The relative phonetic contributions of a cochlear implant and residual acoustic hearing to bimodal speech perception

Background: The number of cochlear implant (CI) recipients who have usable acoustic hearing in at least one ear is continuing to grow. Many such CI users gain perceptual benefits from the simultaneous use of acoustic and electric hearing. In particular, it has been shown previously that use of an acoustic hearing aid (HA) with a CI can often improve speech understanding in noise. Purpose: To determine whether the application of frequency compression in an HA would provide perceptual benefits to CI recipients with usable acoustic hearing, either when used in combination with the CI or when the HA was used by itself. Research Design: A repeated-measures experimental design was used to evaluate the effects on speech perception of using a CI either alone or simultaneously with an HA that had frequency compression either enabled or disabled. Study Sample: Eight adult CI recipients who were successful users of acoustic hearing aids in their nonimplanted ears participated as subjects. Intervention: The speech perception of each subject was assessed in seven conditions. These required each subject to listen with (1) their own HA alone; (2) the Phonak Naida HA with frequency compression (SoundRecover) enabled; (3) the Naida with SoundRecover disabled; (4) their CI alone; (5) their CI and their own HA; (6) their CI and the Naida with SoundRecover enabled; and (7) their CI and the Naida with SoundRecover disabled. Test sessions were scheduled over a period of about 10 wk. During part of that time, the subjects were asked to use the Phonak Naida HA with their CIs in place of their own HAs. Data Collection and Analysis: The speech perception tests included measures of consonant identification from a closed set of 12 items presented in quiet, and measures of sentence understanding in babble noise. The speech materials were presented at an average level of 60 dB SPL from a loudspeaker. Results: Speech perception was better, on average, in all conditions that included use of the CI in comparison with any condition in which only an HA was used. For example, consonant recognition improved by approximately 50 percentage points, on average, between the HA-alone listening conditions and the CI-alone condition. There were no statistically significant score differences between conditions with SoundRecover enabled and disabled. There was a small but significant improvement in the average signal-to-noise ratio (SNR) required to understand 50% of the words in the sentences presented in noise when an HA was used simultaneously with the CI. Conclusions: Although each of these CI users readily accepted the Phonak Naida HA with SoundRecover frequency compression, no benefits related specifically to the use of SoundRecover were found in the particular tests of speech understanding applied in this study. The relatively high levels of perceptual performance attained by these subjects with use of a CI by itself are consistent with the finding that the addition of an HA provided little further benefit. However, the use of an HA with the CI did provide better performance than the CI alone for understanding sentences in noise.

Download Full-text

Logatome Discrimination in Cochlear Implant Users: Subjective Tests Compared to the Mismatch Negativity

The Scientific World JOURNAL ◽

10.1100/tsw.2010.28 ◽

2010 ◽

Vol 10 ◽

pp. 329-339 ◽

Cited By ~ 7

Author(s):

Torsten Rahne ◽

Michael Ziese ◽

Dorothea Rostalski ◽

Roland Mühler

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Mismatch Negativity ◽

Speech Intelligibility ◽

Event Related Potentials ◽

Normal Hearing ◽

Discrimination Test ◽

Speech Database ◽

Automated Speech Recognition ◽

Related Potentials

This paper describes a logatome discrimination test for the assessment of speech perception in cochlear implant users (CI users), based on a multilingual speech database, the Oldenburg Logatome Corpus, which was originally recorded for the comparison of human and automated speech recognition. The logatome discrimination task is based on the presentation of 100 logatome pairs (i.e., nonsense syllables) with balanced representations of alternating “vowel-replacement” and “consonant-replacement” paradigms in order to assess phoneme confusions. Thirteen adult normal hearing listeners and eight adult CI users, including both good and poor performers, were included in the study and completed the test after their speech intelligibility abilities were evaluated with an established sentence test in noise. Furthermore, the discrimination abilities were measured electrophysiologically by recording the mismatch negativity (MMN) as a component of auditory event-related potentials. The results show a clear MMN response only for normal hearing listeners and CI users with good performance, correlating with their logatome discrimination abilities. Higher discrimination scores for vowel-replacement paradigms than for the consonant-replacement paradigms were found. We conclude that the logatome discrimination test is well suited to monitor the speech perception skills of CI users. Due to the large number of available spoken logatome items, the Oldenburg Logatome Corpus appears to provide a useful and powerful basis for further development of speech perception tests for CI users.

