Assistive Technology and Inclusive Design I) Introduction help users who are disabled.

Assistive Technology and Inclusive Design
I) Introduction
Concern here is with attempting to use technology to
help users who are disabled.
GOW
AKA rehabilitation technology
AKA extraordinary HCI
What exactly “disabled” means is a controversial
issue
Eg recent criticisms of the “medical model” of
disability (eg Bishop 2003 p 549)
The social model of disability (eg Shaw 2000) is
often seen as more appropriate – “while people have
impairments, the environment – attitudinal as well
as physical – can be disabling”.
Edward’s reading (1995) of the WHO classification:
impairment - “any loss or abnormality of
psychological, physiological or anatomical structure
or function”
disability - “any restriction or lack (resulting from an
impairment) of ability to perform an activity in the
manner or within the range considered normal for a
human being”
handicap - “a disadvantage for a given individual,
resulting from an impairment or disability, that limits
or prevents [their] fulfilment of a role”
so, impairment
vision
disability
seeing
or impairment
handicap
memory loss
use of Unix
handicap
use of GUI
Compare UK DDA - Disability Discrimination Act
(1995) – a disabled person is someone who has a
physical or mental impairment, which has an effect on
his or her ability to carry out normal day to day
activities. That effect must be substantial, adverse and
long-term.
Much controversy in the area, eg re the DDA: “all of
the terms used in the definition … have been
challenged in court” (Riddell et al 2002)
Hence Moore’s motto for level 6 work:
The more we pursue knowledge, the less we
know
The challenge is to support the differing needs of
people with (and without) these impairments.
Not easy:
physical and visual - main problem = computer I/O
hearing and cognitive - main problem =
communication and language
needs may vary
e.g. GUI - poor for visual impairments, preferred
by other user groups
cf. Edwards - “kerb cut phenomenon” (29)
So - not easy, but are possibilities as well as
problems
e.g. great benefit of IT to many disabled people
a “disability ” may have advantages as well as
disadvantages, IT may be able to utilise them better
e.g. “Skallagrigg” novel
II) The importance of assistive technology
Can suggest several arguments:
•large number of disabled people
BT estimate - 10% of population
EU estimate re UK - 5% of people below 30,
30% at 60, 70% at 80 (Edwards)
50 million disabled people in Europe (TAP 1997
cf. Dix et al 2004, BCS 2000)
exacerbated by demographic trends
more old people
so - any computer system likely to be used by
disabled people, so need to be aware of the issues
when designing any interactive system
•economic argument:
most types of jobs use computers
therefore must be usable by disabled people
further - possible worker shortage because of birthrate trends (Newell)
and good interfaces increase productivity
systems that reduce need for intensive nursing care
or tuition
would be very cost effective
•altruistic argument
i.e. a worthwhile endeavour
current interfaces often poor (e.g. ATMs too high,
screen cannot be read by visually impaired)
HCI expert may be able to influence the design of
new artefacts
to cater better for disabled people
•legal argument
“increasingly..... the rights of people with disabilities
is being enshrined in legislation” (Newell)
eg DDA,
SENDA (BCS 2000)
must ensure system is legally acceptable
•environmental argument
Newell (2004) – non-disabled people can be
handicapped by their environment in the same way
as disabled people are
soldier example
need therefore to allow for impairments even if there
are no “impaired users”
•offshoot argument
the argument here is that working with
extraordinary HCI can have benefits for “general”
HCI research and practice
e.g. Edwards “extra-ordinary users challenge the
boundaries of the subject”
Newell - “taking into account extra-ordinary needs
produces better and more widely useful design
solutions for everyone”
Benyon et al (2005): “if a design works well for people with
disabilities, it works well for everyone”.
