Conditions and possibilities for the detection of speech-signal elements by means of vibrotaction.
Investigations have been carried out in order to determine (1) the sensitivity of the two types of skin for sinusoidal mechanical vibrations under different stimulation conditions, and (2) the sensitivity of the skin for amplitude modulations. Maximum sensitivity was found around 200 Hz, with a threshold of 0.03 microns RMS for the glabrous skin of the inner side of the hand under a static force of at least 0.5 N. The sensitivity of the hairy skin of the arm was 12 dB less (static force at least 3 N). The sensitivity increased with increasing contractor area. Maximum modulation sensitivity was found for sinusoidal carriers between 200 and 400 Hz and extended from modulation frequencies of 1 Hz up to 200 Hz (depending on carrier frequency) at a frequency-independent modulation depth of about 0.1. It was concluded that it is certainly possible for the skin to detect the slow amplitude fluctuations of speech signals as a support for lipreading. Attention was paid to the best way of extracting the envelopes from the speech signal and their presentation, as an amplitude modulation, to the skin.
Lamoré
P J
PJ
Department of Biomedical Physics and Technology, Erasmus University, Rotterdam, The Netherlands.
Keemink
C J
CJ
D003143:Communication Devices for People with Disabilities; D003638:Deafness / Q000534:rehabilitation*; D004867:Equipment Design; D006225:Hand; D006801:Humans; D009633:Nonverbal Communication; D010141:Pacinian Corpuscles / Q000502:physiology; D010812:Physical Stimulation; D012016:Reference Values; D012656:Self-Help Devices; D012684:Sensory Thresholds; D012867:Skin / Q000294:innervation; D013067:Speech Perception; D014110:Touch / Q000502:physiology*; D014732:Vibration