Hearing preservation in paediatric cochlear implantation with the Nucleus Slim Straight Electrode - our experience.

OBJECTIVE: to evaluate the levels of successful hearing preservation and preservation of functional hearing following cochlear implantation (HPCI) in children using the Cochlear Nucleus® Slim Straight Electrode (SSE). DESIGN: retrospective case note review of paediatric HPCI cases in our CI centre from 2013 to 2023. Inclusion criteria were attempted hearing preservation surgery, SSE used for implantation, pre-operative hearing thresholds ≤80dBHL at 250 Hz, CI before 18 years of age. Patients were excluded if no postoperative unaided PTA was obtained (poor attendance). Primairy outcome was hearing preservation using the HEARRING group formula; secondary outcome was residual functional hearing (≤80dBHL at 250 Hz/<90dB LFPTA). STUDY SAMPLE: 56 patients with 94 CI's were included for review. RESULTS: Hearing preservation was achieved in 94.7% (89/94) of ears and complete preservation in 72% (68/94)). Average functional hearing was preserved in 89% using both criteria for preservation. Long-term follow up data was available for 36 ears (average 35.2 months), demonstrating 88.9% (32/36) complete preservation. CONCLUSION: We have reliably achieved and maintained a high success rate of HPCI using the SSE in our paediatric population. The field of HPCI would benefit from unification of outcome reporting in order to optimise the evidence available to professionals, patients and their carers.

Aided Cortical Auditory Evoked Potentials in Infants With Frequency-Specific Synthetic Speech Stimuli: Sensitivity, Repeatability, and Feasibility.

OBJECTIVES: The cortical auditory evoked potential (CAEP) test is a candidate for supplementing clinical practice for infant hearing aid users and others who are not developmentally ready for behavioral testing. Sensitivity of the test for given sensation levels (SLs) has been reported to some degree, but further data are needed from large numbers of infants within the target age range, including repeat data where CAEPs were not detected initially. This study aims to assess sensitivity, repeatability, acceptability, and feasibility of CAEPs as a clinical measure of aided audibility in infants. DESIGN: One hundred and three infant hearing aid users were recruited from 53 pediatric audiology centers across the UK. Infants underwent aided CAEP testing at age 3 to 7 months to a mid-frequency (MF) and (mid-)high-frequency (HF) synthetic speech stimulus. CAEP testing was repeated within 7 days. When developmentally ready (aged 7-21 months), the infants underwent aided behavioral hearing testing using the same stimuli, to estimate the decibel (dB) SL (i.e., level above threshold) of those stimuli when presented at the CAEP test sessions. Percentage of CAEP detections for different dB SLs are reported using an objective detection method (Hotellings T 2 ). Acceptability was assessed using caregiver interviews and a questionnaire, and feasibility by recording test duration and completion rate. RESULTS: The overall sensitivity for a single CAEP test when the stimuli were ≥0 dB SL (i.e., audible) was 70% for the MF stimulus and 54% for the HF stimulus. After repeat testing, this increased to 84% and 72%, respectively. For SL >10 dB, the respective MF and HF test sensitivities were 80% and 60% for a single test, increasing to 94% and 79% for the two tests combined. Clinical feasibility was demonstrated by an excellent >99% completion rate, and acceptable median test duration of 24 minutes, including preparation time. Caregivers reported overall positive experiences of the test. CONCLUSIONS: By addressing the clinical need to provide data in the target age group at different SLs, we have demonstrated that aided CAEP testing can supplement existing clinical practice when infants with hearing loss are not developmentally ready for traditional behavioral assessment. Repeat testing is valuable to increase test sensitivity. For clinical application, it is important to be aware of CAEP response variability in this age group.

Speech Auditory Brainstem Responses: Effects of Background, Stimulus Duration, Consonant-Vowel, and Number of Epochs.

