PATHOLOGICAL VOICE TYPE AND THE ACOUSTIC PREDICTION OF SEVERITY

We hypothesized that acoustic measures would predict dysphonic severit y with differential results for pathological voice types. An instructi onal program based upon synthesized voice signals was developed to fac ilitate an awareness of prototypical voice types. Eighty phonatory ,sa mples representing normal subjects as well as patients with unilateral vocal fold paralysis, vocal nodules, and functional dysphonia were an alyzed acoustically on the basis of four measures: average fundamental frequency (F-0), jitter, shimmer, and harmonic/noise ratio (H/N ratio ). Following training, 29 listeners classified 62% of the phonatory sa mples on the basis of breathy, hoarse, rough, and normal, Dysphonic se verity of rough voices was predicted more successfully by H/N ratio (r (2) = .73) than by shimmer (r(2) = .43). Dysphonic severity of breathy voices was predicted only by the combined features of less jitter, mo re shimmer, and lower H/N ratio (r(2) = .74). NO combination of acoust ic variables was successful in the prediction of the hoarse voice type .