Image and video descriptions in digital speech provide access to those who cannot see the images. Captioning of dialogue, music, or sound effects, accomplished with a combination of text and graphics on screen, provides access to those who cannot hear the sound. The next generation of CAST software tools will go further, offering built-in teaching supports that make these products truly universally designed for learning. Another tool under development at CAST will work with digitized textbooks to help students with learning disabilities develop the organizational skills that are critical to their success in school. Although technology is at the heart of both UDL and assistive technology, it is important to clarify the differences.
Assistive technology is designed to help individual students access the mainstream curriculum.
Under most circumstances, assistive technology is necessary because the mainstream curriculum is inflexible and inaccessible to those students without it. For example, a video enlarger can make a textbook more accessible to a student who has low vision. But the enlarger is not a part of the curriculum, it is a device used by an individual student to overcome a barrier inherent in the curriculum's original design. Assistive technologies can allow the learner to adapt to the curriculum. This way, there is access and the challenge is one that stimulates learning rather than hindering it.