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Objective: A multisite clinical trial was conducted to obtain cochlear implant (CI) efficacy data in adults with asymmetric hearing loss (AHL) and establish an evidence-based framework for clinical decision-making regarding CI candidacy, counseling, and assessment tools. Study hypotheses were threefold: (1) 6-month postimplant performance in the poor ear (PE) with a CI will be significantly better than preimplant performance with a hearing aid (HA), (2) 6-month postimplant performance with a CI and HA (bimodal) will be significantly better than preimplant performance with bilateral HAs (Bil HAs), and (3) 6-month postimplant bimodal performance will be significantly better than aided, better ear (BE) performance., Design: Forty adults with AHL from four, metropolitan CI centers participated. Hearing criteria for the ear to be implanted included (1) pure-tone average (PTA, 0.5, 1, 2 kHz) of >70 dB HL, (2) aided, monosyllabic word score of ≤30%, (3) duration of severe-to-profound hearing loss of ≥6 months, and (4) onset of hearing loss ≥6 years of age. Hearing criteria for the BE included (1) PTA (0.5, 1, 2, 4 kHz) of 40 to 70 dB HL, (2) currently using a HA, (3) aided, word score of >40%, and (4) stable hearing for the previous 1-year period. Speech perception and localization measures, in quiet and in noise, were administered preimplant and at 3-, 6-, 9-, and 12-months postimplant. Preimplant testing was performed in three listening conditions, PE HA, BE HA, and Bil HAs. Postimplant testing was performed in three conditions, CI, BE HA, and bimodal. Outcome factors included age at implantation and length of deafness (LOD) in the PE., Results: A hierarchical nonlinear analysis predicted significant improvement in the PE by 3 months postimplant versus preimplant for audibility and speech perception with a plateau in performance at approximately 6 months. The model predicted significant improvement in postimplant, bimodal outcomes versus preimplant outcomes (Bil HAs) for all speech perception measures by 3 months. Both age and LOD were predicted to moderate some CI and bimodal outcomes. In contrast with speech perception, localization in quiet and noise was not predicted to improve by 6 months when comparing Bil HAs (preimplant) to bimodal (postimplant) outcomes. However, when participants' preimplant everyday listening condition (BE HA or Bil HAs) was compared with bimodal performance, the model predicted significant improvement by 3 months for localization in quiet and noise. Lastly, BE HA results were stable over time; a generalized linear model analysis revealed bimodal performance was significantly better than performance with a BE HA at all postimplant intervals for most speech perception measures and localization., Conclusions: Results revealed significant CI and bimodal benefit for AHL participants by 3-months postimplant, with a plateau in CI and bimodal performance at approximately 6-months postimplant. Results can be used to inform AHL CI candidates and to monitor postimplant performance. On the basis of this and other AHL research, clinicians should consider a CI for individuals with AHL if the PE has a PTA (0.5, 1, 2 kHz) >70 dB HL and a Consonant-Vowel Nucleus-Consonant word score ≤40%. LOD >10 years should not be a contraindication., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Whether, and if so when, a second-ear cochlear implant should be provided to older, unilaterally implanted children is an ongoing clinical question. This study evaluated rate of speech recognition progress for the second implanted ear and with bilateral cochlear implants in older sequentially implanted children and evaluated localization abilities., Method: A prospective longitudinal study included 24 bilaterally implanted children (mean ear surgeries at 5.11 and 14.25 years). Test intervals were every 3-6 months through 24 months postbilateral. Test conditions were each ear and bilaterally for speech recognition and localization., Results: Overall, the rate of progress for the second implanted ear was gradual. Improvements in quiet continued through the second year of bilateral use. Improvements in noise were more modest and leveled off during the second year. On all measures, results from the second ear were poorer than the first. Bilateral scores were better than either ear alone for all measures except sentences in quiet and localization., Conclusions: Older sequentially implanted children with several years between surgeries may obtain speech understanding in the second implanted ear; however, performance may be limited and rate of progress gradual. Continued contralateral ear hearing aid use and reduced time between surgeries may enhance outcomes.

Purpose: The purpose of this study was to examine the rate of progress in the 2nd implanted ear as it relates to the 1st implanted ear and to bilateral performance in adult sequential cochlear implant recipients. In addition, this study aimed to identify factors that contribute to patient outcomes., Method: The authors performed a prospective longitudinal study in 21 adults who received bilateral sequential cochlear implants. Testing occurred at 6 intervals: prebilateral through 12 months postbilateral implantation. Measures evaluated speech recognition in quiet and noise, localization, and perceived benefit., Results: Second ear performance was similar to 1st ear performance by 6 months postbilateral implantation. Bilateral performance was generally superior to either ear alone; however, participants with shorter 2nd ear length of deafness (<20 years) had more rapid early improvement and better overall outcomes than those with longer 2nd ear length of deafness (>30 years). All participants reported bilateral benefit., Conclusions: Adult cochlear implant recipients demonstrated benefit from 2nd ear implantation for speech recognition, localization, and perceived communication function. Because performance outcomes were related to length of deafness, shorter time between surgeries may be warranted to reduce negative length-of-deafness effects. Future study may clarify the impact of other variables, such as preimplant hearing aid use, particularly for individuals with longer periods of deafness.

