Mandy Hill

Binaural benefits for adults who use hearing aids and cochlear implants in opposite ears.

Objective This study aimed to investigate 1) how a hearing aid needs to be adjusted for an adult who uses a cochlear implant in the contralateral ear; 2) whether the use of a hearing aid with a cochlear implant leads to interference; and 3) whether adults derive binaural benefits from using a hearing aid with a cochlear implant for speech perception, localization, and functional performance in everyday life. Design Twenty-one adults (11 female and 10 male) who used either a Nucleus CI-22 (N = 3) or a Nucleus CI-24 (N = 18) cochlear implant system in one ear participated in this study. Twelve of the adults were experienced hearing aid and implant users, whereas nine did not use a hearing aid after implantation. The hearing aids were fitted using the NAL-NL1 prescription, and fine-tuned for each individual by using a paired-comparisons test to identify the frequency response that was best for understanding speech, and a loudness balancing test to find the hearing aid gain that gave the same overall loudness as that perceived in the ear with a cochlear implant. Effects from using a hearing aid with a cochlear implant (bimodal hearing) were assessed by three measures. These included speech perception in noise in diotic and dichotic listening conditions, horizontal localization, and functional performance in everyday life. Performance with cochlear implant and hearing aid (CIHA) was compared with that with cochlear implant alone (CI) and hearing aid alone (HA). Results The NAL-NL1 prescribed appropriate frequency response slope on average, and the mean gain needed for binaural loudness balance was 4 dB lower than the prescribed gain. Individual variations in preferences suggest that it is desirable to fine-tune the hearing aid response slope and gain according to individual needs. The speech test results indicated that the CIHA scores were significantly better than the CI or the HA scores. Localization test results showed that the adults made significantly less error when locating a sound source using CIHA compared with CI or HA. Functional performance questionnaire scores for CIHA were significantly higher than CI scores or HA scores. All adults showed binaural benefits in at least one performance measure. On average, those who derived greater speech benefits also made less localization error and functioned more effectively in real life. Conclusions The results clearly indicate that binaural advantages can be obtained from using a hearing aid with a cochlear implant in opposite ears. It is recommended that bimodal stimulation be standard practice for rehabilitation of adults who wear unilateral cochlear implants. A hearing aid should be fitted to the nonimplanted ear using the NAL-NL1 prescription as a starting point, and the frequency response slope and gain could be fine-tuned to suit individual needs.

Should children who use cochlear implants wear hearing aids in the opposite ear

Objective The aim of this study was to investigate 1) whether a hearing aid needs to be adjusted differently depending on whether a child wears a cochlear implant or another hearing aid in the contralateral ear; 2) whether the use of a hearing aid and a cochlear implant in opposite ears leads to binaural interference; and 3) whether the use of a hearing aid and a cochlear implant in opposite ears leads to binaural benefits in speech perception, localization, and communicative functioning in real life. Design Sixteen children participated in this study. All children used a Nucleus 22 or Nucleus 24 cochlear implant system programmed with the SPEAK strategy in one ear. The hearing aid amplification requirements in the nonimplanted ear of these children were determined using two procedures. A paired comparison technique was used to identify the frequency response that was best for speech intelligibility in quiet, and a loudness balancing technique was used to match the loudness of speech in the ear with a hearing aid to that with a cochlear implant. Eleven of the 16 children participated in the investigation of binaural effects. Performance in speech perception, localization, and communicative functioning was assessed under four aided conditions: cochlear implant with hearing aid as worn, cochlear implant alone, hearing aid alone, and cochlear implant with hearing aid adjusted according to individual requirements. Results Fifteen of the 16 children whose amplification requirements were determined preferred a hearing aid frequency response that was within ±6 dB/octave of the NAL-RP prescription. On average, the children required 6 dB more gain than prescribed to balance the loudness of the implanted ear for a speech signal presented at 65 dB SPL. For all 11 children whose performance was evaluated for investigating binaural effects, there was no indication of significantly poorer performance under bilaterally aided conditions compared with unilaterally aided conditions. On average, there were significant benefits in speech perception, localization, and aural/oral function when the children used cochlear implants with adjusted hearing aids than when they used cochlear implants alone. All individuals showed benefits in at least one of the measures. Conclusions Hearing aids for children who also use cochlear implants can be selected using the NAL-RP prescription. Adjustment of hearing aid gain to match loudness in the implanted ear can facilitate integration of signals from both ears, leading to better speech perception. Given that there are binaural advantages from using cochlear implants with hearing aids in opposite ears, clinicians should advise parents and other professionals about these potential advantages, and facilitate bilateral amplification by adjusting hearing aids after stable cochlear implant MAPs are established.

An Overview of Binaural Advantages for Children and Adults Who Use Binaural/Bimodal Hearing Devices

Aim: The aim of this paper was to summarize the binaural advantages for sentence perception in noise and sound localization obtained by children and adults who wore a cochlear implant (CI) and a hearing aid in opposite ears (bimodal hearing devices). Patients and Methods: We evaluated the speech perception and sound localization ability of 29 children and 21 adults who received a Nucleus CI system in one ear and wore a hearing aid in the other ear. All subjects used hearing aids that were adjusted systematically to complement their CIs. Performance with a CI and a hearing aid was compared with that with a CI alone. Results: On average, both children and adults derived binaural advantages relating to binaural redundancy and head shadow for sentence perception in noise. Neither the degree of hearing loss nor the duration of use of bimodal hearing devices was significantly related to the amount of binaural speech benefits. Both groups also located sounds better with CI and a hearing aid than with CI alone. Conclusions: The evidence supports the implementation of binaural/bimodal fittings as the standard management of children and adults who receive a unilateral CI and who have residual hearing in the nonimplanted ear.

