上海时时乐专家杀号:Overview of “Web Accessibility for Older Users: A Literature Review”
Web Accessibility for Older Users: A Literature Review analyzes guidelines, professional articles, and scientific literature on the requirements of people with web accessibility needs related to ageing.
Who the Literature Review is For
The Literature Review itself is primarily for researchers and academics.
The outcomes of the Literature Review are also being used to:
- promote accessibility solutions for older web users
- develop resources for users, industry, and others
What is in the Literature Review
The Literature Review?summarizes:
- literature and statistics about how older adults use the Web
- age-related functional limitations
- requirements of older Web users
The bulk of the Literature Review analyzes:
- existing literature reviews
- previous approaches to ‘senior friendly’ web guidelines
- relationship with WAI guidelines
- training older adults to use information and communications technology (ICT) and the web
- studies of older web users’ specific disabilities
- aspects of web design affecting the elderly
- involving the elderly in web design and development
- general usability studies involving elderly people
A finding of the Literature Review is that existing?WAI guidelines?address many requirements of older web users. Yet, there is little reference to the WAI guidelines in literature and guidance covering the needs of older Web users.
Summary of Impact and Prevalence
This section provides summaries from the Literature Review.
Ageing and Hearing Loss
Impact of hearing loss:
- Audio can be difficult to discern
- Background sounds can be difficult to filter out
- Higher pitch sounds can be missed
Prevalence of hearing loss:
- 47% of people 61 to 80 years experience some hearing loss
- 93% of people 81+ years experience some hearing loss
Hearing starts to decline at around 50 years and affects a person’s ability to hear higher pitched sounds as well as discern the foreground from background audio such as music or other sounds. Some hearing loss is experienced by 47% of people 61 to 80 years and 93% of people over 81 years. Moderate or severe hearing loss or profound deafness is experienced by 20% of people aged 61 - 80 and 75% of people over 80.
Ageing and Vision Decline
Impact of vision decline:
- Decreasing ability to focus on near tasks
- Changing color perception and sensitivity
- Decreasing contrast sensitivity
Prevalence of significant vision lose:
- 16% of people 65 - 74 years
- 19% of people 75 - 84 years
- 46% of people 85+ years
Vision decline includes:
- Decreasing ability to focus on near tasks, including a computer screen
- Changing color perception and sensitivity - less violet light is registered, making it easier to see reds and yellows than blues and greens, and often making dark blue and black indistinguishable
- Decreasing contrast sensitivity from pupil shrinkage - resulting in the need for more light and higher contrast (an 80 year old typically has 80% less contrast sensitivity than a 20 year old)
Vision decline often starts in a person’s mid-40s. 86% of Australians over 40 require reading glasses to correct for near vision. Significant vision loss (that can’t be corrected) affecting everyday life is estimated to affect 16% of people 65 to 74 years, and 46% of those over 85 years in the UK.
Ageing and Physical Decline
Impact of physical decline:
Motor skill decline can result from many conditions including arthritis, essential tremor, and Parkinson’s Disease:
- Difficulty using mouse or keyboard
- Difficulty with clicking small targets
- Strain from non-ergonomic tasks
Prevalence of physical decline:
Conditions most commonly reported:
- Arthritis affects at least 50% of people over 65
- Essential tremor affects up to 20% of people over 65
- Parkinson’s Disease affects approximately 4% of people over 85
Motor skill decline impacts on dexterity and can result from many conditions, for example arthritis with associated joint stiffening and reduced fine motor control, and essential tremor or Parkinson’s Disease with associated hand trembling, making mouse use difficult or impossible for some and also affecting keyboard use. In particular, older people with physical impairments may have difficulty clicking small links, selecting radio buttons, and using many fly-out or pull-down menus.
Arthritis is estimated to affect at least 50% of people over 65; essential tremor (one of many forms of tremor) is estimated to affect up to 5% of those over 40 and up to 20% of people over 65; and Parkinson’s affects around 4% of those over 85.
Ageing and Cognitive Decline
Impact of cognitive decline:
Navigation, comprehension, and task completion can be affected by:
- Short term memory limitations
- Difficulty with concentration
- Distraction from movement or irrelevant material
- Difficulty coping with information overload
Prevalence of cognitive decline:
Conditions most commonly reported:
- 1.4% of people 65–69 years
- 24% of people 85+ years
Mild cognitive impairment (MCI) is more common:
- Around 20% of people over 70 years are estimated to experience MCI
Cognitive decline is also common, though only dementia and mild cognitive impairment are commonly reported. While Dementia (including Alzheimer’s disease) is experienced by some older people (1.4% of people 65–69 years increasing to 24% of people over 85 years in the UK), forms of mild cognitive impairment (or MCI) are much more common, affecting over 20% of those over 70 years. MCI can result in:
- Short term memory limitations (which may result in a person forgetting the purpose of a website visit if they lose orientation on the site)
- Concentration and distraction issues (consider the volume of information on some pages, and the multiple animated advertisements that are sometimes present)
Status and Technical Report Format
The Literature Review was conducted in 2008. We do not currently plan to update it. Most of the information is still relevant.
The Literature Review follows the?W3C?format for technical reports that includes several sections at the beginning: links to different versions, editors, copyright, abstract, and status.