Non-implanted Ear Research Articles

Cochlear Implantation in Adults With Asymmetric Hearing Loss

Bilateral severe to profound sensorineural hearing loss is a standard criterion for cochlear implantation. Increasingly, patients are implanted in one ear and continue to use a hearing aid in the nonimplanted ear to improve abilities such as sound localization and speech understanding in noise. Patients with severe to profound hearing loss in one ear and a more moderate hearing loss in the other ear (i.e., asymmetric hearing) are not typically considered candidates for cochlear implantation. Amplification in the poorer ear is often unsuccessful because of limited benefit, restricting the patient to unilateral listening from the better ear alone. The purpose of this study was to determine whether patients with asymmetric hearing loss could benefit from cochlear implantation in the poorer ear with continued use of a hearing aid in the better ear. Ten adults with asymmetric hearing between ears participated. In the poorer ear, all participants met cochlear implant candidacy guidelines; seven had postlingual onset, and three had pre/perilingual onset of severe to profound hearing loss. All had open-set speech recognition in the better-hearing ear. Assessment measures included word and sentence recognition in quiet, sentence recognition in fixed noise (four-talker babble) and in diffuse restaurant noise using an adaptive procedure, localization of word stimuli, and a hearing handicap scale. Participants were evaluated preimplant with hearing aids and postimplant with the implant alone, the hearing aid alone in the better ear, and bimodally (the implant and hearing aid in combination). Postlingual participants were evaluated at 6 mo postimplant, and pre/perilingual participants were evaluated at 6 and 12 mo postimplant. Data analysis compared the following results: (1) the poorer-hearing ear preimplant (with hearing aid) and postimplant (with cochlear implant); (2) the device(s) used for everyday listening pre- and postimplant; and (3) the hearing aid-alone and bimodal listening conditions postimplant. The postlingual participants showed significant improvements in speech recognition after 6 mo cochlear implant use in the poorer ear. Five postlingual participants had a bimodal advantage over the hearing aid-alone condition on at least one test measure. On average, the postlingual participants had significantly improved localization with bimodal input compared with the hearing aid-alone. Only one pre/perilingual participant had open-set speech recognition with the cochlear implant. This participant had better hearing than the other two pre/perilingual participants in both the poorer and better ear. Localization abilities were not significantly different between the bimodal and hearing aid-alone conditions for the pre/perilingual participants. Mean hearing handicap ratings improved postimplant for all participants indicating perceived benefit in everyday life with the addition of the cochlear implant. Patients with asymmetric hearing loss who are not typical cochlear implant candidates can benefit from using a cochlear implant in the poorer ear with continued use of a hearing aid in the better ear. For this group of 10, the 7 postlingually deafened participants showed greater benefits with the cochlear implant than the pre/perilingual participants; however, further study is needed to determine maximum benefit for those with early onset of hearing loss.

The Sound Sensation of Apical Electric Stimulation in Cochlear Implant Recipients with Contralateral Residual Hearing

BackgroundStudies using vocoders as acoustic simulators of cochlear implants have generally focused on simulation of speech understanding, gender recognition, or music appreciation. The aim of the present experiment was to study the auditory sensation perceived by cochlear implant (CI) recipients with steady electrical stimulation on the most-apical electrode.Methodology/Principal FindingsFive unilateral CI users with contralateral residual hearing were asked to vary the parameters of an acoustic signal played to the non-implanted ear, in order to match its sensation to that of the electric stimulus. They also provided a rating of similarity between each acoustic sound they selected and the electric stimulus. On average across subjects, the sound rated as most similar was a complex signal with a concentration of energy around 523 Hz. This sound was inharmonic in 3 out of 5 subjects with a moderate, progressive increase in the spacing between the frequency components.Conclusions/SignificanceFor these subjects, the sound sensation created by steady electric stimulation on the most-apical electrode was neither a white noise nor a pure tone, but a complex signal with a progressive increase in the spacing between the frequency components in 3 out of 5 subjects. Knowing whether the inharmonic nature of the sound was related to the fact that the non-implanted ear was impaired has to be explored in single-sided deafened patients with a contralateral CI. These results may be used in the future to better understand peripheral and central auditory processing in relation to cochlear implants.