Background: The use of bilateral amplification is now common clinical practice for hearing aid users but not for cochlear implant recipients. In the past, most cochlear implant recipients were implanted in one ear and wore only a monaural cochlear implant processor. There has been recent interest in benefits arising from bilateral stimulation that may be present for cochlear implant recipients. One option for bilateral stimulation is the use of a cochlear implant in one ear and a hearing aid in the opposite nonimplanted ear (bimodal hearing)., Purpose: This study evaluated the effect of wearing a cochlear implant in one ear and a digital hearing aid in the opposite ear on speech recognition and localization., Research Design: A repeated-measures correlational study was completed., Study Sample: Nineteen adult Cochlear Nucleus 24 implant recipients participated in the study., Intervention: The participants were fit with a Widex Senso Vita 38 hearing aid to achieve maximum audibility and comfort within their dynamic range., Data Collection and Analysis: Soundfield thresholds, loudness growth, speech recognition, localization, and subjective questionnaires were obtained six-eight weeks after the hearing aid fitting. Testing was completed in three conditions: hearing aid only, cochlear implant only, and cochlear implant and hearing aid (bimodal). All tests were repeated four weeks after the first test session. Repeated-measures analysis of variance was used to analyze the data. Significant effects were further examined using pairwise comparison of means or in the case of continuous moderators, regression analyses. The speech-recognition and localization tasks were unique, in that a speech stimulus presented from a variety of roaming azimuths (140 degree loudspeaker array) was used., Results: Performance in the bimodal condition was significantly better for speech recognition and localization compared to the cochlear implant-only and hearing aid-only conditions. Performance was also different between these conditions when the location (i.e., side of the loudspeaker array that presented the word) was analyzed. In the bimodal condition, the speech-recognition and localization tasks were equal regardless of which side of the loudspeaker array presented the word, while performance was significantly poorer for the monaural conditions (hearing aid only and cochlear implant only) when the words were presented on the side with no stimulation. Binaural loudness summation of 1-3 dB was seen in soundfield thresholds and loudness growth in the bimodal condition. Measures of the audibility of sound with the hearing aid, including unaided thresholds, soundfield thresholds, and the Speech Intelligibility Index, were significant moderators of speech recognition and localization. Based on the questionnaire responses, participants showed a strong preference for bimodal stimulation., Conclusions: These findings suggest that a well-fit digital hearing aid worn in conjunction with a cochlear implant is beneficial to speech recognition and localization. The dynamic test procedures used in this study illustrate the importance of bilateral hearing for locating, identifying, and switching attention between multiple speakers. It is recommended that unilateral cochlear implant recipients, with measurable unaided hearing thresholds, be fit with a hearing aid.

Objective: This study examined the relation of electrically evoked compound action potential thresholds obtained using neural response telemetry (NRT) to T- and C-levels in children's speech processor programs optimized for recognition of very soft to loud sounds while ensuring tolerance of very loud sounds., Design: Forty-one children (age 2 to 14 yr) with stable electrical hearing participated. All children were Nucleus 24 System recipients and attended one of three auditory-oral schools that have on-site pediatric audiologists experienced at cochlear implant programming. Speech processor MAPs were created and adjusted over a period of months until aided warble-tone thresholds were between 10 and 30 dB HL at octave frequencies between 250 and 4000 Hz, and understanding of speech was maximized for many listening situations. At least 1 yr postactivation, visual (vNRT) and predicted (tNRT) thresholds were obtained on 9 to 11 electrodes and compared to each child's T- and C-level values on these electrodes in their MAPs. Test-retest stability of NRT thresholds was compared for two test sessions 1 mo apart., Results: NRT-based evoked compound action potential thresholds could be obtained from 36 of the 41 children. vNRT and tNRT test-retest reliability was high; average correlation coefficients (r) across subjects were 0.90 (range: 0.64 to 0.99) and 0.88 (range: 0.31 to 1.00), respectively. Group average correlation coefficients between vNRT and T-level, vNRT and C-level, tNRT and T-level, and tNRT and C-level were low (0.18, 0.21, 0.24, and 0.26, respectively). Group mean tNRT thresholds were four current levels lower than the group mean vNRT thresholds. Subsequent analysis was performed with the vNRT thresholds because the range of test-retest correlation coefficients for individual subjects was narrower than with tNRT. Hierarchical linear modeling was used to determine if vNRT could be used to predict T- and C-levels. This analysis indicated a significant average relation between vNRT and T-levels and between vNRT and C-levels, but significant heterogeneity in the individual-level estimates of those relations. In other words, subjects varied significantly in the size of the relation between their individual vNRT values and both T- and C-levels. Attempts to account for that heterogeneity did not identify any subject characteristics that were significantly related to the individual-level parameters., Conclusions: The position of the group average vNRT and tNRT thresholds in the upper half of the dynamic range between Ts and Cs agrees with previous studies. The fact that the profile of vNRT thresholds did not parallel the profiles of Ts and Cs across electrodes for most children suggests that simply shifting the NRT profile to select T- and C-levels in initial MAPs is likely to result in a loudness imbalance for certain speech frequencies and/or tolerance issues for many children. This was verified by the hierarchical linear modeling analysis, which showed substantial and significant heterogeneity in the relations between vNRT and T-levels and between vNRT and C-levels. In summary, vNRT is not related to T- or C-levels in a simple and uniform way that would allow it to guide MAP fine tuning with any precision. Consequently, it is recommended that MAP fine tuning be based on the child's behavioral responses on individual electrodes.

