Page 317 - Handbook of Electronic Assistive Technology

306 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

the operating system would allow direct mouse and/or keyboard control. Alternatively,
mediated access would be where the software provides an often simplified interface to
specific software on the computer. Mediated access allows the user to integrate access to
all these output functions (e.g., Voice over Internet Protocol calls, word processing, etc.)
14
while reducing either the cognitive or access load on the individual (Fig. 10-5). Grid 3,
15
and Mind Express are examples of the software-mediated model. Benefits and disadvan-
tages of this model are listed in Table 10-4. Pauline’s case study will provide an example of
this model.

Pauline’s Case Study
Pauline is a 35-year-old woman with cerebral palsy and moderate learning difficulty.
Pauline lives in supported accommodation and is independent around the house using a
powered wheelchair with a single switch in her headrest. Pauline controls a communica-
tion aid using a head mouse and uses this as a significant part of her AAC to support her
severely dysarthric speech, particularly when communicating with unfamiliar partners. To
select items on her communication software, Pauline ‘dwells’ – i.e., holds the cursor in the
same cell for a specific time (around 2 seconds). As well as using the device and software
to communicate, Paula uses the system to control her environment – by sending infrared
commands to her television and internal door openers. Pauline also uses the system to
control her phone and to read (using text to speech) and send emails. 16

Operating System Model

This model uses a standard operating system as the integration system. This relies on the oper-
ating system allowing the input method as a control method. This can be supported either:
• Through the operating system supporting devices that emulate standard input
methods such as a mouse (e.g., eye gaze, head mouse, etc.); or
• Where the operating system has specifically made adaptations to accept alternative
input methods such as a switch input. These adaptations would be referred to as part
of the accessibility architecture.

A ‘pure’ version of this model would then allow control of the whole computer
through entirely mainstream applications – however, it is likely that many will use spe-
cifically designed AT software to facilitate some of the functions they wish to control
(e.g., AAC or EC) or to improve the access experience (e.g., a dwell clicker that automati-
cally applies a left click after a user hovers the mouse in a spot for a predefined time).
This model might be considered as more recent; however, as explained in the introduc-
tion, the use of alternative input methods to an operating system has been an integra-
tion option for many years. In addition, this model moves beyond the more conventional

14 https://thinksmartbox.com/grid-3/.
15 www.jabbla.com/products.asp?itemID=9.
16 http://youtu.be/0x0TcekSDM8.