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Strategies for Making Electronic Textbooks Accessible 

Contents of this page:

• Variety of Formats And Media
• General Accessibility Guidelines For Students Who Are Blind or Visually Impaired
• Compatibility Guidelines

Electronic textbooks can take many forms. Each has different advantages and poses different accessibility opportunities and issues. There are, however, some general strategies which apply across most electronic textbook formats. The following section describes some examples of the various formats of electronic textbooks, general accessibility guidelines pertaining to students with visual impairments, and issues related to compatibility between common assistive devices and electronic textbooks.

Variety of Formats And Media

Electronic textbooks may be produced in many different formats. For example, it is possible to deliver a standard movie either as a VHS videocassette, as a videodisc, in digital form on a new digital videodisc (DVD), or as a digital file which is downloaded from the Internet. When viewed, the users would have no idea whether they were looking at a videotape, a videodisc, or a file downloaded from the Internet. Similarly, an interactive textbook might be delivered to the school on a DVD disc, on a CD-ROM, or over the Internet or Internet-like communications link within a single school district (i.e., an intranet).

Regardless of the format in which an electronic textbook is produced, the basic considerations for making it accessible are the same. Some of the delivery formats lend themselves to including accessibility features more than others.

General Accessibility Guidelines For Students Who Are Blind or Visually Impaired

1. All important information which is presented visually should also be available to the user in both auditory and electronic text (e-text). Electronic text is text arranged in a digital form readable by computers and capable of being easily rendered as braille or enlarged text. The phrase "important information" is used to differentiate between visual information which is essential to the use of the electronic textbook and visual presentations which are merely decorative. It is not necessary nor even always desirable to present to the student who is blind all of the decorative aspects along with the more essential information. It can both slow access to the essential information and increase the cognitive load due to the need for the student to evaluate and filter the information.
2. All controls should be operable without vision.
3. Users should be able to zoom in to view portions of the screen in more detail. Where possible, they should also be able to adjust the size and type of font.
4. There should be a way of operating all controls by using commands formatted as electronic text.

Implementation of these general guidelines would also provide access advantages to individuals with reading difficulties and other physical disabilities. They would also allow a greater flexibility of access for all users, including the ability for users to operate devices more easily in very noisy environments or in very quiet environments. For additional guidelines on making electronic textbooks accessible to individuals with a wide range of disabilities, see Appendix B.

Compatibility Guidelines

An electronic textbook without built-in accessibility should be compatible with common assistive devices and software used by people with disabilities. Three types of add-on access solutions are available to make electronic textbooks accessible to students who are blind or visually impaired. These include screen magnification, speech output and braille output.

• Screen magnification results when special software enlarges a selected portion of the presentation to fill the entire screen. This software will enlarge text, graphics, and movies.
• Speech output combines a speech synthesizer and screen review software. This software reads text displayed on the computer screen and sends it to the synthesizer in an intelligent fashion. The students can hear individual characters, lines, words, sentences, or paragraphs, as well as punctuation. Screen reading software also allows students to explore and navigate the text on screen.
• Braille output combines screen review software with a dynamic braille display. That is, the software converts text on the screen into braille characters which are produced almost as quickly as the printed characters on the screen.

Since only approximately ten percent of the people who are legally blind know and use braille, it cannot be used as the only way to make information accessible. For those who do know braille (and a higher proportion of young people who are legally blind know braille), use of a dynamic braille display is a very powerful technique which has advantages over speech, particularly in dealing with spatially formatted information. Therefore, use of a dynamic braille display is an important and effective option.

Although there are a number of assistive technologies available in each of the above categories, the effectiveness of these assistive technologies in providing access to an electronic textbook is dependent upon the design of the electronic textbook. Information which is not available in text form, for example, cannot be displayed using speech or braille. Software which requires an individual to simultaneously monitor two events occurring at opposite edges of the screen would be difficult for someone to operate by using screen magnification. It is not necessary, however, to limit electronic textbooks to purely text presentation in order to make them accessible. Strategies exist for making even richly graphical systems accessible.

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Last Revision: July 30, 2002