Database Reference
In-Depth Information
Table 13.1 Category of
disability from a functional
point of view
User
Disability
Visual impairments
Physical impairments
Hearing impairments
Cognitive and learning difficulties
synthesizer and they are mainly used by users with severe low vision or totally blind.
Braille displays can be jointly used with screen readers to reproduce the content of a
page by raising and lowering different combinations of pins. In addition to these
specific ATs, modern operating systems offer built-in functionalities for setting,
for example, visual output, high-contrast schemes, size, and color of the mouse
cursor.
ATs for Physical Impairments
. Motor impairment is a loss or limitation of body
control. According to the US Census [
7
], around 18 million Americans report
difficulty using their arms or hands that can affect both typing and mouse control.
Users give instructions to computers through the following ATs: alternative key-
boards (e.g., reduced, larger, touch-sensitive membrane) or their emulation on the
screen, alternative mouses (e.g., trackballs, trackpads, and joysticks), pointing devices
(e.g., head-controlled mouses and eye tracking) or touch screens, voice recognition
systems, predictive word processors and programs with built-in word lists. Modern
operating systems offer functionalities for mouse and input typing control.
ATs for Hearing Impairments
. The terms
mild hearing
,
hard of hearing
, and
deaf
are used to describe users with varying levels of hearing impairments. Accord-
ing to the US Census [
7
], almost 8 million Americans over the age of 14 have
difficulty in hearing a conversation, even when wearing a hearing aid.
ATs allow auditory cues and multimedia information to be identified (sounds,
music, audio feedback) and can be considered
accommodation techniques
, i.e.,
techniques supporting information exchange through visual channels (e.g., flashing
lights). They can be used to convey complex auditory information in a text form or
through other communication modes (e.g., sign language, fingerspelling, and cued
speech).
ATs for Cognitive and Learning Difficulties
. Cognitive impairment is any
limitation in the ability of thinking or reasoning that affects the capacity to
perform a task. A person with cognitive impairment can have problems with
memory, language, or other mental functions. According to the US Census, 14.3
million Americans aged 15 or over have a cognitive or emotion-related mental
disability.
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