Diverse Abilities and Barriers

Each individual is unique. People have diverse abilities, skills, tools, preferences, and expectations that can impact how they use the Web. For instance, consider the following aspects:

• Age-related impairments: Many people develop age-related impairments. While they share the same functional requirements as others with disabilities, sometimes there are significant differences in the use of assistive technologies, the level of computer skills, or in the use of the Web in general.
• Multiple disabilities: Some people have combinations of different kinds of disabilities, which may limit their approaches for interacting with the Web. For example, someone who is deaf and has low vision might benefit from captions for audio, but only if these captions have adjustable size and color.
• Health conditions: Some people have health conditions that may affect their stamina, dexterity, or concentration. For instance, some may experience fatigue, pain, or other symptoms that could have an impact on their physical use of the computer or limit the duration or extent of their use of the Web.
• Changing abilities: Some people may be experiencing progressive or recurring functional limitations that impact their use of the Web differently at different times. For example, some may need particular accessibility features on one day, and others or none on another day, depending on their condition.
• Temporary impairments: Some people may be experiencing temporary impairments such as those that may occur due to an accident, surgery, or medication. They may not know about accessibility solutions, may not know how to use accessibility features, and may be unaware of their needs.
• Situational limitations: Some people may be experiencing constraints due to their surrounding or due to other situational aspects. For example, they may be in a loud environment and unable to hear audio, in bright sunlight and unable to see a screen, or they may not be able to afford some technologies.

Websites and web tools designed for people with a broad range of abilities benefit everyone, including people without disabilities. It is, therefore, important to consider the broad diversity of functional needs rather than to categorize people according to medical classifications.

While multimedia on the Web provides many opportunities for people with auditory disabilities, it also poses challenges when content is not designed to be accessible. For example, while video content can be used to communicate information visually, audio content needs to have alternatives, such as transcripts and captions, so that it is accessible for people with auditory disabilities.

To use the Web effectively, people with auditory disabilities often rely on:

• Transcripts and captions of audio content, including audio-only content and audio tracks in multimedia;
• Media players that display captions and provide options to adjust the text size and colors of captions;
• Options to stop, pause, and adjust the volume of audio content (independently of the system volume);
• High-quality foreground audio that is clearly distinguishable from any background noise.

For some people with auditory disabilities, sign language is the primary language, and they may not read the written language as fluently. Providing important information in sign language and using simpler text that is supplemented by images, graphs, and other illustrations help make web content more understandable to many people. However, it is important to remember that not all people with auditory disabilities know sign language.

• Hard of hearing – mild or moderate hearing impairments in one or both ears.
• Deafness – substantial, uncorrectable impairment of hearing in both ears.
• Deaf-blindness – substantial, uncorrectable hearing and visual impairments.

• Audio content, such as videos with voices and sounds, without captions or transcripts.
• Media players that do not display captions and that do not provide volume controls.
• Media players that do not provide options to adjust the text size and colors for captions.
• Web-based services, including web applications, that rely on interaction using voice only.
• Lack of sign language to supplement important information and text that is difficult to read.

• Martine, online student who is hard of hearing
• Kaseem, teenager who is deaf and blind

Computer technologies and the Web provide many opportunities for people with cognitive, learning, and neurological disabilities to interact with content and to process information in ways that are more usable to them. For example, people can navigate web content using different strategies, access information in text, audio, or other formats, and change the presentation of the content according to their individual needs or preferences.

Depending on the individual needs, people with cognitive, learning, and neurological disabilities often rely on:

• Clearly structured content that facilitates overview and orientation;
• Consistent labeling of forms, buttons, and other content parts;
• Predictable link targets, functionality, and overall interaction;
• Different ways of navigating websites, such as hierarchical menu and search;
• Options to suppress blinking, flickering, flashing, and otherwise distracting content;
• Simpler text that is supplemented by images, graphs, and other illustrations;

People with cognitive, learning, and neurological disabilities use different types of web browsing methods, depending on their particular needs. For example, some people use text-to-speech software to hear the information while reading it visually or use captions to read the information while hearing it. Some people use tools that resize text and spacing or customize colors to assist reading. Others use grammar and spelling tools to support writing. For these web browsing methods to work, developers need to consider web accessibility requirements which are often shared by people with hearing, physical, speech, and visual disabilities.

