OPEN SLOPE QUOTIENT - A NEW GLOTTOGRAPHIC PARAMETER

This study introduces a new objective measurement of the vibratory pat tern termed the open slope quotient (OSQ). This parameter is based on the maximum slope of the photoglottographic waveform during glottal op ening. Using an excised canine larynx model, the electroglottographic and photoglottographic waveforms, sound intensity, and subglottic pres sure were recorded as vocal fold tension; glottic width and airflow ra te were systematically varied. Multiple regression analysis of the dat a from nine larynges revealed OSQ to be inversely related to glottic w idth (p < 0.001) and vocal fold tension (p < 0.001) and directly relat ed to glottic resistance (p < 0.001) and subglottic pressure (p < 0.00 1). The OSQ was better correlated with glottic width, subglottic press ure, and glottic resistance than speed quotient. OSQ is related to the velocity of vocal fold opening and largneal resistance. OSQ may also be related to vocal fold stiffness.