QUANTITATIVE-ANALYSIS OF HOARSENESS USING A DIGITAL SOUND SPECTROGRAPH

Using a digital sound spectrograph, we have developed a new, simple, and clinically available method of quantifying the degree of hoarseness. The total acoustic energy of the voice (V) and the energy of the noise component (N) were measured from section displays in the frequency range from 0 to 2 kHz. The most appropriate filter band widths for the measurements were 22.5 Hz for male voices and 37.5 Hz for female voices. The energy of the noise component compared with the total acoustic energy of the voice (N/V) was derived from the measurements. There was a significantly high correlation between the listeners' grading of hoarseness and the N/V. We conclude that this method is useful for objectively assessing the degree of hoarseness.