Range of abilities

Overview

People may think of disability as a limitation. Even the Americans with Disabilities Act (ADA) defines disability in terms of limitation, as "a physical or mental impairment that substantially limits one or more major life activities." 

However, it is often more useful to think about disability in terms of ability that ranges and may require different amounts of support. 

Ability exists on a spectrum 

Ability can also vary from day to day. 

People with the same disability will have different levels of impairment and different support needs; for example, someone who is blind may have a total loss of vision, or may perceive light and dark or blurry shapes.  

Support needs can also vary from day to day or hour to hour. For example, someone may use a wheelchair sometimes but only need a cane at others. 

Not all impairments are permanent 

When you think of someone with a disability, you may picture someone with a permanent disability, such as a blind person using a white cane or a paralyzed person using a wheelchair.  

But people can have a temporary condition, such as a short-term injury, that requires the same support as someone with a permanent disability.  

• Someone with an eye injury or who just had eye surgery can have a temporary vision disability, and may need to use larger text or text-to-speech software, for example, while they recover. 

• Someone with a broken leg has a temporary mobility disability, and may use crutches or a cane, a scooter, or even a wheelchair. 

An environment or circumstances may also create access barriers:  

• Someone in a bright environment looking at their mobile phone screen will benefit from higher contrast, as might someone with low vision or color vision deficiencies might.  

• Someone in a noisy sports bar will appreciate closed captions on a TV screen, using an assistive technology developed for the d/Deaf and hard of hearing. 

Disabilities and impairments can also be acquired at any time. Some people are born with a disability. Others become permanently disabled through injury, illness, or aging. People who are born with a disability may acquire a second disability. 

Categories of disabilities 

While some disabilities are visible, others are not. It's easy to see a wheelchair or white cane. You can't see that someone may have epilepsy. You may not notice that someone is hard of hearing. Many types of disabilities exist.

Vision

Permanent visual disabilities include blindness, low vision, and color vision deficiencies. Many people wear glasses or contacts, or use assistive devices, to correct their vision. The vision of people who are blind or have low vision can't be fully corrected. They may have some vision or no vision in one or both eyes. Color vision deficiencies, or color blindness, can't be cured. 

Learn more from the Web Accessibility Initiative about vision disabilities. 

Hearing 

Hearing impairments can be partial (hard of hearing) or total, in one or both ears. People who are deaf may consider themselves part of a community and culturally Deaf (upper-case D). Others do not consider themselves part of a community and are often referred to as deaf (lower-case d); d/Deaf is used to encompass both. Some people can hear sounds but may have difficulty understanding speech. 

Learn more from the Web Accessibility Initiative about hearing disabilities. 

Deaf-blind 

Deaf-blindness includes both deafness and blindness. Most people who are deaf-blind are not completely deaf nor completely blind. Deaf-blindness is often misunderstood or misconstrued as a cognitive impairment. However, it is a multi-sensory disability and does not limit a person's intelligence or ability to learn. Common assistive technologies and strategies include refreshable braille devices to consume content and tactile sign language interpretation. 

Learn more from the National Center on Deaf-Blindness. 

Mobility and motor 

Mobility disabilities affect a person’s ability to move, while motor impairments involve fine motor skills. Mobility and motor impairments include paralysis, weakness, tremors, joint disorders like arthritis, pain, and missing limbs. A person with a mobility disability may use a wheelchair or cane, sometimes or all the time.  

Learn more from the Web Accessibility Initiative about mobility and motor disabilities.  

Cognitive and psychological