9.4.5 Mobility Aids: Have They Solved the Mobility Challenge?

There is little or no doubt that there are a number of mobility aids available today that perform well in detecting, and in some cases identifying, objects. So do these devices solve the challenge of mobility, of finding a safe path through the immediate environment, for blind and visually impaired people?

9.4.5.1 Appearance

Most modern mobility aids are fairly inconspicuous, though there are some exceptions. This is to say that most are no more noticeable or aesthetically alienating than a long cane. This said, it should be pointed out that some visually impaired people find the conspicuousness of a long cane or guide dog unacceptable. Some individuals will not use any visible mobility aid, preferring to attempt to pass as sighted without the perceived labelling that goes with using a cane or guide dog. Being discreet and unobtrusive is important for many users, even those who accept and welcome the use of a mobility aid.

9.4.5.2 Operation

The handling and operation of most modern mobility aids is simple. Most allow users to switch the device on and off quickly and easily. Being able to silence a mobility aid instantly is of great importance as it allows the user to attend immediately to other crucial sensory information, such as a public announcement or somebody speaking to them. Most modern mobility aids also allow users to change quickly between different modes. In the rapidly changing travel environment this is vital. Imagine, for example, a user coming into a crowded building from a quiet and uncluttered street. Outdoors on the empty street they may walk at a brisk pace, therefore requiring maximum warning of upcoming hazards. Once inside the crowded building a much shorter range will be required. They must be able to make this adjustment without undue pausing. It should, however, be borne in mind that many modern mobility aids require small switches or buttons to be operated. For some potential users, those with limited dexterity, this will be a significant difficulty and may become more significant as miniaturisation of devices continues. Simple operation, by all potential users, is important.

9.4.5.3 Output

Modern mobility aids mostly use vibrations, simple beeps or complex patterns of beeps to inform the user of objects in the environment. All of these methods appear to be effective. It should be noted that most offer only one method of output. Of the five mobility aids discussed in this chapter, only the Laser Cane and the Miniguide allows users to have combined vibrotactile and auditory feedback or to choose between them. Flexibility in output is important to allow users to operate effectively in different environments.

312 9 Electronic Travel Aids: An Assessment

There are currently no tactile mobility aids that assist users in identifying objects. Future developments may see electro-tactile displays used to provide users with tactile information about size, shape and spatial relationships. For a discussion of the use of electro-tactile stimulation as a form of sensory substitution for blind people see Chapter 4 of this volume and the work of Bach-y-Rita et al. (1998).

9.4.5.4 Function

Mobility aids can be categorised as primary or secondary aids. Primary aids provide the essential information to enable the user to make the decision as to whether or not it is safe to take the next steps. Secondary aids augment the information provided by primary aids but do not by themselves provide all of the necessary information. Modern mobility aids include both primary and secondary aids. Primary aids have the advantage of (usually) being a single unit and requiring only one hand to operate it. Secondary aids are in themselves (usually) a single unit but must be used in conjunction with a primary aid. The user, therefore, may have a mobility aid in each hand, leaving neither hand free for other things. Most primary mobility aids combine the long cane with an electronic system. What, then, happens if the cane is damaged by, for example, impact with an object or by a moving vehicle? In many cases, if the damage is irreversible, the entire device must be replaced. Secondary aids are less vulnerable to this kind of damage than are primary aids.

Another distinction can be made between two groups of mobility aids—those which simply inform the user of the presence or absence of obstacles, and thus tell the user whether it is safe or unsafe to continue on the present path, and those which provide richer spatial information about the nature of objects and spatial relationships between objects. Further research is needed to establish how much spatial information is required in a variety of situations and whether all users can benefit from rich spatial information.

9.4.6 Navigation Aids

These are devices that assist the user with way-finding.

9.4.6.1 The BrailleNote GPS and the Victor Trekker

The BrailleNote GPS (see Figure 9.7) and the Victor Trekker are both navigation aids. They can provide assistance before setting out to a destination by calculating a route on a digital map and enabling users to explore that route. Once the user has set out, these devices use the global positioning (satellite) system to identify the user’s location. This location information can be combined with the information from the digital maps to provide directions or information about the route, such as what points of interest are nearby (see Figure 9.8). The BrailleNote GPS software is an optional extra for the BrailleNote or VoiceNote—notetakers that provide access to a number of applications including wordprocessing, email and organiser. The Victor Trekker is currently available as a dedicated unit, whose only purpose is as a navigation aid (see Figure 9.9).

Figure 9.7. The BrailleNote GPS (© PulseData Europe http://www.pulsedata.com. Used with permission.)

Figure 9.8. The BrailleNote GPS in action (© PulseData Europe http://www.pulsedata.com. Used with permission.)

314 9 Electronic Travel Aids: An Assessment

Figure 9.9. The Victor Trekker

9.4.7 Navigation Aids: Have They Solved the Navigation Challenge?

Navigation aids provide blind and visually impaired people with access to maps and to real-time positioning information that would otherwise be inaccessible to them. So have these devices solved the challenge of navigation, of locating oneself within the macro-environment and planning and following a route through it, for blind and visually impaired people?

9.4.7.1 Appearance

The compact units used for accessible navigation aids, such as the BrailleNote GPS and the Victor Trekker, are fairly discreet although they are visibly hightech devices. Their appearance is not alienating and with the increasing number of high-tech electronic devices being used by many people, disabled and non-disabled alike, they do not make the user too conspicuous. However, some potential users do have concerns about carrying anything that looks like expensive technology and would prefer that the technology could be completely hidden in a pocket or mundane and ordinary looking bag.

9.4.7.2 Operation

The functions available on navigation aids require the user to input much more to the device than they must with mobility aids. Inevitably this means that their operation is more complex. However, given this increased necessity for user input, the operation of these devices is relatively simple. Currently they require users to be able to operate a keyboard or to press tactile-marked buttons on a touch sensitive screen. Future developments may see the introduction of speech recognition onto these devices. This is a popular option for users as it allows for hands-free operation. However, some users report that they would feel self-conscious speaking into a device and would prefer to have the option to use a keyboard. Simple operation and a user-selectable choice of the mode of input are important issues to consider.