The effect of enhancing temporal periodicity cues on Cantonese tone recognition by cochlear implantees

Abstract

Objectives: This study investigates the efficacy of a cochlear implant (CI) processing method that enhances temporal periodicity cues of speech. Design: Subjects participated in word and tone identification tasks. Two processing conditions – the conventional advanced combination encoder (ACE) and tone-enhanced ACE were tested. Test materials were Cantonese disyllabic words recorded from one male and one female speaker. Speech-shaped noise was added to clean speech. The fundamental frequency information for periodicity enhancement was extracted from the clean speech. Electrical stimuli generated from the noisy speech with and without periodicity enhancement were presented via direct stimulation using a Laura 34 research processor. Subjects were asked to identify the presented word. Study sample: Seven post-lingually deafened native Cantonese-speaking CI users. Results: Percent correct word, segmental structure, and tone identification scores were calculated. While word and segmental structure identification accuracy remained similar between the two processing conditions, tone identification in noise was better with tone-enhanced ACE than with conventional ACE. Significant improvement on tone perception was found only for the female voice. Conclusions: Temporal periodicity cues are important to tone perception in noise. Pitch and tone perception by CI users could be improved when listeners received enhanced temporal periodicity cues.

Key Words::

• Cochlear implant
• Cantonese
• pitch
• tone perception
• periodicity enhancement

Acknowledgements

We are grateful to all the subjects for their participation in this study.

Note

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

This work was supported by the General Research Fund (Ref. CUHK 414108 and 413811) from Hong Kong Research Grants Council and a project grant from the Shun Hing Institute of Advanced Engineering, The Chinese University of Hong Kong. It was also partly supported by National Natural Science Foundation of China (11104316), Shanghai Natural Science Foundation (11ZR1446000), Open Research Fund Program of Key Laboratory of Speech and Hearing Sciences (East China Normal University), Ministry of Education. The last author was supported by the National Institute of Health (Grant no. R01-DC012300).

Notes

1. In this article, the Jyut Ping system is used for transcribing Cantonese syllables. Jyut Ping was devised by the Linguistic Society of Hong Kong (LSHK), 1997.