Longitudinal Effects of Simultaneous and Sequential Bilateral Cochlear Implantation on Cortical Auditory-Evoked Potentials Recorded at Cz in a Large Cohort of Children.

OBJECTIVES: Auditory development after bilateral cochlear implantation in children has been measured using source localization of multi-channel late latency responses. It is not clear, however, whether this development can be tracked using a more clinically feasible method of recording from one active recording electrode placed at mid-line center of the head (Cz). DESIGN: In this prospective cohort study, cortical auditory-evoked potential responses (CAEPs) were recorded from Cz referenced to each earlobe (Cz-CAEP) from 222 children with bilateral cochlear implant (CI); 128 (mean ± SD age: 2.78 ± 3.30 years) received both CIs in the same surgery (simultaneous group) and 94 (aged 7.72 ± 4.45 years) received a second CI after 4.21 ± 2.98 years of unilateral CI use. We sought to (1) identify cortical development over the first couple of years of bilateral CI use; (2) measure known asymmetries in auditory development between the CIs; and (3) detect the effects of bilateral rather than unilateral CI use. 4556 Cz-CAEPs were recorded across the cohort over 33.50 ± 7.67 months duration of bilateral CI use. Given concerns related to peak picking, amplitude areas were measured across two response time windows (50 to 199 ms and 200 to 400 ms). RESULTS: Results indicated that small response amplitudes occur at initial CI use and amplitudes increase in the negative or positive direction rapidly over the first months of CI use in both time windows. Asymmetries between Cz-CAEPs evoked by each CI were found in the sequential group and reduced with bilateral CI use, particularly in the first time window; these differences increased with longer inter-implant delay. Bilaterally evoked Cz-CAEPs were larger in amplitude than unilateral responses from either CI in the simultaneous group. In the sequential group, bilateral responses were similar to responses from the first implanted side but increased in relative amplitude with bilateral CI use. The Cz-CAEP measures were not able to predict asymmetries or bilateral benefits in speech perception measures. CONCLUSIONS: The Cz-CAEP was able to indicate cortical detection of CI input and showed gross morphological changes with bilateral CI use. Findings indicate Cz-CAEPs can be used to identify gross changes in auditory development in children with bilateral CIs, but they are less sensitive to tracking the remaining abnormalities that are measured by multi-channel CAEPs and speech perception testing.

Effects of Sequential Bilateral Cochlear Implantation in Children: Evidence from Speech-Evoked Cortical Potentials and Tests of Speech Perception.

INTRODUCTION: Benefits of bilateral cochlear implants (CI) may be compromised by delays to implantation of either ear. This study aimed to evaluate the effects of sequential bilateral CI use in children who received their first CI at young ages, using a clinical set-up. METHODS: One-channel cortical auditory evoked potentials and speech perception in quiet and noise were evoked at repeated times (0, 3, 6, 12 months of bilateral CI use) by unilateral and bilateral stimulation in 28 children with early-onset deafness. These children were unilaterally implanted before 3.69 years of age (mean ± SD of 1.98 ± 0.73 years) and received a second CI after 5.13 ± 2.37 years of unilateral CI use. Comparisons between unilaterally evoked responses were used to measure asymmetric function between the ears and comparisons between bilateral responses and each unilateral response were used to measure the bilateral benefit. RESULTS: Chronic bilateral CI promoted changes in cortical auditory responses and speech perception performance; however, large asymmetries were present between the two unilateral responses despite ongoing bilateral CI use. Persistent cortical differences between the two sides at 1 year of bilateral stimulation were predicted by increasing age at the first surgery and inter-implant delay. Larger asymmetries in speech perception occurred with longer inter-implant delays. Bilateral responses were more similar to the unilateral responses from the first rather than the second CI. CONCLUSION: These findings are consistent with the development of the aural preference syndrome and reinforce the importance of providing bilateral CIs simultaneously or sequentially with very short delays.

Optimizing Parameters for Using the Parallel Auditory Brainstem Response to Quickly Estimate Hearing Thresholds.

