Mobility of Visually Impaired People

The aim of this chapter is to highlight the main phenomenological features of lived space, that is, space as it is experienced by the subject through various intentional modes, first of all perception, but also non-perceptual modes, such as trying to remember where something is or how a room is arranged, or thinking about the way to go from A to B (itinerary planning). A general overview of the most important phenomenological accounts made in the literature is proposed, with a focus on the following topics: the relation between bodily skills, and more generally motricity (i.e. the capacity to move), and lived space; the impact of one’s body materiality on one’s experience of space: how possessing a physical body with material properties such as impenetrability and heaviness affects one’s experience of space; the role of the anticipation of possibilities in the enacting and organization of lived space; the role of sociality and the impact of one’s body ‘visibility’, i.e. the fact that one can be perceived by others, in one’s experience of space. The objective of this overview in the context of this book is to get a better understanding of the experience of space in visually impaired people. Based on this phenomenological account, this chapter will, as a result, offer a series of reflections about the peculiarities of the space blind people live in.

A large number of technical devices attempt to help blind persons improve their spatial perception and facilitate their mobility. We wish to present here the principles on which these prosthetic perceptual devices function, the conditions of their appropriation, and the general perspectives they open concerning the role of technical objects and systems in the constitution of human experience.

Classic neuroanatomy teaches that the brain can be divided into five lobes with distinct sensory functions, and a couple small areas of the brain that integrate the information from the different senses. Studies into the plasticity in the blind brain have revealed that the occipital cortex is not solely reserved for visual functions. Congenitally blind people use the occipital cortex to interpret tactile, auditory and olfactory stimuli. In this chapter we also review pain and taste pathways in the blind brain. The reorganisation of the blind brain, across the usual sensory boundaries, demonstrates the amazing multisensory plasticity that can arise when development is irregular. These studies support the hypothesis that instead of being sensory-specific, cortical regions appear to be functionally specific. Understanding the role of vision within the brain can improve current rehabilitation schemes following neuronal damage. More specifically, the extensive plasticity demonstrated in the blind brain can be used to improve assistive technologies built for the blind.

People acquire spatial knowledge by physically experiencing the environment through locomotion. Spatial knowledge generally emerges from the interactions between the specific types of sensory data and the cognitive strategies involved in locomotion. This chapter reviews the fundamental concepts and evidences of spatial cognition. First, the interplay between visual data and mobility is addressed. The importance of landmarks and visual cues is highlighted for implementing both simple and complex navigation strategies such as path integration (PI), landmark-based, and geometry-based, which are the main cognitive mechanisms for spatial learning. Some neural evidences of spatial cognition are given to underline the brain mechanisms involved in cognitive mapping. A review of relevant literature models on cognitive mapping is also presented to better understand how spatial representations are formed at the level of the brain. The chapter provides some insights on how to adapt all these concepts for mobility and spatial knowledge assistance of people with visual impairments.

This chapter reviews the most recent advances in sensory substitution and the neural correlates of navigation in congenital blindness. Studies have established the superior ability of congenitally blind (CB) participants with the aid of Sensory Substitution Devices (SSDs) to navigate new environments and detect the size and shape of obstacles in order to avoid them. These studies suggest that with training, CB can achieve a representation of space that is equivalent to that of the sighted. From a phenomenological point of view, sensation and perception provided by SSDs have been likened to real vision, but the question remains as to the subjective sensations (qualia) felt by users. We review recent theories on the phenomenological properties of sensory substitution and the recent literature on spatial abilities of participants using SSDs. From these different sources of research, we conclude that training-induced plastic changes enable task-specific brain activations. The recruitment of the primary visual cortex by nonvisual SSD stimulations and, the subsequent activations of associative visual cortices in the congenitally blind, suggest that the sensory information is treated in an amodal fashion; i.e.,: in terms of the task being performed rather than the sensory modality. These anatomical changes enable the embodiment of nonvisual information allowing SSD users to accomplish a multitude of “visual” tasks. We will emphasize here the abilities of CB individuals to navigate in real and virtual environments in spite of a large volumetric reduction in the posterior segment of the hippocampus, a key area involved in navigation. In addition, the superior behavioral performance of CB in a variety of sensory and cognitive tasks, combined with anatomical and functional MRI, underlines the susceptibility of the brain to training-induced plasticity.

