The "tracking procedure" is a method to train and evaluate the reception of ongoing speech. A talker and a receiver engage in a dialogue for a designated period of time in which the receiver reports his perception of successive segments of read text and is corrected by the talker until the text is repeated verbatim. Performance is measured in number of words of text repeated correctly per unit of time. The procedure is illustrated by its application to a project for training and evaluating use of a vibrotacile-electrotactile aid to lipreading. Differences between experimental conditions are described over time in terms of absolute words per minute, increment of aided over unaided words-per-minute scores, and percent of normal listening rate. Data from identification tests with syllables, words, and sentences are also presented. Tracking is suggested as an additional procedure for communication training in aural rehabilitation or classroom setting, and for evaluation of other communication systems.

This study provides supportive evidence of brief, frequent eye movements by deaf perceivers over small areas of a video display during reception of visuospatial linguistic information. These movements could be used to enhance activation of brain centers responsible for processing motion, consistent with neurophysiological evidence of attentional mechanisms or visual processes unique to perception of a visual language.

Temporal processing ability in the hearing impaired was investigated in a 2IFC gap-detection paradigm. The stimuli were digitally constructed 50-Hz-wide bands of noise centered at 250, 500, and 1000 Hz. On each trial, two 400-ms noise samples were paired, shaped at onset and offset, filtered, and presented in the quiet with and without a temporal gap. A modified up-down procedure with trial-by-trial feedback was used to establish threshold of detection of the gap. Approximately 4 h of practice preceded data collection; final estimate of threshold was the average of six listening blocks. There were 10 listeners, 19-25 years old. Five had normal hearing; five had a moderate congenital sensorineural hearing loss with relatively flat audiometric configuration. Near threshold (5 dB SL), all listeners performed similarly. At 15 and 25 dB SL, the normal-hearing group performed better than the hearing-impaired group. At 78 dB SPL, equal to the average intensity of the 5-dB SL condition for the hearing impaired, the normal-hearing group continued to improve and demonstrated a frequency effect not seen in the other conditions. Substantial individual differences were found in both groups, though intralistener variability was as small as expected for these narrow-bandwidth signals.

The onset of voicing relative to onset of visible articulation is a potential cue for lipreaders to recognize nasal/stop consonants. The bilabial consonants /p, b, m/ were selected for study because of their high visibility and ease of optical synthesis. A phototransistor behind the teeth and an external microphone indicated mouth opening and voice onset, respectively, to measure relative timing of the two cues in natural speech. Average voicing leads for ten adults were the following: /ma/, +66 ms; foa/, --1 ms; /pa/, --58 ms (/ma-ba/articulatory boundary, +28 ms; foa-pa/articulatory boundary, --18 ms). To test relative timing of voice onset and mouth opening as a potential perceptual cue, we produced synthetic "syllables": The face substitute was an oscilloscope pattern, forming a mouth shape for 250, 400, or 550 ms; the voice substitute was a vowel-like buzz delivered through a hand-held vibrator. Buzz accompanied mouth opening with lead times of from +200 to --200 ms (40-ms steps), and ended simultaneously with mouth closure. Normal-hearing observers labeled each combination "ma," "ba," or "pa." Practiced lipreaders with knowledge of the onset cue subdivided the continuum with mean boundaries at -F 82 ms (/ma-ba/) and --87 ms (foa-pa/). Individual differences occurred in sharpness and location of labeling boundaries. Because articulatory and perceptual boundaries are not coincident, this combined-mode cue appears insufficient for consonant recognition unless performance can be improved through extensive training.