OBJECTIVES: The aims of this study were to systematically explore the effects of stimulus duration, background (quiet versus noise), and three consonant-vowels on speech-auditory brainstem responses (ABRs). Additionally, the minimum number of epochs required to record speech-ABRs with clearly identifiable waveform components was assessed. The purpose was to evaluate whether shorter duration stimuli could be reliably used to record speech-ABRs both in quiet and in background noise to the three consonant-vowels, as opposed to longer duration stimuli that are commonly used in the literature. Shorter duration stimuli and a smaller number of epochs would require shorter test sessions and thus encourage the transition of the speech-ABR from research to clinical practice. DESIGN: Speech-ABRs in response to 40 msec [da], 50 msec [ba] [da] [ga], and 170 msec [ba] [da] [ga] stimuli were collected from 12 normal-hearing adults with confirmed normal click-ABRs. Monaural (right-ear) speech-ABRs were recorded to all stimuli in quiet and to 40 msec [da], 50 msec [ba] [da] [ga], and 170 msec [da] in a background of two-talker babble at +10 dB signal to noise ratio using a 2-channel electrode montage (Cz-Active, A1 and A2-reference, Fz-ground). Twelve thousand epochs (6000 per polarity) were collected for each stimulus and background from all participants. Latencies and amplitudes of speech-ABR peaks (V, A, D, E, F, O) were compared across backgrounds (quiet and noise) for all stimulus durations, across stimulus durations (50 and 170 msec) and across consonant-vowels ([ba], [da], and [ga]). Additionally, degree of phase locking to the stimulus fundamental frequency (in quiet versus noise) was evaluated for the frequency following response in speech-ABRs to the 170 msec [da]. Finally, the number of epochs required for a robust response was evaluated using Fsp statistic and bootstrap analysis at different epoch iterations. RESULTS: Background effect: the addition of background noise resulted in speech-ABRs with longer peak latencies and smaller peak amplitudes compared with speech-ABRs in quiet, irrespective of stimulus duration. However, there was no effect of background noise on the degree of phase locking of the frequency following response to the stimulus fundamental frequency in speech-ABRs to the 170 msec [da]. Duration effect: speech-ABR peak latencies and amplitudes did not differ in response to the 50 and 170 msec stimuli. Consonant-vowel effect: different consonant-vowels did not have an effect on speech-ABR peak latencies regardless of stimulus duration. Number of epochs: a larger number of epochs was required to record speech-ABRs in noise compared with in quiet, and a smaller number of epochs was required to record speech-ABRs to the 40 msec [da] compared with the 170 msec [da]. CONCLUSIONS: This is the first study that systematically investigated the clinical feasibility of speech-ABRs in terms of stimulus duration, background noise, and number of epochs. Speech-ABRs can be reliably recorded to the 40 msec [da] without compromising response quality even when presented in background noise. Because fewer epochs were needed for the 40 msec [da], this would be the optimal stimulus for clinical use. Finally, given that there was no effect of consonant-vowel on speech-ABR peak latencies, there is no evidence that speech-ABRs are suitable for assessing auditory discrimination of the stimuli used.

Speech-ABRs in cochlear implant recipients: feasibility study.

Objective: The aim of this study was to assess the feasibility of recording speech-ABRs from cochlear implant (CI) recipients, and to remove the artefact using a clinically applicable single-channel approach. Design: Speech-ABRs were recorded to a 40 ms [da] presented via loudspeaker using a two-channel electrode montage. Additionally, artefacts were recorded using an artificial-head incorporating a MED-EL CI with stimulation parameters as similar as possible to those of three MED-EL participants. A single-channel artefact removal technique was applied to all responses. Study sample: A total of 12 adult CI recipients (6 Cochlear Nucleus and 6 MED-EL CIs). Results: Responses differed according to the CI type, artefact removal resulted in responses containing speech-ARB characteristics in two MED-EL CI participants; however, it was not possible to verify whether these were true responses or were modulated by artefacts, and artefact removal was successful from the artificial-head recordings. Conclusions: This is the first study that attempted to record speech-ABRs from CI recipients. Results suggest that there is a potential for application of a single-channel approach to artefact removal. However, a more robust and adaptive approach to artefact removal that includes a method to verify true responses is needed.

Beyond motivation: identifying targets for intervention to increase hearing aid use in adults.

