Assistive technology
[Narrator:] Welcome. In this chapter you will learn about assistive technology. We will see what assistive technology is and how it improves the lives of so many people.
Assistive technology in general is a very comprehensive term which includes any piece of equipment, software program or system that is used to increase, maintain or improve the functional capabilities of persons with disabilities. This might include a wheelchair or a prosthesis.
As this course focuses on digital publications, we will limit the definition of assistive technology to technologies that help people to use a personal computer or mobile device to consume or create digital information.
Assistive technology always adapts to the individual needs of a single person. One person can fulfil a specific task better or differently than another person. When choosing the best solution, individual strengths and weaknesses have to be taken into account. As we cannot discuss every individual scenario, we will discuss the following target groups:
- People with auditory impairments.
- People with physical disabilities.
- People with visual impairments or visual disabilities, the target group which faces the biggest challenges when using personal computers or mobile device.
A person with visual impairments has low vision, which cannot be corrected by glasses or contact lenses. There are many different types of visual impairments. In contrast to this, a person with visual disabilities has no vision at all. They are considered to be blind. For every target group there are hardware and software solutions.
Assistive technology for people with hearing impairments – hardware
People with hearing impairments require visual and tactile media to receive and communicate information. Sometimes the audio information cannot be converted into a visual or tactile version. In this case, a hearing aid can be useful. A hearing aid is a device that is designed to amplify sound for the wearer. The user normally wears the device behind or in the ear. The device is typically configured to the individual's needs, so it can compensate for frequency weaknesses.
A hearing aid amplifies sound waves using a microphone, amplifier and speaker. Today most hearing aids use digital technology to convert, filter and synthesise the audio signal. In combination with a personal computer or mobile device, a hearing aid can make use of digital wireless communication, such as Bluetooth. A compatible hearing aid can be configured on a personal computer or mobile device as an audio output device, similar to a Bluetooth speaker.
Assistive technology for people with hearing impairments – software
Beyond hardware solutions, there are also software solutions for people with hearing impairments.
Many video players can display captions in videos. Captions or subtitles render any audio information in text form to the user.
Of course, the same technology can be used to display the audio information in text form using different languages, which makes this technology very useful to many more users. Please refer to the chapter Text transcripts, captions and sign language for more information about captions.
Software equalisers can be used to amplify or attenuate different frequency bands of an audio signal to improve the user's perception. Channel-dependent loudness regulation can ompensate for different hearing impairments in each ear. If your right ear can perceive only half of the loudness that your left ear can, then it is useful to play the audio signal of the right channel using twice the volume of the left channel.
Some operating systems or apps can convert audio information to visual information. For example, a personal computer can replace an alert sound with a screen flash to notify the user.
Assistive technology for people with physical disabilities
In the context of using a personal computer or mobile device, we can limit our definition of physical disabilities to the inability to use the hands. A person in a wheelchair with fully functional hands can make perfect use of a personal computer or touch-based device.
Users who are unable to control their hands will have problems using the keyboard or mouse of a personal computer. When using a touch-based device, like a smartphone or tablet these users will face problems executing gestures, especially multi-touch gestures. There is therefore a need for alternative input devices.
Assistive technology for people with physical disabilities – hardware
Alternative input devices for the keyboard and mouse include:
- A joystick, trackball or trackpad, which is often attached to a wheelchair or table so it can be reached by the user.
- A switch interface, which is most useful to those who have only minimum moving capabilities.
- A mouth-controlled, head-controlled or eye-controlled mouse is for users who have no control over their body and can only move their head or eyes.
- A sip-and-puff device allows users to make selections and navigate computerised interfaces with inhalations and exhalations.
A user with physical disabilities might use one or many of these solutions depending on their personal preferences and capabilities.
Assistive technology for people with physical disabilities – software
Even though hardware solutions can offer many possibilities, they can be improved by software. As the name suggests, an on-screen keyboard displays a keyboard on-screen. Instead of pressing a key on the keyboard, the user types a letter by clicking a character in the on-screen keyboard with the mouse pointer using one of the previously mentioned alternative input devices.
By using speech recognition, a user can give spoken commands to a computer. The user can start and stop applications, invoke menu functions or search databases. Dictation software is often a much faster solution for typing texts than the alternative input devices.
