Communication Analysis and Design Laboratory, Boston, MA


Dr. Rupal Patel


DigitCHAT is a proof-of-concept created after observing older adults using touchscreen phones.


Augmentative and alternative communication systems (AAC) for small-screen mobile devices often use on-screen keyboards that were not designed for people with bigger hands or people with upper limb motor impairments (e.g. tremors). These keyboards usually use less than half of the screen and have small buttons that are positioned adjacent to each other. Many elderly users, much less users with diagnosed motor or vision impairments, have difficulty with these keyboards because of the button and font sizes.


DigitCHAT uses large, visually separated buttons to assist users who may have difficulties making precise movements, especially on mobile devices with smaller screens. DigitCHAT supports continuous motion selection, allowing users to rest their finger or stylus on the screen to provide stability and reduce fatigue. The buttons are organized in a telephone number pad to provide familiarity and reduce the amount of time required to learn the layout. DigitCHAT is a real-time AAC system in that message construction proceeds on a word-by-word basis, but most likely words are spoken aloud immediately to increase communication speed. We have made the prototype Android application available on Google Play and are working with users to improve the interface and prediction algorithms.

Technologies Used

Android, Git, Kivy, Linux, NLTK, OS X, Python