Auditory Prostheses Research Articles

A Bridge over Troubled Listening: Improving Speech-in-Noise Perception by Children with Dyslexia.

Developmental dyslexia is most commonly associated with phonological processing difficulties. However, children with dyslexia may experience poor speech-in-noise perception as well. Although there is an ongoing debate whether a speech perception deficit is inherent to dyslexia or acts as an aggravating risk factor compromising learning to read indirectly, improving speech perception might boost reading-related skills and reading acquisition. In the current study, we evaluated advanced speech technology as applied in auditory prostheses, to promote and eventually normalize speech perception of school-aged children with dyslexia, i.e., envelope enhancement (EE). The EE strategy automatically detects and emphasizes onset cues and consequently reinforces the temporal structure of the speech envelope. Our results confirmed speech-in-noise perception difficulties by children with dyslexia. However, we found that exaggerating temporal "landmarks" of the speech envelope (i.e., amplitude rise time and modulations)-by using EE-passively and instantaneously improved speech perception in noise for children with dyslexia. Moreover, the benefit derived from EE was large enough to completely bridge the initial gap between children with dyslexia and their typical reading peers. Taken together, the beneficial outcome of EE suggests an important contribution of the temporal structure of the envelope to speech perception in noise difficulties in dyslexia, providing an interesting foundation for future intervention studies based on auditory and speech rhythm training.

Assessment of music experience after cochlear implantation: A review of current tools and their utilization.

ObjectiveTo provide an overview of the current available music assessment tools after cochlear implantation (CI); to report on the utilization of music assessments in the literature; to propose potential future directions in music assessment after CI.MethodsA thorough search was performed in PubMed, Embase, and The Cochrane Library through October 31, 2020. MeSH search terms, keywords, and phrases included “cochlear implant,” “cochlear prosthesis,” “auditory prosthesis,” “music,” “music assessment,” “music questionnaire,” “music perception,” “music enjoyment, and “music experience.” Potentially relevant studies were reviewed for inclusion, with particular focus on assessments developed specifically for the cochlear implant population and intended for widespread use.Results/conclusionsSix hundred and forty-three studies were screened for relevance to assessment of music experience among cochlear implantees. Eighty-one studies ultimately met criteria for inclusion. There are multiple validated tools for assessment of music experience after cochlear implantation, each of which provide slightly differing insights into the patients’ subjective and/or objective post-activation experience. However, no single assessment tool has been adopted into widespread use and thus, much of the literature pertaining to this topic evaluates outcomes non-uniformly, including single-use assessments designed specifically for the study at hand. The lack of a widely accepted universal tool for assessment of music limits our collective understanding the contributory and mitigating factors applicable to current music experience of cochlear implantees, and limits our ability to uniformly evaluate the success of new implant technologies or music training paradigms.

Response of primary auditory neurons to stimulation with infrared light in vitro

Objective. Infrared light can be used to modulate the activity of neuronal cells through thermally-evoked capacitive currents and thermosensitive ion channel modulation. The infrared power threshold for action potentials has previously been found to be far lower in the in vivo cochlea when compared with other neuronal targets, implicating spiral ganglion neurons (SGNs) as a potential target for infrared auditory prostheses. However, conflicting experimental evidence suggests that this low threshold may arise from an intermediary mechanism other than direct SGN stimulation, potentially involving residual hair cell activity. Approach. Patch-clamp recordings from cultured SGNs were used to explicitly quantify the capacitive and ion channel currents in an environment devoid of hair cells. Neurons were irradiated by a 1870 nm laser with pulse durations of 0.2–5.0 ms and powers up to 1.5 W. A Hodgkin-Huxley-type model was established by first characterising the voltage dependent currents, and then incorporating laser-evoked currents separated into temperature-dependent and temperature-gradient-dependent components. This model was found to accurately simulate neuronal responses and allowed the results to be extrapolated to stimulation parameter spaces not accessible during this study. Main results. The previously-reported low in vivo SGN stimulation threshold was not observed, and only subthreshold depolarisation was achieved, even at high light exposures. Extrapolating these results with our Hodgkin-Huxley-type model predicts an action potential threshold which does not deviate significantly from other neuronal types. Significance. This suggests that the low-threshold response that is commonly reported in vivo may arise from an alternative mechanism, and calls into question the potential usefulness of the effect for auditory prostheses. The step-wise approach to modelling optically-evoked currents described here may prove useful for analysing a wider range of cell types where capacitive currents and conductance modulation are dominant.

