Speechreading sentences with single-channel vibrotactile presentation of voice fundamental frequency.
The main goal of this study was to investigate the efficacy of four vibrotactile speechreading supplements. Three supplements provided single-channel encodings of fundamental frequency (F0). Two encodings involved scaling and shifting glottal pulses to pulse rate ranges suited to tactual sensing capabilities; the third transformed F0 to differential amplitude of two fixed-frequency sinewaves. The fourth supplement added to one of the F0 encodings a second vibrator indicating high-frequency speech energy. A second goal was to develop improved methods for experimental control. Therefore, a sentence corpus was recorded on videodisc using two talkers whose speech was captured by video, microphone, and electroglottograph. Other experimental control issues included use of visual-alone control subjects, a multiple-baseline, single-subject design replicated for each of 15 normal-hearing subjects, sentence and syllable pre- and post-tests balanced for difficulty, and a speechreading screening test for subject selection. Across 17 h of treatment and 5 h of visual-alone baseline testing, each subject performed open-set sentence identification. Covariance analyses showed that the single-channel supplements provided a small but significant benefit, whereas the two-channel supplement was not effective. All subjects improved in visual-alone speechreading and maintained individual differences across the experiment. Vibrotactile benefit did not depend on speechreading ability.
Eberhardt
S P
SP
Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland 21218.
Bernstein
L E
LE
Demorest
M E
ME
Goldstein
M H
MH
D000328:Adult; D001288:Attention; D003131:Combined Modality Therapy; D003143:Communication Devices for People with Disabilities; D003638:Deafness / Q000534:rehabilitation*; D004867:Equipment Design; D005260:Female; D006310:Hearing Aids; D006801:Humans; D008085:Lipreading; D008297:Male; D010700:Phonetics; D011571:Psychoacoustics; D014110:Touch; D014732:Vibration