ACOUSTIC PREDICTION OF SEVERITY IN COMMONLY OCCURRING VOICE PROBLEMS

The relative effectiveness of three acoustic measures (jitter, shimmer , and harmonic/noise ratio) in predicting the dysphonic severity of a diverse clinical population singly and together was investigated. Phon atory samples were recorded from 20 normal subjects and 60 patients re presenting 3 laryngeal groups (nodules, paralysis, and functional). Th e phonatory samples were evaluated by 22 listeners using a 7-point equ al-appearing interval scale. Shimmer produced a bivariate correlation of 0.54 with dysphonic severity; harmonic/noise ratio correlated - 0.3 2 with dysphonic severity; and jitter produced no significant correlat ion with severity. The combination of acoustic variables through multi ple regression analysis produced a correlation of 0.56, with only shim mer and average F(o) contributing to the correlation. For this particu lar clinical population, therefore, findings indicated that (a) none o f the variables was strongly correlated with dysphonia ratings, and (b ) a combination of acoustic predictors was no more successful than a s ingle predictor of dysphonic severity, namely, shimmer.