OBJECTIVE: The present study investigated: (a) how motivated patients are to use their hearing aid, and (b) whether post-motivational variables (e.g. action planning, coping planning) have anything to offer in terms of developing interventions to boost hearing aid use. DESIGN: participants completed a questionnaire designed to tap Health Action Process Approach constructs prior to their hearing aid prescription and fitting. STUDY SAMPLE: Sixty-seven patients attending NHS audiology clinics. RESULTS: Participants reported very strong intentions to use hearing aids (Median = 7.00 Q1 and Q3 = 6.67, 7.00, on a +1 to +7 scale) and high self-efficacy (Median = 7.00, Q1 and Q3 = 6.00, on a +1 to +7 scale) leaving little room for improvement. In contrast, participants reported moderate levels of post-motivational variables (action planning Median = 4.25, Q1 and Q3 = 1.13, 7.00 and coping planning Median = 2.75, Q1 and Q3 = 1.00, both measured on +1 to +7 scales) thereby showing significant scope for change. CONCLUSIONS: Future interventions to increase hearing aid use should focus on ensuring that patients' motivation is translated into action, rather than further trying to boost motivation.

Electrode Selection and Speech Understanding in Patients With Auditory Brainstem Implants.

OBJECTIVES: The objective of this study was to evaluate whether speech understanding in auditory brainstem implant (ABI) users who have a tumor pathology could be improved by the selection of a subset of electrodes that were appropriately pitch ranked and distinguishable. It was hypothesized that disordered pitch or spectral percepts and channel interactions may contribute significantly to the poor outcomes in most ABI users. DESIGN: A single-subject design was used with five participants. Pitch ranking information for all electrodes in the patients' clinic maps was obtained using a pitch ranking task and previous pitch ranking information from clinic sessions. A multidimensional scaling task was used to evaluate the stimulus space evoked by stimuli on the same set of electrodes. From this information, a subset of four to six electrodes was chosen and a new map was created, using just this subset, that the subjects took home for 1 month's experience. Closed-set consonant and vowel perception and sentences in quiet were tested at three sessions: with the clinic map before the test map was given, after 1 month with the test map, and after an additional 2 weeks with their clinic map. RESULTS: The results of the pitch ranking and multidimensional scaling procedures confirmed that the ABI users did not have a well-ordered set of percepts related to electrode position, thus supporting the proposal that difficulty in processing of spectral information may contribute to poor speech understanding. However, none of the subjects benefited from a map that reduced the stimulation electrode set to a smaller number of electrodes that were well ordered in place pitch. CONCLUSIONS: Although poor spectral processing may contribute to poor understanding in ABI users, it is not likely to be the sole contributor to poor outcomes.

Progress of hearing loss in neurofibromatosis type 2: implications for future management.

The objective of this study was to describe changes in hearing over time in patients with neurofibromatosis type 2 (NF2) treated conservatively. A retrospective case review was conducted in a tertiary referral centre. Pure tone audiometry, speech discrimination scores, serviceable hearing (American Academy of Otolaryngology class A or B) and measurement of vestibular schwannoma (VS) size on magnetic resonance imaging were evaluated in 56 patients (89 ears) with NF2 with at least one conservatively managed VS. Over a mean follow-up period of 7 years (range 0.8-21 years) pure tone average thresholds increased gradually with a mean annual rate of 1.3 dB for the right ear (p = 0.0003) and 2 dB for the left ear (p = 0.0009). Speech discrimination scores dropped with an average annual rate of 1.3 and 0.34% in the right and left ear, respectively. Patients maintained serviceable hearing for an average of 7.6 years (range 2.7-19.3 years). The average annual VS growth was 0.4 mm without any correlation with hearing loss. There was a correlation between patients' age and pure tone threshold increase (p < 0.05 for both ears). In this selected population of patients with NF2, hearing threshold increases were very slow. In NF2 patients with indolently behaving tumours, serviceable hearing can be maintained for a significant length of time, making conservative management an attractive option.

Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial.

