It has been reported that normal-hearing Chinese speakers base their lexical tone recognition on fine structure regardless of temporal envelope cues. However, a few psychoacoustic and perceptual studies have demonstrated that listeners with sensorineural hearing impairment may have an impaired ability to use fine structure information, whereas their ability to use temporal envelope information is close to normal. The purpose of this study is to investigate the relative contributions of temporal envelope and fine structure cues to lexical tone recognition in normal-hearing and hearing-impaired native Mandarin Chinese speakers. Twenty-two normal-hearing subjects and 31 subjects with various degrees of sensorineural hearing loss participated in the study. Sixteen sets of Mandarin monosyllables with four tone patterns for each were processed through a "chimeric synthesizer" in which temporal envelope from a monosyllabic word of one tone was paired with fine structure from the same monosyllable of other tones. The chimeric tokens were generated in the three channel conditions (4, 8, and 16 channels). Results showed that differences in tone responses among the three channel conditions were minor. On average, 90.9%, 70.9%, 57.5%, and 38.2% of tone responses were consistent with fine structure for normal-hearing, moderate, moderate to severe, and severely hearing-impaired groups respectively, whereas 6.8%, 21.1%, 31.4%, and 44.7% of tone responses were consistent with temporal envelope cues for the above-mentioned groups. Tone responses that were consistent neither with temporal envelope nor fine structure had averages of 2.3%, 8.0%, 11.1%, and 17.1% for the above-mentioned groups of subjects. Pure-tone average thresholds were negatively correlated with tone responses that were consistent with fine structure, but were positively correlated with tone responses that were based on the temporal envelope cues. Consistent with the idea that the spectral resolvability is responsible for fine structure coding, these results demonstrated that, as hearing loss becomes more severe, lexical tone recognition relies increasingly on temporal envelope rather than fine structure cues due to the widened auditory filters.

The purpose of this study is to develop and evaluate disyllabic Mandarin speech test materials (MSTMs) in order to facilitate wider use of speech audiometry in Chinese audiology clinics. Phonologically balanced Mandarin disyllabic materials with high familiarity were designed based on the basic rules for developing speech materials and the particular characteristics of Mandarin, and recorded digitally. In order to establish the validity and reliability of these Mandarin disyllabic materials, equivalence of difficulty between the word lists was evaluated for a group of 60 subjects (age-range 18-25 years) with normal hearing. Subsequently, performance-intensity (PI) functions were measured in a group of 30 subjects with normal hearing (age-range 18-25 years), and a group of 35 subjects with sensineural hearing loss. The nine lists of Mandarin disyllabic materials were found to have sufficient reliability and validity to be used in clinical situations.

In this study, monosyllabic Mandarin speech test materials (MSTMs) were developed for use in word recognition tests for speech audiometry in Chinese audiology clinics. Mandarin monosyllabic materials with high familiarity were designed with regard to phonological balance and recorded digitally with a male voice. Inter-list equivalence of difficulty was evaluated for a group of 60 subjects (aged 18-25 years) with normal hearing. Seven lists with 50 words each were found to be equivalent. These seven equivalent lists were used to measure performance-intensity (PI) functions for a group of 32 subjects with normal hearing and a group of 40 subjects with mild to moderate sensorineural hearing loss. The mean slope of PI function was found to be 4.1%/dB and 2.7%/dB, respectively. The seven lists of Mandarin monosyllabic materials were found to have sufficient reliability and validity to be used in clinical situations.

Six Nucleus cochlear implant recipients participated in a study investigating the effect of place of stimulation on melody perception using rate-pitch cues. Each stimulus was a pulse train delivered on either a single electrode or multiple electrodes sequentially. Four spatial stimulation patterns were used: a single apical electrode, a single mid electrode, a pair of electrodes (apical and mid), and 11 electrodes (from apical to mid). Within one block of trials, all stimuli had the same spatial stimulation pattern, with pulse rate varying from 131 to 262 pps. An additional pulse rate range of 262 to 523 pps was tested with the single-electrode stimuli. Two experimental procedures were used: note ranking; and a modified melodies test with backwards and warp modification. In each trial of the modified melodies test, a familiar melody and a version with modified pitch were presented (in random order), and the subject’s task was to select the unmodified melody. There were no significant differences in performance for stimulation on 1, 2, or 11 electrodes, implying that recipients were unable to combine temporal information from different places in the cochlea to give a stronger pitch cue. No advantage of apical electrodes was found: at the lower pulse rates, there were no significant differences between electrodes; and at the higher pulse rates, scores on the apical electrode dropped more than those on the mid electrode.