ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

4aSC20. Modeling pathologic vocal quality. Part I.

Jody Kreiman

Bruce R. Gerratt

Div. of Head and Neck Surgery, UCLA School of Medicine, 31-24 Rehab Ctr., Los Angeles, CA 90024-1794

Previous studies of pathologic vocal quality have not yielded a standard set of scales for describing disordered voices, possibly due to the limited number of voices studied. The present study used large sets (n=80) of male and female voices, representing a broad range of diagnoses and vocal severities. Eight experts judged the dissimilarity of each pair of voices, and responses were analyzed using nonmetric individual differences multidimensional scaling. Results indicate that differences between listeners in perceptual strategy are so great that the fundamental assumption of a common perceptual space must be questioned. Group spaces revealed a single ``feature'' (severity of pathology). Spaces for individual listeners were characterized by clusters of voices which seemed structured by ``family resemblances'': Each voice in a cluster resembled others with rspect to some property, but the same property did not constitute the resemblance for all voice pairs. Further, voices did not appear consistently in the same clusters across listeners. In the absence of a common perceptual space---of a shared sense of how voices sound similar---valid perceptual scales cannot be defined. The results lead to the conclusion that standardization of perceptual labels for voice quality is theoretically impossible.