Wavelength-specific optoacoustic-induced vibrations of the guinea pig tympanic membrane.

.Significance: Optoacoustic-induced vibrations of the hearing organ can potentially be used for a hearing device. To increase the efficiency of such a hearing device, the conversion of the light energy into vibration energy within each type of irradiated tissue has to be optimized.Aim: To analyze the wavelength-dependency of optoacoustic-induced vibrations within the tympanic membrane (TM), and to define the most efficient and best-suited optical stimulation parameters for a novel auditory prosthesis.Approach: Single nanosecond laser pulses, continuously tunable in a range of visible to near-infrared, were used to excite the guinea pig TM. The induced vibrations of the hearing organ were recorded at the malleus using a laser Doppler vibrometer.Results: Our results indicate a strong wavelength-dependency of the vibration’s amplitude correlating with the superposition of the absorption spectra of the different specific tissue components.Conclusions: We investigated the spectrum of the vibrations of the hearing organ that were induced optoacoustically within a biological membrane embedded in air, in an animal model. First applications for these results can be envisioned for the optical stimulation of the peripheral hearing organ as well as for research purposes.

Consistency of Using an Auditory Prosthesis Device Post a Sequentially Implanted Cochlear Implant: Data-Logging Evidence.

ObjectivesThe aim of this study was to explore: 1) the average use of each device in sequentially implanted cochlear implants; 2) whether the inter-implant duration between implants produced any significant difference in the average use of the second implant; and 3) whether wearing hearing aids before the implantation of the second cochlear implant affects its average use.Materials and methodsThe study included 20 participants with bilateral Nucleus 24 implants (Cochlear Corporation, Lone Tree, CO). Data regarding various variables were extracted and then analyzed with IBM SPSS Statistics for Mac, version 23 (IBM Corp., Armonk, NY).ResultsThe pediatric group included 14 subjects (average age 7.5 years) while the adult group comprised six subjects (average age 37.5 years). The average use of the second device was 0.9 hours per day more than the first in the pediatric group while it was 1.22 hours per day more in the adult group. We also divided the subjects on the basis of duration between the first and second devices and calculated the average use of each device by them. There was no significant difference (p>0.05). The average use by subjects who did and did not use hearing aids before implantation was also insignificant (p>0.05).ConclusionsNo significant difference between the average use of the first and second implants, between the inter-implant duration of the first and second implants, the average use of the second implant, and between using hearing aids before the implantation of the second device and the average use was observed.

An Optimal Envelope-Based Noise Reduction Method for Cochlear Implants: An Upper Bound Performance Investigation

Cochlear implants (CI) are surgically implanted auditory prostheses for partially compensating severe to profound sensorineural hearing losses. Despite providing significant intelligibility levels under silent conditions, their performance is highly affected by additive noise. Time-frequency masks, such as the binary mask, the Wiener filter (WF) and their variations, have been widely employed for noise reduction. However, they were not originally designed for CI applications, which have very particular characteristics. In this work, we propose a new method for noise reduction, especially designed for CI. It is based on the minimization of the mean square error between the squared envelopes of the estimated and target speech. The theoretical derivation of the proposed time-frequency mask is presented and a closed-form for the one-coefficient optimal solution is obtained. Numerical simulations with objective criteria indicate that the proposed method results in higher intelligibility scores as compared to the time-domain implementation of the WF time-frequency mask. Psychoacoustic experiments with normal hearing volunteers and vocoded signals, as well as CI users, corroborate simulation results, showing significant increases in intelligibility, especially for SNR < −5 dB. The proposed method may result in an intelligibility increase of up to 70%, for SNR = −25 dB, as compared to the WF. These findings were obtained considering an ideal signal-to-noise ratio estimator.

