Vocal responses to frequency modulated composite sinewaves via auditory and vibrotactile pathways

Feedback control mechanisms for speaking have been examined using the transformed auditory feedback (TAF) technique. Previous studies have shown that speakers demonstrate fundamental frequency (F0) changes when they monitor their voice with artificial alterations of F0. However, those studies underestimate the role of vibrotactile information involved in feedback F0 control. This pilot study aims at exploring whether and how vibrotactile information from the larynx influences vowel F0. Participants in our experiment were asked to sustain vowel with their F0 adjusted to composite sinewave stimuli, which were given via auditory and vibrotactile channels using a headset on the ears or a bone-conduction transducer on the larynx. Results revealed the greater compensatory responses to combined vibrotactile-auditory stimuli than to the responses to auditory-only stimuli. The effect of vibrotactile stimuli on feedback F0 adjustment was also observed with the shorter latency of the responses.