Natural history of contralateral residual hearing in unilateral cochlear implant users – long-term findings

Conclusion: The long-term stability of low-frequency residual hearing found in a significant number of bilateral-bimodal users (cochlear implant (CI) in one ear and a hearing aid (HA) on the other ear; CI/HA) with severe-to-profound or profound hearing loss in the non-implanted ear justifies bilateral-bimodal fitting efforts in this group. Since low-frequency residual hearing tends to deteriorate in some of these CI/HA users, periodic evaluation, which includes pure-tone thresholds and speech perception tests, is mandatory for determining the point in time at which CI/HA hearing is no longer effective, and the patient should accordingly be considered as a candidate for contralateral cochlear implantation. Objective: To determine, in bilateral-bimodal (CI/HA) users with severe-to-profound or profound hearing loss in the non-implanted ear, the rate of residual hearing deterioration in the non-implanted ear after cochlear implantation. Methods: Pure-tone aided and unaided thresholds in the non-implanted ears of 39 CI/HA users at 0.25–4.0 kHz were recorded prospectively up to 6 years after implantation. Results: Group mean threshold values in the non-implanted ears remained stable over 3, 4, 5 and 6 years post-implantation, except for significant deterioration at 4.0 kHz of both unaided (4.2, 5.2, 9.0 and 8.2 dB, respectively) and aided thresholds (8.1, 4.6, 6.1 and 8.3 dB, respectively).

Contralateral hearing aid use in cochlear implanted patients: Multicenter study of bimodal benefit

Conclusion: The use of a hearing aid (HA) in combination with a cochlear implant (CI) significantly improved performance for speech perception in quiet, in noise, and for localization compared with monaural conditions. No significant differences in functional performance were observed following optimization of HA fitting. Objectives: To evaluate the binaural benefits derived from using a contralateral HA in conjunction with a CI in subjects with significant functional hearing in the nonimplanted ear and the effects of HA fitting optimization. Methods: Fifteen adult CI users, intra-subject controls, were enrolled in a prospective repeated-measure multicenter study. Evaluation of performance for speech understanding, localization, and subjective impressions was conducted before and following HA fitting optimization for CI alone, HA alone, and CI + HA. Results: For speech testing in quiet, bimodal scores were significantly better than for HA alone and CI alone conditions (p < 0.01). For speech and noise (S0N0) at 0° azimuth the scores were significantly better in the bimodal condition than for CI alone (p = 0.01), indicating binaural summation. When noise was presented to the HA side (S0NHA) bimodal scores were significantly better than for CI alone (p < 0.01 and p < 0.05, respectively), suggesting a significant binaural squelch effect. Sound localization ability was significantly improved in the bimodal condition compared with the CI alone condition (p = 0.002).

THE PSYCHOPHYSICS OF LOW-FREQUENCY ACOUSTIC HEARING IN ELECTRIC AND ACOUSTIC STIMULATION (EAS) AND BIMODAL PATIENTS

This paper provides a review of the current literature on psychophysical properties of low-frequency hearing, both before and after implantation, with a focus on frequency selectivity, nonlinear cochlear processing, and speech perception in temporally modulated maskers for bimodal listeners as well as patients with hearing preservation in the implanted ear and receiving combined electric and acoustic stimulation (EAS). In this paper we review our work, the work of others, and report results not previously published for speech perception in steady-state and temporally fluctuating maskers; the degree of masking release and frequency resolution for 11 bimodal, 6 hearing preservation patients; and 5 control subjects with normal hearing. The results demonstrate that a small masking release is possible with acoustic hearing in just one ear, with the degree of masking release being correlated with the low-frequency pure tone average in the non-implanted ear; furthermore, frequency selectivity as defined by the width of the auditory filter was not correlated with the degree of masking release. Descriptions of the clinical utility of hearing preservation in the implanted ear for improving speech perception in complex listening environments, as well as directions for the future, are discussed.