When language outgrows them: Comprehension of ambiguous sentences in children with normal hearing and children with hearing loss

BackgroundIn spite of recent gains in language development made by children with hearing loss (HL) as a result of improved auditory prostheses and earlier starts to intervention, these children continue to struggle academically at higher grade levels. We hypothesize that one reason for these incongruent outcomes for language and academics may be that the language demands of school escalate as grade level increases, outstripping the language abilities of children with HL. We tested that hypothesis by examining a higher level skill that is essential for success with academic language, the ability to access multiple interpretations for a sentence. Method122 children participated at the end of middle school: 56 with normal hearing (NH), 15 with moderate HL who used hearing aids (HAs), and 51 with severe-to-profound HL who used cochlear implants (CIs). Children's abilities to provide more than one interpretation for an ambiguous sentence were assessed. These sentences were ambiguous due either to words having multiple meanings or to syntactic structure that could evoke more than one interpretation. Potential predictors of those abilities were evaluated, including expressive vocabulary, comprehension of syntactic structures, grammaticality judgments, forward digit span, and several audiologic factors. ResultsChildren with NH performed best, children with CIs performed poorest, and children with HAs performed intermediately to those groups. Children in all groups achieved higher scores on the multiple meanings than on the syntactic structure items. The variables that were associated with performance varied across groups. Audiologic factors did not explain any variability in performance on the ambiguous sentences task for children with HL. ConclusionsThe kind of linguistic flexibility needed to consider more than one interpretation for sentences lacking immediate, real-world context is essential to processing academic language. Children with HL – especially those with severe-to-profound HL who required CIs – showed deficits in this skill, which could contribute to their ongoing academic struggles. Continued language support is needed for these children to allow them to acquire the higher level language skills necessary for success through all of their years in school.

The Devil in the Details Can Be Hard to Spot: Malapropisms and Children With Hearing Loss

Purpose Better auditory prostheses and earlier interventions have led to remarkable improvements in spoken language abilities for children with hearing loss (HL), but these children often still struggle academically. This study tested a hypothesis for why this may be, proposing that the language of school becomes increasingly disconnected from everyday discourse, requiring greater reliance on bottom-up phonological structure, and children with HL have difficulty recovering that structure from the speech signal. Participants One hundred nineteen fourth graders participated: 48 with normal hearing (NH), 19 with moderate losses who used hearing aids (HAs), and 52 with severe-to-profound losses who used cochlear implants (CIs). Method Three analyses were conducted. #1: Sentences with malapropisms were created, and children's abilities to recognize them were assessed. #2: Factors contributing to those abilities were evaluated, including phonological awareness, phonological processing, vocabulary, verbal working memory, and oral narratives. #3: Teachers' ratings of students' academic competence were obtained, and factors accounting for those ratings were evaluated, including the five listed above, along with word reading and reading comprehension. Results #1: Children with HAs and CIs performed more poorly on malapropism recognition than children with NH, but similarly to each other. #2: All children with HL demonstrated large phonological deficits, but they were especially large for children with CIs. Phonological awareness explained the most variance in malapropism recognition for children with CIs. Vocabulary knowledge explained malapropism recognition for children with NH or HAs, but other factors also contributed. #3: Teachers rated academic competence for children with CIs more poorly than for children with NH or HAs, and variance in those ratings for children with CIs were primarily explained by malapropism scores. Conclusion Children with HL have difficulty recognizing acoustic-phonetic detail in the speech signal, and that constrains their abilities to follow conversations in academic settings, especially if HL is severe enough to require CIs. Supplemental Material https://doi.org/10.23641/asha.13133018.

