Discourse Tracking Research Articles

The assessment of lipreading ability: some practical considerations in the use of the tracking procedure.

Continuous discourse tracking is potentially a very useful clinical technique and the practical difficulties it may present to the inexperienced user can readily be overcome. Some modifications to the traditional scoring procedure are described to provide a measure of fluency in addition to the basic word per minute score. Suggestions are offered regarding the practical management of the timing and the choice and preparation of the text. The procedure is discussed in the context of evaluating different augmentative approaches to lipreading for individual patients.

Effect of Text Complexity upon Connected Discourse Tracking

Effect of Text Complexity upon Connected Discourse Tracking

The transmission of prosodic information via an electrotactile speechreading aid.

Variations in voice fundamental frequency were extracted from naturally produced speech samples and transmitted to an electrocutaneous display consisting of 10 electrodes arranged in a linear array along the forearm. Changes in fundamental frequency were encoded as changes in stimulus location. Speechreading performance, with and without the electrocutaneous aid, was examined for both sentence and connected discourse materials with one profoundly hearing-impaired listener and one normally hearing listener whose hearing was masked. After 20 hours of speechreading training in connected discourse tracking procedure, both subjects showed higher tracking rates and faster learning rates with the aid than without the aid. Results from closed-set sentence-identification tests showed that patterns of intonation, stress, and phrase structure, which are not easily speechread, are readily available with the aid.

The contribution of fundamental frequency, amplitude envelope, and voicing duration cues to speechreading in normal-hearing subjects.

The ability to combine speechreading (i.e., lipreading) with prosodic information extracted from the low-frequency regions of speech was evaluated with three normally hearing subjects. The subjects were tested in a connected discourse tracking procedure which measures the rate at which spoken text can be repeated back without any errors. Receptive conditions included speechreading alone (SA), speechreading plus amplitude envelope cues (AM), speechreading plus fundamental frequency cues (FM), and speechreading plus intensity-modulated fundamental frequency cues (AM + FM). In a second experiment, one subject was further tested in a speechreading plus voicing duration cue condition (DUR). Speechreading performance was best in the AM + FM condition (83.6 words per minute,) and worst in the SA condition (41.1 words per minute). Tracking levels in the AM, FM, and DUR conditions were 73.7, 73.6, and 65.4 words per minute, respectively. The average tracking rate obtained when subjects were allowed to listen to the talker's normal (unfiltered) speech (NS condition) was 108.3 words per minute. These results demonstrate that speechreaders can use information related to the rhythm, stress, and intonation patterns of speech to improve their speechreading performance.

Validation of the Audiometer Telephone Interface (ATI)

Speech discrimination scores and connected discourse tracking (CDT) measurements were used to compare the clinical use of the Audiometer Telephone Interface (ATI) [R. G. Stoker, Hear. Instrum. 33(6), 26–29, 46 (1982)] with actual telephone performance on a local telephone company loop. Thirty hearing‐impaired subjects from three hearing‐loss categories—moderate, sloping; moderate, precipitous; and severe, sloping were used. Subjects were evaluated using standard audiometric procedures (under headphones) and with the ATI (telephone handset with simulated telephone network). Testing was also performed at the subjects' home by providing each subject with an amplifier handset so that the test could be performed at a Most Preferred Listening level (MCL). Stimuli for both the clinical trial and the home trial were the nu‐6 word lists and connected discourse tracking using a novel passage with neutral emotional content. Results suggest that the ATI effectively simulates the average hearing difficulty experienced by hearing‐impaired telephone users when using their own phones over a local loop served by a variety of central office systems.