Spolsky (2000, see
http://www.joelonsoftware.com/uibook/chapters/fo
g0000000064.html, [accessed Feb 2 2009]):
“I don't really believe that people are dolts, but I
think that if you constantly try to design your
program so that it's easy enough for dolts to use,
you are going to make a popular, easy to use
program that people like. And you will be surprised
by how what seem like small usability
improvements translate into lots more customers.”
in particular:
may be useful to evaluate systems with disabled
people
may reveal problems that would otherwise be
overlooked
designer is forced into considering individual
differences
normative model clearly not appropriate
spin-offs of specific artefacts (Newell):
e.g. speech transcription system developed for deaf
users now used for transcription in law courts
future possibilities:
symbol system research may lead to useful info re
using icons in HCI
mainstream HCI researchers ...[may have]... too
narrow a view of their user population
“Most contemporary user interfaces are designed
for healthy, young adults” (Leventhal and Barnes 2008: 24)
and conversely, AT people should become more
aware of HCI research
Possible counter-arguments re importance of
extraordinary HCI :
Expense
Difficulty
Size of target population
III) Approaches to Assistive Technology
Essentially there are two possibilities:
a) create specific artefacts for the disabled user
using the technology as “prostheses”
b) adaptation of the interface to existing artefacts to
make them more accessible to users with disabilities
adaptations
the interface between the adaptation and the
underlying system is fixed
attempt to adapt the interface it presents to the
user, e.g. by providing alternative input devices
(see below)
ideally one adaptation will fit several applications
(e.g. a spoken front end which works for a word
processor and a database system (Edwards))
Edwards cites 3 reasons for using adaptations rather
than building new applications from scratch:
data transfer
different preferences amongst the disabled user
population
users’ self esteem
may prefer to be seen to be using the same
kit
Prostheses
designed for a specific user
therefore no constraints from the target software
therefore likely to be less of a user interface
problem (end-user variability much less important
an issue), but remaining UI issues covered in the
module will still be important
Seen the general approaches, consider now
differing types of disability.
IV)Visual impairments
Most significant sensory impairment re computer
systems given current predominance of VDUs
Need to distinguish between people with partial sight
and people who are blind
people with partial sight
11.5 million people in Europe with partial sight (TAP
1997, cf. BCS 2000)
evidence suggests they prefer to use their sight
rather than an interface designed for blind users
(Edwards)
need therefore appropriate aids, e.g.
enlargement
but beware - may make some problems, e.g.
tunnel vision, worse
better lighting
blind users
1.1 million blind people in Europe (TAP 1997)
must use touch or hearing or both
touch
computer generated braille
hard copy - printout
A Braille Embosser.
soft braille - on the screen
Braille chord keyboards
keyboards with marked keys
hearing
speech I/O
“screen readers”
Cf. “auditory icons” and “earcons”
V) Hearing impairments
Less of a problem than visual
But an increasing problem given the advent of
multimedia computing
Early attempts to support sign language output
are underway
Text terminals can be used in a prosthetic role for
distant communication, e.g. Minicom
VI) Physical impairments
Need considerable motor skill to use current
computer technology
Users may have varying degrees of impairment
regarding these motor skills
18 million such people in Europe (Howey 1995)
Need therefore to cater for these - very important
computer often used to control prosthetic devices,
e.g. wheelchair (Edwards)
No part of the body can be used to operate keyboard
switches likely to be used
e.g. operated by suck and puff
eye gaze interfaces being researched
as are “Neural Interface Devices”
No hand use possible
may use “unicorn stick” (Edwards)
may use speech input, e.g. to control house lights
Hand use possible but impaired
e.g. hand tremor
plastic keyguard maybe
turn off autorepeat
Goransson (2004) discusses a PDA for people with
Parkinson’s disease
keyboards sized for wide or narrow reach
chord keyboards
thinking as a means of input (?!)
prediction software
Speech impairment
“augmentative communication”
VII) Cognitive impairments
Four groups of impairments (Edwards):
memory problems
perception problems
problem solving impairments
e.g. difficulty in evaluating a proposed solution
conceptual problems
e.g. difficulty in generalising learned concepts
Tentative guidelines:
simplify language
provide on-line help
keep displays simple
e.g. symbols and icons rather than (or well
as) text
simplified language
be consistent
speech to support written information (Karlsson)
artificial intelligence and decision support
Cf. Research at Leeds Met re dyslexia (Powell et
al 2004) and autism (Moore et al 2005)
VIII) Multimodality and
redundancy
One general approach to making interactive
systems accessible to people with
disabilities is to build in “redundancy” (Dix
et al 2004, p. 366f)
“Redundancy” here refers to providing more
than one way of doing the same thing.
