Acoustic Signs of Supraglottal Constriction in Pathological Voices
Purpose: This study aims to identify the acoustic signs of supraglottal constriction and effects of some vocal manipulation techniques. It is hypothesized that some task-related acoustic contrasts would differ between voice patients with and without supraglottal constriction due to different vocal tract configurations. Method: Classified through videostroboscopic examinations, 30 participants were gender and age-matched to form two comparison groups (“constricted” and “non-constricted”), with five males and ten females in each group. Participants were asked to sustain a vowel (/a/ or /i/) for approximately three seconds in five tasks, including normal-pitch, low-pitch, high-pitch, /m/-onset (i.e., with the consonant /m/ preceding the vowel at normal pitch), and /h/-onset tasks. Acoustic signals were analyzed to extract measures from the mid-portion of the vowel. Results: The “constricted” group showed a lack of task-related contrasts on signal-to-noise ratio, singing power ratio, frequency of the second formant, and the amplitude difference between the first formant and the first harmonic. Conclusion: Further investigations are needed to assess the predictive power of the proposed task-based acoustic approach for detecting supraglottal constriction.