Beneficial acoustic speech cues for cochlear implant users with residual acoustic hearing

This study investigated which acoustic cues within the speech signal are responsible for bimodal speech perception benefit. Seven cochlear implant (CI) users with usable residual hearing at low frequencies in the non-implanted ear participated. Sentence tests were performed in near-quiet (some noise on the CI side to reduce scores from ceiling) and in a modulated noise background, with the implant alone and with the addition, in the hearing ear, of one of four types of acoustic signals derived from the same sentences: (1) a complex tone modulated by the fundamental frequency (F0) and amplitude envelope contours; (2) a pure tone modulated by the F0 and amplitude contours; (3) a noise-vocoded signal; (4) unprocessed speech. The modulated tones provided F0 information without spectral shape information, whilst the vocoded signal presented spectral shape information without F0 information. For the group as a whole, only the unprocessed speech condition provided significant benefit over implant-alone scores, in both near-quiet and noise. This suggests that, on average, F0 or spectral cues in isolation provided limited benefit for these subjects in the tested listening conditions, and that the significant benefit observed in the full-signal condition was derived from implantees' use of a combination of these cues.

Talker-identification training using simulations of binaurally combined electric and acoustic hearing: Generalization to speech and emotion recognition

Understanding speech in background noise, talker identification, and vocal emotion recognition are challenging for cochlear implant (CI) users due to poor spectral resolution and limited pitch cues with the CI. Recent studies have shown that bimodal CI users, that is, those CI users who wear a hearing aid (HA) in their non-implanted ear, receive benefit for understanding speech both in quiet and in noise. This study compared the efficacy of talker-identification training in two groups of young normal-hearing adults, listening to either acoustic simulations of unilateral CI or bimodal (CI+HA) hearing. Training resulted in improved identification of talkers for both groups with better overall performance for simulated bimodal hearing. Generalization of learning to sentence and emotion recognition also was assessed in both subject groups. Sentence recognition in quiet and in noise improved for both groups, no matter if the talkers had been heard during training or not. Generalization to improvements in emotion recognition for two unfamiliar talkers also was noted for both groups with the simulated bimodal-hearing group showing better overall emotion-recognition performance. Improvements in sentence recognition were retained a month after training in both groups. These results have potential implications for aural rehabilitation of conventional and bimodal CI users.

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

The addition of low-passed (LP) speech or even a tone following the fundamental frequency (F0) of speech has been shown to benefit speech recognition for cochlear implant (CI) users with residual acoustic hearing. The mechanisms underlying this benefit are still unclear. In this study, eight bimodal subjects (CI users with acoustic hearing in the non-implanted ear) and eight simulated bimodal subjects (using vocoded and LP speech) were tested on vowel and consonant recognition to determine the relative contributions of acoustic and phonetic cues, including F0, to the bimodal benefit. Several listening conditions were tested (CI/Vocoder, LP, T(F0-env), CI/Vocoder + LP, CI/Vocoder + T(F0-env)). Compared with CI/Vocoder performance, LP significantly enhanced both consonant and vowel perception, whereas a tone following the F0 contour of target speech and modulated with an amplitude envelope of the maximum frequency of the F0 contour (T(F0-env)) enhanced only consonant perception. Information transfer analysis revealed a dual mechanism in the bimodal benefit: The tone representing F0 provided voicing and manner information, whereas LP provided additional manner, place, and vowel formant information. The data in actual bimodal subjects also showed that the degree of the bimodal benefit depended on the cutoff and slope of residual acoustic hearing.

Contralateral recovery of cochlear function after cochlear implantation

Significant recovery of sensorineural hearing loss in either ear after cochlear implantation (CI) is rare. We present the case of a 57-year-old lady with medically treated depression and a background of chronic suppurative otitis media (CSOM) in the non-implanted ear, who clearly fulfilled audiological criteria for CI. Two years post-implantation her CSOM in the non-implanted ear was addressed with blind sac closure of the ear. Post-operatively the hearing thresholds in this ear had improved to the extent that a bone-anchored hearing aid became a viable option. The literature is carefully reviewed to consider possible explanations of this phenomenon.

