Auditory Brainstem Implant Research Articles

Options and strategies for hearing restoration in pediatric neurofibromatosis type 2.

In this article, we will review the mechanisms and natural history of hearing loss in neurofibromatosis type 2 (NF2) and discuss the hearing outcomes with different rehabilitation options. Review of the published literature. NF2 is a rare autosomal dominant syndrome characterized by vestibular schwannomas and other intracranial and spinal tumors. Bilateral vestibular schwannomas are the hallmark of the disease which occur in 90 to 95% of the patients. As a result, hearing loss will eventually occur in almost all NF2 patients. Deafness can occur from tumor progression or from treatment of vestibular schwannomas and is among the most debilitating aspects of NF2. A number of surgical and non-surgical rehabilitation options are available for these patients including cochlear and auditory brainstem implants. The audiologic outcomes with surgical rehabilitation options have been variable but most patients are able to achieve sound awareness and benefit from auditory cues in lip reading. Early identification and treatment of NF2 patients can help in achieving better hearing outcomes in the pediatric population. An increasing number of NF2 patients are receiving open set word understanding with refinement in surgical techniques.

Ipsilateral Cochlear Implantation in the Presence of Observed and Irradiated Vestibular Schwannomas.

Historically, eventual loss of cochlear nerve function has limited patients with neurofibromatosis type 2 (NF2) to auditory brainstem implants (ABI), which in general are less effective than modern cochlear implants (CI). Our objective is to evaluate hearing outcomes following ipsilateral cochlear implantation in patients with NF2 and irradiated vestibular schwannomas (VS), and sporadic VS that have been irradiated or observed. Multi-center retrospective analysis of ipsilateral cochlear implantation in the presence of observed and irradiated VS. MESH search in NCBI PubMed database between 1992 and 2019 for reported cases of cochlear implantation with unresected vestibular schwannoma. Seven patients underwent ipsilateral cochlear implantation in the presence of observed or irradiated vestibular schwannomas. Four patients had sporadic tumors with severe-profound contralateral hearing loss caused by presbycusis/hereditary sensorineural hearing loss, and three patients with NF2 lost contralateral hearing after prior surgical resection. Prior to implantation, one VS was observed without growth for a period of 7 years and the others were treated with radiotherapy. Mean post-operative sentence score was 63.9% (range 48-91) at an average of 28 (range 2-84) months follow up. All patients in this cohort obtained open set speech perception. While analysis of the literature is limited by heterogenous data reporting, 85% of implants with observed schwannomas achieved some open set perception, and 67% of patients previously radiated schwannomas. Furthermore, blending literature outcomes for post implantation sentence testing in quiet without lip-reading show 59.0 ± 35% for patients with CI and observed tumors and 55.7 ± 35% for patients with radiated tumors, with both groups ranging 0 to 100%. This retrospective series and literature review highlight that hearing outcomes with CI for VS patients are superior to those achieved with ABI. However, important considerations including imaging, delayed hearing loss, and observation time cannot be ignored in this population.

Auditory and language skills in children with auditory brainstem implants

ObjectiveThe aim of this study is to characterize the development of auditory and language skills in children during the first 3 years of auditory brainstem implant (ABI) use. MethodIt is a retrospective longitudinal analysis of auditory and language skills in 12 children and pre-adolescents with pre-lingual deafness following ABI surgery (mean age at surgery: 4 years; age range: 2–11 years). Responses were analyzed aboutInfant Toddler Meaningful Auditory Integration Scale (IT-MAIS), MAIS, and Meaningful Use of Speech Scale (MUSS) at 1, 3, 6, 12, 18, 24, and 36 months after ABI activation. ResultsMaximum IT-MAIS/MAIS and MUSS scores after 3 years of ABI use were 45.35% and 35.28%, respectively. ConclusionPediatric patients exhibit slow progressive development of auditory and language skills following ABI activation.

Simultaneous Cochlear and Auditory Brainstem Implantation in Children With Severe Inner Ear Malformations: Initial Surgical and Audiological Results

To report the initial surgical and audiological outcomes of three pediatric patients with severe inner ear malformations who were simultaneously implanted with cochlear and brainstem implants in the same surgical session. Retrospective case review. Tertiary referral center. Three pediatric patients with severe inner ear malformations between ages of 1.9 to 2.5 years, who were simultaneously implanted with cochlear implant in one ear and auditory brainstem implant in the other ear. Simultaneous application of cochlar implant in one ear, auditory brainstem implant in the other ear. Free field thresholds with cochlear and brainstem implants. Surgical issues are also discussed. The study is descriptive in nature. Free field thresholds with each device alone and together showed good progress. One of the patients had slower progress possibly due to comorbid CHARGE syndrome. The results showed good progress in terms of audition with both devices. Simultaneous cochlear and brainstem application serves as a remedy for pediatric patients who are candidates for cochlear implant on one side and brainstem implant on the other side. With this simultaneous application precious time for auditory development is not lost.