BACKGROUND: Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear. However, the indiscriminate routing of signals to a single ear can have detrimental effects when interfering sounds are located on the side of the impaired ear. Recent published evidence has suggested that cochlear implantation in individuals with a single-sided deafness can restore access to the binaural cues which underpin the ability to localise sounds and segregate speech from other interfering sounds. METHODS/DESIGN: The current trial was designed to assess the efficacy of cochlear implantation compared to a contra-lateral routing of signals hearing aid in restoring binaural hearing in adults with acquired single-sided deafness. Patients are assessed at baseline and after receiving a contra-lateral routing of signals hearing aid. A cochlear implant is then provided to those patients who do not receive sufficient benefit from the hearing aid. This within-subject longitudinal design reflects the expected care pathway should cochlear implantation be provided for single-sided deafness on the UK National Health Service. The primary endpoints are measures of binaural hearing at baseline, after provision of a contra-lateral routing of signals hearing aid, and after cochlear implantation. Binaural hearing is assessed in terms of the accuracy with which sounds are localised and speech is perceived in background noise. The trial is also designed to measure the impact of the interventions on hearing- and health-related quality of life. DISCUSSION: This multi-centre trial was designed to provide evidence for the efficacy of cochlear implantation compared to the contra-lateral routing of signals. A purpose-built sound presentation system and established measurement techniques will provide reliable and precise measures of binaural hearing. TRIAL REGISTRATION: Current Controlled Trials http://www.controlled-trials.com/ISRCTN33301739 (05/JUL/2013).

Blinded comparison of computed tomography, ultrasound and needle methods to measure skin flap thickness for cochlear implantation.

PURPOSE: Patient suitability for cochlear implant (CI) devices compatible with magnetic resonance imaging and CI processor configuration is dependent on their retro-auricular skin flap thickness. This is typically measured intra-operatively using a needle and therefore patients are not guaranteed their implant of choice prior to surgery. We aimed to identify an accurate method to measure skin flap thickness pre-operatively to streamline CI selection and simplify the consent process. METHODS: Blinded prospective skin flap thickness measurements for patients undergoing CI surgery were recorded using pre-operative computed tomography (CT) and ultrasound (US), and intraoperative needle measurement. RESULTS: Fifty-six adult patients (36 females, 20 males; mean age 59 years) were included. The mean flap thickness was measured highest by CT (6.9 mm, 95% CI 6.5-7.3 mm), followed by US (6.3 mm, 95% CI 5.9-6.7 mm) and lastly needle (5.5 mm, 95% CI 5.1-5.9 mm) (p < 0.0001). A strong positive correlation (p < 0.001) was noted between all three modalities: CT vs needle (r = 0.869), US vs needle (r = 0.865), and CT vs US (r = 0.849). CONCLUSION: Accurate, non-invasive measurement of skin flap thickness prior to CI surgery can be achieved using CT or US. We recommend the routine use of US in the outpatient clinic to minimise unnecessary radiation exposure.

Worldwide Variation in Cochlear Implant Candidacy.

BACKGROUND: The aim of this study was to find out how candidacy criteria have evolved differently across the globe. METHODS: Candidacy criteria and outcome measurements applied in 19 HEARRING clinics were analyzed. RESULTS: Candidacy criteria vary between clinics. Overall, both bilateral implantation and cochlear implantation in patients with single-sided deafness are becoming more frequent. CONCLUSION: Standardized outcome measurement instruments need to be applied to provide access to the hearing world to all patients with hearing loss who would benefit from cochlear implantation.

Cochlear Implantation in Neurofibromatosis Type 2: Experience From the UK Neurofibromatosis Type 2 Service.

