Spectral noise level measurements used to track voice improvement in one patient

In this report we present one example of the utilization of an acoustic measurement to aid in describing voice roughness objectively in a clinical context. Vowel spectral noise level (SNL) and fundamental voice frequency (F0) measurements were acquired for five sustained vowels produced by one patient having bilateral vocal fold nodules. The measurements were obtained at specific time intervals while the patient underwent voice therapy. Clinically observed changes over the course of therapy included an improvement in perceived voice quality, a general reduction in vowel SNL, and an increase in vowel F0. These observations were accompanied by visually detected laryngeal tissue changes. The results suggest that acoustic SNL measurements can be employed clinically to verify and support perceptual judgments of voice quality.