OBJECTIVES: Timely assessments are critical to providing early intervention and better hearing and spoken language outcomes for children with hearing loss. To facilitate faster diagnostic hearing assessments in infants, the authors developed the parallel auditory brainstem response (pABR), which presents randomly timed trains of tone pips at five frequencies to each ear simultaneously. The pABR yields high-quality waveforms that are similar to the standard, single-frequency serial ABR but in a fraction of the recording time. While well-documented for standard ABRs, it is yet unknown how presentation rate and level interact to affect responses collected in parallel. Furthermore, the stimuli are yet to be calibrated to perceptual thresholds. Therefore, this study aimed to determine the optimal range of parameters for the pABR and to establish the normative stimulus level correction values for the ABR stimuli. DESIGN: Two experiments were completed, each with a group of 20 adults (18-35 years old) with normal-hearing thresholds (≤20 dB HL) from 250 to 8000 Hz. First, pABR electroencephalographic (EEG) responses were recorded for six stimulation rates and two intensities. The changes in component wave V amplitude and latency were analyzed, as well as the time required for all responses to reach a criterion signal-to-noise ratio of 0 dB. Second, behavioral thresholds were measured for pure tones and for the pABR stimuli at each rate to determine the correction factors that relate the stimulus level in dB peSPL to perceptual thresholds in dB nHL. RESULTS: The pABR showed some adaptation with increased stimulation rate. A wide range of rates yielded robust responses in under 15 minutes, but 40 Hz was the optimal singular presentation rate. Extending the analysis window to include later components of the response offered further time-saving advantages for the temporally broader responses to low-frequency tone pips. The perceptual thresholds to pABR stimuli changed subtly with rate, giving a relatively similar set of correction factors to convert the level of the pABR stimuli from dB peSPL to dB nHL. CONCLUSIONS: The optimal stimulation rate for the pABR is 40 Hz but using multiple rates may prove useful. Perceptual thresholds that subtly change across rate allow for a testing paradigm that easily transitions between rates, which may be useful for quickly estimating thresholds for different configurations of hearing loss. These optimized parameters facilitate expediency and effectiveness of the pABR to estimate hearing thresholds in a clinical setting.

Cortical hemispheric asymmetries are present at young ages and further develop into adolescence.

Specialization of the auditory cortices for pure tone listening may develop with age. In adults, the right hemisphere dominates when listening to pure tones and music; we thus hypothesized that (a) asymmetric function between auditory cortices increases with age and (b) this development is specific to tonal rather than broadband/non-tonal stimuli. Cortical responses to tone-bursts and broadband click-trains were recorded by multichannel electroencephalography in young children (5.1 ± 0.8 years old) and adolescents (15.2 ± 1.7 years old) with normal hearing. Peak dipole moments indicating activity strength in right and left auditory cortices were calculated using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer. Monaural click-trains and tone-bursts in young children evoked a dominant response in the contralateral right cortex by left ear stimulation and, similarly, a contralateral left cortex response to click-trains in the right ear. Responses to tone-bursts in the right ear were more bilateral. In adolescents, peak activity dominated in the right cortex in most conditions (tone-bursts from either ear and to clicks from the left ear). Bilateral activity was evoked by right ear click stimulation. Thus, right hemispheric specialization for monaural tonal stimuli begins in children as young as 5 years of age and becomes more prominent by adolescence. These changes were marked by consistent dipole moments in the right auditory cortex with age in contrast to decreases in dipole activity in all other stimulus conditions. Together, the findings reveal increasingly asymmetric function for the two auditory cortices, potentially to support greater cortical specialization with development into adolescence.

Children With Single-Sided Deafness Use Their Cochlear Implant.