Direct Entry of Gadolinium into the Vestibule Following Intratympanic Applications in Guinea Pigs and the Influence of Cochlear Implantation

Although intratympanic (IT) administration of drugs has gained wide clinical acceptance, the distribution of drugs in the inner ear following IT administration is not well established. Gadolinium (Gd) has been previously used as a marker in conjunction with magnetic resonance imaging (MRI) to visualize distribution in inner ear fluids in a qualitative manner. In the present study, we applied gadolinium chelated with diethylenetriamine penta-acetic acid (Gd-DTPA) to the round window niche of 12 guinea pigs using Seprapack(TM) (carboxlmethylcellulose-hyaluronic acid) pledgets which stabilized the fluid volume in the round window niche. Gd-DTPA distribution was monitored sequentially with time following application. Distribution in normal, unperforated ears was compared with ears that had undergone a cochleostomy in the basal turn of scala tympani and implantation with a silastic electrode. Results were quantified using image analysis software. In all animals, Gd-DTPA was seen in the lower basal scala tympani (ST), scala vestibuli (SV), and throughout the vestibule and semi-circular canals by 1h after application. Although Gd-DTPA levels in ST were higher than those in the vestibule in a few ears, the majority showed higher Gd-DTPA levels in the vestibule than ST at both early and later time points. Quantitative computer simulations of the experiment, taking into account the larger volume of the vestibule compared to scala tympani, suggest most Gd-DTPA (up to 90%) entered the vestibule directly in the vicinity of the stapes rather than indirectly through the round window membrane and ST. Gd-DTPA levels were minimally affected by the implantation procedure after 1h. Gd-DTPA levels in the basal turn of scala tympani were lower in implanted animals, but the difference compared to non-implanted ears did not reach statistical significance.

F030 Hybrid-L and CI422 for treatment of partial deafness in children

The electrically elicited stapedius reflex thresholds (eSRT) measurement has been suggested as a simple, reliable and useful tool to add to the speech processor programming procedure in children. This study assessed the stability of eSRT over time. The material consisted of 11 implanted children aged from 2 years and 6 months to 5 years and 2 months. eSRT was measured in the nonimplanted ear using electroacoustic immittance instrument 1 and 12 months after implant activation. The differences in eSRT were less than 10% after 1 year. The stability of eSRT threshold over time was demonstrated in pediatric population. This is important for the consideration of pediatric fitting procedure based on eSRT measurements.

F009 Comparison of eSRTs and comfort levels in users of Digisonic SP cochlear implants

The electrically elicited stapedius reflex thresholds (eSRT) measurement has been suggested as a simple, reliable and useful tool to add to the speech processor programming procedure in children. This study assessed the stability of eSRT over time. The material consisted of 11 implanted children aged from 2 years and 6 months to 5 years and 2 months. eSRT was measured in the nonimplanted ear using electroacoustic immittance instrument 1 and 12 months after implant activation. The differences in eSRT were less than 10% after 1 year. The stability of eSRT threshold over time was demonstrated in pediatric population. This is important for the consideration of pediatric fitting procedure based on eSRT measurements.

A comparison of the speech recognition and pitch ranking abilities of children using a unilateral cochlear implant, bimodal stimulation or bilateral hearing aids

ObjectiveThe present study compared the speech recognition and pitch ranking abilities of normally hearing children (n=15) to children using a cochlear implant (CI) alone (n=8), bilateral hearing aids (HAs) (n=6), or bimodal stimulation (BMS) (n=9). It was hypothesised that users of BMS would score higher on tasks of speech and pitch perception than children using a CI alone, but not children using HAs. MethodsParticipants were assessed on tasks of monosyllabic word recognition in quiet, sentence recognition in quiet and noise (10dB signal-to-noise ratio), and a pitch ranking task using pairs of sung vowels one, half, and a quarter of an octave apart. ResultsThere were no significant differences between the mean percentage-correct scores of the four participant groups for either words in quiet or sentences in quiet and noise. However, the proportion of bimodal users who scored >80% correct (80%) was significantly greater than the proportion of high-scoring unilateral CI (25%) or bilateral HA users (17%). Contrary to expectations, there was also no significant difference between the pitch ranking scores of users of BMS and users of a CI alone for all three interval sizes (p<0.05, RM-ANOVA). However participants using only acoustic hearing (i.e. the NH and HA groups) scored significantly higher than participants using electrical stimulation (i.e. the CI and BMS groups) on the pitch ranking task (p<0.05; RM-ANOVA). ConclusionsContrary to findings in postlingually deafened adults, we found no significant bimodal advantage for pitch perception in prelingually deafened children. However, the performance of children using electrical stimulation was significantly poorer than children using only acoustic stimulation. Further research is required to investigate the contribution of the non-implanted ears of users of BMS to pitch perception, and the effect of hearing loss on the development of pitch perception in children.

