Evaluating vocal fold function.

In the effort to develop a non-invasive method for the evaluation of the vibratory characteristics of the vocal folds in patients with vocal pathology, some of the newer methods for evaluating vocal function in normal speech are being considered. Inverse filtering of the glottal airflow waveform and ways of measuring vocal fold contact area are described and evaluated for their potential use in the clinic. Knowledge of the vibratory behavior of a patient's vocal folds is important to our understanding of problems such as spastic dysphonia, dysphonia plica and functional aphonia as well as the problems of the professional voice user.