Bilateral cochlear implantation.

Binaural hearing has certain benefits while listening in noisy environments. It provides the listeners with access to time, level and spectral differences between sound signals, perceived by the two ears. However, single sided deaf (SSD) or unilateral cochlear implant (CI) users cannot experience these binaural benefits due to the acoustic input coming from a single ear. The translational research on bilateral CIs started in the year 1998, initiated by J. Müller and J. Helms from Würzburg, Germany in association with MED-EL. Since then, several clinical studies were conducted by different research groups from across the world either independently or in collaboration with MED-EL. As a result, the bilateral CI has become the standard of care in many countries along with reimbursement by the health care systems. Recent data shows that children particularly, are given high priority for the bilateral CI implantation, most often performed simultaneously in a single surgery, as the binaural hearing has a positive effect on their language development. This article covers the milestones of translational research from the first concept to the widespread clinical use of bilateral CI.

Cochlear Implant Electrode Array From Partial to Full Insertion in Non-Human Primate Model.

OBJECTIVES: To determine the feasibility of progressive insertion (two sequential surgeries: partial to full insertion) of an electrode array and to compare functional outcomes. MATERIAL AND METHODS: 8 normal-hearing animals (Macaca fascicularis (MF)) were included. A 14 contact electrode array, which is suitably sized for the MF cochlea was partially inserted (PI) in 16 ears. After 3 months of follow-up revision surgery the electrode was advanced to a full insertion (FI) in 8 ears. Radiological examination and auditory testing was performed monthly for 6 months. In order to compare the values a two way repeated measures ANOVA was used. A p-value below 0.05 was considered as statistically significant. IBM SPSS Statistics V20 was used. RESULTS: Surgical procedure was completed in all cases with no complications. Mean auditory threshold shift (ABR click tones) after 6 months follow-up is 19 dB and 27 dB for PI and FI group. For frequencies 4, 6, 8, 12, and 16 kHz in the FI group, tone burst auditory thresholds increased after the revision surgery showing no recovery thereafter. Mean threshold shift at 6 months of follow- up is 19.8 dB ranging from 2 to 36dB for PI group and 33.14dB ranging from 8 to 48dB for FI group. Statistical analysis yields no significant differences between groups. CONCLUSION: It is feasible to perform a partial insertion of an electrode array and progress on a second surgical time to a full insertion (up to 270º). Hearing preservation is feasible for both procedures. Note that a minimal threshold deterioration is depicted among full insertion group, especially among high frequencies, with no statistical differences.

Towards a Complete In Silico Assessment of the Outcome of Cochlear Implantation Surgery.

Cochlear implantation (CI) surgery is a very successful technique, performed on more than 300,000 people worldwide. However, since the challenge resides in obtaining an accurate surgical planning, computational models are considered to provide such accurate tools. They allow us to plan and simulate beforehand surgical procedures in order to maximally optimize surgery outcomes, and consequently provide valuable information to guide pre-operative decisions. The aim of this work is to develop and validate computational tools to completely assess the patient-specific functional outcome of the CI surgery. A complete automatic framework was developed to create and assess computationally CI models, focusing on the neural response of the auditory nerve fibers (ANF) induced by the electrical stimulation of the implant. The framework was applied to evaluate the effects of ANF degeneration and electrode intra-cochlear position on nerve activation. Results indicate that the intra-cochlear positioning of the electrode has a strong effect on the global performance of the CI. Lateral insertion provides better neural responses in case of peripheral process degeneration, and it is recommended, together with optimized intensity levels, in order to preserve the internal structures. Overall, the developed automatic framework provides an insight into the global performance of the implant in a patient-specific way. This enables to further optimize the functional performance and helps to select the best CI configuration and treatment strategy for a given patient.

Considerations and Rationale for Cochlear Implant Electrode Design - Past, Present and Future.

The electrode array of a cochlear implant forms a permanent, often lifelong interface between the implanted electronics and neural structures of the cochlea. A cochlear implant is primarily prescribed to restore hearing via electrical stimulation of the auditory nerve. As with any neural stimulator intended to either deliver electrical stimulus or record a neural response, the aim is to place the electrodes in close proximity to the target neural structures. The broadening of indications and the concept of preservation of low-frequency residual hearing over the last two decades has resulted in an increased understanding of the mechanisms and implications of intracochlear trauma for both the hearing preservation surgery and electrical stimulation outcomes with cochlear implantation, as well as the influence of many biographic and audiological patient factors correlated with achieving better hearing outcomes. These two goals, the proximity to the cochlear nerve for electrical stimulation and the preservation of cochlear structures, have typically been viewed as mutually exclusive, with perimodiolar electrode arrays being preferred for the former, and lateral wall electrode arrays for the latter. The design evolution of both the lateral wall and perimodiolar electrodes is presented, considering the cochlea anatomy and continued understanding of the mechanics and dynamics of electrode insertion, along with the influence of the ongoing changes to the intracochlear environment to provide a rationale for the electrode design with the intent to provide the greatest patient benefit over their implanted lifetime.

Barriers to early cochlear implantation.