Are Cochlear Implants a Viable Option Following Temporal Bone Fracture?

Are Cochlear Implants a Viable Option Following Temporal Bone Fracture?

Human Cochlear Nucleus on 7 Tesla Diffusion Tensor Imaging: Insights Into Micro-anatomy and Function for Auditory Brainstem Implant Surgery.

The cochlear nucleus (CN) is the target of the auditory brainstem implant (ABI). Most ABI candidates have Neurofibromatosis Type 2 (NF2) and distorted brainstem anatomy from bilateral vestibular schwannomas. The CN is difficult to characterize as routine structural MRI does not resolve detailed anatomy. We hypothesize that diffusion tensor imaging (DTI) enables both in vivo localization and quantitative measurements of CN morphology. We analyzed 7 Tesla (T) DTI images of 100 subjects (200 CN) and relevant anatomic structures using an MRI brainstem atlas with submillimetric (50 μm) resolution. Tertiary referral center. Young healthy normal hearing adults. Diagnostic. Diffusion scalar measures such as fractional anisotropy (FA), mean diffusivity (MD), mode of anisotropy (Mode), principal eigenvectors of the CN, and the adjacent inferior cerebellar peduncle (ICP). The CN had a lamellar structure and ventral-dorsal fiber orientation and could be localized lateral to the inferior cerebellar peduncle (ICP). This fiber orientation was orthogonal to tracts of the adjacent ICP where the fibers run mainly caudal-rostrally. The CN had lower FA compared to the medial aspect of the ICP (0.44 ± 0.09 vs. 0.64 ± 0.08, p < 0.001). 7T DTI enables characterization of human CN morphology and neuronal substructure. An ABI array insertion vector directed more caudally would better correspond to the main fiber axis of CN. State-of-the-art DTI has implications for ABI preoperative planning and future image guidance-assisted placement of the electrode array.

Bimodal stimulation in children with inner ear malformation: One side cochlear implant and contralateral auditory brainstem implant.

To determine audiological outcomes of children who use a cochlear implant (CI) in one ear and an auditory brainstem implant (ABI) in the contralateral ear. Retrospective case review. Tertiary referral hospital. Twelve children followed with CI and contralateral auditory brainstem implant (ABI) by Hacettepe University Department of Otorhinolaryngology and Audiology in Turkey. All children were diagnosed with different inner ear malformations with cochlear nerve aplasia/hypoplasia. CI was planned in the ear with better sound detection during behavioural testing with inserted ear phones and with better CN as seen on MRI. Due to the limited auditory and speech progress with the cochlear implant, ABI was performed on the contralateral ear in all subjects. Audiological performance and auditory perception skills of children with cochlear nerve deficiency (CND) who use bimodal electrical stimulation with CI and contralateral ABI. Mean age of the subjects was 84.00±33.94months. Age at CI surgery and ABI surgery was 25.00±10.98months and 41.50±16.14months, respectively. However, hearing thresholds only with CI and only with ABI did not reveal significant difference, and auditory perception scores improved with bimodal stimulation. The MAIS scores were significantly improved from unilateral CI to bimodal stimulation (P=.002). Pattern perception and word recognition scores were significantly higher with the bimodal condition when compared to CI only and ABI only conditions. Children with CND showed better performance with CI and contralateral ABI combined. Depending on the audiological and radiological results, bimodal stimulation should be advised for children with CND.

Performing MRI Scans on Cochlear Implant and Auditory Brainstem Implant Recipients: Review of 14.5 Years Experience.

