Comparison of aerodynamic and electroglottographic parameters in evaluating clinically relevant voicing patterns

The purpose of the present study was to identify one or more aerodynamic or electroglottographic measures that distinguish among voicing patterns that are clinically relevant for nodule pathogenesis and regression: a presumably pathogenic pattern (pressed voice), a neutral pattern (normal voice), and two presumably therapeutic patterns (resonant voice and breathy voice). Trained subjects with normal voices produced several tokens of each voice type on sustained vowels /a/, /i/, and /u/. For each token, maximum flow declination rate, alternating current flow, and minimum flow were obtained from inverse-filtered airflow signals, and closed quotient and closing time were obtained from electroglottographic signals. The results indicate that for /a/ and /i/ (but not for /u/), the closed quotient provides a sensitive tool for distinguishing the voice types in physiologically interpretable directions. Further, post-hoc analyses confirmed a direct relationship between the closed quotient and videoscopic ratings of laryngeal adduction, which previous work links to nodule pathogenesis and regression.