Abstract
Visual substitution devices, such as the Brainport tongue stimulator, which converts visual images into patterns of electrotactile stimulation through a 20 x 20 electrode grid array on the tongue, provide promise for individuals with visual impairments. However, very few studies have systematically assessed the effectiveness of such devices in conveying visual information. In order to evaluate the usefulness of the Brainport device, we conducted four experiments that examined the ability to discriminate electrotactile stimuli presented for 500 ms on the tongue. Experiment 1 demonstrates that it is difficult to discriminate shape stimuli, regardless of whether the shapes are filled or outlined. Experiment 2 indicates that a training block of 200 trials with accuracy feedback does not improve performance. Experiment 3 suggests that line orientations that differ by 30-degree angles are also difficult to differentiate. Finally, Experiment 4 shows that subjects can discriminate between line orientations that differ by 45-degree angles (i.e., three different line orientations). These experiments indicate that the tongue's discrimination abilities may not be adequate enough to use the Brainport device for object recognition, however, it might be useful for providing three-alternative discrimination information, which might be useful for purposes such as navigation.
Meeting abstract presented at VSS 2014