To assess the complication rate of magnetic resonance imaging (MRI) using 1.5 T scanners on cochlear implant (CI) and auditory brainstem implant (ABI) recipients over 14.5 years. Prospective study conducted in a tertiary referral center for cochlear and auditory brainstem implantation, including patients with neurofibromatosis 2. The primary outcome was complications related to MRI scanning in implant recipients, including failure to complete MRI sessions. The secondary outcome was magnet void size due to MRI scanning with magnet in situ. Ninety-seven patients (21 ABI recipients, 76 CI recipients of whom 23 were bilateral) underwent a total of 428 MRI sessions consisting of 680 MRI procedures, which generated 2,601 MRI sequences (excluding localizers). Of these, 28/428 (6.5%) MRI sessions were performed with magnet removed, and the remaining 400/428 (93.4%) with the magnet in situ. The overall complication rate per session was 15/428 (3.5%). The majority of complications were accounted for by patient discomfort, in some cases requiring abandoning the scan session, but 5 magnet dislocations were also recorded. There were no cases of implant device failure or excessive demagnetization of the receiver stimulator magnet.For CI and ABI recipients, the implant caused large voids of around 110 mm × 60 mm with the magnet in situ which reduced to 60 mm × 30 mm when the magnet was removed. However, it was usually possible to visualize the internal acoustic meatus and cerebellopontine angle by positioning the implant package higher and further forward compared with conventional positioning. MRI scanning in ABI and CI recipients is generally safe and well tolerated without magnet removal, and carries a low rate of complications. However, patients should be fully informed of the possibility of discomfort, and precautions such as local anesthetic injection and head bandaging may reduce the likelihood of adverse events.

Perfil clínico y resultados obtenidos en los pacientes tratados mediante implante auditivo del tronco del encéfalo

IntroductionCochlear implants have been able to treat some types of hearing loss, but those related to cochlear nerve impairment made it necessary to find new ways to manage these deficits; leading to auditory brainstem implants (ABI). AimOur objective is to present the clinical profile of patients treated through an ABI and the results obtained from 1997 to 2017. Material and methodsOn the one hand, patients with statoacoustic nerve tumours (VIIIcranial nerve) were selected, and on the other hand, patients withoutVIII tumours with congenital malformations of the inner ear. Before and after the placement of the ABI, hearing was assessed through tonal audiometry, from which the PTA (Pure Tone Average) and the CAP (Categories of Auditory Performance) scale were obtained. ResultsA total of 20 patients undergoing ABI surgery were included. Eight were of tumour cause (40%) and 12 non-tumour (60%). In 15 subjects (75%) a suboccipital approach was performed and in 5 (25%) translabyrinthine. The mean of active electrodes before the implantation of Cochlear® (Nucleus ABI24) was 13/21 (61.90%) versus 8.5/12 (70.83%) of the Med-el® (ABI Med-el). An improvement in the mean PTA of 118.49dB was found against 46.55dB at 2years. On the CAP scale, values of1 were obtained in the preimplantation and of 2.57 (1-5) in the 2-year revision. ConclusionThe ABI is a safe option, and with good hearing results when the indication is made correctly.

Effects of Age at Auditory Brainstem Implantation: Impact on Auditory Perception, Language Development, Speech Intelligibility.

To study the effect of age at auditory brainstem implant (ABI) surgery on auditory perception, language, and speech intelligibility. Retrospective single cohort design. Tertiary referral center. In this study, 30 pediatric ABI users with no significant developmental issues were included. Participants were divided into two groups, according to age at surgery (Early Group: < 3 yr old [n = 15], Late Group: ≥ 3 yr old [n = 15]). Groups were matched by duration of ABI use and participants were evaluated after 5 years (±1 yr) experience with their device. The mean age at ABI surgery was 22.27 (ranged ± 6.5) months in the early group, 45.53 (ranged ± 7.9) months in the late group. Retrosigmoid craniotomy and ABI placement. Auditory perception skills were evaluated using the Meaningful Auditory Integration Scale and Categories of Auditory Performance from the Children's Auditory Perception Test Battery. We used a closed-set pattern perception subtest, a closed-set word identification subtest, and an open-set sentence recognition subtest. Language performance was assessed with the Test of Early Language Development and Speech Intelligibility Rating, which was administered in a quiet room. In this study, the results demonstrated that the Early Group's auditory perception performance was better than the Late Group after 5 years of ABI use, when children had no additional needs (U = 12, p < 0.001). Speech intelligibility was the most challenging skill to develop, in both groups. Due to multiple regression analysis, we found that auditory perception categories can be estimated with speech intelligibility scores, pattern perception scores, receptive language scores, and age at ABI surgery variables in ABI users with no additional handicaps. ABI is a viable option to provide auditory sensations for children with cochlear anomalies. ABI surgery under age 3 is associated with improved auditory perception and language development compared with older users.

