THE MULTIDIMENSIONAL NATURE OF PATHOLOGICAL VOCAL QUALITY

Although the terms ''breathy'' and ''rough'' are frequently applied to pathological voices, widely accepted definitions are not available an d the relationship between these qualities is not understood. To inves tigate these matters, expert listeners judged the dissimilarity of pat hological voices with respect to breathiness and roughness. A second g roup of listeners rated the voices on unidimensional scales for the sa me qualities. Multidimensional scaling analyses suggested that breathi ness and roughness are related, multidimensional constructs. Unidimens ional ratings of both breathiness and roughness were necessary to desc ribe patterns of similarity with respect to either quality. Listeners differed in the relative importance given to different aspects of voic e quality, particularly when judging roughness. The presence of roughn ess in a voice did not appear to influence raters' judgments of breath iness; however, judgments of roughness were heavily influenced by the degree of breathiness, the particular nature of the influence varying from listener to listener. Differences in how listeners focus their at tention on the different aspects of multidimensional perceptual qualit ies apparently are a significant source of interrater unreliability (n oise) in voice quality ratings.