Do Adults With Cochlear Implants Rely on Different Acoustic Cues for Phoneme Perception Than Adults With Normal Hearing?

Abstract

Purpose Several acoustic cues specify any single phonemic contrast. Nonetheless, adult, native speakers of a language share weighting strategies, showing preferential attention to some properties over others. Cochlear implant (CI) signal processing disrupts the salience of some cues: in general, amplitude structure remains readily available, but spectral structure less so. This study asked how well speech recognition is supported if CI users shift attention to salient cues not weighted strongly by native speakers. Method 20 adults with CIs participated. The /bɑ/-/wɑ/ contrast was used because spectral and amplitude structure varies in correlated fashion for this contrast. Normal-hearing adults weight the spectral cue strongly, but the amplitude cue negligibly. Three measurements were made: labeling decisions, spectral and amplitude discrimination, and word recognition. Results Outcomes varied across listeners: some weighted the spectral cue strongly, some weighted the amplitude cue, and some weighted neither. Spectral discrimination predicted spectral weighting. Spectral weighting explained the most variance in word recognition. Age of onset of hearing loss predicted spectral weighting, but not unique variance in word recognition. Conclusions The weighting strategies of listeners with normal hearing likely support speech recognition best, so efforts in implant design, fitting, and training should focus on developing those strategies.

Using speech sounds to test functional spectral resolution in listeners with cochlear implants

“…Previous phonetic cue-weighting studies with CI listeners suggest that limitations in the use of preferred acoustic cues can be complemented by increases in the use of secondary cues (Winn et al, 2012;Moberly et al, 2014), and the current study suggests that this phenomenon has implications for word recognition in general. CI listeners in this study who showed a cue-weighting pattern most similar to NH listeners in the unprocessed condition also tended to show best word recognition.…”

Neural Correlates of Phonetic Learning in Postlingually Deafened Cochlear Implant Listeners

“…However, they did find that the CI users that utilized formant transition perceptual weighting strategies most similar to NH listeners when categorizing the /ba/-/da/ contrast exhibited the best word recognition scores. Similarly, Moberly et al (2014) documented that CI users that utilized perceptual weighting strategies most similar to NH listeners when categorizing the /ba/-/wa/ contrast exhibited superior word recognition performance as well. It is possible that the listeners in our study that exhibited the greatest training-related gains were using a different perceptual listening strategy to categorize the speech sounds than the CI users that showed only small behavioral changes.…”

The Relationship Between Environmental Sound Awareness and Speech Recognition Skills in Experienced Cochlear Implant Users

“…All measures were prerecorded to maintain consistent presentation levels and presented at 68 dB SPL. Spoken word recognition was measured using a Central Institute for the Deaf Word List (CID-W22) of 50 words, selected because previous work has demonstrated a wide range of variability in CI users when tested in quiet (21,22). Recognition of spoken words in meaningful sentences was tested using the Institute of Electrical and Electronics Engineers (IEEE) corpus (23), chosen because these 25 sentences are more complex than most clinical batteries (e.g., AzBio or HINT), and a wide range of performance has been demonstrated among adult CI users.…”