An acoustic analysis of the effects of surgical therapy on voice quality.

An automated computer system was used to measure changes in vocal quality resulting from laryngeal surgery. Five acoustic parameters were computed and seven listeners made judgments on vowel samples recorded before and after surgery from 37 patients. Presurgery and postsurgery changes in the five acoustic measures were compared with the perception of change in vocal harshness. A multiple regression analysis showed that four of the five acoustic measures accounted for a large amount of the variance in the judgment of change of voice quality following surgery. The measures may provide a quick and relatively sensitive method that may be clinically useful in measuring change in vocal quality.