Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: A laboratory study

To evaluate different signal-processing algorithms for tactile identification of environmentalsounds in a monitoring aid for the deafblind.subjects: two men and three women, sensorineurally deaf or profoundly hearing impaired with experienceof vibratory experiments, age 22-36 years.method: a closed set of 45 representative environmental sounds were processed using two transposing(trha, tr1/3) and three modulating algorithms (am, amfm, ammc) and presented as tactile stimuliusing a portable vibrator in three experiments. the algorithms trha, tr1/3, amfm and ammc had twoalternatives (with and without adaption to vibratory thresholds). in exp. 1, the sounds were preprocessedand directly fed to the vibrator. in exp. 2 and 3, the sounds were presented in an acoustic test room, withoutor with background noise (snr=+5 db), and processed in real time.results: in exp. 1, algorithm amfm and amfm(a) consistently had the lowest identification scores,and were thus excluded in exp. 2 and 3. trha, am, ammc, and ammc(a) showed comparable identificationscores (30%-42%) and the addition of noise did not deteriorate the performance.conclusion: algorithm trha, am, ammc, and ammc(a) showed good performance in all three experimentsand were robust in noise; they can therefore be used in further testing in real environments.