Download Full-text

The Spatial Selective Auditory Attention of Cochlear Implant Users in Different Conversational Sound Levels

Journal of Clinical Medicine ◽

10.3390/jcm10143078 ◽

2021 ◽

Vol 10 (14) ◽

pp. 3078

Author(s):

Sara Akbarzadeh ◽

Sungmin Lee ◽

Chin-Tuan Tan

Keyword(s):

Cochlear Implant ◽

Sound Level ◽

Auditory Attention ◽

Impaired Hearing ◽

Speech Stimuli ◽

Electric Hearing ◽

Sound Levels ◽

Acoustic Hearing ◽

Speech Envelope ◽

Different Levels

In multi-speaker environments, cochlear implant (CI) users may attend to a target sound source in a different manner from normal hearing (NH) individuals during a conversation. This study attempted to investigate the effect of conversational sound levels on the mechanisms adopted by CI and NH listeners in selective auditory attention and how it affects their daily conversation. Nine CI users (five bilateral, three unilateral, and one bimodal) and eight NH listeners participated in this study. The behavioral speech recognition scores were collected using a matrix sentences test, and neural tracking to speech envelope was recorded using electroencephalography (EEG). Speech stimuli were presented at three different levels (75, 65, and 55 dB SPL) in the presence of two maskers from three spatially separated speakers. Different combinations of assisted/impaired hearing modes were evaluated for CI users, and the outcomes were analyzed in three categories: electric hearing only, acoustic hearing only, and electric + acoustic hearing. Our results showed that increasing the conversational sound level degraded the selective auditory attention in electrical hearing. On the other hand, increasing the sound level improved the selective auditory attention for the acoustic hearing group. In the NH listeners, however, increasing the sound level did not cause a significant change in the auditory attention. Our result implies that the effect of the sound level on selective auditory attention varies depending on the hearing modes, and the loudness control is necessary for the ease of attending to the conversation by CI users.

Download Full-text

Meta-Analysis—Correlation between Spiral Ganglion Cell Counts and Speech Perception with a Cochlear Implant

Audiology Research ◽

10.3390/audiolres11020020 ◽

2021 ◽

Vol 11 (2) ◽

pp. 220-226

Author(s):

Yew-Song Cheng ◽

Mario A. Svirsky

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Ganglion Cells ◽

Meta Analysis ◽

Spiral Ganglion ◽

Spiral Ganglion Cell ◽

Cell Counts ◽

Temporal Bones ◽

The Relationship ◽

Existing Data

The presence of spiral ganglion cells (SGCs) is widely accepted to be a prerequisite for successful speech perception with a cochlear implant (CI), because SGCs provide the only known conduit between the implant electrode and the central auditory system. By extension, it has been hypothesized that the number of SGCs might be an important factor in CI outcomes. An impressive body of work has been published on findings from the laborious process of collecting temporal bones from CI users and counting the number of SGCs to correlate those numbers with speech perception scores, but the findings thus far have been conflicting. We performed a meta-analysis of all published studies with the hope that combining existing data may help us reach a more definitive conclusion about the relationship between SGC count and speech perception scores in adults.

Download Full-text

Psychophysical and speech perception studies: A case report on a binaural cochlear implant subject

The Journal of the Acoustical Society of America ◽

10.1121/1.407223 ◽

1993 ◽

Vol 94 (6) ◽

pp. 3178-3189 ◽

Cited By ~ 50

Author(s):

R. J. M. van Hoesel ◽

Y. C. Tong ◽

R. D. Hollow ◽

G. M. Clark

Keyword(s):

Case Report ◽

Speech Perception ◽

Cochlear Implant

Download Full-text

Reduction in High-Frequency Hearing Aid Gain Can Improve Performance in Patients With Contralateral Cochlear Implant: A Pilot Study

American Journal of Audiology ◽

10.1044/2015_aja-15-0045 ◽

2015 ◽

Vol 24 (4) ◽

pp. 462-468 ◽

Cited By ~ 6

Author(s):

Jessica J. Messersmith ◽

Lindsey E. Jorgensen ◽

Jessica A. Hagg

Keyword(s):

Speech Perception ◽

Cochlear Implant ◽

Chart Review ◽

Hearing Aid ◽

Retrospective Chart Review ◽

Improve Performance ◽

Bimodal Condition ◽

Overall Performance ◽

Age Range ◽

Clinic Population

Purpose The purpose of this study was to determine whether an alternate fitting strategy, specifically adjustment to gains in a hearing aid (HA), would improve performance in patients who experienced poorer performance in the bimodal condition when the HA was fit to traditional targets. Method This study was a retrospective chart review from a local clinic population seen during a 6-month period. Participants included 6 users of bimodal stimulation. Two performed poorer in the cochlear implant (CI) + HA condition than in the CI-only condition. One individual performed higher in the bimodal condition, but the overall performance was low. Three age range–matched users whose performance increased when the HA was used in conjunction with a CI were also included. The HA gain was reduced beyond 2000 Hz. Speech perception scores were obtained pre- and postmodification to the HA fitting. Results All listeners whose HA was programmed using the modified approach demonstrated improved speech perception scores with the modified HA fit in the bimodal condition when compared with the traditional HA fit in the bimodal condition. Conclusion Modifications to gains above 2000 Hz in the HA may improve performance for bimodal listeners who perform more poorly in the bimodal condition when the HA is fit to traditional targets.

Download Full-text