For an objective measure to be useful in a clinical setting it must correlate with perceptions of the speaker and what is considered “normal” (Kreiman, Gerratt, Kempster, Erman, & Berke, 1993). Perceptions of the functional communicative abilities of people with aphasia do not correlate well with changes on decontextualised linguistic measures (Wertz, 1999). In addition, the current practice of reliance on specific perceptual ratings of fluency of speech has been shown to be unreliable (Gordon, 1998; Kent, 1996,). Using a multidimensional scaling technique Kreiman, Gerratt & Precoda (1990) found that naïve and expert listeners attended to different aspects of voice when making similarity judgments. They recommended that naïve listeners become the “gold standard” for perceptual judgment tasks as their listening experiences were more homogenous.
Listeners learn, through the computational analysis of connected speech, that pause duration information is an important factor in determining how spoken discourse is segmented, analyzed and interpreted, as pauses allow the listener to identify discourse structures and links between related materials (Fox Tree & Schrock, 1999). Perception of speech is achieved holistically, and values obtained for any one dimension may be highly influenced by co-occurring dimensions and the range of individual past listening experiences (Kent, 1996, 1997; Lehar, 2003). The development of a classification method derived from acoustic measures offers an objective approach to the correlates of speaking fluency. Fluency in this instance is considered a system measure rather than an isolable characteristic of spontaneous speech.
The aim of this study was to explore (a) the relationship between objective pause data and naïve listeners’ similarity judgments of aphasic connected speech samples using MDS (b) the relationship between objective pause data and naïve listeners’ direct magnitude fluency estimates of aphasic connected speech samples and (c) the way listeners employ descriptors and concepts when describing aphasic speech samples.
Hird, K., Silvestri, J., Dunn, J., & Kirsner, K. (2005). Aphasia classification: The relationship between objective measures of spontaneous speaking samples and naive listener judgments of similarity and fluency. Paper presented at the 35th Clinical Aphasiology Conference. Sanibel Island, FL, May 31-June 4, 2005.