Acoustic phonetic effects of two types of verbal feedback in dysarthric subjects.

The effects of two different forms of verbal feedback on speech production were studied in 7 dysarthric speakers. Both forms of verbal feedback signaled that the listener failed to understand the message. The more general form of feedback gave no specific cues regarding the reason the listener failed to understand. The more specific feedback indicated that a voiceless initial consonant was perceived as its voiced cognate. The subjects studied had inconsistent voicing errors. Voice onset times (VOTs) and syllabic intensity, duration, and rate were measured in the phrases produced prior to and after verbal feedback. The results showed a significant change in VOT after the specific feedback and no significant change in VOT after the more general feedback. The use of specific feedback to induce articulatory change during speech treatment is discussed.