Time relations between cricothyroid muscle activity and the voice fundamental frequency (F0) during sinusoidal modulations of F0

Electromyographic (EMG) recordings from the cricothyroid (CT) muscle were obtained in two adult male subjects attempting to modulate their voice fundamental frequency (F0) sinusoidally between 150 and 225 Hz or between 300 and 450 Hz at a rate of 1 Hz. Sinusoidal modulations of F0 were associated with similar modulations in the rectified CT EMG. Signal averaging and spectral analysis techniques were used to assess the time relation between the rectified CT EMG and F0 signals. At a rate of 1-Hz F0 modulation, the F0 signal lagged behind the CT EMG signal by 52°-57°, corresponding to a time lag of 144–158 ms. These findings are discussed in relation to previous measures of the EMG-F0 time relationship and the mechanisms of F0 control.