Effects of temporal fine structure stimulation on Mandarin speech recognition in cochlear implant users

Abstract

Conclusion: The investigated experimental coding strategies significantly improved tone identification as compared with the participants’ everyday audio processor settings. However, this benefit could not be attributed entirely to temporal fine structure stimulation but seems to be caused by decreasing the lower corner frequency of the filter bank. The 6 week habituation period used in this study might have been too short to allow the listeners to derive additional lexical information from the unfamiliar stimulation patterns. Objectives: To evaluate a cochlear implant coding strategy that explicitly conveys temporal fine structure information in the context of the tonal language Mandarin. Methods: The study was designed as a longitudinal, monocentric, prospective, controlled, and randomized cross-over study and included 12 postlingually deafened adults, who were experienced cochlear implant users. Two experimental coding strategies, one of which explicitly presents temporal fine structure information, were compared to the participants’ personal TEMPO+ speech processors, which do not convey fine structure information. Results: Both experimental coding strategies improved tone identification by approximately 11 percentage points. This improvement was significant in the female speaker test. Sentence perception, as assessed with the M-HINT test, and quality of life scores were identical with all three coding strategies.

Keywords::

• Coding strategy
• tonal language
• tone identification
• continuous interleaved sampling

Acknowledgments

The authors thank Dr Guoping Li from the University of Southampton for his helpful comments on an earlier version of this manuscript and Noelani Peet from MED-EL for proofreading. This study was supported by the Science and Technology Ministry of China (2009DFA32200), National Natural Science Foundation of China (81070796), Beijing Natural Science Foundation (7123210, 7122034), Beijing Municipal Health Bureau (2009-3-29), and also by the C. Doppler Research Association, Austria.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.