Imaging in congenital inner ear malformations—An algorithmic approach

Malformations of the inner ear are an important cause of congenital deaf-mutism. Arrest in embryologic development of inner ear during various stages gives rise to the variety of malformations encountered. Current treatment options include hearing aids, cochlear implants, and auditory brainstem implants (ABI). With the advent of cochlear implant surgery and ABI, decent functional outcomes can be obtained provided such cases are diagnosed correctly and timely. To that end, high-resolution computed tomography (HRCT) has a fundamental role in the assessment of these conditions, ably supplemented by magnetic resonance imaging (MRI). The purpose of this pictorial essay is to illustrate the imaging features of inner ear anomalies in children with congenital deaf-mutism as per the latest terminology and classification and provide an algorithmic approach for their diagnosis.

The link between Brain and Hearing system

There are some studies which confirmed that dysfunction in Central Nervous System(CNS) may cause a malfunction in the Peripheral Auditory system (Cochlea_ Auditory Nerve, Auditory Neuropathy), but the question is could Brain Disorder without any lesion in the Cochlea and/or Auditory nerve cause Sensorineural Hearing Loss? It means that the Audiogram shows that the patient suffers from sensorineural hearing loss but the site of the lesion is neither Sensory nor Neural while Brain may be involved in charge of this. And if the answer is yes then could we hear with our Brain and without Cochlea and /or Auditory nerve? We deal with this subject in this paper by: Otosclerosis and Meniere’s disease and The Brain Involvement. Hearing Loss following dysfunction in the Central Auditory and/or central non auditory system. Auditory Brainstem Implant in Patients who suffer from Neurofibromatosis Type two compare to Non Tumor cases, Mondini Syndrome, Michel aplasia. Possible role of Utricle and Saccule in Auditory (Hearing) System We propose a new Hypothesis that the External Ear Canal is not the only input of Auditory Signals, Sounds could transfer by our eyes and skin to the Cerebral Cortex and approach to the Cochlea (Backward Auditory input pathway of Sounds).

Pediatric Auditory Brainstem Implants, Adult Single-Sided Deafness, and Teaching

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Profiling Long-term Outcomes in children with Auditory Brainstem Implant

Profiling Long-term Outcomes in children with Auditory Brainstem Implant

Auditory brainstem implantation (ABI) in children without neurofibromatosis type II (NF2): communication performance and safety after 24 months of use

Objectives: To assess the safety and communication performance of auditory brainstem implant (ABI) provision in children who were contraindicated for cochlear implantation and do not have neurofibromatosis type II (NF2).Methods: Communication performance was assessed via a battery of tests up to 24 months after first fitting. Safety was assessed intra-operatively and via post-operative adverse event reports.Results: Ten children participated in the study. The mean communication skills on all 8 tests for which inferential statistics were possible increased significantly from pre-operatively to 12 months and either again increased significantly or remained stable from 12 to 24 months. Communication development was variable: some children achieved high scores while others did not. Two serious adverse events that were device or procedure-related were reported and successfully resolved.Discussion: ABI provision in this population group was safe. Participants’ auditory abilities were significantly better after 24 months of ABI use than at pre-implantation. Development was slower than that of children with a cochlear implant but may continue progressing after 24 months of use.Conclusion: ABI provision and use is safe and allows significant auditory development in children without NF2 who are contradicted for cochlear implantation.

Management of sporadic vestibular schwannoma with contralateral nonserviceable hearing.

To outline a possible decision-making process for sporadic vestibular schwannoma (VS) with contralateral nonserviceable hearing at diagnosis. Retrospective case series. Diagnosed VS was studied in a tertiary referral center from 1995 to 2013. Twenty-eight patients were included, with a mean follow-up of 6.9 years (range = 0.5-20 years). Ten were stage 1, 10 were stage 2, five were stage 3, and three were stage 4. Ipsilateral hearing levels were A (n = 3), B (n = 10), C (n = 7) and D (n = 8) American Academy of Otolaryngology-Head and Neck Surgery classification. Contralateral hearing levels were C (n = 11) and D (n = 17). Initial VS management included surveillance (n = 12) or surgery (n = 16), and four patients were later treated with surgery (n = 3) or stereotactic irradiation (n = 1). Hearing was improved by hearing aids and/or etiological treatment (n = 8), restored by contralateral (n = 15) or ipsilateral (n = 4) cochlear implants (CIs), or ipsilateral auditory brainstem implants (ABIs) (n = 3). Finally, 18 CIs were active daily; 14 of them presented high or moderate benefit with mean open-set dissyllabic word scores (WRS) of 58.1% and sentence recognition scores (SRS) of 69.7%, but only one ABI was still active (WRS of 70% and SRS of 87% with lip reading). When early removal of VS was not necessary, contralateral CI or etiological treatment for hearing loss might be recommended initially. Ipsilateral CI is proposed, whereas VS should be operated on if previous hearing restoration was not successful. ABI should be reserved for the rare cases where a contralateral CI could not be implanted or the cochlear nerve was sectioned during VS removal. 3 Laryngoscope, 130:E407-E415, 2020.