OBJECTIVES: To assess acceptance of a cochlear implant (CI) by children with single-sided deafness (SSD) as measured by duration of CI use across daily listening environments. DESIGN: Datalogs for 7 children aged 1.1 to 14.5 years (mean ± SD: 5.9 ± 5.9 years old), who had SSD and were implanted in their deaf ear, were anonymized and extracted from their CI processors. Data for all available follow-up clinical appointments were included, ranging from two to six visits. Measures calculated from each datalog included frequency and duration of time the coil disconnected from the internal device, average daily CI use, and both duration (hr/day) and percentage of CI use (% daily use) in different intensity ranges and environment types. Linear mixed effects regression analyses were used to evaluate the relationships between CI experience, daily CI use, frequency of coil-offs, and duration of coil-off time. Nonlinear regression analyses were used to evaluate CI use with age in different acoustic environments. RESULTS: Children with SSD used their CI on average 7.4 hr/day. Older children used their CI for longer periods of the day than younger children. Longitudinal data indicated consistent CI use from the date of CI activation. Frequency of coil-offs reduced with CI experience, but did not significantly contribute to hours of coil-off time. Children used their CI longest in environments that were moderately loud (50 to 70 dB A) and classified as containing speech-in-noise. Preschoolers tended to spend less time in quiet but more time in music than infants/toddlers and adolescents. CONCLUSIONS: Children with SSD consistently use their CI upon activation in a variety of environments commonly experienced by children. CI use in children with SSD resembles reported bilateral hearing aid use in children but is longer than reported hearing aid use in children with less severe unilateral hearing loss, suggesting that (1) the normal-hearing ear did not detract from consistent CI use; and (2) a greater asymmetry between ears presents a significant impairment that may facilitate device use to access bilateral sound.

Music perception improves in children with bilateral cochlear implants or bimodal devices.

The objectives of this study were to determine if music perception by pediatric cochlear implant users can be improved by (1) providing access to bilateral hearing through two cochlear implants or a cochlear implant and a contralateral hearing aid (bimodal users) and (2) any history of music training. The Montreal Battery of Evaluation of Musical Ability test was presented via soundfield to 26 bilateral cochlear implant users, 8 bimodal users and 16 children with normal hearing. Response accuracy and reaction time were recorded via an iPad application. Bilateral cochlear implant and bimodal users perceived musical characteristics less accurately and more slowly than children with normal hearing. Children who had music training were faster and more accurate, regardless of their hearing status. Reaction time on specific subtests decreased with age, years of musical training and, for implant users, better residual hearing. Despite effects of these factors on reaction time, bimodal and bilateral cochlear implant users' responses were less accurate than those of their normal hearing peers. This means children using bilateral cochlear implants and bimodal devices continue to experience challenges perceiving music that are related to hearing impairment and/or device limitations during development.

The effects of asymmetric hearing on bilateral brainstem function: findings in children with bimodal (electric and acoustic) hearing.

As implantation criteria are broadening to include children with asymmetric hearing loss, it is important to determine the degree of residual hearing needed to protect the bilateral auditory pathways for binaural hearing and whether there is a sensitive period in development for implantation in these children. We have been studying these questions in a growing cohort of children. In the present study, auditory brainstem responses were recorded in 21 children who had 2.2 ± 2.2 years of bimodal hearing. Responses were evoked by 11-Hz acoustic clicks presented to the non-implanted ear and with biphasic electric pulses presented to the implanted ear. Twelve of these children also completed a behavioural task in which they were asked to which side of their heads bilaterally presented clicks/pulses that varied in interaural level or timing lateralized. All children experienced a delay in the non-implanted ear that resulted in 2.0 ± 0.35 ms longer peak latencies. These were further prolonged in 7 children as measured by longer interwave latencies from this ear than from the implanted ear. Despite large asymmetries in timing of brainstem activity between the two ears, all children perceived changes in interaural level differences. They were unable to detect differences in interaural timing cues. Symmetric brainstem function suggests bilateral development was preserved in some children. Future work will explore whether these children have better potential for developing binaural hearing using bimodal input.

Fundamental frequency predominantly drives talker differences in auditory brainstem responses to continuous speech.

