Vocal shimmer in sustained phonation of normal and pathologic voice.

Vocal shimmer during sustained phonation was measured in normal subjects and patients with laryngeal polyps, using the mean amplitude difference between consecutive cycles expressed in dB. A small laboratory computer was then used for measuring each discrete amplitude and for data processing. The results showed some overlap between the values for two groups studied, but nevertheless it appears that the measured value may be a useful index in screening for laryngeal disorders and for definitive diagnosis of such disorders.