Bimodal Hearing or Bilateral Cochlear Implants: A Review of the Research Literature

Over the past 10 years, there have been an increasing number of patients fitted with either bimodal hearing devices (unilateral cochlear implant [CI], and hearing aid on the other ear) or bilateral cochlear implants. Concurrently, there has been an increasing interest in and number of publications on these topics. This article reviews the now fairly voluminous research literature on bimodal hearing and bilateral cochlear implantation in both children and adults. The emphasis of this review is on more recent clinical studies that represent current technology and that evaluated speech recognition in quiet and noise, localization ability, and perceived benefit. A vast majority of bilaterally deaf subjects in these studies showed benefit in one or more areas from bilateral CIs compared with listening with only a unilateral CI. For patients who have sufficient residual low-frequency hearing sensitivity for the provision of amplification in the nonimplanted ear, bimodal hearing appears to provide a good nonsurgical alternative to bilateral CIs or to unilateral listening for many patients.

Comparison of Bimodal and Bilateral Cochlear Implant Users on Speech Recognition With Competing Talker, Music Perception, Affective Prosody Discrimination, and Talker Identification

Despite excellent performance in speech recognition in quiet, most cochlear implant users have great difficulty with speech recognition in noise, music perception, identifying tone of voice, and discriminating different talkers. This may be partly due to the pitch coding in cochlear implant speech processing. Most current speech processing strategies use only the envelope information; the temporal fine structure is discarded. One way to improve electric pitch perception is to use residual acoustic hearing via a hearing aid on the nonimplanted ear (bimodal hearing). This study aimed to test the hypothesis that bimodal users would perform better than bilateral cochlear implant users on tasks requiring good pitch perception. Four pitch-related tasks were used. 1. Hearing in Noise Test (HINT) sentences spoken by a male talker with a competing female, male, or child talker. 2. Montreal Battery of Evaluation of Amusia. This is a music test with six subtests examining pitch, rhythm and timing perception, and musical memory. 3. Aprosodia Battery. This has five subtests evaluating aspects of affective prosody and recognition of sarcasm. 4. Talker identification using vowels spoken by 10 different talkers (three men, three women, two boys, and two girls). Bilateral cochlear implant users were chosen as the comparison group. Thirteen bimodal and 13 bilateral adult cochlear implant users were recruited; all had good speech perception in quiet. There were no significant differences between the mean scores of the bimodal and bilateral groups on any of the tests, although the bimodal group did perform better than the bilateral group on almost all tests. Performance on the different pitch-related tasks was not correlated, meaning that if a subject performed one task well they would not necessarily perform well on another. The correlation between the bimodal users' hearing threshold levels in the aided ear and their performance on these tasks was weak. Although the bimodal cochlear implant group performed better than the bilateral group on most parts of the four pitch-related tests, the differences were not statistically significant. The lack of correlation between test results shows that the tasks used are not simply providing a measure of pitch ability. Even if the bimodal users have better pitch perception, the real-world tasks used are reflecting more diverse skills than pitch. This research adds to the existing speech perception, language, and localization studies that show no significant difference between bimodal and bilateral cochlear implant users.

Bilateral Cochlear Implants in Children

This article provides a brief overview of the advantages of two-ear hearing in children and discusses the limitations, from a psychophysical and a technical perspective, which may constrain the ability of cochlear implant users to gain these benefits. The latest outcomes for children using bilateral cochlear implants are discussed, which suggest that results are more favorable for children who receive both devices before the age of 3.5 to 4 years. The available studies that have investigated electrophysiological responses for children receiving bilateral implants are discussed. These also support the notion that optimum development of binaural auditory skills may be more difficult after the age of 3.5 to 4 years. Studies that investigate the alternative for some children of using a hearing aid on the opposite ear to the cochlear implant are briefly discussed. These indicate that advantages for speech perception in noise and localization can be obtained consistently for children with significant residual hearing in the nonimplanted ear. The article concludes with an attempt to bring the available scientific evidence into the practical clinical context with suggestions that may assist clinicians in making recommendations for families considering bilateral cochlear implantation. Although the evidence remains limited at this time, it is reasonable to suggest that bilateral cochlear implantation can provide improved auditory skills over a single implant for children with severe and profound bilateral hearing loss. The available data suggest that the benefit may be maximized by introducing both implants as early as possible, at least before 3.5 to 4 years of age. Copyright © 2011 by Thieme Medical Publishers, Inc.