Deriving human neural responses to natural speech is now possible, but the responses to male- and female-uttered speech have been shown to differ. These talker differences may complicate interpretations or restrict experimental designs geared toward more realistic communication scenarios. This study found that when a male and female talker had the same fundamental frequency, auditory brainstem responses (ABRs) were very similar. Those responses became smaller and later with increasing fundamental frequency, as did click ABRs with increasing stimulus rates. Modeled responses suggested that the speech and click ABR differences were reasonably predicted by peripheral and brainstem processing of stimulus acoustics.

Exposing distinct subcortical components of the auditory brainstem response evoked by continuous naturalistic speech.

Speech processing is built upon encoding by the auditory nerve and brainstem, yet we know very little about how these processes unfold in specific subcortical structures. These structures are deep and respond quickly, making them difficult to study during ongoing speech. Recent techniques have begun to address this problem, but yield temporally broad responses with consequently ambiguous neural origins. Here, we describe a method that pairs re-synthesized 'peaky' speech with deconvolution analysis of electroencephalography recordings. We show that in adults with normal hearing the method quickly yields robust responses whose component waves reflect activity from distinct subcortical structures spanning auditory nerve to rostral brainstem. We further demonstrate the versatility of peaky speech by simultaneously measuring bilateral and ear-specific responses across different frequency bands and discuss the important practical considerations such as talker choice. The peaky speech method holds promise as a tool for investigating speech encoding and processing, and for clinical applications.

Fit to targets, preferred listening levels, and self-reported outcomes for the DSL v5.0 a hearing aid prescription for adults.

STUDY OBJECTIVE: This study evaluated how closely the DSL v5.0 a prescription could be approximated with hearing aids, its relationship to preferred listening levels (PLLs) of adults with acquired hearing loss, and the self-reported outcomes of the resulting fittings. PARTICIPANTS: Thirty adults with varying degrees and configurations of hearing loss ranging from mild to severe. METHODS: Hearing aid output was measured after the initial fitting to DSL v5.0 a targets and after determination of the PLL after approximately 90 days. The Client Oriented Scale of Improvement (COSI) was used to evaluate outcome. RESULTS: The 95% confidence interval of fits to target ranged from 5.8 to 8.4 dB across frequency. The DSL v5.0 a adult algorithm approximated the PLLs of the participants within 2.6 dB on average. Hearing aid fittings provided positive subjective outcome improvements on the COSI. CONCLUSIONS: Findings suggest that the use of DSL v5.0 a for the fitting of hearing aids on adults with acquired hearing loss was feasible and provided an appropriate initial fitting.

Consistent and chronic cochlear implant use partially reverses cortical effects of single sided deafness in children.

Potentially neuroprotective effects of CI use were studied in 22 children with single sided deafness (SSD). Auditory-evoked EEG confirmed strengthened representation of the intact ear in the ipsilateral auditory cortex at initial CI activation in children with early-onset SSD (n = 15) and late-onset SSD occurring suddenly in later childhood/adolescence (n = 7). In early-onset SSD, representation of the hearing ear decreased with chronic CI experience and expected lateralization to the contralateral auditory cortex from the CI increased with longer daily CI use. In late-onset SSD, abnormally high activity from the intact ear in the ipsilateral cortex reduced, but responses from the deaf ear weakened despite CI use. Results suggest that: (1) cortical reorganization driven by unilateral hearing can occur throughout childhood; (2) chronic and consistent CI use can partially reverse these effects; and (3) CI use may not protect children with late-onset SSD from ongoing deterioration of pathways from the deaf ear.

The Parallel Auditory Brainstem Response.

