Measurement of performance of a peripheral vision lipreading aid

Lipreading, as the most important tool of speech understanding for profoundly deaf people, carries only a limited amount of information about speech. We explored the usefulness of a peripheral vision display in providing profoundly deaf people with supplementary information to lipreading. A pair of eye-glasses with a commercially available two-dimensional red LED array, and associated electronics was developed. The display is located on the rim of the eyeglasses in the temporal field and the horizontal meridian of the right eye. Selected speech features were encoded as visual patterns for presentation to the lipreader. These features (the fundamental frequency of the speech, high-frequency energy, and low-passed speech signal or total energy envelope) provide information about voicing and plosion/friction in order to supplement lipreading. Experiments with 3 normal and 5 deaf subjects demonstrated the capability of the aid to convey speech information for video taped vowel-consonant-vowel (VCV) nonsense syllables. Average identification of 12 VCV syllables using the aid was about 76%, as compared with 40% without the aid.