Textual content can be delivered in different modes to help people with cognitive disabilities comprehend it. These modes can include:
- text to speech (TTS)
- text with contextually-relevant images;
- text with consistent icons and graphics; and/or
- text replaced or augmented by symbol sets.
Challenges for People with Cognitive Disabilities
Difficulty of text comprehension by people with cognitive disabilities ranges from minimal to extreme. They may comprehend most of a web page’s textual content, or none at all.
Effect of memory impairments
People with cognitive disabilities may have to:
- read text several times to aid comprehension; and/or
- repeat aloud or otherwise reiterate text multiple times to retain it.
Effect of impaired executive function
People with cognitive disabilities may not:
- sufficiently process / understand text as they read it; and/or
- understand text because they did not understand the text that preceded it.
Effect of attention-related limitations
People with cognitive disabilities:
- may not attend to important concepts and relevant details; and/or
- may be significantly distracted by extraneous text.
Effect of impaired language-related functions
People with cognitive disabilities:
- may have comprehension problems exacerbated by text or instructions presented in a non-native language;
- may not understand text written in their native language, but not written in language from the same culture.
Effect of impaired literacy-related functions
Some people with cognitive disabilities may not:
- understand text because it is not literal and written plainly; and/or
- comprehend text-only instructions in order to adequately follow them.
Effect of perception-processing limitations
Many people with cognitive disabilities may not:
- comprehend text that can’t be enlarged without distortion;
- recognize characters if they do not form words, or are shown in different fonts or styles, e.g., italics.
Effect of reduced knowledge
Some people with cognitive disabilities may not comprehend text because:
- they do not have relevant background knowledge; and/or
- background concepts are not explained simply.
Text is written communication.
Textual content can be provided in a variety of alternative modes / formats as described below. Ideally, people with cognitive disabilities should be able to choose that content is delivered in the mode they comprehend best. (This is an important component of the proposed Global Public Inclusive Infrastructure.)
Text To Speech
Text To Speech (TTS) is hardware and/or software that produces human speech by a device such as a computer. Most TTS reads text aloud in a voice. Other TTS converts symbols, such as those employed by augmentative and alternative communication (AAC), into spoken speech.
Many people with cognitive disabilities, such as Dyslexia, may have the capacity to use a screen reader for text to speech (TTS). However, people with severe cognitive disabilities, such as intellectual disabilities, may require simpler TTS delivery.
A common one is a TTS widget embedded in a website. An alternative is a CSS speech module, as proposed by the W3C. Advantages include that there is nothing to download and install; and learning how to use a TTS widget or a CSS speech module is dramatically simpler than learning how to use a screen reader.
The TTS should be limited to relevant content, and exclude such text as found in menus, footers, and advertisements. Another helpful feature is the visual highlighting of text as it is read aloud. Such features may help people with cognitive disabilities who are overwhelmed even by simple TTS delivery.
Video is a short film clip of moving visual images with or without audio.
To aid comprehension, video with audio should be captioned and/or have audio description, which provides important information not described or spoken in the main sound track. For example, see “Autistic spectrum, captions and audio description”.
WCAG 2.0 Success Criterion References:
- 1.2.2 Captions (Prerecorded): Captions are provided for all prerecorded audio content in synchronized media, except when the media is a media alternative for text and is clearly labeled as such. (Level A)
- 1.2.5 Audio Description (Prerecorded): Audio description is provided for all prerecorded video content in synchronized media. (Level AA)
- 1.2.7 Extended Audio Description (Prerecorded): Where pauses in foreground audio are insufficient to allow audio descriptions to convey the sense of the video, extended audio description is provided for all prerecorded video content in synchronized media. (Level AAA)
Text With Contextually-Relevant Images
An image is a picture, a representation of a visual perception.
User research has shown that text comprehension is significantly enhanced where accompanied by contextually-relevant images. A picture of an object may be easier to recognize than a textual description of it.
Diagrams and charts as visual representations could be helpful for textual descriptions of processes or flows. Employing HTML Canvas, as proposed by the W3C, diagrams and charts could be interactive and have additional descriptions for their parts to aid comprehension.
Text With Consistent Icons And Graphics
An icon is a small image or drawing that commonly represents a function. A graphic is a drawing of a visual perception or an abstract concept, or is otherwise a representation of an object or an idea.
Text accompanied by consistent iconography helps convey meaning, such as by associating discrete textual passages with each other. Similarly, a pie-chart graphic may help convey meaning easier to comprehend than a table of statistics.
Text Replaced Or Augmented By Symbol Sets
A symbol is a sign that represents or suggests an idea, an object, an action, or a belief.
Symbol sets can be used for augmentative and alternative communication to support people with cognitive disabilities who have severe speech and/or language difficulties. This can include those who may understand speech, but who are unable to express what they wish to say, perhaps because of a physical disability. (It is common for people with cognitive disabilities to also have physical disabilities.) Ideally, interoperable symbol sets could be used to replace or to augment web-based text.
Text should be written clearly and simply using the following attributes:
- plain-language standards relevant to language and culture;
- (Examples for English include:
- literal explanations, e.g., without jargon, slang, and metaphors;
- active voice, not passive voice; and
- no or minimal use of acronyms and abbreviations.)
- visual and organizational structures, e.g., headings and bulleted lists;
- large font size; and
- sans-serif font
The first 2 attributes, especially the clear structures, will help comprehension via text-to-speech.
- I welcome your suggestions. Please add a comment.
- This is version 3 of an issue paper I wrote as part of my work as a member of the W3C’s Cognitive and Learning Disabilities Accessibility Task Force. It is a work-in-progress.
- Other task force members who have contributed to the content so far are:
- References in this document to “some people with cognitive disabilities” are to people with the lowest-functioning intellectual capacity, such as people with intellectual disabilities.