The frequency-specific tone-evoked auditory brainstem response (ABR) is an indispensable tool in both the audiology clinic and research laboratory. Most frequently, the toneburst ABR is used to estimate hearing thresholds in infants, toddlers, and other patients for whom behavioral testing is not feasible. Therefore, results of the ABR exam form the basis for decisions regarding interventions and hearing habilitation with implications extending far into the child's future. Currently, responses are elicited by periodic sequences of toneburst stimuli presented serially to one ear at a time, which take a long time to measure multiple frequencies and intensities, and provide incomplete information if the infant wakes up early. Here, we describe a new method, the parallel ABR (pABR), which uses randomly timed toneburst stimuli to simultaneously acquire ABR waveforms to five frequencies in both ears. Here, we describe the pABR and quantify its effectiveness in addressing the greatest drawback of current methods: test duration. We show that in adults with normal hearing the pABR yields high-quality waveforms over a range of intensities, with similar morphology to the standard ABR in a fraction of the recording time. Furthermore, longer latencies and smaller amplitudes for low frequencies at a high intensity evoked by the pABR versus serial ABR suggest that responses may have better place specificity due to the masking provided by the other simultaneous toneburst sequences. Thus, the pABR has substantial potential for facilitating faster accumulation of more diagnostic information that is important for timely identification and treatment of hearing loss.

Cortical plasticity with bimodal hearing in children with asymmetric hearing loss.

This longitudinal study aimed to identify auditory plasticity promoted by a cochlear implant in children with asymmetric hearing loss. Participants included 10 children who experienced (mean ±â€¯SD) 3.1 ±â€¯3.6 years of asymmetric hearing (difference of 47.2 ±â€¯47.6 dB) before receiving an implant at age 8.7 ±â€¯5.1 years. Multi-channel electroencephalography was measured at initial implant use (5.8 ±â€¯3.2 days) and after 10.2 ±â€¯4.1 months in each child. Monaurally presented stimuli consisted of 36 ms trains of 9 acoustic clicks/biphasic electric pulses at a rate of 250 Hz, repeated at 1 Hz. The time-restricted artifact and coherent source suppression (TRACS) beamformer was used to locate sources underlying peak amplitudes of cortical responses. Results indicated consistent activity from the non-implanted ear but significant implant-driven changes to the auditory cortices. Initially, the newly implanted ear evoked activity which strongly lateralized to the ipsilateral auditory cortex and contributed to a significant aural preference for implant stimulation in children with limited acoustic experience pre-implantation. Cochlear implant use reversed these abnormalities, but the resolution was limited in children with longer periods of asymmetric hearing. These findings suggest that early implantation of children with asymmetric hearing rapidly restores hemispheric representations of bilateral auditory input in the auditory cortex. Most recorded changes were isolated to pathways stimulated by the cochlear implant, potentially reflecting an abnormal independence of the bilateral pathways with possible consequences for binaural integration in these bimodal listeners.

Vestibular and balance function is often impaired in children with profound unilateral sensorineural hearing loss.

RATIONALE: Children with unilateral deafness could have concurrent vestibular dysfunction which would be associated with balance deficits and potentially impair overall development. The prevalence of vestibular and balance deficits remains to be defined in these children. METHODS: Twenty children with unilateral deafness underwent comprehensive vestibular and balance evaluation. RESULTS: Retrospective review revealed that more than half of the cohort demonstrated some abnormality of the vestibular end organs (otoliths and horizontal canal), with the prevalence of end organ specific dysfunction ranging from 17 to 48% depending on organ tested and method used. In most children, impairment occurred only on the deaf side. Children with unilateral deafness also displayed significantly poorer balance function than their normal hearing peers. CONCLUSIONS: The prevalence of vestibular dysfunction in children with unilateral deafness is high and similar to that of children with bilateral deafness. Vestibular and balance evaluation should be routine and the functional impact of combined vestibulo-cochlear sensory deficits considered.

Music Perception Testing Reveals Advantages and Continued Challenges for Children Using Bilateral Cochlear Implants.

