Emphasis of short-duration acoustic speech cues for cochlear implant users.

A new speech-coding strategy for cochlear implant users, called the transient emphasis spectral maxima (TESM), was developed to aid perception of short-duration transient cues in speech. Speech-perception scores using the TESM strategy were compared to scores using the spectral maxima sound processor (SMSP) strategy in a group of eight adult users of the Nucleus 22 cochlear implant system. Significant improvements in mean speech-perception scores for the group were obtained on CNC open-set monosyllabic word tests in quiet (SMSP: 53.6% TESM: 61.3%, p<0.001), and on MUSL open-set sentence tests in multitalker noise (SMSP: 64.9% TESM: 70.6%, p<0.001). Significant increases were also shown for consonant scores in the word test (SMSP: 75.1% TESM: 80.6%, p<0.001) and for vowel scores in the word test (SMSP: 83.1% TESM: 85.7%, p<0.05). Analysis of consonant perception results from the CNC word tests showed that perception of nasal, stop, and fricative consonant discrimination was most improved. Information transmission analysis indicated that place of articulation was most improved, although improvements were also evident for manner of articulation. The increases in discrimination were shown to be related to improved coding of short-duration acoustic cues, particularly those of low intensity.