use photos augmented with path arrows. As the use of landmarks in wayfinding has been found to be beneficial, and landmark-based directions are becoming more widely available because of the growing availability of geotagged photos and other location information, my study results inform the creation of criteria for choosing landmarks useful to wayfinding. A recurring theme found in my studies has been the need to address the wide variation in individual wayfinding abilities and preferences. Addressing this need is a challenge as manually adjusting an interface's design, tailoring it for each individual user, has required significant cost in the past. To support such variation, I have developed a theoretical framework that creates customized and adaptable wayfinding directions to individual users. The framework relies on a Markov Decision Process (MDP) problem formulation to create understandable sequences of directions for a given user. The MDP uses a model to describe the user's likelihood of correctly following possible directions in different wayfinding situations. We can improve model accuracy by incorporating new usage data over time, allowing the system to adapt. Adaptation is an important capability as the physical and mental effort of wayfinding limits how much observational data can be collected at once. My user studies involving the framework generating directions show that individuals with cognitive impairments can successfully wayfind when they have access to tailored wayfinding directions, demonstrating the design's potential to reduce a significant barrier to their quality of living.