Types of Disabilities and Associated Barriers

To understand where accessibility issues can arise, it is helpful to have a basic understanding of a range of disabilities and their related barriers found in digital content.

Not all people with disabilities encounter barriers in digital content, and those with different types of disabilities encounter different types of barriers. For instance, if a person is in a wheelchair, they may encounter no barriers at all in digital content. A person who is blind will experience different barriers than a person with limited vision. Many of the barriers that people with disabilities encounter on the Web are often barriers found in electronic documents and multimedia. Different types of disabilities and some of their commonly associated barriers are described here.

Watch the following video to see how students with disabilities experience the Internet.

Video: Experiences of Students with Disabilities by Jared Smith

In this video, David Berman talks about types of disabilities and their associated barriers.

Video: Web Accessibility Matters: Difficulties and Technologies: Avoiding Tradeoffs by davidbermancom

People Who Are Blind

People who are blind tend to face the most barriers in digital content, given the visual nature of much digital content. They will often use a screen reader to access their computer or device, and they may use a refreshable Braille display to convert text to Braille.

Common barriers for this group include:

• Visual content that has no text alternative
• Functional elements that cannot be controlled with a keyboard
• Overly complex or excessive amounts of content
• Inability to navigate efficiently within a page of content
• Content that is not structured (i.e., missing proper headings)
• Inconsistent navigation
• Time limits (insufficient time to complete tasks)
• Unexpected actions (e.g., redirect when an element receives focus)
• Multimedia without audio description

For a quick look at how a person who is blind might use a screen reader like JAWS to navigate the Web, watch the following video.

Video: Accessing the web using screen reading software by rscnescotland

People with Low Vision

People with low vision are often able to see digital content if it is magnified. They may use a screen magnification program to increase the size and contrast of the content to make it more visible. They are less likely to use a screen reader than a person who is blind, though in some cases they will. People with low vision may rely on the magnification or text customization features in their web browser or word processor, or they may install other magnification or text reading software.

Common barriers for this group include:

• Content sized with non-resizable absolute measures
• Inconsistent navigation
• Images of text that degrade or pixelate when magnified
• Low contrast (inability to distinguish text from background)
• Time limits (insufficient time to complete tasks)
• Unexpected actions (e.g., redirect when an element receives focus)

See the following video for a description of some of the common barriers for people with low vision.

Video: Creating an accessible web (AD)  by the Centre for Inclusive Design

People Who Are Deaf or Hard of Hearing

Most people who are deaf tend to face barriers when audio content is presented without text-based alternatives, and they encounter relatively few barriers in digital content otherwise. Those who are deaf and blind will face many more barriers, including those described for people who are blind. For those who communicate with American Sign Language (ASL) or other sign languages, like Langue des signes québécoise (LSQ), the written language of a website may produce barriers similar to those faced when reading in a second language.

Common barriers for this group include:

• Audio without a transcript
• Multimedia without captions or transcript
• Lack of ASL interpretation (for ASL/Deaf community)

People with Mobility-Related Disabilities

Mobility-related disabilities are quite varied. As mentioned earlier, one could be limited to a wheelchair for getting around and face no significant barriers in digital content. Those who have limited use of their hands or who have fine motor impairments that limit their ability to target and click elements in digital content with a mouse pointer may not use a mouse at all. Instead, they might rely on a keyboard or their voice to control movement (i.e., speech recognition) through digital content, along with switches to control mouse clicks.

Common barriers for this group include:

• Clickable areas that are too small
• Functional elements that cannot be controlled with a keyboard
• Time limits (insufficient time to complete tasks)

People with Some Types of Learning or Cognitive Disabilities

Learning and cognitive-related disabilities can be as varied as mobility-related disabilities, perhaps more so. These disabilities can range from a mild reading-related disability to very severe cognitive impairments that may result in limited use of language and difficulty processing complex information. For most of the disabilities in this range, there are some common barriers and others that only affect those with more severe cognitive disabilities.

Common barriers for this group include:

• Use of overly complex/advanced language
• Inconsistent navigation
• Overly complex or excessive amounts of content
• Time limits (insufficient time to complete tasks)
• Unstructured content (no visible headings, sections, topics, etc.)
• Unexpected actions (e.g., redirect when an element receives focus)

More specific disability-related issues include:

• Reading: Text justification (inconsistent spacing between words)
• Reading: Images of text (not readable with a text reader)
• Visual: Visual content with no text description
• Math: Images of math equations (not readable with a math reader)

Everyone

While we generally think of barriers in terms of access for people with disabilities, there are some barriers that impact all types of users, though these are often thought of in terms of usability. Usability and accessibility go hand-in-hand. Adding accessibility features improves usability for others. Many people, including those who do not consider themselves to have a specific disability (such as those over the age of 50) may find themselves experiencing typical age-related loss of sight, hearing, or cognitive ability. Those with varying levels of colour blindness may also fall into this group.

Some of these usability issues include:

• Link text that does not describe the destination or function of the link
• Overly complex content
• Inconsistent navigation
• Low contrast
• Unstructured content