Binaural redundancy and inter-aural time difference cues for patients wearing a cochlear implant and a hearing aid in opposite ears.

We investigated speech perception advantages arising from the use of inter-aural time difference cues, and from the provision of redundant information by the use of a hearing aid contralateral to a cochlear implant (bimodal hearing devices). Thirty-eight subjects (14 normally hearing and 23 hearing-impaired) participated in this study. The effect of binaural redundancy was assessed by comparing the signal-to-noise ratio (SNR) required for 50% correct identification of sentences in noise when listening monaurally to that when listening binaurally. The use of inter-aural time difference cues was determined by comparing the binaural SNRs obtained with or without a noise delay of 700 µs between ears. Results indicated adults who used bimodal hearing devices benefited from binaural redundancy, but children did not. Whereas normally hearing subjects used inter-aural time difference cues to improve speech perception in noise, neither adults nor children who used bimodal hearing devices were able to do so.

The effect of auditory experience on speech perception, localization, and functional performance of children who use a cochlear implant and a hearing aid in opposite ears

This study was aimed at determining the effect of auditory experience on binaural benefits from using a cochlear implant and a hearing aid in opposite ears. Eighteen children were evaluated using tests of speech perception, horizontal localization, and functional performance when they used either a cochlear implant alone (CI) or a cochlear implant with a hearing aid (CIHA). Eight were experienced CIHA users, whereas ten had not worn a hearing aid in the non-implanted ear for up to eight years prior to participation. All children were fitted with a hearing aid in the non-implanted ear using the NAL–RP prescription, and the hearing aids were fine-tuned individually using a paired-comparisons procedure and a loudness balancing test. Evaluation results indicated that performance for all measures was significantly better with CIHA than with CI for both groups of children. We conclude that children who receive a unilateral cochlear implant should be encouraged to wear a hearing aid in the opposite ear where there is usable residual hearing. Sumario El propósito de este estudio fue determinar el efecto de la experiencia auditiva sobre los beneficios binaurales al utilizar un implante coclear y un auxiliar auditivo en oídos opuestos. Se evaluó a dieciocho niños por medio de pruebas de percepción del lenguaje, de localización horizontal, y de desempeño funcional cuando utilizaban el implante coclear (CI) aisladamente, o un implante coclear con un auxiliar auditivo (CIHA). Ocho eran usuarios con experiencia en CIHA, mientras que ocho nunca había usado un auxiliar auditivo en el oído no implantado hasta 8 años antes de su participación. A todos los niños se les adaptó un auxiliar auditivo en el oído no implantado usando la prescripción NAL-RP, y éste fue configurado individualmente utilizando un procedimiento de comparaciones pareadas y una prueba de balance de la sonoridad. Los resultados de las evaluaciones indicaron que el desempeño en todas las medidas fue significativamente mejor con CIHA que con el CI para ambos grupos de niños. Concluimos que los niños que reciben un implante coclear unilateral deben ser motivados a usar un auxiliar auditivo en el oído opuesto cuando exista una audición residual utilizable.

Performance in children with hearing aids or cochlear implants: Bilateral stimulation and binaural hearing

It is well recognised that normal hearing people use their hearing in both ears to locate sounds and to understand speech in complex listening conditions. Whereas it is standard practice to provide two hearing aids to children with bilateral hearing loss, the situation with cochlear implantation is less certain. Questions remain as to what binaural aided functioning is possible for children who use a hearing aid and a cochlear implant in opposite ears (bimodal hearing). The first part of this paper draws on research at the National Acoustic Laboratories to show that children who used bimodal hearing devices obtained binaural advantages in localization. They could also take advantage of head shadow and binaural redundancy for speech intelligibility. The second part presents data showing that some hearing-impaired children may have binaural processing deficits even when bilateral stimulation is provided. Additional strategies may be necessary to develop or enable the use of binaural cues by these children.

Effect of variations in hearing-aid frequency response on real-life functional performance of children with severe or profound hearing loss

This study examined the effect of variations in hearing-aid frequency response on real-life functional performance of children with severe to profound hearing loss. A cross-over design was used in a double-blind comparison of the NAL prescription with alternatives that produced either a BOOST or a CUT (6dB/octave from 0.5 to 2kHz), relative to the NAL response. The functional performance of 30 children (aged 7 months to 16 years) when wearing hearing aids adjusted to each response over two to four weeks was assessed by using parents’ and teachers’ observations (PEACH and TEACH scales). Intelligibility judgments and self-reports were also obtained from school-aged children. Results indicated that on average, variations in frequency response resulted in differences in functional performance in real life. There were significant correlations between PEACH and TEACH, and also between childrens intelligibility judgments and subjective reports from children and their parents and teachers. The findings support the use of the NAL response for initial fitting, and the evaluation of childrens amplification needs by a systematic use of parents’ and teachers’ observations.

Would children who did not wear a hearing aid after implantation benefit from using a hearing aid with a cochlear implant in opposite ears

Our study revealed that the mechanism underlying the perception of environmental sounds in postlingually deafened patients with cochlear implants is not perfect even in the closed set and it is not different between patients with cochlear implant and auditory nerve disease. However, it is clear that patients with cochlear implants are completely different from patients with cortical deafness and the perception is better. This result demonstrates that the auditory mechanism in patients with cochlear implants has a certain limitation regarding perception of environmental sounds. Perceptive ability of environmental sounds in patients with cochlear implants is similar to auditory nerve disease but completely different from cortical deafness. This suggests that the perceptive mechanism of cochlear implant in adults with acquired deafness is not cognitive disorder but perceptive disorder in the cochlear nerve.