Tactile presentation of voice fundamental frequency as an aid to the speechreading of sentences.

In two experiments, the perception of words in sentences was measured by speechreading with and without tactile presentation of voice fundamental frequency (F0). The first experiment involved normally hearing subjects and two kinds of tactile display of F0: (1) a spatial, multichannel display; and (2) a temporal, single-channel display. Mean performance with the tactile displays was found to be slightly, but significantly, better than speechreading alone, but no significant difference was found between the two displays. The second experiment involved hearing-impaired subjects and only the spatial, multi-channel display of F0. For all three subjects, after extended training, speechreading performance was significantly better with the addition of the tactile display than by speechreading alone. The improvement amounted to reductions of word recognition error of 24, 33, and 50% in the three subjects.