Identification of auditory evoked potentials of one's own voice

Objective: We recorded vocalization related cortical potentials (VRCP) with complete masking of one's own voice, and separated the feedback auditory p otentials following vocalization from the VRCP complex. Methods: We used 9 right-handed healthy subjects. We recorded VRCP during s imple vowel vocalizing under two conditions, (1) without masking (control); (2) with masking. Electroencephalography (EEG) was recorded from seven are as, Fz, Cz,Pz, C3, C4, T3 and T4, of the International 10-20 system. The tr igger point was the onset of vocalized sound recorded through a microphone. Results: In both control and masking conditions, similar negative potential s prior to the vocalization were observed. However, the amplitude just afte r the onset of vocalization was significantly smaller in the masking than t he control condition. The difference waveform, obtained by subtracting the waveforms in the masking from those in the control condition, showed a simp le negative peak after the vocalization onset. Conclusions: We considered that the difference waveform indicated the audit ory evoked potentials following own voice in the auditory feedback process. Since there was no difference of the negative potentials before vocalizati on between the two conditions, we speculated that the masking effect on aud itory feedback following vocalization was crucial, while its effect on the preparatory process of simple vocalization might be minimal. (C) 2000 Elsev ier Science Ireland Ltd. All rights reserved.