RESUMO
Objective Event related potentials (ERP), especially mismatch negativity (MMN), as index, was utilized to study the processing of Chinese tones recognized by cochlear implant (CI) users and normal hearing subjects. Methods The auditory materials were Chinese words with four tones consisting of three different oddball blocks. The ERP and MMN of CI users and normal hearing subjects were recorded and analyzed in relation to the discrimination of those tones as tested. Results The ERP and MMN of CI users and normal hearing subjects were presented. The MMN of CI users includes two negative waves: the first negative wave (MMN1) occurred approxi-mately 100 ms, and the second wave (MMN2) at 300 ms. The MMN of normal hearing subjects includes two nega-tive waves too: the first negative wave (MMN1) occurred approximately 150 ms, and the second wave (MMN2) al-so at 300 ms. The MMN1 peak latency of CI users was obviously shorter than that of normal hearing subjects and the MMN2 peak latency of CI users shorter than that of normal hearing subjects too, but the difference of MMN2 peak latency between CI users and normal hearing subjects was not as significant as that of MMN1. Conclusion In the preattentive stage, CI users could process Chinese tones as normal hearing subjects, but compared with the pro-cessing of normal hearing subjects, there are some differences in the processing of CI users.