Application of Some Acoustic Measures for the Evaluation of Laryngeal Dysfunction.

Abstract

Perturbation of pitch period of voice was studied both on patients with laryngeal diseases and on normal subjects. Sound was extracted through the skin and other tissues in front of the trachea by a contact microphone during vowel phonation. Special attention was paid to the initial period of phonation and the data of this period were compared with those of steady periods of phonation. It was revealed that in the initial period there exist marked perturbations of pitch, and they were closely related with the type of initiation. Fundamental frequency was also found to affect the pitch perturbation. A relative average perturbation was defined on the basis of a smoothed trend line of the pitch. Pathologic cases showed essentially different values in respect to this measure according to the degree and nature of changes in the physical properties of the glottis, caused by the diseases. Possibility of applying this measure for screening and evaluating laryngeal disorders was discussed.