OBJECTIVE: To review the outcomes of cochlear implants (CI) in patients with neurofibromatosis type 2 (NF2) in a large cohort, and identify factors associated with poor hearing benefit. STUDY DESIGN: Fifteen-year retrospective national observational case series. SETTING: United Kingdom regional NF2 multidisciplinary teams. PATIENTS: Consecutive patients with NF2 receiving a CI. INTERVENTIONS: CI for hearing rehabilitation. MAIN OUTCOME MEASURES: 1) Audiometric performance at 9 to 12 months after implantation using City University of New York (CUNY) sentence recognition score, and Bamford- Kowal-Bench (BKB) word recognition score in quiet (BKBq), and in noise (BKBn). 2) CI use at most recent review. RESULTS: Sixty four consecutive patients, median age 43 years, were included. Nine to 12 months mean audiometric scores were: CUNY 60.9%, BKBq 45.8%, BKBn 41.6%. There was no difference in audiometric outcomes between VS treatment modalities. At most recent review (median 3.6 years from implantation), 84.9% with device in situ/available data were full or part-time users. Between 9 and 12 months and most recent review there was an interval reduction in mean audiometric scores: CUNY -12.9%, BKBq -3.3%, BKBn -4.9%. Larger tumor size and shorter duration of profound hearing loss were the only variables associated with poorer audiometric scores. Tumor growth at the time of surgery was the only variable associated with CI non-use. Individual patient response was highly variable. CONCLUSIONS: CI can provide significant and sustained auditory benefits to patients with NF2 independent of tumor treatment modality, with the majority of those implanted becoming at least part-time users. Larger datasets are required to reliably assess the role of independent variables.

Brain stem responses evoked by stimulation of the mature cochlear nucleus with an auditory brain stem implant.

OBJECTIVES: The Nucleus auditory brain stem implant (ABI) has been used in the hearing rehabilitation of totally deaf individuals for whom a cochlear implant is not an option such as in the case of neurofibromatosis type 2 (NF2). Intraoperative electrically evoked auditory brain stem responses (EABRs) are recorded to assist in the placement of the electrode array over the dorsal and ventral cochlear nuclei in the lateral recess of the IVth ventricle of the brain stem. This study had four objectives: (1) to characterize EABRs evoked by stimulation with an ABI in adolescents and adults with NF2, (2) to evaluate how the EABR morphology relates to auditory sensations elicited from stimulation by an ABI, (3) to establish whether there is evidence of morphology changes in the EABR with site of stimulation by the ABI, and (4) to investigate how the threshold of the EABR relates to behavioral threshold and comfortably loud sensations measured at initial device activation. DESIGN: Intraoperative EABRs were recorded from 34 subjects with ABIs: 19 male and 15 female, mean age 27 yrs (range 12 to 52 yrs). ABI stimulation was applied at seven different sites using either wide bipolar stimulation across the array or in subsections of the array from medial to lateral and inferior to superior. The EABRs were analyzed with respect to morphology, peak latency, and changes in these characteristics with the site of stimulation. In a subset of eight subjects, additional narrow bipolar sites were stimulated to compare the intraoperative EABR threshold levels with the behavioral threshold (T) and comfortably loud (C) levels of stimulation required at initial device activation. RESULTS: EABRs were elicited from 91% of subjects. Morphology varied from one to four vertex-positive peaks with mean latencies of 0.76, 1.53, 2.51, and 3.64 msecs, respectively. The presence of an EABR from stimulation by electrodes across the whole array had a high predictive value for the presence of auditory electrodes at initial device activation. When examining subsections of the array, the absence of an EABR was a poor predictor for the absence of auditory electrodes. The morphology of the EABRs varied with site of stimulation in 16 cases, but there was no consistent pattern of change with stimulation site. There was a trend for more auditory electrodes to be present in stimulation sites that evoked EABRs with a higher number of peaks in the waveform. The EABR threshold was closer to the behavioral C level than the T level, but there was no overall correlation between the intraoperative EABR threshold level and the behavioral T and C levels. CONCLUSIONS: The presence of an intraoperative EABR corresponded well to the presence of auditory electrodes. The absence of an EABR from stimulating subsections of the array was not; however, a good indicator for the absence of auditory electrodes and the EABR from such stimulation would not be of assistance in identifying the nonauditory sections of the array to exclude in behavioral fitting of the device. The morphology of the EABR did not relate to site of stimulation. More peaks in the EABR was associated with a greater number of electrodes with auditory sensations, suggesting that correct positioning of the ABI activated more auditory subsystems within the cochlear nucleus. The intraoperative EABR thresholds did not correlate with the behavioral T and C levels and could not be used to assist in device fitting.

Brain stem responses evoked by stimulation with an auditory brain stem implant in children with cochlear nerve aplasia or hypoplasia.