Cytotoxicity studies of an optoacoustic stimulation strategy for the development of laser-based hearing aids.

.Significance: Worldwide, people suffer from disabling hearing impairment. Many of these patients are still not sufficiently supplied with currently available auditory technologies. Optical stimulation of the hearing organ offers a promising alternative for a new generation of auditory prostheses.Aim: To assess the biocompatibility margins of our laser pulse amplitude strategy in vitro, we designed a protocol and present the effects on normal human dermal fibroblasts, human chondrocytes, and human osteoblasts.Approach: Laser pulses of 532 nm were applied over 120 s using our laser pulse amplitude modulation strategy. We then assessed cell viability and cytotoxicity through fluorescence staining and quantitative polymerase chain reaction-analysis regarding 84 key player-genes for cytotoxicity and stress response.Results: The first in vitro biocompatibility margins for our stimulation parameters applied to cells of the peripheral hearing organ were between 200 and 223 mW (). After irradiation with a subphototoxic laser power of 199 mW (), only the fibroblasts showed a significant upregulation of GADD45G.Conclusion: Further studies are underway to optimize parameters for the optoacoustic stimulation of the auditory system. Our protocol and results on laser–tissue interactions can be useful for translational laser applications in various other irradiated biological tissues.

Unilateral Hearing Loss and Single-Sided Deafness in Children: an Update on Diagnosis and Management

This review highlights our current understanding of the impact of unilateral hearing loss and single-sided deafness in children, offering insight into diagnosis and management. Children with unilateral hearing loss develop an aural preference toward their better hearing ear, leading to difficulties with spatial navigation, balance, speech/language skills, and quality of life when compared with typical hearing peers. Cochlear nerve aplasia and cytomegalovirus are among the most common etiologies for unilateral hearing loss, which has important implications for treatment. Hearing rehabilitation relies upon early correction of hearing loss with an appropriate auditory prosthesis. In children with single-sided deafness, cochlear implants are the only intervention that potentially offers restoration of bilateral hearing, and studies continue to refine candidacy protocols. Unilateral hearing loss has important consequences for children. Recent studies emphasize the importance of early diagnosis and investigate ways to appropriately restore bilateral hearing in these children.

Measuring access to high-modulation-rate envelope speech cues in clinically fitted auditory prostheses.

The signal processing used to increase intelligibility within the hearing-impaired listener introduces distortions in the modulation patterns of a signal. Trade-offs have to be made between improved audibility and the loss of fidelity. Acoustic hearing impairment can cause reduced access to temporal fine structure (TFS), while cochlear implant processing, used to treat profound hearing impairment, has reduced ability to convey TFS, hence forcing greater reliance on modulation cues. Target speech mixed with a competing talker was split into 8-22 frequency channels. From each channel, separate low-rate (EmodL, <16 Hz) and high-rate (EmodH, <300 Hz) versions of the envelope modulation were extracted, which resulted in low or high intelligibility, respectively. The EModL modulations were preserved in channel valleys and cross-faded to EModH in channel peaks. The cross-faded signal modulated a tone carrier in each channel. The modulated carriers were summed across channels and presented to hearing aid (HA) and cochlear implant users. Their ability to access high-rate modulation cues and the dynamic range of this access was assessed. Clinically fitted hearing aids resulted in 10% lower intelligibility than simulated high-quality aids. Encouragingly, cochlear implantees were able to extract high-rate information over a dynamic range similar to that for the HA users.