A modified version of the child's Montreal Battery of Evaluation of Amusia (cMBEA) was used to assess music perception in children using bilateral cochlear implants. Our overall aim was to promote better performance by children with CIs on the cMBEA by modifying the complement of instruments used in the test and adding pieces transposed in frequency. The 10 test trials played by piano were removed and two high and two low frequency trials added to each of five subtests (20 additional). The modified cMBEA was completed by 14 children using bilateral cochlear implants and 23 peers with normal hearing. Results were compared with performance on the original version of the cMBEA previously reported in groups of similar aged children: 2 groups with normal hearing (n = 23: Hopyan et al., 2012; n = 16: Polonenko et al., 2017), 1 group using bilateral cochlear implants (CIs) (n = 26: Polonenko et al., 2017), 1 group using bimodal (hearing aid and CI) devices (n = 8: Polonenko et al., 2017), and 1 group using unilateral CI (n = 23: Hopyan et al., 2012). Children with normal hearing had high scores on the modified version of the cMBEA and there were no significant score differences from children with normal hearing who completed the original cMBEA. Children with CIs showed no significant improvement in scores on the modified cMBEA compared to peers with CIs who completed the original version of the test. The group with bilateral CIs who completed the modified cMBEA showed a trend toward better abilities to remember music compared to children listening through a unilateral CI but effects were smaller than in previous cohorts of children with bilateral CIs and bimodal devices who completed the original cMBEA. Results confirmed that musical perception changes with the type of instrument and is better for music transposed to higher rather than lower frequencies for children with normal hearing but not for children using bilateral CIs. Overall, the modified version of the cMBEA revealed that modifications to music do not overcome the limitations of the CI to improve music perception for children.

Delayed access to bilateral input alters cortical organization in children with asymmetric hearing.

Bilateral hearing in early development protects auditory cortices from reorganizing to prefer the better ear. Yet, such protection could be disrupted by mismatched bilateral input in children with asymmetric hearing who require electric stimulation of the auditory nerve from a cochlear implant in their deaf ear and amplified acoustic sound from a hearing aid in their better ear (bimodal hearing). Cortical responses to bimodal stimulation were measured by electroencephalography in 34 bimodal users and 16 age-matched peers with normal hearing, and compared with the same measures previously reported for 28 age-matched bilateral implant users. Both auditory cortices increasingly favoured the better ear with delay to implanting the deaf ear; the time course mirrored that occurring with delay to bilateral implantation in unilateral implant users. Preference for the implanted ear tended to occur with ongoing implant use when hearing was poor in the non-implanted ear. Speech perception deteriorated with longer deprivation and poorer access to high-frequencies. Thus, cortical preference develops in children with asymmetric hearing but can be avoided by early provision of balanced bimodal stimulation. Although electric and acoustic stimulation differ, these inputs can work sympathetically when used bilaterally given sufficient hearing in the non-implanted ear.

Limiting asymmetric hearing improves benefits of bilateral hearing in children using cochlear implants.

Neurodevelopmental changes occur with asymmetric hearing loss, limiting binaural/spatial hearing and putting children at risk for social and educational challenges. These deficits may be mitigated by providing bilateral hearing in children through auditory prostheses. Effects on speech perception and spatial hearing were measured in a large cohort of >450 children who were deaf and used bilateral cochlear implants or bimodal devices (one cochlear implant and a contralateral hearing aid). Results revealed an advantage of bilateral over unilateral device use but this advantage decreased as hearing in the two ears became increasingly asymmetric. Delayed implantation of an ear with severe to profound deafness allowed asymmetric hearing, creating aural preference for the better hearing ear. These findings indicate that bilateral input with the most appropriate device for each ear should be provided early and without delay during development.

Cortical organization restored by cochlear implantation in young children with single sided deafness.

Early treatment of single sided deafness in children has been recommended to protect from neurodevelopmental preference for the better hearing ear and from social and educational deficits. A fairly homogeneous group of five young children (≤3.6 years of age) with normal right sided hearing who received a cochlear implant to treat deafness in their left ears were studied. Etiology of deafness was largely cytomegalovirus (n = 4); one child had an enlarged vestibular aqueduct. Multi-channel electroencephalography of cortical evoked activity was measured repeatedly over time at: 1) acute (0.5 ± 0.7 weeks); 2) early chronic (1.1 ± 0.2 months); and 3) chronic (5.8 ± 3.4 months) cochlear implant stimulation. Results indicated consistent responses from the normal right ear with marked changes in activity from the implanted left ear. Atypical distribution of peak amplitude activity from the implanted ear at acute stimulation marked abnormal lateralization of activity to the ipsilateral left auditory cortex and recruitment of extra-temporal areas including left frontal cortex. These abnormalities resolved with chronic implant use and contralateral aural preference emerged in both auditory cortices. These findings indicate that early implantation in young children with single sided deafness can rapidly restore bilateral auditory input to the cortex needed to improve binaural hearing.

