Introduction to People with Disabilities

Descriptions of Disability

Following are four major categories of disability and a brief description of each [1]:

• Visual impairment
• Hearing impairment
• Physical impairment
• Cognitive or language impairment

"Visual impairment represents a continuum, from people with very poor vision, to people who can see light but no shapes, to people who have no perception of light at all. However, for general discussion it is useful to think of this population as representing two broad groups: those with low vision and those who are legally blind.

"A person is termed legally blind when their visual acuity (sharpness of vision) is 20/200 or worse after correction, or when their field of vision is less than 20 degrees; in the best eye after correction. Low vision includes problems (after correction) such as dimness of vision, haziness, film over the eye, foggy vision, extreme near- or farsightedness, distortion of vision, spots before the eyes, color distortions, visual field defects, tunnel vision, no peripheral vision, abnormal sensitivity to light or glare, and night blindness.

"Hearing impairment means any degree and type of auditory disorder, while deafness means an extreme inability to discriminate conversational speech through the ear. Deaf people, then, are those who cannot use their hearing for communication. People with a lesser degree of hearing impairment are called hard of hearing. Usually, a person is considered deaf when sound must reach at least 90 decibels (5 to 10 times louder than normal speech) to be heard, and even amplified speech cannot be understood.

"Problems faced by individuals with physical impairments include poor muscle control, weakness and fatigue, difficulty walking, talking, seeing, speaking, sensing or grasping (due to pain or weakness), difficulty reaching things, and difficulty doing complex or compound manipulations (push and turn). Individuals with spinal cord injuries may be unable to use their limbs and may use "mouthsticks" for most manipulations. Twisting motions may be difficult or impossible for people with many types of physical disabilities (including cerebral palsy, spinal cord injury, arthritis, multiple sclerosis, muscular dystrophy, etc.).

"Cognitive impairments are varied, but may be categorized as memory, perception, problem-solving, and conceptualizing disabilities. Memory problems include difficulty getting information from short-term storage, long term and remote memory. This includes difficulty recognizing and retrieving information. Perception problems include difficulty taking in, attending to, and discriminating sensory information. Difficulties in problem solving include recognizing the problem, identifying, choosing and implementing solutions, and evaluation of outcome. Conceptual difficulties can include problems in sequencing, generalizing previously learned information, categorizing, cause and effect, abstract concepts, comprehension and skill development. Language impairments can cause difficulty in comprehension and/or expression of written and/or spoken language."

Statistics on the U.S. Disability Community

Census 2000 [2] counted 49.7 million people with some type of long lasting condition or disability. They represented 19.3 percent of the 257.2 million people who were aged 5 and older in the civilian noninstitutionalized population - or nearly one person in five. Within this population, Census 2000 found:

• 9.3 million (3.6 percent) with a sensory disability involving sight or hearing.
• 21.2 million (8.2 percent) with a condition limiting basic physical activities, such as walking, climbing stairs, reaching, lifting, or carrying.
• 12.4 million (4.8 percent) with a physical, mental, or emotional condition causing difficulty in learning, remembering, or concentrating.
• 6.8 million (2.6 percent) with a physical, mental, or emotional condition causing difficulty in dressing, bathing, or getting around inside the home.
• 18.2 million of those aged 16 and older with a condition that made it difficult to go outside the home to shop or visit a doctor (8.6 percent of the 212.0 million people this age).
• 21.3 million of those aged 16 to 64 with a condition that affected their ability to work at a job or business (11.9 percent of the 178.7 million people this age).

Potential Market for Accessible Technology

"In 2003, Microsoft Corporation [3] commissioned Forrester Research, Inc., to conduct a study to measure the potential market of people in the United States who are most likely to benefit from the use of accessible technology for computers. Accessible technology enables individuals to adjust their computers to meet their visual, hearing, dexterity, cognitive, and speech needs. It includes both accessibility options built into products as well as specialty hardware and software products (assistive technology products) that help individuals interact with a computer.

"The study identified individuals who considered themselves to have an impairment as well as those who did not but did report having difficulty performing daily tasks. This approach allowed the study to capture information about individuals who "self-identify" as having a disability or impairment as well as individuals who have difficulty with certain tasks but who do not identify themselves as having a disability or impairment.

"The survey covered the five types of difficulties and impairments that would most likely impact computer use: visual, dexterity, hearing, speech, and cognitive. The findings in this study show that the majority of working-age adults are likely to benefit from the use of accessible technology. As shown in the chart, 60% (101.4 million) of working-age adults are likely or very likely to benefit from the use of accessible technology.

Number of Working Age Adults Likely to Benefit from the Use of Accessible Technology

• A Brief Introduction to Disabilities, from the Trace Center, which provides an overview of the major disability groups and some of the specific accessibility barriers that they encounter.
• How People with Disabilities Use the Web, from the World Wide Web Consortium (W3C), which provides a general introduction to how people with different kinds of disabilities use the Web. It also includes scenarios that describe how "representative" people with disabilities use various assistive technologies or adaptive strategies to access the Web.
• Disability Statistics Center, which is hosted by the University of California San Francisco.
• US Census Bureau - Disability, which provides the U.S. Census Bureau’s data on disability.
• Resource on Person-First Language, which advocates putting the person first instead of the disability when describing people with disabilities.

References

1. Vanderheiden, Gregg C. and Vanderheiden, Katherine R., (1991). A brief introduction to the major disability groups and some specific barriers to accessibility they encounter. http://www.tracecenter.org/docs/population/populat.htm.
2. U.S. Census Bureau (2003). Disability Status: 2000, Census 2000 Brief. http://www.census.gov/hhes/www/disable/disabstat2k/disabstat2ktxt.html#_ftn1.
3. Microsoft, Forrester Research (2003). The Wide Range of Abilities and Its Impact On Computer Technology. http://www.microsoft.com/enable/research/default.aspx.