More info: http://www.w3.org/WAI/EO/Drafts/PWD-Use-Web/#diff

Abilities vary greatly from person to person and can be temporary or chronic. Many of these barriers can apply to all sorts of users. For example:

• They may not be able to see, hear, move, or may not be able to process some types of information easily or at all.
• They may have difficulty reading or comprehending text.
• They may not have or be able to use a keyboard or mouse.
• They may have a text-only screen, a small screen, or a slow Internet connection.
• They may not speak or understand fluently the language in which the document is written.
• They may be in a situation where their eyes, ears, or hands are busy or interfered with (e.g., driving to work, working in a loud environment, etc.).
• They may have an early version of a browser, a different browser entirely, a voice browser, or a different operating system.

Some Disabilities:

Visual Impairments

Blindness

May use screen readers that output information to a speech synthesizer or refreshable braille display. May tab through headings and links rather than read every word on the page.

Barriers

• images with no alternative text
• non standard document formats that can't be interpreted by their screen reader

Low Vision

May use extra-large monitors, and increase the size of fonts and images.

Barriers

• pages with absolute font sizes that don't change easily
• pages because of inconsistent layout are difficult to navigate when enlarged
• text presented as images
• pages with poor contrast

Colour Blindness

May not be able to distinguish between green and red and less often between yellow and blue.

Barriers

• when colour is used as a unique marker to emphasize content
• text that inadequately contrasts with background colour or pattern

Hearing Impairments

Deafness

First language may be sign language. May need captions for audio to highlight content.

Barriers

• audio without captions or transcripts
• no images in pages full of text
• lack of clear and simple language

Physical Disabilities

Motor

May use special mouse, keyboard, voice-recognition software etc.

Barriers

• sites that don't allow keyboard alternatives for mouse commands
• forms that can't be tabbed through in logical order

Cognitive and Neurological Disabilities

Dyslexia

May have difficulty processing written language.

Barriers

• lack of alternative modalities for info on website

Attention Deficit Disorder

May have difficulty focusing on information.

Barriers

• distracting visuals
• lack of clear and consistent organization

Intellectual Impairments

May learn more slowly, or have difficulty understanding complex concepts.

Barriers

• use of unnecessarily complex language
• lack of graphics
• lack of clear and consistent organization

Memory Impairments

May have problems with short term or long term memory and language.

Barriers

• lack of clear and consistent organization and navigation

Mental Health

May have difficulty focusing, or may have side effects of medication.

Barriers

• distracting elements
• absolute font sizes

Seizure disorders

May be triggered by visual flickering or audio signals.

Barriers

• Use of visual or audio frequencies