Effects of supplemental linguistic cues on the intelligibility of severely dysarthric speakers

Abstract

Severely dysarthric speakers who are considering an augmentative form of communication may think this option precludes use of their residual speech. Current procedures used to assess speech intelligibility have not addressed how natural speech might be incorporated into a total communication system for an individual with severe dysarthria. The purpose of this investigation was to determine if any of three types of linguistic cues (first letter, word class, combined first letter and word class) aided listeners in their ability to understand three speakers with different severity levels of dysarthria. Speech intelligibility was judged by four panels of 10 unfamiliar listeners (N = 40) using a word transcription task. A two-factor (4 × 3) mixed design was used to determine the effects of cuing conditions and severity of dysarthria on speech intelligibility scores expressed as the number of correctly transcribed single words. The two factors were linguistic cue, having four levels (no cue, first-letter cue, word-class cue, combined first-letter and word-class cue), and speaker severity level, having three levels (profound/severe/moderately severe). Significant main effects were found for the two independent variables. A significant first-order interaction was found for cuing condition by speaker severity. All three supplemental cuing conditions increased speech intelligibility scores, with the combined cuing condition providing the greatest enhancement of scores. Results are discussed with reference to the most effective cuing condition for each speaker severity level. The findings support the use of a combination of linguistic cues to augment the speech intelligibility of severe and profoundly dysarthric speakers.

• augmentative communication
• contextual and linguistic cues
• dysarthria
• information processing
• speech intelligibility