Noise tolerance in human frequency-following responses to voice pitch.

Speech communication usually occurs in the presence of background noise. This study examined noise tolerance in the brainstem's processing of voice pitch, as reflected by the scalp-recorded frequency-following response (FFR) from 12 normal-hearing adults. By systematically manipulating signal-to-noise ratio (SNR) across three different stimulus intensities, the results indicated that Frequency Error, Slope Error, and Tracking Accuracy remained relatively stable until SNR was degraded to 0 dB or lower (i.e., a turning point). This turning point not only provided physiological evidence supporting pitch tolerance of noise but also allowed recommendation of a minimal SNR when evaluating pitch processing in difficult-to-test patients.