The development of spatial navigation is one of the most intriguing stories of the contemporary cognitive neuroscience. It is assisted by the information given from multiple modalities. Infant’s visual development is characterized by critical periods in many notable visual functions. The maturation of ventral and dorsal systems authorise them to transform visual information into cognitive representations associated with object’s recognition and location in the egocentric space all along static and dynamic motion activities. Together with the visual information, bilateral vestibular organisation not only contribues to the equilibrioception in three axis (sagittal, vertical, and lateral) at cortical and subcortical levels, but it is directly and indirectly involved in internal representation of the body, navigation, memory and orientation. In our context, the internal representation of the body in space is thought as an egocentric reference providing spatial navigation and orientation. Multimodal visuomotor, vestibular and somesthetic (proprioceptive and exteroceptive-haptic) abilities give children and adults in extension the possibility to explore actively or passively the space. Cognitive factors potentially influence ego motion in children and in adults. Attentional factors and memory process specially those associated with visuospatial working memory are decisive elements of ego motion in real as well as in virtual environments. In the absence of visual information, blind individuals rely more on vestibular and somesthetic feedback for ego motion control than do sighted subjects.

The goal of orientation and mobility training is to prepare people with visual impairment to travel in a variety of environments, both familiar and unfamiliar, and to increase the skills of moving in the environment in a safe and efficient way. The chapter describes the training of visually impaired persons in orientation and mobility, and the specific mobility challenges of visually impaired people. The strategies and techniques, used to improve orientation and mobility are described in this chapter.

This chapter explains the cognitive and psychological basis of teaching visually impaired children, especially when teaching them spatial mobility and spatial orientation. The tyflological approach is proposed.

As mobility is significantly correlated with autonomy and quality of life, a vast majority of the developed approaches and devices dedicated to visually impaired individuals attempts to augment or support orientation and mobility abilities and maximize independence and safety. Therefore, various methods and technical solutions have been proposed for generating a representation of the visual scene and transmitting this information to the user. As different visual impairments can be distinguished, from congenital blindness to low vision, dedicated solutions have been put forward to accommodate these different needs and abilities. These solutions may be used universally or take advantage of the specificity of the visual impairment (e.g., low vision, late blindness). Through the presentation of sensory supplementation, technical aids and visual neuro-prostheses studies, we will explore the approaches and technical solutions that have been proposed or are still in development. Additionally, we will provide some general recommendations regarding scene representation design and discuss the benefits of providing specialized information dedicated to mobility as opposed to a general purpose representation.

This paper reports the results of three experiments on tactile perception, spatial representation, and tactile display design for assistive mobility devices for blind, partially sighted, and deaf blind people. The results indicate the potentials of tactile displays for supporting environmental exploration and mobility. Voluntary test subjects showed reasonably good ability to determine the direction of motion of an arrow, with best recognition rates in the up and right directions. They showed reasonably good ability to use a tactile display to detect and avoid obstacles after a very short learning period and more limited ability to learn and remember an environmental representation using information from a tactile display and walking through the environment without specific instructions.

A model has been developed to analyse the basic requirements and tasks involved to ensure that optimum solutions to guarantee accessibility to public spaces are possible for all types of user in any situation. This model, called SOLID, adopts a systematic approach which was developed originally for applications for the blind and visually impaired persons (VIPs) in public transport, but can also be applied to analyse accessibility in many other situations. In the context of transportation systems it enables us to identify the essential tasks, requirements, and information needed at each stage of the chain of displacements. SOLID is an acronym for the initial letters of the five essential elements of the model, which are Safety, Orientation, Localisation, Information and Displacement. Ensuring maximum safety and security for all users in all circumstances and all phases of the journey is of course the primary function of the transport operator. The efficiency of the design of the infrastructure and systems put in place to provide a safe environment and satisfactory accessibility for all depends on the success of optimising the principles of inclusion and removing barriers at all stages of the journey including, the man machine interfaces and the modes of communication and guidance to cater to the physical and cognitive capacities of all users. Orientation, localisation and access to information are particularly important for the visually impaired to enable them to complete their journey safely. A perfect solution is, of course, difficult to achieve when redesigning transport systems that may have been originally designed more than a hundred years ago and which are often affected by an unfavourable local environment and multiple technical constraints, due to historical, structural, functional and economic factors, particularly in the case of metro or underground systems. In circumstances where older existing transport systems are being updated to comply with the new European regulations on accessibility coming into force, it is sometimes easier to propose alternative transport solutions, but much can still be done to improve accessibility in existing systems. The advantages of using this model are illustrated by the analysis of real problems and solutions applied in metro and train stations for blind and visually impaired users.

The chapter provides an overview of the factors to be considered in the design of travel aids which meet the needs of blind, visually impaired and deafblind people. The chapter consists of two main parts. The first part comprises an introduction, brief discussions of the long cane as a successful travel aid (with limitations) and how blind people travel; a categorisation of travel aids and an overview of the three main phases of travel aid development. The second part considers the specifics of good design practice. The topics covered include specific principles of good design practice, app design, end-user involvement and particular features, including functionality, the interface, sensors, privacy and context awareness.