Objective: The primary purpose of this study was to determine if the contour of visual (vNRT) or predicted (tNRT) neural response telemetry (NRT) thresholds across electrodes could predict the contour of behaviorally programmed T-levels (minimum stimulation) and/or C-levels (maximum stimulation) across electrodes for well-fit MAPs. The secondary purpose was to determine the relation between NRT thresholds and loudness judgments obtained at the subject's MAP rate (250, 900, 1200, or 1800 pulses per second [pps]) and the NRT stimulus rate (80 pps)., Design: Twelve adult Nucleus 24 cochlear implant recipients participated in the study. The T- and C-levels from a preferred MAP, which had been worn for a minimum of 3 mo, were used in this study. Electrically evoked compound action potentials were measured on 11 active electrodes with NRT software (v3.0). Ascending loudness judgments from first hearing to maximum acceptable loudness were completed on these electrodes with the subject's preferred MAP rate stimulus, using the R126 (v.2.0) software and with an 80 pps rate stimulus, using the NRT software (v3.0). All measures were repeated approximately 1 mo later to determine their reliability., Results: The reliability of the behavioral and objective measures was very high from the first to the second half of the study. The mean tNRT thresholds had a lower reliability (r = 0.73) than vNRT thresholds (r = 0.91). The loudness judgment dynamic range was notably different between rates. The NRT rate (80 pps) stimulus resulted in the narrowest dynamic range followed by increasingly wider dynamic range as the MAP rate increased. The NRT thresholds had a stronger correlation with loudness judgments made with the NRT rate stimulus than with the MAP rate stimulus. The group mean NRT thresholds were significantly correlated with C-levels (vNRT r = 0.69) (tNRT r = 0.66) but not T-levels. The relation between NRT thresholds and T- and C-levels varied for different MAP rates, with the NRT thresholds being closest to the C-levels for the 250 pps MAP rate. Each subject's vNRT thresholds and MAP levels were examined by fitting a third-order polynomial to the data. This analysis revealed significant variability demonstrating that no one fit predicts T- and C-levels well for all subjects., Conclusions: The results of this study provide important insight into the relation between NRT thresholds and loudness judgments for different stimulation rates and T- and C-levels at various MAP rates. The loudness judgment dynamic range and MAP dynamic range (T- and C-levels) varied notably for different stimulation rates. As a result, the relation of NRT thresholds to these measures also varied with stimulation rate. Overall, the mean vNRT thresholds fell higher in the loudness judgment dynamic range than the tNRT thresholds. Mean NRT thresholds fell between the judgments of medium soft and maximum acceptable loudness for all stimulation rates. Mean vNRT thresholds fell above C-levels, whereas almost half of tNRT thresholds fell just below C-levels. However, the relation between NRT thresholds and C-levels varied substantially for different MAP stimulation levels. In addition, there is substantial individual variability in the relation between NRT thresholds and MAP levels that is not reflected in the group data. The prediction of the contour of T- and C-levels from the contour of NRT thresholds across electrodes would not be appropriate for half of the subjects. Therefore, great care should be taken when applying a fitting rule that incorporates NRT thresholds without considering these individual differences. For adults who can provide appropriate loudness judgments and threshold responses it appears to be most efficient to primarily use behavioral measures to create MAPs.

This article describes the major statistical analyses used in a large-scale study of prelingually deaf children implanted before 5 yr of age. Two major challenges posed by the data were the need to reduce the number of outcome measures to a reasonable number while retaining the important information underlying the multiple measures, and the need to determine the unique contributions of multiple sets of predictor variables. The approach taken-principal components analysis of the outcome measures followed by hierarchical multiple regression-provided a compromise between statistical complexity and ease of interpretation.