[Classification of glottal dysfunctions on the basis of electroglottography]

The close relationship between the muscular tension at the level of the glottis and the glottal opening time, closing time, and open quotient encourages the use of these temporal measures as an aid in classifying functional dysphonias. The validity of a 'quasi-open quotient' (QOQ) derived from the electroglottogram was explored by means of a crescendo singing task at comfortable frequency. The pattern of QOQ change during the crescendo task was determined and the range of the variable measured. In normal speakers QOQ varied from 0.75 (at low vocal intensity) to 0.40 (at high intensity). In contrast, the range of QOQ values was significantly restricted in patients with hyper- and hypofunctional dysphonia. The electroglottographical curves were registered and documented by a computer system (IBM AT, Gould DASA).