Clinical Study on the Parameters for Evaluation of the Phonatory Function

Abstract

In order to evaluate the expiration flow performace during easy phonation, a parameter called“I/F index”was proposed. This index was defined as subtracting the standard intensity level of 60 dB S. P. L. from voice intensity and divided by air flow rate. The I/F index was measured through the“easy”sustained phonation of /o/, that was induced by the examiner so as to follow the same pitch and intensity of the examinee's normal speech voices.
A retrospective comparative study on this index to other phonatory parameters, such as mean flow rate, maximum phonaton time and the wave-flow index by Kakita, was performed supposing that those parameters were applied as a screening test for 151 cases of dysphonia due to laryngeal lesion.
As a result, the I/F index showed the smallest false negative rate either in male or female subject group. This suggests that the I/F index can most satisfactorily indicate the state of phonatory funtion.