Age-related variability in pediatric scalp thickness: Implications for auditory prostheses

ObjectivesMinimizing soft tissue reduction during the placement of percutaneous implants has been encouraged to improve cosmesis and perhaps decrease soft tissue complications. However, the fidelity of sound transmission and retention of transcutaneous magnet devices relates to the intervening soft tissue thickness. The objective of this study was to examine age-related variability in scalp thickness in patients receiving either percutaneously implanted or transcutaneous magnet-retained auditory prostheses. MethodsChildren undergoing percutaneous implant retained prostheses or cochlear implantation underwent two scalp thickness measurements: 1) a superior measurement at the conventional marked site for cochlear implant receiver stimulator and 2) an inferior measurement 1.5 cm below the superior measurement representing the conventional marked site for cochlear implant fantail. Linear regression was used for statistical analysis. ResultsEighty-five children (median age 6 years; range 9 months–17 years) were examined. Scalp thickness at the two sites ranged from 1 to 10 mm (superior mean = 4.1 mm; inferior mean = 4.3 mm). A strong correlation was observed between age and scalp thickness at the superior (R = 0.62, p < 0.01) measurement, while a moderate correlation was observed at the inferior (R = 0.45, p < 0.01) sites. Children younger than 7 years displayed little variability in scalp thickness, and no correlation between age and scalp thickness (R = 0.002, p = 0.74). ConclusionIn older children, scalp thickness varies significantly with age. However, children younger than 7 years consistently have scalp thicknesses of 3–4 mm. Lack of variability in scalp thickness in children younger than 7 years argues against the use of an age-adjusted approach to soft tissue management in this age group.

Practices and Attitudes That Enhance Music Engagement of Adult Cochlear Implant Users.

BackgroundCochlear implants (CIs) are auditory prostheses designed to support spoken communication in persons with severe to profound hearing loss. Many post-lingually deaf adult CI users achieve good speech recognition in quiet; unfortunately, CI technology conveys a degraded representation of pitch and timbre, essential components of music. Not surprisingly, most CI users achieve significantly poorer perception and enjoyment of music compared with normal hearing listeners. Anecdotal evidence indicates that this impacts music engagement, particularly singing and playing instruments requiring ongoing tuning to external pitches or producing intervallic ratios. Interestingly, a small cohort of adult CI users has shown remarkable success in recovering or developing musical skills, but their success is poorly understood. Greater understanding of their efforts and attitudes may suggest potential rehabilitative approaches for other CI users.PurposeThis article documented personal characteristics and experiences perceived to contribute to high level musicianship. Research questions included: (1) What forms of practice/experience have most contributed to (re)establishing satisfying music making? (2) What situations or musical tasks are most frustrating or challenging? (3) What attitudes, motivational factors, or forms of support help CI users persist in working toward improved music engagement?MethodsQualitative and patient–engaged research methodologies were used. Our study involved a unique collaboration of six CI users engaged in high levels of musicianship and a researcher whose scholarship focuses on music and CIs. The CI recipients conveyed their experiences and attitudes regarding music and CIs through open-ended narratives. These narratives were analyzed using an integrative approach of inductive and deductive coding methods. The codes and themes that emerged through inductive methods were then organized within the Dynamic Problem Solving Model for Management of Music Listening Environments (Gfeller et al., 2019a).Outcomes:This paper provides reflections of six CI users who successfully engage in active music making, including on-going tuning to external pitches and ensemble participation. Their perspectives emphasize the importance of pre-CI music instruction, extensive practice and immersion in music listening and playing, persistence and self-efficacy, and problem solving skills that optimize music engagement, and suggest possible strategies useful to other CI users interested in improving music experiences.

A program-dependent digital compressor for auditory prostheses specialized for signal transients

Dynamic range compressors found in hearing aids and cochlear implants are designed to have a programmable response time. In particular, the attack and release parameters control the rate at which a compressor responds to the onset and offset of a signal transient. Some previous perceptual studies have found preferences for faster response times, while other studies have found preferences for slower response times. An explanation for the conflicting results is that the experiments’ stimuli and perceptual measures have varied. These results are indicative of the challenge in designing compressors for a wide range of speech, environmental, and musical signals each with unique transient characteristics. Researchers have proposed using multiple wide-band compressors or parallel narrow-band compressors with different response times. This research presents an alternative approach for a single compressor having adaptive, program-dependent, attack and release times. Specifically, the response times depend on the rate of change of the compressor’s gain reduction. When a transient causes a large change in gain reduction, the response times are faster. During periods with small changes in gain reduction, the response times are slower. Considerations for real-time implementation are discussed.

