Vocal Analysis Related to Changes in Frequency of Pure Tone Auditory Feedback

PURPOSE Many studies have shown that subjects show a change of vocal fundamental frequency (F0) when phonating subjects hear their vocal pitch feedback shifted upward or downward. This study was performed to demonstrate whether vocal parameters [F0, intensity, jitter, shimmer, and noise to harmonic ratio (NHR)] in normal males respond to changes in frequency of pure tone masking. MATERIALS AND METHODS Twenty healthy male subjects participated in this study. Subjects vocalized /a/ vowel sounds while listening to a pitch- shift pure tone through headphones (upward pitch-shift in succession: 1 kHz to 2 kHz and 1 kHz to 4 kHz at 50 dB or 80 dB, respectively, downward pitch-shift in succession: 1 kHz to 250 Hz and 1 kH to 500 Hz at 50 dB or 80 dB, respectively). RESULTS Vocal intensity, F0, was increased, whereas jitter was decreased as the pitch of pure tone was shifted upward. However, there was no correlation between shimmer and NHR with pitch-shift feedback for pure tones. Unlike vocal pitch- shift feedback in other studies, upward pitch-shift feedback of pure tones caused the vocal F0 and intensity to change in the same direction as pitch-shift. CONCLUSION The results of this study demonstrated that auditory kinesthetic feedback is affected by pitch-shift in pure tone.