Computer Accessibility – Grade 12 revision

Accessibility options
Screen magnifiers are one accessibility option.

Jon Honeyball from PCPro has an interesting article about how software interfaces affect disabled users (positively or negatively). This might be a good time to recap accessibility features ready for the exam.

Accessibility clearly relates to the ITGS social issue 1.6 The digital divide and equality of access. Usually we consider four main types of disability:

  • Eyesight problems (including blindness)
  • Hearing problems
  • Mobility problems
  • Cognitive problems (such as learning disabilities like dyslexia)

Accessibility relates to a wide range of ITGS scenarios, including in the home, the office, and the classroom. In each case, accessibility options can help include users who might otherwise be excluded. A child with dyslexia, for example, can use text-to-speech options on a computer to assist with classroom reading. High contrast screen settings can enable an office worker to use a word processor despite eyesight problems. A severely disabled user can use a head wand to touch keys or switches to communicate. In cases of extreme mobility disabilities, computers can be the only method of communication for a user.

Accessibility Options

Most modern operating systems have some accessibility options built in – in Windows they are found in the Ease of Access centre. Microsoft’s web site has a good section dedicated to accessibility, with videos of various features. Which of these accessibility options are you able to describe? Which disabilities do they address?

Screen magnification
Sticky keys
Pointer trails
Large pointer
Voice recognition
Voice control
On screen keyboard
Head wand
High contrast mode
Text to speech / screen reader
Braille keyboards
Braille printers
Head control systems
Input switches
Eye tracking software
Sip and puff controllers
Computer user with disability
A user with severe mobility problems casts a vote using a head wand. (Image: WikiMedia CC-SA)

Designing Software and Web pages
Accessibility features are not the whole story though. Developers are also responsible for making systems accessible. Web page developers, for example, can take a series of steps to improve their pages.

Developing web pages using Flash might look nice, but they stop screen readers from working because they cannot read graphical content. Images are an important part of web pages, but a screen reader needs HTML ALT tags so it can read a description of the image for a partially sighted user.

A colour blind user may be unable to see hyperlinks if the only thing which distinguishes them is their colour (ever notice that most links are also underlined – there is a reason for this!).

The good news for designers is that research shows pages which are more accessible for disabled users are also easier for everyone else to use too.

Extreme Accessibility
World renowned physicist Stephen Hawking uses a computer as his only method of communication. Hawking has motor neurone disease and has had severely limited mobility for many years. In earlier versions of his computer system, he communicated by clicking a simple on-off switch with his thumb – the only part of his body he could reliably move. Using this method he could write approximately one word per minute, which was then read aloud by a speech synthesizer.

As Hawking’s disease progressed, even his control over his thumb degraded. His new computer system uses an infra-red sensor attached to his glasses, which measures the reflected light as he twitches his cheek muscles, and translates this into speech.

This interview with the engineer who designed Hawking’s system is a good read.

Accessibility hardware and software

If you are revising from the textbook, accessibility issues are covered in Chapter 1 Hardware (page 29) and Chapter 10 Education (page 229).

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