An adaptive comb filtering method as applied to acoustic analyses of pathological voice

An adaptive comb filtering method, which was initially investigated by Frazier et al. [5] for the enhancement of degraded speech due to additive noise, is applied for estimating vocal noise generated at the glottis due to pathological changes of the vocal folds. In applying the method, special emphasis is placed on the accurate determination of pitch period durations. The amount of estimated vocal noise is quantified by a novel acoustic measure, normalized noise energy(NNE). Experiments with vowel samples spoken by 64 normal control subjects and 50 patients with glottic cancer have shown that the NNE is useful for the distinction between normal and pathological voice status.