Acoustic Measures for Detecting Laryngeal Pathology

Perturbations in the fundamental pitch and in the peak amplitude of the acoustic signal derived with a contact microphone system were investigated for the purpose of developing useful measures for the detection of laryngeal pathology. Sixty-three patients with various laryngeal pathologies and 31 normal subjects were studied. In 14 cases high speed motion pictures of the larynx were taken in order to examine the physiological mechanisms giving rise to the perturbations in the acoustic signal. The collected acoustic data were statistically processed, and a "critical ellipse" was computed for each subject category. The significance of the concept of a "normal standard" was discussed. It was pointed out that the physiological mechanisms for the acoustic perturbations were rather complicated and that many physiological aspects may have to be taken into account. The need for basic physiological research in relation to pathologic speech production was emphasized.