OBJECTIVES: The inclusion criteria for an auditory brain stem implant (ABI) have been extended beyond the traditional, postlingually deafened adult with Neurofibromatosis type 2, to include children who are born deaf due to cochlear nerve aplasia or hypoplasia and for whom a cochlear implant is not an option. Fitting the ABI for these new candidates presents a challenge, and intraoperative electrically evoked auditory brain stem responses (EABRs) may assist in the surgical placement of the electrode array over the dorsal and ventral cochlear nucleus in the brain stem and in the postoperative programming of the device. This study had four objectives: (1) to characterize the EABR by stimulation of the cochlear nucleus in children, (2) to establish whether there are any changes between the EABR recorded intraoperatively and again just before initial behavioral testing with the device, (3) to establish whether there is evidence of morphology changes in the EABR depending on the site of stimulation with the ABI, and (4) to investigate how the EABR relates to behavioral measurements and the presence of auditory and nonauditory sensations perceived with the ABI at initial device activation. DESIGN: Intra- and postoperative EABRs were recorded from six congenitally deaf children with ABIs, four boys and two girls, mean age 4.2 yrs (range 3.2 to 5.0 yrs). The ABI was stimulated at nine different bipolar sites on the array, and the EABRs recorded were analyzed with respect to the morphology and peak latency with site of stimulation for each recording session. The relationship between the EABR waveforms and the presence or absence of auditory electrodes at initial device activation was investigated. The EABR threshold levels were compared with the behavioral threshold (T) and comfortably loud (C) levels of stimulation required at initial device activation. RESULTS: EABRs were elicited from all children on both test occasions. Responses contained a possible combination of one to three peaks from a total of four identifiable peaks with mean latencies of 1.04, 1.81, 2.61, and 3.58 msecs, respectively. The presence of an EABR was a good predictor of an auditory response; however, the absence of the EABR was poor at predicting a site with no auditory response. The morphology of EABRs often varied with site of stimulation and between EABR test occasions. Postoperatively, there was a trend for P1, P3, and P4 to be present at the lateral end of the array and P2 at the medial end of the array. Behavioral T and C levels showed a good correlation with postoperative EABR thresholds but a poor correlation with intraoperative EABR thresholds. CONCLUSIONS: The presence of an intraoperative EABR was a good indicator for the location of electrodes on the ABI array that provided auditory sensations. The morphology of the EABR was often variable within and between test sessions. The postoperative EABR thresholds did correlate with the behavioral T and C levels and could be used to assist with initial device fitting.

Translabyrinthine resection of NF2 associated vestibular schwannoma with cochlear implant insertion.

The authors present the case of a 24-year-old female with neurofibromatosis type 2. Growth of the left vestibular schwannoma and progressive hearing loss prompted the decision to proceed to translabyrinthine resection with cochlear nerve preservation and cochlear implant insertion. Complete resection with preservation of the facial and cochlear nerves was achieved. The patient had grade 1 facial function and was discharged on postoperative day 4 following suturing of a minor CSF leak. This case highlights the feasibility of cochlear nerve preservation and cochlear implant insertion in appropriately selected patients, offering a combination of effective tumor control and hearing rehabilitation. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID21122.

Outcome from surgery for vestibular schwannomas in children.

OBJECT: A review of sporadic and NF2-related vestibular schwannoma surgery in children (under 18 years of age) with a specific interest in resection rates, recurrence, facial nerve outcomes, hearing preservation, hearing rehabilitation and genetic analysis. METHODS: A retrospective analysis of prospectively collected data of 35 consecutively operated vestibular schwannomas in 29 paediatric patients that underwent 38 operations between 1992 and 2007. Pre- and post-operative radiology, facial nerve function, pure tone audiogram and speech discrimination tests were performed with a mean follow-up of 4.5 years. Tumour and blood mutations were analysed in 86% of patients. RESULTS: Total resection was achieved in all sporadic cases and 68% of NF2 cases. Near total resection led to tumour recurrence in 5 out of 10 cases. The facial nerve was anatomically preserved in 92%. Facial nerve function was excellent to good (Grades 1-3) in 88% with outcome related to tumour size. Hearing preservation was successful in 3 of 11 cases. CONCLUSIONS: Surgery with complete resection results in excellent tumour control, but it is more difficult to attain total resection in NF2 with a relatively high recurrence rate of persistently growing tumours. A better facial outcome is associated with smaller tumours, near-total resection and first time surgery. Hearing preservation is possible in a minority. Hearing rehabilitation can be successful by utilising cochlear implants and auditory brain stem implants (ABI) as appropriate. Overall there is a low complication rate and results are comparable with adult series.

