Page 126 - Handbook of Electronic Assistive Technology

114 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

Table 5-1 Keyboard Access Settings

Access Option What It Does Why It Is Useful
Slow Keys Slow Keys sets a delay from the time Slow Keys is helpful for users who have difficulty
(acceptance delay) the key or item is pressed to when it is targeting accurately and who accidentally hit the
accepted. It therefore filters and ignores wrong key. It can also be helpful for users with
short accidental activations. tremor.
Bounce Keys Bounce Keys filters and ignores repeated Bounce Keys is useful for users with tremor or
hits on the same key. who ‘bounce’ when activating the key. The delay
means that the repeated activations are ignored.
Often, Bounce Keys is not provided in a system
and Slow Keys has to be used instead. It can be
helpful to have separate control over Slow Keys
and Bounce Keys: when Slow Keys is applied to
all activations, it can be irritating because the first
activation is delayed.
Repeat Keys Repeat Repeat Delay is the delay before the first Some users have difficulty releasing a key after
Delay repeated keystroke is accepted when a key they press it, and generate several unwanted
is held down. activations. Prevent this by increasing the Repeat
Delay and Rate, or turn the repeat off completely.
Repeat Keys Repeat Repeat Rate is the speed at which Slowing down the Repeat Rate prevents repeated
Rate subsequent keystrokes are accepted when activations if the user has difficulty releasing the
a key is held down. key.
Key Click Key Click gives an audible click or sound Particularly useful if you have Slow Keys, Repeat
when the key is pressed and accepted. Keys or Sticky Keys switched on.
Sticky Keys Sticky Keys lets the user press a modifier Sticky Keys is helpful for users who cannot hold
key (Shift, Ctrl, Alt, Option, etc.) and then down two keys at once, for example, who type
press a second key (e.g., CTRL + o to open). using a single finger, mouthstick or headpointer.

Sticks and Pointers
Mouth and head sticks and pointers were among the very earliest assistive technology
control interfaces, and still have a role today. Sticks and pointers are also available for use
by hand and can enable access for users who have difficulty extending a finger.
They are inexpensive, practical and multipurpose – for example, a mouthstick can both
operate a computer keyboard and hold a paintbrush. 1

Barrie’s Case Study
Barrie has used a Zygo chin pointer since he was 5 years old. Over the years he evaluated a
range of access technologies, including enlarged keyboards and a head-operated mouse,
but prefers the chin pointer because he finds it faster and more convenient. He uses a
compact keyboard with a keyguard mounted on a stand. For mouse control, he has a sepa-
rate numeric keypad, again with a keyguard, positioned just above the keyboard. He uses
MouseKeys software to control the mouse with the number pad. Barrie can generate text

1 Henry Fraser, artist: http://www.henryfraser.org/.