A relationship between processing speech in noise and dysarthric speech.

There is substantial individual variability in understanding speech in adverse listening conditions. This study examined whether a relationship exists between processing speech in noise (environmental degradation) and dysarthric speech (source degradation), with regard to intelligibility performance and the use of metrical stress to segment the degraded speech signals. Ninety native speakers of American English transcribed speech in noise and dysarthric speech. For each type of listening adversity, transcriptions were analyzed for proportion of words correct and lexical segmentation errors indicative of stress cue utilization. Consistent with the hypotheses, intelligibility performance for speech in noise was correlated with intelligibility performance for dysarthric speech, suggesting similar cognitive-perceptual processing mechanisms may support both. The segmentation results also support this postulation. While stress-based segmentation was stronger for speech in noise relative to dysarthric speech, listeners utilized metrical stress to parse both types of listening adversity. In addition, reliance on stress cues for parsing speech in noise was correlated with reliance on stress cues for parsing dysarthric speech. Taken together, the findings demonstrate a preference to deploy the same cognitive-perceptual strategy in conditions where metrical stress offers a route to segmenting degraded speech.