Speech Auditory Brainstem Responses in Adult Hearing Aid Users: Effects of Aiding and Background Noise, and Prediction of Behavioral Measures.

Evaluation of patients who are unable to provide behavioral responses on standard clinical measures is challenging due to the lack of standard objective (non-behavioral) clinical audiological measures that assess the outcome of an intervention (e.g., hearing aids). Brainstem responses to short consonant-vowel stimuli (speech-auditory brainstem responses [speech-ABRs]) have been proposed as a measure of subcortical encoding of speech, speech detection, and speech-in-noise performance in individuals with normal hearing. Here, we investigated the potential application of speech-ABRs as an objective clinical outcome measure of speech detection, speech-in-noise detection and recognition, and self-reported speech understanding in 98 adults with sensorineural hearing loss. We compared aided and unaided speech-ABRs, and speech-ABRs in quiet and in noise. In addition, we evaluated whether speech-ABR F0 encoding (obtained from the complex cross-correlation with the 40 ms [da] fundamental waveform) predicted aided behavioral speech recognition in noise or aided self-reported speech understanding. Results showed that (a) aided speech-ABRs had earlier peak latencies, larger peak amplitudes, and larger F0 encoding amplitudes compared to unaided speech-ABRs; (b) the addition of background noise resulted in later F0 encoding latencies but did not have an effect on peak latencies and amplitudes or on F0 encoding amplitudes; and (c) speech-ABRs were not a significant predictor of any of the behavioral or self-report measures. These results show that speech-ABR F0 encoding is not a good predictor of speech-in-noise recognition or self-reported speech understanding with hearing aids. However, our results suggest that speech-ABRs may have potential for clinical application as an objective measure of speech detection with hearing aids.

Extracochlear Stimulation of Electrically Evoked Auditory Brainstem Responses (eABRs) Remains the Preferred Pre-implant Auditory Nerve Function Test in an Assessor-blinded Comparison.

OBJECTIVE: Electrically evoked auditory brainstem responses (eABRs) can be recorded before cochlear implant (CI) surgery to verify auditory nerve function, and is particularly helpful in to assess the function of the auditory nerve in cases of auditory nerve hypoplasia. This is the first study to compare three preimplant eABRs recording techniques: 1) standard extracochlear, 2) novel intracochlear, and 3) conventional intracochlear with the CI. STUDY DESIGN: A within-participants design was used where eABRs were sequentially measured during CI surgery using three methods with stimulation from: 1) an extracochlear electrode placed at the round window niche, 2) two different electrodes on a recently developed Intracochlear Test Array (ITA), and 3) two different electrodes on a CI electrode array. SETTING: New adults implantees (n = 16) were recruited through the Manchester Auditory Implant Centre and eABR measurements were made in theater at the time of CI surgery. PATIENTS: All participants met the clinical criteria for cochlear implantation. Only participants with radiologically normal auditory nerves were recruited to the study. All participants were surgically listed for either a MED-EL Synchrony implant or a Cochlear Nucleus Profile implant, per standard practice in the implant centre. OUTCOME MEASURES: Primary outcome measures were: 1) charge (µC) required to elicit a threshold response, and 2) latencies (ms) in the threshold waveforms. Secondary outcome measures were: 1) morphologies of responses at suprathreshold stimulation levels and 2) wave V growth patterns. RESULTS: eABRs were successfully measured from 15 participants. In terms of primary outcome measures, the charge required to elicit a response using the extracochlear electrode (median = 0.075 µC) was approximately six times larger than all other electrodes and the latency of wave V was approximately 0.5 ms longer when using the extracochlear electrode (mean = 5.1 ms). In terms of secondary outcomes, there were some minor quantitative differences in responses between extracochlear and intracochlear stimulation; in particular, ITA responses were highly variable in quality. The ITA responses were rated poor quality in 33% of recordings and in two instances did not allow for data collection. When not disrupted by open circuits, the median ITA response contained one more waveform than the median extracochlear response. CONCLUSIONS: In this first study comparing intracochlear and extracochlear stimulation, the results show that both can be used to produce an eABR that is representative of the one elicited by the CI. In the majority of cases, extracochlear stimulation was the preferred approach for preimplant auditory nerve function testing because of consistency, recordings that could be analyzed, and because extracochlear placement of the electrode does not require a cochleostomy to insert an electrode.

