Inclusive New Media Design

including people with intellectual disabilities in the WWW

Switches

Many intellectually disabled (ID) web users with more severe or profound disability are likely to access computers via switches, even in the absence of significant physical impairments.

The majority of switch users without ID, use switches via assistive software, to provide sophisticated means of keyboard or mouse emulation. For these users, predictive text and dynamic scanning grids allow an efficient means of entering text or controlling applications using standard keyboard controls and shortcuts. From the developer’s perspective such switch users can be effectively included online, providing attention is given to WCAG2.0 guidelines, particularly in respect of keyboard operability.

switch-1ball switchswitch-2single switch

Switch users with ID are less likely to be using accessibility ‘middleware’ and custom controls accepting keypresses directly will often be required, if users with severe and profound are to be supported by an application. Most switches used by this group are connected to the computer via a simple interface which allows the keypresses sent by switches to be selected, but a good default choices would be ‘1’ and ‘2’. Sometimes users may map two switches to ‘tab’ and ‘enter’ as a means of navigating web pages generically.

Single switch users rely on the application they are using, or accessibility middleware, to move focus automatically Рin a web page context akin to pressing the ‘tab’ key automatically after a set delay, leaving the user to press ‘enter’ when the desired item has focus. A more able user may be able to undertake more complex and efficient operations via single switch, for instance narrowing a number of group selections to a single item, rather than stepping through a large number of items individually.

Even if switch users are not targeted or provided with custom controls, consideration should be given with respect to difficulties certain common practices present to switch users.

A single switch user accessing a page with a 2 second scan delay for instance could take 1 minute to arrive at the 30th link on a page. Use of prominent in page navigation therefore can be an essential aid to switch users, rather than simply a usability convenience. The increasing trend to employ off page positioning for in-page navigation, without focused items to view, effectively prevents their use by many users. Likewise using text links without graphical annotation for in page navigation is likely to exclude many ID users accessing a page via switches.

SAW5 is a free Windows application from which simple and complex switch scanning grids to be created, sample grids for common browsers are included.
new-window-blu-mini www.ace-centre.org.uk/saw5

HotSpots 2.0 provides a free and simple means of retrofitting switch accessibility to web applications without the need for custom controls to be scripted. This application is used to define a sequence of absolute (screen) positions for progression by switch. Ensuring a fixed screen resolution is defined and the requesting browsers are run fullscreen, allows a measure of consistency to be assumed between different users.
new-window-blu-mini www.ace-centre.org.uk/hotspots2

For further reference and testing, a large suite of free switch-accessible software and applications, mostly intended for non-ID users be downloaded from:
new-window-blu-mini www.rsc-ne-scotland.ac.uk/accessapps/

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