Analysis of Miniaturization Effects and Channel Selection Strategies for EEG Sensor Networks With Application to Auditory Attention Detection.

Concealable, miniaturized electroencephalography (mini-EEG) recording devices are crucial enablers toward long-term ambulatory EEG monitoring. However, the resulting miniaturization limits the inter-electrode distance and the scalp area that can be covered by a single device. The concept of wireless EEG sensor networks (WESNs) attempts to overcome this limitation by placing a multitude of these mini-EEG devices at various scalp locations. We investigate whether optimizing the WESN topology can compensate for miniaturization effects in an auditory attention detection (AAD) paradigm. Starting from standard full-cap high-density EEG data, we emulate several candidate mini-EEG sensor nodes that locally collect EEG data with embedded electrodes separated by short distances. We propose a greedy group-utility based channel selection strategy to select a subset of these candidate nodes to form a WESN. We compare the AAD performance of this WESN with the performance obtained using long-distance EEG recordings. The AAD performance using short-distance EEG measurements is comparable to using an equal number of long-distance EEG measurements if, in both cases, the optimal electrode positions are selected. A significant increase in performance was found when using nodes with three electrodes over nodes with two electrodes. When the nodes are optimally placed, WESNs do not significantly suffer from EEG miniaturization effects in the case of AAD. WESN-like platforms allow us to achieve similar AAD performance as with long-distance EEG recordings while adhering to the stringent miniaturization constraints for ambulatory EEG. Their applicability in an AAD task is important for the design of neuro-steered auditory prostheses.

Introduction to the Special Issue: 15th Symposium on Cochlear Implants in Children.

In July 2017, the American Cochlear Implant Alliance, Stanford University, and the University of California at San Francisco presented the 15th Symposium on Cochlear Implants in Children in San Francisco, California. The meeting brought together over 1,300 participants with diverse multidisciplinary backgrounds in the largest meeting of its kind to date. American Cochlear Implant Alliance (ACI Alliance) is a unique non-profit organization that promotes access to cochlear implants through research, advocacy, and awareness. It promotes sharing of clinical research at an annual meeting. Additional resources from the San Francisco symposium and other conferences may be found on the organization's website www.acialliance.org. The year 2017 marked the 60th anniversary of the publication of the first surgically-implanted electronic auditory prosthesis by Djourno and Eyries. This milestone provided us with the opportunity to reflect on the progress made and the challenges remaining as cochlear implantation enters its 7th decade. It was a particular honor for the home institutions of UC San Francisco and Stanford to co-host this event and to recognize the contributions of each institution during the field's early critical phase. For this special issue of Otology and Neurotology, we have selected highlights from the more than 100 outstanding podium presentations delivered. These manuscripts represent state-of-the-art research in the fields of optimized cochlear implant education, surgical technique, hearing preservation, audiometric assessment, and music perception. We would like to thank the publishers of Otology and Neurotology, Wolters Kluwer, and its editor-in-chief, Lawrence Lustig, M.D. for the opportunity to present these proceedings. We would also like to acknowledge the Board of Directors of the ACI Alliance, and the Organizing Committees from Stanford and UC San Francisco for their leadership efforts. Finally, we would like to thank all of the presenters, co-authors, our corporate partners, and the scientific program committee who made the meeting such a success.