Acoustic Cues for Consonant Perception with Combined Acoustic and Electric Hearing in Children

Many children who use a cochlear implant in one ear have usable residual hearing in the opposite ear. There is consensus that bilateral stimulation should be provided to these children by fitting a hearing aid in the nonimplanted ear. The combination of acoustic amplification via a hearing aid with electrical stimulation via a cochlear implant is commonly referred to as “bimodal hearing.” This article examines speech perceptual benefits associated with the use of bimodal hearing in children. First, a brief description of the acoustic basis for phonetic contrasts is provided. Second, information on children's consonant perception and information transmission via the use of cochlear implants with or without hearing aids is presented. Finally, a summary of fitting strategies is presented with validation results. These results support the optimization of a hearing aid with a cochlear implant for children.

Exploring the Factors Influencing Discontinued Hearing Aid Use in Patients With Unilateral Cochlear Implants

Studies have shown that unilateral cochlear implant users who have residual hearing in the contralateral ear can benefit from combining a hearing aid in the nonimplanted ear with their cochlear implant. The purpose of this study was to better understand the factors influencing decision making by adults. Adults who had discontinued hearing aid use shortly after cochlear implantation were selected from one Canadian cochlear implant program. An examination of hearing aid use revealed that of 96 patients, who used hearing aids preimplant, 49 had discontinued hearing aid use. Patient perspectives on the decision and experience of combining a hearing aid and a cochlear implant were collected through 12 individual semistructured interviews. The interviews were analyzed qualitatively to identify key themes. Questionnaires, based on the interview findings, were developed and sent to the 49 adults to further explore the factors affecting hearing aid decisions. Interview and questionnaire findings from 28 adults indicated that three factors primarily influenced patients' decision to discontinue hearing aid use: their perceptions of the experience with hearing aids prior to implantation, their views of superiority of a unilateral cochlear implant in comparison with hearing aids, and their perceptions of interference with sound quality when a cochlear implant and hearing aid were combined. This study provides information about patient perceptions, experiences, and understanding of the potential difficulties of a bimodal fitting that may assist clinicians in pre- and postimplant counseling.

Effect of REZ-I cochlear implantation on residual hearing in adult patients

To evaluate the effect of cochlear implantation with REZ-I straight electrodes on residual hearing of postlingually deafened adults, and to explore the audiologically safety and injury characteristics of cochlear implantation. Sixteen unilateral REZ-I (22 channels) cochlear implantation recipients from September 2009 to December 2009 were picked out. Their pre-and post-implantation audiometry data including pure-tone audiometry (PTA), auditory steady-state responses (ASSR), auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE) were retrospectively analyzed, in order to compare the change between pre- and post-implantation residual hearing. Among the 12 recipients who had some measurable residual hearing before implantation, 5 (41.6%) patients had conserved some measurable hearing but the other 7 (58.4%) recipients had lost all measurable hearing after implantation on the implanted side. The implanted ears had an average PTA threshold drop of 9.5 dB HL and a statistically significant difference between pre- and post-implantation (P < 0.05) PTA thresholds in the frequencies of 250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. Compared to non-implanted ears, the drop in 500 Hz and 1kHz had a statistically significant difference between pre- and post-implantation PTA thresholds (P < 0.05). The ASSR residual hearing threshold elevation were statistically significant (P < 0.05) between pre- and post-implantation ASSR at 250 Hz and 500 Hz on the implanted side, while the The ASSR residual hearing threshold elevation were statistically significant (P < 0.05) at 500 Hz when compared to non-implanted side. The difference of residual hearing between pre- and post-implantation was not statistically significant for both DPOAE and ABR. There will be a certain degree of damage to residual hearing of the implanted side following REZ-I cochlear implantation.

The Use of Frequency Compression by Cochlear Implant Recipients with Postoperative Acoustic Hearing

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. 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. 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. Eight adult CI recipients who were successful users of acoustic hearing aids in their nonimplanted ears participated as subjects. 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. 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. 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. 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.