Outcomes Using the Optimized Pitch and Language Strategy Versus the Advanced Combination Encoder Strategy in Mandarin-Speaking Cochlear Implant Recipients.

Objectives: The experimental Optimized Pitch and Language (OPAL) strategy enhances coding of fundamental frequency (F0) information in the temporal envelope of electrical signals delivered to channels of a cochlear implant (CI). Previous studies with OPAL have explored performance on speech and lexical tone perception in Mandarin- and English-speaking CI recipients. However, it was not clear which cues to lexical tone (primary and/or secondary) were used by the Mandarin CI listeners.

Results using the OPAL strategy in Mandarin speaking cochlear implant recipients.

Objective: To evaluate the effectiveness of an experimental pitch-coding strategy for improving recognition of Mandarin lexical tone in cochlear implant (CI) recipients.

Design: Adult CI recipients were tested on recognition of Mandarin tones in quiet and speech-shaped noise at a signal-to-noise ratio of +10 dB; Mandarin sentence speech-reception threshold (SRT) in speech-shaped noise; and pitch discrimination of synthetic complex-harmonic tones in quiet. Two versions of the experimental strategy were examined: (OPAL) linear (1:1) mapping of fundamental frequency (F0) to the coded modulation rate; and (OPAL+) transposed mapping of high F0s to a lower coded rate.

Enhancement of temporal cues to pitch in cochlear implants: effects on pitch ranking.

The abilities to hear changes in pitch for sung vowels and understand speech using an experimental sound coding strategy (eTone) that enhanced coding of temporal fundamental frequency (F0) information were tested in six cochlear implant users, and compared with performance using their clinical (ACE) strategy. In addition, rate- and modulation rate-pitch difference limens (DLs) were measured using synthetic stimuli with F0s below 300 Hz to determine psychophysical abilities of each subject and to provide experience in attending to rate cues for the judgment of pitch. Sung-vowel pitch ranking tests for stimuli separated by three semitones presented across an F0 range of one octave (139-277 Hz) showed a significant benefit for the experimental strategy compared to ACE.

Development of a temporal fundamental frequency coding strategy for cochlear implants.

A sound-coding strategy for users of cochlear implants, named enhanced-envelope-encoded tone (eTone), was developed to improve coding of fundamental frequency (F0) in the temporal envelopes of the electrical stimulus signals. It is based on the advanced combinational encoder (ACE) strategy and includes additional processing that explicitly applies F0 modulation to channel envelope signals that contain harmonics of prominent complex tones. Channels that contain only inharmonic signals retain envelopes normally produced by ACE.

Parameter selection and programming recommendations for the ACE and CIS speech-processing strategies in the Nucleus 24 cochlear implant system.

This study evaluated a range of programming parameters available for the ACE and CIS speech-processing strategies in the Nucleus 24 cochlear implant system. Specifically, the effect on speech perception of adjustments to the number of channels and the stimulation rate in the CIS strategy, and the effect of adjustments to the number of maxima in the ACE strategy were investigated in a group of adult subjects. Based on these findings, and the results of a previous study (Vandali et al.

New cochlear implant coding strategy for tonal language speakers.

Accurate pitch perception on the basis of fundamental frequency patterns is essential for the processing of lexical tones in tonal languages such as Cantonese. Speech intelligibility in Cantonese-speaking CI recipients was compared using current signal processing strategies, which typically result in poor pitch perception, and a new strategy, known as the multi-channel envelope modulation (MEM) strategy, was designed to enhance temporal periodicity cues to the fundamental frequency. Performance of nine postlingually hearing-impaired adult cochlear implant users was measured twice using each strategy, initially after a four week trial, and again after two weeks of use with each strategy.

Speech recognition with the advanced combination encoder and transient emphasis spectral maxima strategies in nucleus 24 recipients.

One of the difficulties faced by cochlear implant (CI) recipients is perception of low-intensity speech cues. A. E.

Pitch ranking ability of cochlear implant recipients: a comparison of sound-processing strategies.

Pitch ranking of sung vowel stimuli, separated in fundamental frequency (F0) by half an octave, was measured with a group of eleven Nucleus 24 cochlear implant recipients using different sound coding strategies. In three consecutive studies, either two or three different sound coding strategies were compared to the Advanced Combinational Encoder (ACE) strategy. These strategies included Continuous Interleaved Sampling (CIS), Peak Derived Timing (PDT), Modulation Depth Enhancement (MDE), F0 Synchronized ACE (FOSync), and Multi-channel Envelope Modulation (MEM), the last four being experimental strategies.