Auditory Brainstem Implantation: An Overview

An auditory brainstem implant (ABI) is a surgically implanted central neural auditory prosthesis for the treatment of profound sensorineural hearing loss in children and adults who are not cochlear implant candidates due to a lack of anatomically intact cochlear nerves or implantable cochleae. The device consists of a multielectrode surface array which is placed within the lateral recess of the fourth ventricle along the brainstem and directly stimulates the cochlear nucleus, thereby bypassing the peripheral auditory system. In the United States, candidacy criteria for ABI include deaf patients with neurofibromatosis type 2 (NF2) who are 12 years or older undergoing first- or second-side vestibular schwannoma resection. In recent years, several non-NF2 indications for ABI have been explored, including bilateral cochlear nerve avulsion from trauma, complete ossification of the cochlea due to meningitis, or a severe cochlear malformation not amenable to cochlear implantation. In addition, growing experience with ABI in infants and children has been documented with encouraging outcomes. While cochlear implantation generally remains the first-line option for hearing rehabilitation in NF2 patients with stable tumors or post hearing preservation surgery where hearing is lost but a cochlear nerve remains accessible for stimulation, an ABI is the next alternative in cases where the cochlear nerve is absent and/or if the cochlea cannot be implanted. Herein, we review ABI device design, clinical evaluation, indications, operative technique, and outcomes as it relates to lateral skull base pathology.

Abstract #8: Array of Penetrating Silicon-Based Microelectrodes as Auditory Brainstem Prosthesis for Profound Hearing Loss

Abstract #8: Array of Penetrating Silicon-Based Microelectrodes as Auditory Brainstem Prosthesis for Profound Hearing Loss

Application of auditory cortical evoked potentials for auditory assessment in people using auditory prosthesis.

The present study explored the application of auditory cortical evoked potentials (ACEP) in the auditory assessment of people using an auditory prosthesis. There were 126 patients with prelingual deafness who were selected from January 2012-June 2017 from the First People's Hospital of Kunshan (Kunshan, China). HEARLab™ system was used to induce a P1-N1-P2 waveform under the condition of 60 dB sound pressure level at /m/, /g/ and /t/ acoustic stimulations. Speech production ability and auditory perception ability of patients were evaluated by speech intelligibility rating (SIR) and categories of auditory performance (CAP). Extraction rate of P1 waves of patients with auditory prosthesis was higher than that of N1 and P2 waves under different acoustic stimulations. A younger initial age and shorter deafness duration before patients used an auditory prosthesis led to more marked P1-N1-P2 waveforms and longer P1 latencies. At /m/ acoustic stimulation, P1 latency and amplitude were negatively associated with the usage time of auditory prosthesis. There were significant differences in the results of SIR and CAP and the initial age of use of auditory prosthesis and deafness duration before patients used the auditory prosthesis. These findings suggest that ACEP can be used to evaluate the auditory assessment of people using an auditory prosthesis. The initial age of use of an auditory prosthesis and deafness duration can affect the P1-N1-P2 waveform and P1 latency of prelingual deafness.

Paediatric auditory brainstem implantation: The South Asian experience

IntroductionPaediatric Auditory Brainstem Implantation (ABI) is indicated for children with congenital cochlear aplasia, absent/hypoplastic vestibulocochlear nerve, for whom cochlear implantation is not possible. Knowledge of the anatomical landmarks and variants in anatomy of the brainstem is vital for ABI surgery. MethodStudy was done at Auditory implant centre in Madras ENT research foundation, which includes 24 children who had undergone ABI surgery and are being followed up for 1 year, post operatively. Aims were to study the anatomical variants and the outcomes of ABI implantation. To determine if different anatomical variants effect placement of ABI electrode. To assess the patient outcomes by Categories of auditory Performance (CAP) scores and Speech Intelligibility Ratings (SIR) scores. ResultsAll the candidates showed gradual improvement in audiological and verbal outcomes after the ABI. The mean CAP and SIR scores after 6 months of AVHT were 2.07 and 1.37 respectively. After 1 year of auditory verbal rehabilitation therapy CAP was 3.42 and SIR was 2.33. Flocculus of the cerebellum can be of different grades. Though, there was difficulty in insertion of the electrode in subjects with anatomical variants, the outcomes were comparable with other subjects. ConclusionABI surgery involves frequent anatomical variations surrounding the lateral recess which makes the positioning of the auditory prosthesis difficult. Variants during the surgery can make the placement of ABI electrodes difficult, but promising results were seen all the implantees.