GLOTTAL AREA AND VIBRATORY PATTERNS STUDIED WITH SIMULTANEOUS STROBOSCOPY, FLOW GLOTTOGRAPHY, AND ELECTROGLOTTOGRAPHY

The purpose of the present study was to examine the relationship betwe en variations in glottal area and vibratory patterns during phonation studied with stroboscopy and glottographic methods. Two normal speakin g male and three female subjects were examined by means of simultaneou s stroboscopy, flow glottography, and electroglottography. Estimations were made of the glottal area from pressure and flow data using the f ormula described by van den Berg. Significant correlations were found for the male phonations between estimations and measurements of the mi nimum glottal area (glottal insufficiency). Estimations of the peak gl ottal area were also significantly correlated to measured peak glottal are for values below 25 mm2. The estimated minimum area tended to be higher, whereas the estimated peak area values were lower than the cor responding glottal area measurements. This might be explained by varia tions in glottal and supraglottal geometry for different modes of phon ation and by sub- and supraglottal acoustic interaction. Several glott ographic parameters for the male phonations were highly correlated wit h the measurements of glottal insufficiency and also differed signific antly between normal, pressed, and breathy hypofunctional modes of pho nation. The presence of a hump in the first part of the closed phase f or the flow glottogram seems to indicate that a clearly visible mucosa l wave is present during vocal fold vibration.