Microstructured thin-film electrode technology enables proof of concept of scalable, soft auditory brainstem implants.

Auditory brainstem implants (ABIs) provide sound awareness to deaf individuals who are not candidates for the cochlear implant. The ABI electrode array rests on the surface of the cochlear nucleus (CN) in the brainstem and delivers multichannel electrical stimulation. The complex anatomy and physiology of the CN, together with poor spatial selectivity of electrical stimulation and inherent stiffness of contemporary multichannel arrays, leads to only modest auditory outcomes among ABI users. Here, we hypothesized that a soft ABI could enhance biomechanical compatibility with the curved CN surface. We developed implantable ABIs that are compatible with surgical handling, conform to the curvature of the CN after placement, and deliver efficient electrical stimulation. The soft ABI array design relies on precise microstructuring of plastic-metal-plastic multilayers to enable mechanical compliance, patterning, and electrical function. We fabricated soft ABIs to the scale of mouse and human CN and validated them in vitro. Experiments in mice demonstrated that these implants reliably evoked auditory neural activity over 1 month in vivo. Evaluation in human cadaveric models confirmed compatibility after insertion using an endoscopic-assisted craniotomy surgery, ease of array positioning, and robustness and reliability of the soft electrodes. This neurotechnology offers an opportunity to treat deafness in patients who are not candidates for the cochlear implant, and the design and manufacturing principles are broadly applicable to implantable soft bioelectronics throughout the central and peripheral nervous system.

Editorial introductions

Editorial introductions

Dimensions of artefacts caused by cochlear and auditory brainstem implants in magnetic resonance imaging

Background: The aim of the study was to investigate the extent of MRI artefacts due to the magnet of selected auditory implants.Study design: Artefacts of the Synchrony cochlear implant at 1.5 T as well as at 3 T MRI devices were examined in cadavers and compared to the artefacts in MRI scans at 1.5 T of 17 patients implanted with CI (n = 12) and auditory brainstem implants (ABI) (n = 5).Results: None of the scanned implants showed any failure after MRI. After removal of the magnet, only a portion of the images in the direct neighbourhood of the implant, especially in the temporal and parietal lobe, contained artefacts. More anatomical substructures were visible without artefacts using the MedEl Synchrony device.Conclusion: Artefacts can be markedly reduced by rotating, self-aligning magnet. Removal of the magnet also results in reduction of artefacts.

Pediatric Auditory Brainstem Implant Users Compared With Cochlear Implant Users With Additional Disabilities.

To evaluate long-term language development in children with prelingual deafness who received auditory brainstem implants (ABIs) compared with children who received cochlear implants (CIs) at the same hospital. Additional non-auditory disabilities were taken into account. Retrospective cohort study. Tertiary referral center. Ten children with bilateral malformations of the cochlea and/or cochlear nerve who received ABIs, including seven with additional disabilities, and 147 children with CIs as a reference group, including 22 children with additional disabilities. ABIs were implanted at 1.3 to 6.2 years of age. Follow-up ranged from 1.1 to 7.7 years. Receptive and expressive language abilities were assessed using the Infant Toddler Meaningful Auditory Integration Scale (IT-MAIS), the Categories of Auditory Performance (CAP), the Meaningful Use of Speech Scale (MUSS), and the Speech Intelligibility Rate (SIR). Of the 10 children with ABIs, seven had long-term follow-up data. Within 1 year, six of the seven children with ABIs could identify sounds, respond to speech, and use their voice to attract attention. Language skills developed at a slower rate than in children with CIs and reached the same competence level when additional disabilities were absent. These language skills matched, on average, those of children with CIs with additional disabilities. For deaf children with bilateral inner ear malformations, ABIs provide satisfactory auditory input. Children with ABIs are able to develop receptive and expressive language skills comparable to those of children with CIs with additional disabilities. Using this knowledge, preoperative parent counselling can be refined.