The width-length quotient of the glottis as a measure of amplitude values

Abstract

The vibratory width of the glottis plays an important role in the diagnosis of functional voice disorders. The experienced examiner decides if the amplitudes of the vocal folds are normal, too small or too wide, always with regard to the length of the glottis. Therefore the width-length quotient is an adequate measurement for the vibratory width of the glottis. To standardize this quotient, we made stroboscopic measurements in 82 normal-voiced persons; 41 were female, 41 male. The pitch was in the range of the speaking voice at medium loudness. Statistical evaluation was done by box-and whisker plots. The width-length quotient of the glottis shows a minimum of 0.1 in both sexes with a maximum of 0.31 in men and 0.26 in women. The average was 0.16 in men and 0.17 in women. 50% of the width-length quotient near the median are inside the box, ranging from 0.14 to 0.2. Results on the lower part of the scale point towards a hyperfunctional voice disorder (small amplitude), while results in the upper part (0.2 and more) show a tendency towards hypofunction with comparatively wide amplitudes.