If a user can only use one hand, Sticky Keys can be helpful. Imagine you can only use one hand and you have to type a combined key combination like Shift-Control-Option U. This would be really difficult. When activated, the system adds all keystrokes that can be used in combination with other keys; like Shift, Control or Option, until a character key is pressed. So you can type Shift, Control, Option, U in sequence, instead of at the same time, to activate this key combination.
Slow Keys allow the user to specify the duration for which one must press-and-hold a key before the system accepts the key press. This feature prevents unintentional keystrokes caused by trembling motions.
An app or website can allow a user to use keyboard-based navigation as a mouse alternative. By pressing different key combinations, a document can be navigated or a program function can be invoked.
Assistive technology for people with visual impairments – hardware
People with low vision can use large-print or tactile keyboards to assist them in typing text. They can use a magnifying solution, like a magnifying glass or a camera-based digital magnifying solution.
Digital solutions offer the possibility to apply several filters to the resulting image to improve the user's perception.
An e-book reader can be used to read e-books as these can display text using larger font sizes or read the text aloud using a speech synthesiser. E-book readers exist as single devices or as software apps on a personal computer or mobile device.
For more information on how to create an accessible e-book file, please refer to the ePub chapter.
Assistive technology for people with visual impairments – software
Of course there are also software solutions for this target group.
A screen magnifier can enlarge the whole screen or parts of the screen on a personal computer or mobile device.
A reading assistant reads text aloud to the user. Typically a user selects the text and the system will forward the selection to the speech synthesiser for reading.
[Screen reader:] Find out everything you need to know about the European Union's achievement in 2018.
[Narrator:] A colour corrector enables the personal computer or mobile device to compensate for colour blindness. All colours on the monitor are shifted to a different spectrum, allowing the user to perceive the different elements on the screen.
There are many different types of colour blindness, so the corrector needs to be able to perform different colour spectrum shifts.
Assistive technology for people with visual disabilities – hardware
When users are unable to use the screen at all, we need completely different technologies.
Braille is a tactile writing system using rectangular cells with raised dots. A full braille cell contains six raised dots arranged in two columns each column having three dots. The number and arrangement of the dots distinguish one character from another.
A braille keyboard is an input device that allows the user to type and enter text or instructions for the computer in braille. Every key represents one of the six dots in braille. The user types text by pressing the keys simultaneously to define a specific character.
A refreshable braille display is an electro-mechanical device for displaying braille characters, usually by means of round-tipped pins raised through holes in a flat surface. Users with visual impairments can use it to read text output. Braille displays can present a limited number of characters simultaneously. Typically braille displays present 20, 40 or 80 characters at the same time. Often braille keyboards and braille displays are combined in a single device.
E-book readers can also be used by people with visual impairments.
Assistive technology for people with visual disabilities – software
As monitors cannot be used by people with visual disabilities, we need a different way to communicate this information.
A screen reader works closely with the computer’s operating system to read all content on the screen to the user. Beyond pure text-based information, a screen reader can provide information about icons, menus, dialogue boxes, files and folders.
[Screen reader:] EU in 2018, heading level 1. The EU in 2018, heading level 2. Blank. Find out everything you need to know about the European Union's achievements in 2018. Blank. The general report on the activities of the European Union brings you up to date on how the EU is delivering on its ten priorities including actions...
[Narrator:] For more information about screen readers, please refer to the Screen readers chapter.
Where to continue?
You have gained a basic understanding of what assistive technology is and how it improves the lives of so many people. Depending on your personal interests, you could continue with one of the following chapters.
If you want to learn more about assistive technology, please continue with the software specific chapter for:
- Assistive technology – Windows.
- Assistive technology – macOS.
- Assistive technology – iOS.
- Assistive technology – Android.
If you want to learn more about how people with visual disabilities use their personal computer or mobile device, please continue with the chapter on Screen readers.
If you want to learn more about other accessibility concepts, then please continue with one of the chapters on:
- Fonts, sizes and colours.
- Alternative text.
- Text transcripts, captions and sign language.
- Plain language.
[Automated voice:] Accessibility. For more information visit: op.europa.eu/en/web/accessibility.