Development and Clinical Evaluation of New Phonation Analyzer

Preliminary report

Abstract

Vocal efficiency as one of the criteria for evaluating the vocal function has been a subject of investigation in phoniatrics. Advances in instrumentation have made it more practical to measure the subglottic pressure, both DC (direct current) and AC (alternating current) components of the expiratory air flow and SPL of voice. A variety of indices were proposed to represent or substitute the real vocal efficiency which is the ratio of the acoustic power to the subglottic power. They are the air flow rate or, AC/DC where AC is the efficiency value (root-mean-square) of AC component of expiratory air flow and DC is the mean flow rate. Isshiki's (1981) proposed index of glottal flow efficiency (AC/DC ratio) and an instrument designed to measure the index (PA-500) were evaluated. We performed clinical tests to evaluate the new phonation analyzer system (PA-1000). This system is capable of measuring the glottal flow efficiency (AC/DC ratio), glottal flow, SPL, and fundamental frequency simultaneously and continuously for about 6.5 seconds. The new model of phonation analyzer is advantageous over the prototype in that all the measures are digitally recorded so that later any particular portion of interest can be picked up for expression in both digital and analog ways.