• Attention deficit hyperactivity disorder (ADHD) (formerly “attention deficit disorder (ADD)”) – involves difficulty focusing on a single task, focusing for longer periods, or being easily distracted.
• Autism spectrum disorder (ASD) (includes “autism,” “Asperger syndrome,” and “pervasive developmental disorder” (PDD)) - involves impairments of social communication and interaction abilities, and sometimes restricted habits and interests.
• Intellectual disabilities (sometimes called “learning disabilities” in Europe and some other countries, and “developmental disabilities” in other regions) – involves impairments of intelligence, learning more slowly, or difficulty understanding complex concepts. Down syndrome is one among many different causes of intellectual disabilities.
• Learning disabilities – is a functional term rather than a medical condition, and is not uniformly defined. In Europe and some other countries, it refers to intellectual disabilities, while in Australia, Canada, the U.S., and some other countries it refers to perceptual disabilities.
• Mental health disabilities – includes anxiety, delirium, depression, paranoia, schizophrenia, and many other disorders. These conditions may cause difficulty focusing on information, processing information, or understanding it. In particular medication for these disorders may have side effects including blurred vision, hand tremors, and other impairments.
• Memory impairments – involves limited short-term memory, missing long-term memory, or limited ability to recall language. Dementia is one among many different causes of memory impairments.
• Multiple sclerosis – causes damage to nerve cells in the brain and spinal cord, and can affect auditory, cognitive, physical, or visual abilities, in particular during relapses.
• Neurodiversity – is a societal rather than medical term to describe the natural diversity in neurocognitive functioning, like gender, ethnicity, sexual orientation, and disability.
• Perceptual disabilities (sometimes called “learning disabilities” in Australia, Canada, the U.S., and some other countries) – involves difficulty processing auditory, tactile, visual, or other sensory information. This can impact reading (dyslexia), writing (dysgraphia), processing numbers (dyscalculia), or spatial and temporal orientation.
• Seizure disorders – includes different types of epilepsy and migraines, which may be in reaction to visual flickering or audio signals at certain frequencies or patterns.

• Complex navigation mechanisms and page layouts that are difficult to understand and use.
• Complex sentences that are difficult to read and unusual words that are difficult to understand.
• Long passages of text without images, graphs, or other illustrations to highlight the context.
• Moving, blinking, or flickering content, and background audio that cannot be turned off.
• Web browsers and media players that do not provide mechanisms to suppress animations and audio.
• Visual page designs that cannot be adapted using web browser controls or custom style sheets.

• Preety, middle school student with Attention Deficit Hyperactivity Disorder and Dyslexia
• Yun, retiree with low vision, hand tremor, and mild short-term memory loss
• Luis, supermarket assistant with Down syndrome

To use the Web, people with physical disabilities often use specialized hardware and software such as:

• Ergonomic or specially designed keyboard or mouse;
• Head pointer, mouth stick, and other aids to help with typing;
• On-screen keyboard with trackball, joysticks, or other pointing devices;
• Switches operated by foot, shoulder, sip-and-puff, or other movements;
• Voice recognition, eye tracking, and other approaches for hands-free interaction.

People with physical disabilities may be using a mouse or mouse-like device only, or keyboard or keyboard-like device only to operate the computer. People with physical disabilities rely on keyboard support to activate functionality provided on web pages. They may need more time to type, click, or carry out other interaction, and they may type single keystrokes in sequence rather than typing simultaneous keystrokes (“chording”) to activate commands. Such keystrokes include commands for special characters, shortcut keys, and to active menu items.

People with physical disabilities may have trouble clicking small areas and are more likely to make mistakes in typing and clicking. Providing large clickable areas, enough time to complete tasks, and error correction options for forms are important design aspects. Other important design aspects include providing visible indicators of the current focus, and mechanisms to skip over blocks, such as over page headers or navigation bars. People with cognitive and visual disabilities share many of these requirements.

• Amputation – includes missing fingers, limbs, or other parts of the human body.
• Arthritis (previously called “rheumatism”) – inflammation, degeneration, or damage to the joints.
• Fibromyalgia (formerly called “rheumatism”) – the chronic pain of muscle and connective tissues.
• Rheumatism – typically refers to arthritis and other causes of bone or joint pain, and sometimes to fibromyalgia and other causes for muscular and other soft tissue pain.
• Reduced dexterity – is a functional term (rather than a medical condition) that describes the ability to control the hand, such as hand-eye coordination of people with cognitive and neurological disabilities.
• Muscular dystrophy – progressive weakness and degeneration of muscles, sometimes including in arms and hands.
• Repetitive stress injury (RSI) (also called “repetitive motion disorder” (RMD) and “cumulative trauma disorder” (CT)) - involves injuries to the musculoskeletal system (bones, joints, tendons, and other connective tissues) and the nervous system from repetitive tasks and damage.
• Tremor and spasms – involuntary movement or muscle contraction, including short twitches, and continual or rhythmic muscle contractions.
• Quadriplegia (sometimes called “tetraplegia”) - partial or total paralysis (includes motor control and sensation) to all four body limbs (legs and arms) and the torso.