The importance of involving the persons intended to use a design, already in the design process leading up to the final product or service, is increasingly acknowledged. This chapter is intended to provide both inspiration and practical suggestions for anyone interested in designing for and with persons with visual impairments. The text focuses on co-design, but many of the adaptations and materials presented can also be used in more traditional design activities, such as usability testing. The chapter rests on an inclusive mindset. In other words, we focus on how to expand and enhance existing methods regarding who is involved, and how to provide means for participation to wider target groups, rather than how to create “special” methods for “special” users with “special” needs.

In this chapter, we summarize several years of research efforts aimed at building ICT (Information and Communications Technologies) based systems for aiding the blind in travel and navigation at the Lodz University of Technology, mainly as part of the “Naviton” project (http://​www.​naviton.​pl), from a Polish Ministry of Higher Education grant. We report on different approaches we undertook in these challenging goals which comprise the following prototype solutions: (1) sonified stereovision system for obstacle avoidance and environment imaging, (2) radio beacons for local navigation, (3) remote assistance system, (4) mobile navigation applications, (5) real-time tracking of public transport vehicles, (6) haptic imaging. We shortly describe these technologies and discuss user feedback from the trials of these technological aids. Finally, we point out the key objectives and first results of a Horizon 2020 project entitled “Sound of Vision: natural sense of vision through acoustics and haptics” (http://​www.​soundofvision.​net) that started in 2015.

There are 285 million visually impaired people (VIP) worldwide, among whom 39 million are blind (WHO 2014).

Tactile maps are commonly used to give visually impaired users access to geographical representations. Although those relief maps are efficient tools for acquisition of spatial knowledge, they present several limitations and issues such as the need to read braille. Several research projects have been led during the past three decades in order to improve access to maps using interactive technologies. In this chapter, we present an exhaustive review of interactive map prototypes. We classified existing interactive maps into two categories: Digital Interactive Maps (DIMs) that are displayed on a flat surface such as a screen; and Hybrid Interactive Maps (HIMs) that include both a digital and a physical representation. In each family, we identified several subcategories depending on the technology being used. We compared the categories and subcategories according to cost, availability, and technological limitations, but also in terms of content, comprehension, and interactivity. Then we reviewed a number of studies showing that those maps can support spatial learning for visually impaired users. Finally, we identified new technologies and methods that could improve the accessibility of graphics for visually impaired users in the future.

This chapter focuses on indoor localization implemented by traditional and advanced enabling technologies, measurement strategies and applications. In particular, the discussion is oriented to perform a benchmark between different solutions with a specific focus in the framework of Active and Assisted Living. A case of study of an Assistive Systems supporting blind people during the exploitation of indoor environments is also presented. The system uses ultrasound technology, an advanced trilateration paradigm to perform a real time and continuous indoor localization and tools dedicated to gain the awareness of user/environment interaction and contextualization. Such features allow to provide the user with an efficient assistance for a safe exploitation of indoor environments

This paper reports on the findings from an experiment on human performance in tactile language learning and tactile memory. A set of four vibrotactile patterns representing verbal words was presented to a group of 20 voluntary subjects. Upon learning, subjects were capable of recognizing the patterns with high accuracy. Patterns were then combined with the aim of constructing sentences that gradually represent more complex ideas. Recognition rates remained satisfactory for sentences involving two, three, and four tactile words. A novel approach of tactile stimuli was explored: podotactile stimulation. For this study, a prototype of wearable electronic tactile display that stimulates the foot sole with vibrations was used. Results obtained suggest that it is possible to construct tactile languages that could enhance situational awareness feedback provided by assistive devices.

Up until now there has been no available treatment for diseases causing the permanent impairment of retinal photoreceptors.

There are an estimated 285 million visually impaired people globally, with 39 million of them blind (Pascolini and Mariotti in Br J Ophthalmol: bjophthalmol-2011, [1]). Nearly 10% of the estimated 1.1 million blind people in the USA use a long cane and just under 1% a guide dog. The chapter discusses the importance of mobility for participation in society and the factors that can lead to the inclusion or exclusion of blind, partially sighted and deafblind people. Exclusionary fctors include lack of full accessibility of public transport and continuins stigma which can affect the use of mobility technologies. Recommendations for the design of accessible environments to increase the participation and inclusion of blind, partially sighted and deafblind people are proposed and accessible public transport and pedestrian crossings are discussed.