Hideaki Matsushita

Acoustical analysis for voice disorders

Glottal sound waveforms were derived by an inverse filtering method from sustained vowels uttered by 217 patients of laryngeal diseases and by 20 normal speakers. Various parameters which indicate individual characteristics were extracted from autocorrelation function, correlograms of time series of fundamental period and peak amplitude in each fundamental period, and spectral envelope of the glottal sound waveform. Then, interdependency among the acoustical parameters and the relation between those and medical parameters utilized in diagnosis were examined by principal-component analysis. Using canonical analysis, classification of some laryngeal diseases was attempted based on those acoustical parameters.

An Apparatus for Ultra-High-Speed Cinematography of the Vocal Cords

In order to expand the studies of vocal cord vibration into greater varieties, normal and pathological, a photographic apparatus has been developed which meets the following needs: 1) Ultra high speed photographing can be done with any subject whose larynx is visualized under a laryngeal mirror; 2) The illumination is bright enough for high framing rates up to 10,000 frames per second and for color photographing; 3) The operation of the equipment is simple in order to obtain adequate films easily and consistently. The present paper describes the structure and the operation of the apparatus in detail.