H-Index: a new measure of glottal efficiency for the pathologic voice.

Taking advantage of the extended dynamic range of digital analysis of voice the H-Index represents the first proposed acoustical measure of glottal efficiency. "Hi" /hai/ was chosen to evaluate glottal efficiency since it provides an excellent test of glottal transformation from voiceless to voiced sound energy, the upper vocal tract having a neutral effect. Fifteen individuals with normal voices and 30 patients with hoarse voices were asked to say "hi." The power ratio of /h/ to /a/ was calculated from peak power of each measure from the power envelope. Voice quality had a highly significant effect on measured values (P < .001). A high degree of correlation (P < .001) was found with the AC/DC ratio, a standard aerodynamic measure of glottal efficiency. The results indicate that the H-Index represents an excellent measure of glottal efficiency, obviating the need of invasive techniques or expensive, highly specialized equipment.