Dynamic Display Devices
A dynamic display communication aid is usually a portable tablet style, touch screen computer running specially designed software. The software usually provides numerous communication displays that can be set-up for the user. Individual cells within each display (or page) may contain letters, words, symbols, or pictures, and verbal speech will be generated when cells or sequences of cells are selected. The user can navigate the numerous pages sequentially, or interactively as pop-up windows, by selecting cells which link one page to another. The dynamic feature refers to the changing of pages electronically, branching from page to page.
Messages can be recorded from human voice which are played back by the device user to "speak" a given message. Devices can play back any number of electronic media files, like WAV, MP3, and more to play messages or sounds. You can also use text-to-speech to create novel expressions spoken by computer-generated, synthesized voice. Buttons (or cells) can also be used to send infrared signals, send letters or words to other computer programs (when used as an on-screen keyboard), and many other stored computer functions.
The user can access devices by directly touching the screen, pointing and clicking a mouse, by head tracking mouse, eye gaze systems, joystick, or by scanning with a mechanical switch. Dynamic display devices may have one or several input methods available to the user, so you will need to match the user's abilities to the features of the devices you are considering.