Analysis of pathological voices with a sound spectrograph

Abstract

Our previous study demonstrated that some acoustical parameters derived by a computer analysis of pathologic voices were useful to differentiate causative diseases to some extent [S. Hiki, S. Imaizumi, M. Hirano, and H. Matsushita, J. Acoust. Soc. Am. 58, S111(A) (1975)]. In this paper, possibility of utilizing a sound-spectrograph for the same purpose was investigated. Voice materials used were sustained vowels uttered by patients of polyp or nodule (42 cases), sulcus vocalis (20), recurrent laryngeal nerve paralysis (33) and cancer (15), and normal speakers (20). Acoustical parameters, which were revealed to be valuable in our previous study, such as degree of the fluctuation of fundamental frequency and that of amplitude, declination of the spectral envelope of harmonic components, and amount of noise components in various frequency ranges were measured from the pattern, section and amplitude display of the sound-spectrograms. The results indicated that sound-spectrographic analysis was of significant value in differenciating the pathological voice from the normal and also in differentiating the voice of cancer from that of the other pathologies.