Preliminary research with a three channel vibrotactile speech reception aid for the deaf

Envelopes of signals from an accelerometer attached to the talker's nose, a microphone near his mouth, and an accelerometer attached to his throat were multiplied by a 100 Hz square wave and the products were used to drive three vibrators. Normally hearing subjects with simulated total loss of hearing for speech felt signals on vibrator 1 proportional to the amplitude of vibration in the talker's nose, on vibrator 2 proportional to the amplitude of sound near the talker's mouth, and on vibrator 3 proportional to the amplitude of vibration in the talker's larynx. The vibrators were on separate fingers of the same hand or on a single finger. When the three channel aid is used with lipreading, scores on syllable and word tests are better (sometimes dramatically) than with lipreading alone. Improvement is demonstrated for nasal/oral, voiced/voiceless, and continuant/interrupted discriminations. Variations in vowel duration as with voiced and voiceless final consonants are clearly felt.