Reinhold Schatzer

The aim of this study was to develop comprehensive test material for Mandarin tone identification in noise (M-TINT) based on the linguistic characteristics in Chinese. In keeping with both the reliability and efficiency in clinical practice, a primary list consisted of 320 words(80 syllables in four tones each) was designed according to the following principles: shortness of the lists, word familiarity and with a meaning in all four tones. The digital sound file was recorded by a male speaker and a female speaker (both of them are radio broadcaster). The tonal identification material database, which included 288 items (72 loudness-balanced syllables in all 4 Mandarin tones) was established by digital filler and balanced for equal loudness. The complete material was recorded in two CDs in a male version and a female version. The speaker-specific masking noises were generated by filtering Gaussian white noise to the speaker's long-term average speech spectrum (LTASS) and by scaling the masking noises to the same RMS amplitudes, as those of the speech, in order to acquire the effective sound masking. The speaker-specific masking noises could be able or disable during the word presentation. The sound pressure level could be selected concerning on the test setting. The mandarin tonal identification materials were designed by both the tonal acoustic properties and the psychophysics characteristic of adults. It is an useful speech test in clinical work and research, and can potentially be used as the basic list for other tonal language identification test in the future.

Conclusion: Acute comparisons between continuous interleaved sampling (CIS) and a temporal fine structure (TFS) coding strategy in Cantonese-speaking cochlear implant (CI) users did not reveal any significant differences in speech perception. Performance with the unfamiliar TFS coding strategy was on a par with CIS. Benefits of extended fine structure use observed in other studies should be investigated for tonal languages. Objectives: CIS-based stimulation strategies lack an explicit representation of fine structure, which is crucial for tonal language speech perception. The aim of this study was to assess speech recognition with a TFS coding strategy in Cantonese-speaking CI users with no prior fine structure experience. Methods: The fine structure coding strategy encodes TFS on a few apical channels, while the remaining more basal channels carry CIS stimuli. Twelve MED-EL implantees and long-term CIS users participated in a study comparing recognition for Cantonese lexical tones and CHINT sentences between CIS and fine structure stimulation. Results: Mean tone identification scores in 12 subjects were 59.2% with CIS and 59.2% with fine structure stimulation using 4 TFS channels, mean scores of CHINT sentences in 8 subjects were 54.2% with CIS and 55.9% with TFS stimulation. Differences between the two strategies were not significant for any speech test. Two additional versions of TFS strategy and pulse rates were tested in six subjects. No significant differences between strategies were found.