Graeme Clark Collection

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Author: McDermott, Hugh × End date: 1998 × Start date: 1990 × Type: Journal Article × Subject: speech processing ×

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    Evaluation of the Nucleus Spectra 22 Processor and New Speech Processing Strategy (SPEAK) in postlinguistically deafened adults
    Whitford, Lesley A. ; Seligman, Peter M. ; Everingham, Colleen E. ; Antognelli, Trisha ; Skok, Marisa C. ; Hollow, Rodney D. ; Plant, Kerrie L. ; Gerin, Elvira S. ; Staller, Steve J. ; McDermott, Hugh J. ; Gibson, William R. ; Clark, Graeme M. ( 1995)
    A new speech processing strategy (SPEAK) has been compared with the previous Multipeak (MPEAK) strategy in a study with 24 postlinguistically deafened adults. The results show that performance with the SPEAK coding strategy was significantly better for 58.3% of subjects on closed-set consonant identification, for 33.3% of subjects on closed-set vowel identification and open-set monosyllabic word recognition, and for 81.8% of subjects on open-set sentence recognition in quiet and in competing noise (+ 10 dB signal-to-noise ratio). By far the largest improvement observed was for sentence recognition in noise, with the mean score across subjects for the SPEAK strategy twice that obtained with MPEAK.
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    Evaluation of a new Spectral Peak coding strategy for the Nucleus 22 channel cochlear implant system
    Skinner, Margaret W. ; Clark, Graeme M. ; Whitford, Lesley A. ; Seligman, Peter M. ; Staller, Steven J. ; Shipp, David B. ; Shallop, Jon K. ; Everingham, Colleen ; Menapace, Christine M. ; Arndt, Patti L. ; Antogenelli, Trisha ; Brimacombe, Judith A. ; Pijl, Sipke ; Daniels, Paulette ; George, Catherine R. ; McDermott, Hugh J. ; Beiter, Anne L. ( 1994)
    Sixty-three postlinguistically deaf adults from four English-speaking countries participated in a 17-week field study of performance with a new speech coding strategy, Spectral Peak (SPEAK), and the most widely used strategy, Multipeak (MPEAK), both of which are implemented on wearable speech processors of the Nucleus 22 Channel Cochlear Implant System; MPEAK is a feature-extraction strategy, whereas SPEAK is a filterbank strategy. Subjects' performance was evaluated with an experimental design in which use of each strategy was reversed and replicated (ABAB). Average scores for speech tests presented sound-only at 70 dB SPL were higher with the SPEAK strategy than with the MPEAK strategy. For tests in quiet, mean scores for medial vowels were 74.8 percent versus 70.1 percent; for medial consonants, 68.6 percent versus 56.6 percent; for monosyllabic words, 33.8 percent versus 24.6 percent; and for sentences, 77.5 percent versus 67.4 percent. For tests in noise, mean scores for Four-Choice Spondees at +10 and +5 dB signal-to-noise ratio (S/N) were 88.5 percent versus 73.6 percent and 80.1 percent versus 62.3 percent, respectively; and for sentences at +15 dB, +10, and +5 dB S/N, 66.5 percent versus 43.4 percent, 61.5 percent versus 37.1 percent, and 60.4 percent versus 31.7 percent, respectively. Subjects showed marked improvement in recognition of sentences in noise with the new SPEAK filterbank strategy. These results agree closely with subjects' responses to a questionnaire on which approximately 80 percent reported they heard best with the SPEAK strategy for everyday listening situations.
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    Preliminary results with a six spectral maxima speech processor for The University of Melbourne/Nucleus multiple electrode cochlear implant
    McKay, Colette M. ; McDermott, Hugh J. ; VANDALI, ANDREW ; Clark, Graeme M. ( 1991)
    An improved sound processor for a multiple-channel cochlear implant hearing prosthesis has been developed. The spectral maxima sound processor (SMSP) extracts the six largest frequency components of speech and presents stimuli at a rate of 250 Hz to electrodes at positions selected on the basis of the spectral frequencies. It was designed for use initially with the advanced cochlear implant recently developed at the University of Melbourne, which is capable of high rate and quasi-simultaneous stimulation. The present study, however, was carried out with two subjects who have the more widely used 22-electrode implant produced commercially by Cochlear Pty Limited (formerly Nucleus Limited). Preliminary results comparing the performance of the SMSP with that of previous speech processing techniques (F0/F1/F2 strategy) are presented. The results indicate that the SMSP is capable of providing implanters with significantly greater information about speech.