• Websites, web browsers, and authoring tools that do not provide full keyboard support.
• Insufficient time limits to respond or to complete tasks, such as to fill out online forms.
• Controls, including links with images of text, that do not have equivalent text alternatives.
• Missing visual and non-visual orientation cues, page structure, and other navigational aids.
• Inconsistent, unpredictable, and overly complicated navigation mechanisms and page functions.

• Alex, reporter with repetitive stress injury
• Yun, retiree with low vision, hand tremor, and mild short-term memory loss

People with speech disabilities encounter barriers with voice-based services, such as automated web-based hotlines and web applications that are operated using voice commands. To use services that rely on voice, people with speech disabilities need alternative modes of interaction such as a text-based chat to interact with hotline representatives and keyboard commands to operate web applications. Also, websites that provide telephone numbers as the only means of communicating with an organization pose barriers for people with speech disabilities. Alternative means of communication include e-mail and feedback forms.

• Apraxia of speech (AOS) – includes inconsistent articulation and production of speech sounds, and errors producing sounds in the correct order so that spoken words or phrases become difficult to understand.
• Cluttering (also called “tachyphemia”) – includes increased speaking rate, incorrect rhythm, intonation, and co-articulation of sounds, and other influent speech that is sometimes similar to stuttering.
• Dysarthria – involves weakness or complete paralysis of muscles that are necessary to produce speech, including lips, lungs, throat, tongue, and others.
• Speech sound disorder – involves difficulty or inability to produce certain sounds or patterns of sound and sometimes results in addition, distortion, omission, or substitution of such sounds with others.
• Stuttering – includes influent speech, repetition of individual sounds or entire words and phrases, and misplacement or prolongation of pauses and sounds while speaking that is different from cluttering.
• Muteness (also called “mutism”) – involves the inability to speak due to various reasons such as anxiety, brain injuries, or inability to hear and learn speech.

• Web-based services, including web applications, that rely on interaction using voice only.
• Websites that offer phone numbers as the only way to communicate with the organizations.

People with visual disabilities typically rely on changing the presentation of web content into forms that are more usable for their particular needs. For example by:

• Enlarging or reducing text size and images;
• Customizing settings for fonts, colors, and spacing;
• Listening to text-to-speech synthesis of the content;
• Listening to audio descriptions of video in multimedia;
• Reading text using refreshable Braille.

For these web browsing methods to work, developers need to ensure that the presentation of web content is independent of its underlying structure and that the structure is correctly coded so that it can be processed and presented in different ways by web browsers and assistive technologies. For example, some people do not see the content and rely on lists, headings, tables, and other page structures to be properly coded so that they can be identified by web browsers and assistive technologies.

Some people are only seeing small portions of the content at a time or are perceiving the colors and design differently. Some people are using customized fonts, colors, and spacing to make the content more readable, or they are navigating through the content using keyboard only because they cannot see the mouse pointer. An accessible design supports different presentations of the web content and different ways of interaction.

• Color blindness – includes difficulty distinguishing between colors such as between red and green, or between yellow and blue, and sometimes inability to perceive any color.
• Low vision – (in some regions also called “partial sight”) includes poor acuity (vision that is not sharp), tunnel vision (seeing only the middle of the visual field), central field loss (seeing only the edges of the visual field), and clouded vision.
• Blindness – substantial, uncorrectable loss of vision in both eyes.
• Deaf-blindness – substantial, uncorrectable visual and hearing impairments.

• Images, controls, and other structural elements that do not have equivalent text alternatives.
• Text, images, and page layouts that cannot be resized, or that lose information when resized.
• Missing visual and non-visual orientation cues, page structure, and other navigational aids.
• Video content that does not have text or audio alternatives, or an audio-description track.
• Inconsistent, unpredictable, and overly complicated navigation mechanisms and page functions.
• Text and images with insufficient contrast between foreground and background color combinations.
• Websites, web browsers, and authoring tools that do not support the use of custom color combinations.
• Websites, web browsers, and authoring tools that do not provide full keyboard support.

• Lee, online shopper with color blindness
• Ilya, senior staff member who is blind
• Yun, retiree with low vision, hand tremor, and mild short-term memory loss
• Kaseem, teenager who is deaf and blind