Psychophysical studies evaluating the feasibility of a speech processing strategy for a multiple‐channel cochlear implant

Objectives: The purpose of this investigation was to determine if adult bilateral cochlear implant recipients could benefit from using a speech processing strategy in which the input spectrum was interleaved among electrodes across the two implants. Design: Two separate experiments were conducted. In both experiments, subjects were tested using a control speech processing strategy and a strategy in which the full input spectrum was filtered so that only the output of half of the filters was audible to one implant, while the output of the alternative filters was audible to the other implant. The filters were interleaved in a way that created alternate frequency “holes” between the two cochlear implants. Results: In experiment one, four subjects were tested on consonant recognition. Results indicated that one of the four subjects performed better with the interleaved strategy, one subject received a binaural advantage with the interleaved strategy that they did not receive with the control strategy, and two subjects showed no decrement in performance when using the interleaved strategy. In the second experiment, 11 subjects were tested on word recognition, sentences in noise, and localization (it should be noted that not all subjects participated in all tests). Results showed that for speech perception testing one subject achieved significantly better scores with the interleaved strategy on all tests, and seven subjects showed a significant improvement with the interleaved strategy on at least one test. Only one subject showed a decrement in performance on all speech perception tests with the interleaved strategy. Out of nine subjects, one subject preferred the sound quality of the interleaved strategy. No one performed better on localization with the interleaved strategy. Conclusion: Data from this study indicate that some adult bilateral cochlear implant recipients can benefit from using a speech processing strategy in which the input spectrum is interleaved among electrodes across the two implants. It is possible that the subjects in this study who showed a significant improvement with the interleaved strategy did so because of less channel interaction; however, this hypothesis was not directly tested.

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Efficacy of a Cochlear Implant Simultaneous Analog Stimulation Strategy Coupled with a Monopolar Electrode Configuration

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348940511401113 ◽

2005 ◽

Vol 114 (11) ◽

pp. 886-893 ◽

Cited By ~ 8

Author(s):

Li Xu ◽

Teresa A. Zwolan ◽

Catherine S. Thompson ◽

Bryan E. Pfingst

Keyword(s):

Speech Recognition ◽

Cochlear Implant ◽

Speech Processing ◽

Dynamic Range ◽

Recognition Performance ◽

Electrode Configuration ◽

Processing Strategy ◽

Open Set ◽

Hearing In Noise ◽

Noise Test

Objectives: The present study was performed to evaluate the efficacy and clinical feasibility of using monopolar stimulation with the Clarion Simultaneous Analog Stimulation (SAS) strategy in patients with cochlear implants. Methods: Speech recognition by 10 Clarion cochlear implant users was evaluated by means of 4 different speech processing strategy/electrode configuration combinations; ie, SAS and Continuous Interleaved Sampling (CIS) strategies were each used with monopolar (MP) and bipolar (BP) electrode configurations. The test measures included consonants, vowels, consonant-nucleus-consonant words, and Hearing in Noise Test sentences with a +10 dB signal-to-noise ratio. Additionally, subjective judgments of sound quality were obtained for each strategy/configuration combination. Results: All subjects but 1 demonstrated open-set speech recognition with the SAS/MP combination. The group mean Hearing in Noise Test sentence score for the SAS/MP combination was 31.6% (range, 0% to 92%) correct, as compared to 25.0%, 46.7%, and 37.8% correct for the CIS/BP, CIS/MP, and SAS/BP combinations, respectively. Intersubject variability was high, and there were no significant differences in mean speech recognition scores or mean preference ratings among the 4 strategy/configuration combinations tested. Individually, the best speech recognition performance was with the subject's everyday strategy/configuration combination in 72% of the applicable cases. If the everyday strategy was excluded from the analysis, the subjects performed best with the SAS/MP combination in 37.5% of the remaining cases. Conclusions: The SAS processing strategy with an MP electrode configuration gave reasonable speech recognition in most subjects, even though subjects had minimal previous experience with this strategy/configuration combination. The SAS/MP combination might be particularly appropriate for patients for whom a full dynamic range of electrical hearing could not be achieved with a BP configuration.

