Techniques for augmenting scanning communication

Scanning communication systems provide a unique set of opportunities for the application of augmentative communication technologies. Possibilities include optimization of the row-column matrix, dynamic rearrangement of the matrix, addition of character or word lists, and combinations of these techniques. A series of descriptive experiments were performed to establish the switch savings performance of 14 different scanning configurations. A common software platform and a strictly regimented testing procedure were employed to ensure the reliability and consistency of the data, facilitating comparisons between the different paradigms. Within each configuration, a systematic analysis of the relevant parameters was performed. The best character prediction method provided an average switch savings of 40.5% over a baseline row-column configuration, while the best word prediction technique provided an average savings of only 38.8%. Both of these configurations used seven-element prediction lists, which did not present any predictions until after selection of the first letter of each word. Additionally, the row-column matrices of these designs were optimized for use with the prediction list such that the more frequently selected matrix entries tended to be in more rapidly accessible matrix locations.