Hearing preservation cochlear implantation in children: The HEARRING Group consensus and practice guide.

OBJECTIVES: To provide multidisciplinary cochlear implant teams with a current consensus statement to support hearing preservation cochlear implantation (HPCI) in children, including those children with symptomatic partial deafness (PD) where the intention is to use electric-acoustic stimulation (EAS). The main objectives are to provide guidelines on who is a candidate, how to assess these children and when to implant if Med-El Flex electrode arrays are chosen for implantation. METHODS: The HEARRING group reviewed the current evidence and practice regarding the management of children to be considered for HPCI surgery emphasizing the assessment needed prior to implantation in order to demonstrate the benefits in these children over time. The consensus statement addresses following three key questions: (1) Should these children be treated? (2) How to identify these children? (3) How to manage these children? SUMMARY: The HEARRING group concludes that irrespective of the degree of residual hearing present, the concepts of hearing and structure preservation should be applied in every child undergoing cochlear implantation and that HPCI is a safe and reliable treatment option. Early detection and multidisciplinary assessment are key to the identification of children with symptomatic PD, these children should undergo HPCI as early as possible.

Changes in psychophysical parameters during the first month of programming the nucleus contour and contour advance cochlear implants.

This retrospective study evaluated the psychophysical parameters of 29 postlingually deafened adults who had received a Nucleus Contour or Contour Advance implant during the first month of fitting in order to determine how many sessions were required to obtain a stable implant MAP. The T-levels did not differ significantly across the five fitting sessions, but the C-levels as well as the dynamic range showed an increase up to the fourth session. For all psychophysical parameters the basal, medial and apical portion of the electrode array differed significantly across sessions. Subjects with a Nucleus Contour implant had higher comfortable levels than subjects with a Contour Advance implant. The duration of deafness, presence of preoperative tinnitus, aetiology, frequency of fitting, stimulus rate and number of active channels did not significantly influence the psychophysical levels. These results suggested that four fitting sessions within the first three weeks after switch on should initially suffice and the fifth session could be planned beyond one month.

Cochlear implantation in early deafened, late implanted adults: Do they benefit?

OBJECTIVES: The aim of this study was to quantify the benefit gained from cochlear implantation in pre- or peri-lingually deafened patients who were implanted as adults Methods: This was a retrospective case-control study. Auditory (BKB/CUNY/3AFC/Environmental sounds), quality of life (GBI/HUI3) and cognitive (customized questionnaire) outcomes in 26 late implanted pre- or peri-lingually deafened adults were compared to those of 30 matched post-lingually deafened, traditional cochlear implant users. RESULTS: There was a statistically significant improvement in all scores in the study group following cochlear implantation. BKB scores for cases was 49.8% compared to 83.6% for controls (p=0.037). CUNY scores for cases was 61.7% compared to 90.3% for controls (p=0.022). The 3AFC and environmental sounds scores were also better in controls compared to cases but the difference was not statistically significant. Quality of life scores improved following implantation in cases and controls but the improvement was only statistically significant in the controls. There was a 7.7% non-user rate in the cases. There were no non-users in the control group. DISCUSSION: Early deafened,,late implanted patients can benefit audiologically from cochlear implantation and in this study the improvement in speech discrimination scores was greater than expected perhaps reflecting careful selection of patients. Nevertheless, audiological benefits are limited compared to traditional cochlear implant recipients with the implant acting as an aid to lip reading in most cases. CONCLUSION: With careful selection of candidates, cochlear implantation is beneficial in early deafened, late implanted patients.