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Psychophysical studies for two multiple‐channel cochlear implant patients

The Journal of the Acoustical Society of America ◽

10.1121/1.387342 ◽

1982 ◽

Vol 71 (1) ◽

pp. 153-160 ◽

Cited By ~ 85

Author(s):

Y. C. Tong ◽

G. M. Clark ◽

P. J. Blamey ◽

P. A. Busby ◽

R. C. Dowell

Keyword(s):

Cochlear Implant ◽

Multiple Channel ◽

Psychophysical Studies

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The multiple-channel cochlear implant: the interface between sound and the central nervous system for hearing, speech, and language in deaf people—a personal perspective

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1782 ◽

2006 ◽

Vol 361 (1469) ◽

pp. 791-810 ◽

Cited By ~ 62

Author(s):

Graeme M Clark

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Cochlear Implant ◽

Speech Processing ◽

Temporal Coding ◽

Personal Perspective ◽

Deaf People ◽

Multiple Channel ◽

The Central Nervous System ◽

Electrical Stimuli

The multiple-channel cochlear implant is the first sensori-neural prosthesis to effectively and safely bring electronic technology into a direct physiological relation with the central nervous system and human consciousness, and to give speech perception to severely-profoundly deaf people and spoken language to children. Research showed that the place and temporal coding of sound frequencies could be partly replicated by multiple-channel stimulation of the auditory nerve. This required safety studies on how to prevent the effects to the cochlea of trauma, electrical stimuli, biomaterials and middle ear infection. The mechanical properties of an array and mode of stimulation for the place coding of speech frequencies were determined. A fully implantable receiver–stimulator was developed, as well as the procedures for the clinical assessment of deaf people, and the surgical placement of the device. The perception of electrically coded sounds was determined, and a speech processing strategy discovered that enabled late-deafened adults to comprehend running speech. The brain processing systems for patterns of electrical stimuli reproducing speech were elucidated. The research was developed industrially, and improvements in speech processing made through presenting additional speech frequencies by place coding. Finally, the importance of the multiple-channel cochlear implant for early deafened children was established.

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Effects of Speech Processing Strategy on Chinese Tone Recognition by Nucleus-24 Cochlear Implant Users

Ear and Hearing ◽

10.1097/01.aud.0000145125.50433.19 ◽

2004 ◽

Vol 25 (5) ◽

pp. 501-508 ◽

Cited By ~ 40

Author(s):

Qian-Jie Fu ◽

Chuan-Jen Hsu ◽

Mei-Ji Horng

Keyword(s):

Cochlear Implant ◽

Speech Processing ◽

Processing Strategy ◽

Tone Recognition ◽

Nucleus 24

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Speech-Processing Strategies and Their Implementation

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894870960s136 ◽

1987 ◽

Vol 96 (1_suppl) ◽

pp. 71-74 ◽

Cited By ~ 6

Author(s):

P. Seligman

Keyword(s):

Cochlear Implant ◽

Pulse Rate ◽

Speech Processing ◽

Temporal Coding ◽

Electrode Position ◽

Processing Strategy ◽

Limited Information ◽

Processing Strategies ◽

Speech Information

Since 1979, the Australian speech-processing strategy has been based on the presentation of an estimate of F2 coded by electrode position and F0 coded by pulse rate. Although providing limited information, this strategy has produced good results with significant hearing-alone performance. This paper describes a number of strategies that provide further speech information in an attempt to increase hearing-alone performance to a level where the cochlear implant is able to operate in its own right rather than as an adjunct to lipreading. The strategies are all based on the addition of F1 to the existing strategy. Both electrode and temporal coding of F1 is described, and the performance and percepts produced are discussed. Amplitudes of the two formants must be carefully controlled to avoid masking. The implications of the strategies on the design of hardware are described.

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