Inventory of Electronic Mobility Aids for Persons with Visual Impairments: A Literature Review
Roentgen, Uta R., Gelderblom, Gert Jan, Soede, Mathijs, de Witte, Luc P., Journal of Visual Impairment & Blindness
Abstract: This literature review of existing electronic mobility aids for persons who are visually impaired and recent developments in this field identified and classified 146 products, systems, and devices. The 21 that are currently available that can be used without environmental adaptation are described in functional terms.
Independent travel in unfamiliar environments is one of the major challenges that persons who are visually impaired (both those who are blind and those who have low vision) have to face in their daily lives (Marston & Golledge, 2003). The main problems include the lack of preview, knowledge of the environment, and access to information for orientation (Golledge, Marston, & Costanzo, 1997; Harper, Pettitt, & Goble, 2003; Helal, Moore, & Ramachandran, 2001). These problems frequently lead to less engagement in travel and activities outside the home, which affects productivity, employment, leisure and self-maintenance activities (Marston & Golledge, 2003; Walker & Lindsay, 2006), resulting in less participation in society.
To support their ability to move safely and purposefully, people who are visually impaired make use of several kinds of assistance, including sighted guides, white or long canes, and dog guides (Baldwin, 2003; Farmer & Smith, 1997; Zelek, Bromley, Asmar, & Thompson, 2003). Of the estimated 1.1 million persons who are blind in the United States, 10,000 own dog guides and 109,000 use white canes. Almost two-thirds of these cane users are younger than age 65, a noteworthy figure, since only one-third of all persons with visual impairments are younger than 65 (Demographics Update, 1994). Reliable data on the use of mobility devices in the Netherlands do not yet exist (Finsveen, Redeker, & Van Rooij, 2004). The white cane, in itself, however, is not sufficient for mobility; the user needs to acquire strategies for using it, which require intensive training by orientation and mobility (O&M) instructors. Furthermore, the white cane has a number of shortcomings, including an incomplete capacity for discrimination and protection against drop-offs; limited object-, surface-, and foot-placement previews; and no protection against collision with obstacles on the upper part of the body (Farmer & Smith, 1997).
Electronic mobility aids were developed after World War II to augment the functionality of the conventional tools used for mobility by people with visual impairments or to replace them with new, comprehensive ones. In the 1960s, the first electronic mobility aids, such as Kay's Sonic Torch and Russell's Pathsounder, became commercially available. The introduction of the Global Positioning System (GPS) in the mid-1990s led to the emergence of a new type of electronic mobility aid to foster navigation. Innovative electronic mobility aids integrate technologies, which developed quickly in the mainstream consumer market, made electronic mobility aids affordable, small, lightweight, and portable. Standard devices, such as cell phones and personal digital assistants (PDAs), combined with infrared or sonar sensors and GPS navigation that make use of wireless connectivity and multiple input-output modalities, have promising potential for people who are visually impaired (Baldwin, 2003; Fruchterman, 2003; Gill, 2005).
The use of electronic mobility aids is not yet widespread. From the developers' point of view, this lack of use could be attributed to the fact that earlier devices did not fully meet the needs of persons with visual impairments, motivating the ongoing search for an ultimate solution. Little research on electronic mobility aids has dealt with questions related to the field of rehabilitation because most of the information is restricted to technical specifications (Farcy et al., 2006). Reports of users' experiences have thus far depicted the advantages of electronic mobility aids, described in general as increased safety, preview, mobility, and travel speed; a greater level of independence; the readiness to travel in unknown or unfamiliar environments; and the reduction of stress and discomfort. …