During a design review, someone asked for more specific information about cognitive disabilities. As a result, I pulled out all my resources to see if I could distill the information in an easy-to-understand answer.
What is cognition?
The mental action or process of acquiring knowledge and understanding through thought, experience, and the senses.
Lexico / Cognition
What is a cognitive disability or impairment?
You will often find the terms, ‘cognitive disability’ and ‘cognitive impairment’, being used to describe similar concepts. Here are a few examples from credible sources below.
Cognitive and learning disabilities impact how people process information.
World Wide Web Consortium – Web Accessibility Initiative (W3C-WAI)
Cognitive impairment is when a person has trouble remembering, learning new things, concentrating, or making decisions that affect their everyday life.
Center for Disease Control (CDC)
A cognitive disability can affect a person’s ability to learn and process information; communicate through spoken or written language; and infer information correctly from social cues and body language.
Society for Human Resource Management (SHRM)
Cognitive impairment refers to a broad range of disabilities, from people with intellectual disabilities who may have the most-limited capabilities, to age-related issues with thinking and remembering.
Mozilla Developer Network (MDN) / Cognitive accessibility
While there is a difference between a disability and impairment, we will use disability as a broader concept here. For more information on the difference between disability, impairment, and handicap, ACC Institute of Human Services has a great article, Impairment, Disability, and Handicap: What’s the Difference?
Types of Cognitive Disabilities
In no particular order, the following list contains both general and specific types of disabilities where people have difficulties with cognitive functions.
- Reading Disabilities
- Intellectual / Learning Disabilities
- Math and Computational Disabilities
- Attention Deficit Hyperactivity Disorder (ADHD)
- Autism Spectrum Disorder (ASD)
- Non-verbal Learning Disability (NVLD)
Anyone diagnosed with a cognitive disability may have one or more type of cognitive difficulty. For example, some people are fine with reading but struggle with math.
How many people have cognitive disability?
The percentage of the population is pulled from the listed source in the last column. The population size is calculated using the percentage of the population with the population size provided by Worldometer as of May 2022.
- World population - 7,900,000,000 or 7.9 billion
- USA population - 331,000,000 or 331 million
| Type of Cognitive Disability | Percentage of Population (Earth or USA) | Population Size | Source |
|---|---|---|---|
| Intellectual and Learning Disability | 1 to 3 percent (Earth) | 70 to 210 million people (Earth) | IAAP |
| Attention Deficit Hyperactivity Disorder (ADHD) | 11 percent (Earth) | 869 million people | IAAP |
| Autism Spectrum Disorder | 1 percent (Earth) | 79 million people (Earth) | World Health Organization (WHO) |
| Non-verbal Learning Disability (NLVD) | 1 percent (Earth) | 79 million people (Earth) | IAAP |
| Math and Computational Disabilities | 3 to 7 percent (USA) | 9 to 23 million people (USA) | National Library of Medicine |
| Dyscalculia | 3 to 6 percent (Earth) | 237 million people (Earth) | IAAP |
The financial costs of cognitive disability
While it is difficult to measure the true impact of cognitive disability, we do have various sources can help us better understand the financial costs of cognitive disabilities.
The Center for Disease Control (CDC) released a report [PDF] in 2011 after acquiring data from fives states that started assessing the impact of cognitive disability on the state level.
- People with cognitive impairment report more than three times as many hospital stays as individuals who are hospitalized for some other condition.
- The average Medicaid payment for a person aged 65 or older with Alzheimer’s or other dementias is nine times higher than that for other beneficiaries in the same age group.
Cognitive disability and web accessibility
When it comes to web accessibility, five of the most common types of disabilities.
- Visual – relating to the sense of seeing
- Aural – relating to the sense of hearing
- Verbal – relating to speech
- Mobility – relating to movement
- Thinking – relating to cognition
