The use of tactile supplements in lipreading Swedish and English: a single-subject study.

The speech perception skills of GS, a Swedish adult deaf man who has used a "natural" tactile supplement to lipreading for over 45 years, were tested in two languages: Swedish and English. Two different tactile supplements to lipreading were investigated. In the first,"Tactiling," GS detected the vibrations accompanying speech by placing his thumb directly on the speaker's throat. In the second, a simple tactile aid consisting of a throat microphone, amplifier, and a hand-held bone vibrator was used. Both supplements led to improved lipreading of materials ranging in complexity from consonants in [aCa] nonsense syllables to Speech Tracking. Analysis of GS's results indicated that the tactile signal assisted him in identifying vowel duration, consonant voicing, and some manner of articulation categories. GS's tracking rate in Swedish was around 40 words per minute when the materials were presented via lipreading alone. When the lipreading signal was supplemented by tactile cues, his tracking rates were in the range of 60-65 words per minute. Although GS's tracking rates for English materials were around half those achieved in Swedish, his performance showed a similar pattern in that the use of tactile cues led to improvements of around 40% over lipreading alone.