E.g. graphical information is also
available in readable text or speech.
This relies on “multimodal interaction” – it
uses more than one mode of interaction.
Thus, some combination of the following
should be considered for use:
Vision
The main channel currently
Many systems WIMP based
Windows, icons, menus, pointers
Sound
Speech recognition
Thus far only “single-user systems that
require considerable training” (Dix et al
2004 p. 371)
Speech synthesis
Other sounds
E.g. auditory icons
Touch
Haptic interface
Possibilities for the future: gesture
recognition, mind-reading (?!),
physiological input-output (e.g. wearable
computers).
IX) Universal design
So far, we have had a very interesting look at how
we might design interactive systems so that they
are more usable by people with disabilities.
Such design is an important aspect of “universal
design” – defined by Dix et al (2004, p. 366) as
“the process of designing products so that they
can be used by as many people as possible in
as many situations as possible”.
Universal design involves these areas of human
diversity: people with disabilities, older people,
children, cultural differences.
Seven general principles of universal design have
been proposed:
Equitable use – no user is excluded
Flexibility in use - design accommodates a wide range
of individual preferences and abilities
Simple and Intuitive Use - use of the design is easy to
understand, regardless of the user's experience,
knowledge, language skills, or current concentration
level.
Perceptible Information - the design communicates
necessary information effectively to the user,
regardless of ambient conditions or the user's sensory
abilities.
Tolerance for Error - the design minimizes hazards
and the adverse consequences of accidental or
unintended actions.
Low Physical Effort - the design can be used
efficiently and comfortably and with a minimum
of fatigue.
Size and Space for Approach and Use appropriate size and space is provided for
approach, reach, manipulation, and use
regardless of user's body size, posture, or
mobility.
• More details of the 7 principles at:
http://www.design.ncsu.edu/cud/about_ud/u
dprinciplestext.htm
[accessed 2.2.09]
Web accessibility
The concern here is web use by people with disabilities.
Important to make the web accessible to people with
disabilities
Eg Mills (2000): disabled people have “among the lowest rates
of use of these technologies, and the problem is largely one
of access”.
Nielsen - it should be relatively unproblematic if HTML is used
correctly – ie to encode meaning rather than appearance.
GOW
Specialist browsers can then interpret
the meaning appropriately.
Nielsen offers principles to help make web sites more
accessible – see appendix (on X-stream).
• The World Wide Web Consortium (W3C)
has developed guidelines for web
accessibility http://www.w3.org/TR/WCAG10-TECHS/
[accessed 2/2/09]
• There are 14 guidelines, with a total of 60
checkpoints that must be followed to
ensure a site is accessible.
• The checkpoints are broken down into 3
different priority levels.
• Priority 1
• A Web content developer must satisfy this
checkpoint. Otherwise, one or more groups
will find it impossible to access information in
the document. Satisfying this checkpoint is a
basic requirement for some groups to be able
to use Web documents.
• Satisfying this checkpoint leads to “level A”
conformance:
• Priority 2
• A Web content developer should
satisfy this checkpoint. Otherwise,
one or more groups will find it
difficult to access information in the
document. Satisfying this
checkpoint will remove significant
barriers to accessing Web
documents.
• Satisfying this checkpoint leads
to “Double-A” conformance:
• Priority 3
• A Web content developer may address this
checkpoint. Otherwise, one or more groups
will find it somewhat difficult to access
information in the document. Satisfying this
checkpoint will improve access to Web
documents.
• Satisfying this checkpoint leads to “TripleA” conformance:
• Web pages deemed acceptable from the
accessibility perspective can apply for
“Bobby Approval” and display a “Bobby
Approved” logo.
• Bobby is a web-based tool that analyses web
pages for accessibility
• It used to be free, but not any more it seems http://www.cast.org/bobby/ [accessed 27/10/09]
• Such automated approaches have recently been
called into question (eg Witt and McDermott
2004)
And the “stamp of approval” cannot meaningfully
be policed(?).
X) Summary
• Looked at some ways in which IT might promote the
integration of disabled people into society
• Interesting and important area
• Hosam??
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