Binaural integration: a challenge to overcome for children with hearing loss.

PURPOSE OF REVIEW: Access to bilateral hearing can be provided to children with hearing loss by fitting appropriate hearing devices to each affected ear. It is not clear, however, that bilateral input is properly integrated through hearing devices to promote binaural hearing. In the present review, we examine evidence indicating that abnormal binaural hearing continues to be a challenge for children with hearing loss despite early access to bilateral input. RECENT FINDINGS: Behavioral responses and electrophysiological data in children, combined with data from developing animal models, reveal that deafness in early life disrupts binaural hearing and that present hearing devices are unable to reverse these changes and/or promote expected development. Possible limitations of hearing devices include mismatches in binaural place, level, and timing of stimulation. Such mismatches could be common in children with hearing loss. One potential solution is to modify present device fitting beyond providing audibility to each ear by implementing binaural fitting targets. SUMMARY: Efforts to better integrate bilateral input could improve spatial hearing in children with hearing loss.

Hearing Benefit and Rated Satisfaction in Children with Unilateral Conductive Hearing Loss Using a Transcutaneous Magnetic-Coupled Bone-Conduction Hearing Aid.

BACKGROUND: Bilateral hearing is important for learning, development, and function in complex everyday environments. Children with conductive and mixed hearing loss (HL) have been treated for years with percutaneous coupling through an abutment, which achieves powerful output, but the implant site is susceptible to skin reactions and trauma. To overcome these complications, transcutaneous magnetic coupling systems were recently introduced. PURPOSE: The purpose of the study was to evaluate whether the new transcutaneous magnetic coupling is an effective coupling paradigm for bone-conduction hearing aids (BCHAs). We hypothesized that magnetic coupling will (1) have limited adverse events, (2) provide adequate functional gain, (3) improve spatial hearing and aid listening in everyday situations, and (4) provide satisfactory outcomes to children and their families given one normal hearing ear. RESEARCH DESIGN: Retrospective analysis of audiological outcomes in a tertiary academic pediatric hospital. STUDY SAMPLE: Nine children aged 5-17 yr with permanent unilateral conductive HL (UCHL) or mixed HL were implanted with a transcutaneous magnet-retained BCHA. Average hearing thresholds of the better and implanted ears were 12.3 ± 11.5 dB HL and 69.1 ± 11.6 dB HL, respectively, with a 59.4 ± 4.8 dB (mean ± standard deviation) conductive component. DATA COLLECTION AND ANALYSIS: Data were extracted from audiology charts of the children with permanent UCHL or mixed HL who qualified for a surgically retained BCHA and agreed to the magnetic coupling. Outcomes were collected from the 3- to 9-mo follow-up appointments, and included surgical complications, aided audiometric thresholds with varying magnet strength, speech performance in quiet and noise, and patient-rated benefit and satisfaction using questionnaires. Repeated measures analysis of variance was used to analyze audiometric outcomes, and nonparametric tests were used to evaluate rated benefit and satisfaction. RESULTS: All nine children tolerated the device and only one child had discomfort at the wound site. Similar access to sound was achieved regardless of magnet strength. Speech performance did not significantly improve in quiet or noise conditions with +10 and +5 dB signal-to-noise ratio. Children benefited from spatially separating the noise from the speech signal, regardless of whether the noise was directed to the implanted or better ear. When wearing the BCHA, the children reported satisfaction and significant implant benefit, particularly in background noise, but at the expense of increased aversiveness to sound. CONCLUSIONS: Our findings, therefore, indicate that providing a transcutaneous magnetic-coupled BCHA to children who have UCHL or mixed HL provides benefit on some objective measures of bilateral hearing, as well as some subjective benefit in noise and everyday situations.