Previous research has shown that vocal errors can be simulated using a pitch perturbation technique. Two types of responses are observed when subjects are asked to ignore changes in pitch during a steady vowel production, a compensatory response countering the direction of the perceived change in pitch and a following response in the same direction as the pitch perturbation. The present study investigated the nature of these responses by asking subjects to volitionally change their voice fundamental frequency either in the opposite direction ("opposing" group) or the same direction ("following" group) as the pitch shifts (6100 cents, 1000 ms) presented during the speaker's production of an /a/ vowel. Results showed that voluntary responses that followed the stimulus directions had significantly shorter latencies (150 ms) than opposing responses (360 ms). In addition, prior to the slower voluntary opposing responses, there were short latency involuntary responses that followed the stimulus direction. These following responses may involve mechanisms of imitation or vocal shadowing of acoustical stimuli when subjects are predisposed to respond to a change in frequency of a sound. The slower opposing responses may represent a control strategy that requires monitoring and correcting for errors between the feedback signal and the intended vocal goal.

Objective/Hypothesis It is known that singers are able to control their voice to maintain a relatively constant vocal quality while transitioning between vocal registers; however, the neural mechanisms underlying this effect are not understood. It was hypothesized that greater attention to the acoustical feedback of the voice and increased control of the vocal musculature during register transitions compared to singing within a register would be represented as neurological differences in event-related potentials (ERPs). Study Design/Methods Nine singers sang musical notes at the high end of the modal register (the boundary between the modal and head/falsetto registers) and at the low end (the boundary between the modal and fry/pulse registers). While singing, the pitch of the voice auditory feedback was unexpectedly shifted either into the adjacent register (“toward” the register boundary) or within the modal register (“away from” the boundary). Singers were instructed to maintain a constant pitch and ignore any changes to their voice feedback. Results Vocal response latencies and magnitude of the accompanying N1 and P2 ERPs were greatest at the lower (modal-fry) boundary when the pitch shift carried the subjects’ voices into the fry register as opposed to remaining within the modal register. Conclusions These findings suggest that when a singer lowers the pitch of their voice such that it enters the fry register from the modal register, there is increased sensory-motor control of the voice, reflected as increased magnitude of the neural potentials to help minimize qualitative changes in the voice.

Objective The present study was designed to test for neural signs of impulsivity related to voice motor control in young adults with ADHD and healthy control young adults using EEG recordings in a voice pitch perturbation paradigm. Methods Two age-matched groups of young adults were presented with brief pitch shifts of auditory feedback during vocalization. Compensatory behavioral and corresponding bioelectrical brain responses were elicited by the pitch-shifted voice feedback. Results The analysis of bioelectrical responses showed that the ADHD group had shorter peak and onset latency of motor-related bioelectrical brain responses as compared to the controls. Conclusions These results were interpreted to suggest differences in executive functions between ADHD and control participants. Significance We hypothesize that more rapid motor-related bioelectrical responses found in the present study may be a manifestation of impulsiveness in adults with ADHD at the involuntary level of voice control.

Singers require great effort to avoid vocal distortion at register boundaries, as they are trained to diminish the prominence of register breaks. We examined neural mechanisms underlying voice error detection in singers at their register boundaries. We hypothesized that event-related potentials (ERPs), reflecting brain activity, would be larger if a singer’s pitch was unexpectedly shifted toward, rather than away, from their register break. Nine trained singers sustained a musical note for ~3 seconds near their modal register boundaries. As the singers sustained these notes, they heard their voice over headphones shift in pitch ( + /- 400 cents, 200 ms) either toward or away from the register boundary. This procedure was repeated for 200 trials. The N1 and P2 ERP amplitudes for three central electrodes (FCz, Cz, Fz) were computed from the EEGs of all participants. Results of a multivariate analysis of variance for shift direction ( + 400c, -400c) and register (low, high) showed significant differences in N1 and P2 amplitude for direction at the low boundary of modal register, but not the high register boundary. These results may suggest increased neural activity in singers when trying to control the voice when crossing the lower register boundary.