Introduction
Users with disabilities face many different problems when they try to access
the Internet - Web developers should try to take these difficulties into account
when designing their sites. Obviously there are numerous types (and sub-types)
of disability. For the purpose of this article these types of disability have
been separated into
four generic groups.
These
groups,
in no particular order, include users with the following disabilities.
- visual
- aural
- physical (motor)
- cognitive
It should be noted that certain individuals may suffer from multiple disabilities.
For each disability group I will consider the ‘barriers to access’ faced
by that group and the Assistive Technology (AT) available to them. AT enables
users who are affected by these various barriers to access the Web provided
that the actual Web pages are coded correctly.
Disability Statistics
Disability statistics tend to reflect
users who are registered as disabled. Many disabled people do not consider
themselves to be disabled or prefer not to register as such. The consequence
of this is that disability statistics only approximate the true numbers
and almost certainly underestimated them. However, according to Michael Paciello
in his book 'Web Accessibility for People with Disabilities', there
are approximately:
-
- 500 million disabled people worldwide
- 8.5 million disabled
people in UK
- 52.6 million disabled people in USA
- 37 million disabled people in
EU
- 4.2 million disabled people in Canada
- 3.7 million disabled people in
Australia
Temporary disabilities are NOT included in these statistics. Additionally,
Paciello estimates that between 95% and 99% of all Web sites are inaccessible.
Visual Barriers to Access
This category includes people with little or no vision, people with colour
blindness, people who use Screen Readers, and people who use screen magnifiers.
In the UK 1 person in 60 of the whole population is blind or partially sighted.
In addition, 6 out of 10 visually impaired adults have another illness or disability.
It is
presumed that these UK figures, and other UK statistics cited later in the article,
are representative of disability statistics worldwide.
Many people assume that visually disabled means total blindness. In fact
only 1 in 5 of the visually impaired are totally blind. Likewise, people assume
that
the visually disabled can read Braille and have a guide dog. In fact only about
5% can read Braille and only about 1% actually have a
guide dog.
Users with visual disabilities will, to varying degrees, have difficulty
seeing the computer screen. This can range from total blindness where the user
cannot
see anything, to somebody who is near or far sighted and therefore able to
read the text with the aid of spectacles or perhaps a screen magnifier. Some
dyslexics have problems with certain colour combinations, as do people with
colour blindness.
There is a range of AT designed to help people who have trouble seeing the
screen including:
- Screen readers
- Web browsers
- Cast E-Reader
- IBM Homepage Reader
- Refreshable Braille displays
- Voice recognition software
- Screen magnification software
In effect all of these AT solutions perform the same function; namely they
convert on-screen text into a format which can be understood by the disabled
person.
Web developers can code special ‘skip navigation’ links
which provide a means for visually disabled users to avoid the main navigation
controls
of a Web page and jump straight to the main content of the page. This means
that the visually disabled user does not have to listen to the screen reader
reading out the navigation links on every page.
Aural Barriers to Access
This category includes people who have been deaf from birth, deafened people,
and those who have partial hearing. A deafened person is someone who was
born with hearing but then developed a hearing impairment later in life,
perhaps
as a result of an illness or an accident.
In the UK 1 in 7 of the whole population has a hearing impairment (8.7
million). This number is rising as the general age of the population rises.
About 8% of these are severely or profoundly deaf, a high proportion of
which have other disabilities as well. In the UK there are approximately
50,000 Sign Language users.
The barriers to access faced by users with hearing difficulties depends, to
a certain extent, on whether the user has been deaf from birth or deafened
later in life. It is important from a Web developer’s perspective to
differentiate between the two groups.
Users who are deaf from birth communicate using Sign Language. Sign Language
is a language in its own right and has different grammar and structure to spoken
English. Sign Language users
must
learn English in the same way that others may learn French or German. Web
developers cannot assume that Sign Language users can read and understand the
content of their Web
pages. Did you know that there are even national and regional sign language
dialects?
There is an assumption that users who become deaf later in life can read
and understand English. It may be true in some cases but many of these
users communicate
using Sign Supported English (SSE); a combination of Sign Language and
English.
Users with hearing difficulties require visual representation of auditory
information such as a transcript or captions. MAGpie is a free piece
of software enabling
the creation of captions and subtitles for, and integrating audio descriptions
with, digital multimedia such as video.
Physical Barriers to Access
This is a wide ranging category and includes people with a range of physical
disabilities including amputees, people who may have suffered a stroke,
have spinal cord injuries, lost the use of limbs or digits, and people
with manual
dexterity or physical co-ordination problems.
Myalgic Encephalomyelitis (ME) is thought to affect about
2% of the UK population at any one time, one in 100 people over the age of
65 have Parkinson's disease, and eight in 100 over the age of 65 are affected
by Alzheimer’s disease.
Most Web sites are created assuming that the user can see the screen and
use a mouse. Many physically disabled users cannot use a mouse. Many Web sites
include links which are extremely small. Again many physically disabled users,
even if they can use a mouse, cannot hold the mouse pointer steady for a long
enough period of time to enable them to select the link.
There are a number of AT devices available to help users with physical disabilities
including Retinal scanning devices and Voice Recognition software such as Dragon
Naturally Speaking. In addition the Windows operating system has a
number of built-in accessibility features such as ‘sticky keys’.
Sticky Keys allow users to select keyboard combinations one key at a time.
In addition Web developers can add special code to their Web pages to allow
physically disabled users to navigate their site. This special code allows
physically disabled users to navigate via their keyboard using special access
keys. Access keys enable users to quickly visit key links within a site.
Cognitive Barriers to Access
‘Cognitive disability’ is any disability that affects mental processes
including mental retardation, attention deficit disorder, brain damage, dementia
and other psychiatric and behavioural disorders. This category also includes
people with learning difficulties and dyslexia / dyscalculia. People with learning
difficulties may have problems with literacy, information technology, and understanding
information generally. Dyslexia includes people who have problems reading,
writing and spelling. Dyscalculia describes people who have problems with mathematical
calculations.
‘Mental load’ is also a factor; that is, the demands placed upon a person's
cognitive abilities when performing a task. This is a problem for all people,
and especially for users of AT. For persons with cognitive and/or behavioural
disorders the problem is magnified. Web designers should avoid using background
images and music and should use a consistent design layout. These measures
will not only reduce mental load for the cognitively disabled but will help
all users to access their Web site.
There is no specific AT available for people with cognitive disabilities
although much can be done to increase accessibility when designing the content
of a
Web site. For example, users with learning difficulties may struggle to read
long paragraphs or certain fonts. This problem can be minimized by keeping
paragraphs short and using CSS. It is also difficult for some users with
cognitive disabilities to read justified text so text should be left justified.
Flashing
text should also be avoided as this can cause certain people to have epileptic
seizures.
The Plain
English Campaign has produced a number of free guides to help
Web developers produce accessible content for the cognitively disabled. Page
content tips include keeping the average sentence to between 15 and 20 words,
using active rather than passive verbs, using clear and helpful headings,
and leaving plenty of ‘whitespace’ on the screen.
Summary
Web developers should try to create Web sites which can
cater for the diverse needs of all users. Web developers must be aware
of the various user needs and the AT available to help such users.
It is relatively easy to create an accessible Web site for a user with
a specific disability. The problem is that Web sites must be accessible
for all users,
including users with multiple disabilities.
It is also worth mentioning that this article has only covered user needs
in a general sense. Each user is an individual and may have very specific
requirements.
This demonstrates how difficult it is to fully comply with the disability
legislation. |
