Pitch encoding in speech and nonspeech contexts in the human auditory brainstem.

Frequency-following responses were recorded from Chinese and English participants at the level of the brainstem in response to four Mandarin tonal contours presented in a speech and nonspeech context. Pitch strength analysis of these preattentive brainstem responses showed that the Chinese group exhibited stronger pitch representation than the English group regardless of context. Moreover, the Chinese group exhibited relatively more robust pitch representation of rapidly changing pitch segments. These findings support the view that at early preattentive stages of subcortical processing, neural mechanisms underlying pitch representation are shaped by particular features of the auditory stream rather than speech per se. These findings have implications for optimizing signal-processing strategies for cochlear implant design for speakers of tonal languages.