OBJECTIVE: Identify variables associated with paediatric access to cochlear implants (CIs). DESIGN: Part 1. Trends over time for age at CI surgery (N = 802) and age at hearing aid (HA) fitting (n = 487) were examined with regard to periods before, during, and after newborn hearing screening (NHS). Part 2. Demographic factors were explored for 417 children implanted under 3 years of age. Part 3. Pre-implant steps for the first 20 children to receive CIs under 12 months were examined. RESULTS: Part 1. Age at HA fitting and CI surgery reduced over time, and were associated with NHS implementation. Part 2. For children implanted under 3 years, earlier age at HA fitting and higher family socio-economic status were associated with earlier CI. Progressive hearing loss was associated with later CIs. Children with a Connexin 26 diagnosis received CIs earlier than children with a premature / low birth weight history. Part 3. The longest pre-CI steps were Step 1: Birth to diagnosis/identification of hearing loss (mean 16.43 weeks), and Step 11: MRI scans to implant surgery (mean 15.05 weeks) for the first 20 infants with CIs under 12 months. CONCLUSION: NHS implementation was associated with reductions in age at device intervention in this cohort.

New expectations: pediatric cochlear implantation in Japan.

FUNDING FOR COCHLEAR IMPLANTS: The Japanese health-care system provides universal health coverage for the entire 127 million population of Japan. This includes all aspects of cochlear implantation, from diagnosis to implantation to mapping and habilitation aftercare. Japan has the third largest developed economy; however, the uptake rate for cochlear implants is lower than that of countries with similar economic status. Japan has an uptake rate of approximately 1% of potentially suitable subjects of all ages, compared with 5.6% in the USA. COCHLEAR IMPLANT PROVISION FOR CHILDREN: In Japan, about 55% of cochlear implant recipients are children of less than 18 years of age. This represents an increase of 20% in the last 10 years, with a relative increase in the numbers of children receiving implants compared with the numbers of adults. However, only 3-4% of children under the age of 3 years are being implanted at less than 18 months of age. This is in accordance with the Japanese ENT Academy's guidelines, which currently puts the minimum age limit for implants in children at 18 months. NEONATAL SCREENING: For hearing loss was first piloted nationally in Japan in 2000. Funding for screening subsequently stopped in 2005, though the national treasury provided a further 2 years' funding. Since 2007 local government organizations have been given responsibility to support these screening programs, but there remains considerable variation in funding between different prefectures. In one prefecture, Okayama, 95% of babies were screened and followed up for 2 years. However, the support system for children who need further diagnostic testing after screening remains insufficient. REFERRAL: When diagnosed, children with hearing loss are referred for counselling, hearing aids and habilitation. The responsibility for these is divided between the Ministry of Health and Welfare (including surgery, device programming, and therapy) and the Ministry of Education. Schools for the deaf and preschool hearing impaired education centers have had most of the responsibility for early intervention, educational choices and referral for cochlear implantation. In the past 98% of schools for children with hearing loss have used communication methods relying mostly on visual cues. In recent years, however, there has been a shift toward 'inclusive' mainstream education. Between 2008 and 2011 the number of children with cochlear implants in special needs schools increased to 16%. It is now estimated that 67% of children with cochlear implants may now be in mainstream schools. There is still the need for support services for these implanted children attending mainstream schools, with adequate provision of resources. CONCLUSION: Cochlear Implantation has had a significant role in changing the medical management and education of children in Japan with hearing loss. Much remains to be done, though the situation has greatly improved in recent years and continues to do so.

Complicaciones en el implante coclear pediátrico en la Clínica José A. Rivas. Bogotá - Colombia / Complications in pediatric cochlear implant Clinic Jose A. Rivas. Bogotá – Colombia

Introducción: La cirugía de implante coclear, como cualquier otro acto quirúrgico, puede asociarse a complicaciones inherentes al procedimiento o por un fallo atribuible al dispositivo. Objetivo: Identificar y reportar la tasa de complicaciones asociadas a la implantación coclear en menores de 18 años atendidos en el programa de implante coclear en una institución en Bogotá, Colombia. Diseño: Estudio retrospectivo. Métodos: Se incluyeron pacientes a quienes se les realizaron implantes cocleares pediátricos en el período 1994 al 2011. Se analiza en este estudio a los que recibieron implante coclear a la edad de 18 años o menos. Desenlaces principales: tasa global de complicaciones; tasa discriminada de complicaciones por tipo: médico-quirúrgica, y complicaciones atribuibles a fallo del dispositivo. Resultados: Del total de implantes cocleares (920) realizados durante el período de estudio, se selecciona el grupo con edad ≤ 18 años a la fecha del implante, 598 (65%). Total complicaciones identificadas: 49 (8,2%). Complicaciones médico-quirúrgicas: 15 (2,5%). Fallos relacionados con el dispositivo: 5,7%. Conclusiones: La tasa global de complicaciones y fallos identificada en este estudio se asemeja a la reportada por diferentes estudios, la cual varía entre el 5 y el 13% …

Introduction: Cochlear implant surgery, like any surgery, can be associated with complications inherent to the procedure or a failure attributable to the device. Objective: To identify and report the rate of complications associated with cochlear implantation in children under 18 years who presented to the cochlear implant program at a school in Bogota, Colombia. Design: Retrospective. Methods: Patients who underwent pediatric cochlear implants performed in the period 1994-2011. Is analyzed in this study who received cochlear implant at the age of 18 years or less. Main outcome measures: overall complication rate, rate of complications discriminated by type: medical-surgical complications due to device failure. Results: A total of cochlear implants (920) performed during the study period is selected age group ≤ 18 years at the time of implantation, 598 (65%). Total complications identified: 49 (8.2%). Medical-surgical complications: 15 (2.5%). Device-related failures: 5.7%. Conclusions: The overall rate of complications and failures identified in this study is similar to that reported by different studies, which varies between 5 and 13%…

Cochlear implantation in patient with Dandy-walker syndrome

Introduction: Dandy Walker Syndrome is a congenital abnormality in the central nervous system, characterized by a deficiency in the development of middle cerebelar structures, cystic dilatation of the posterior pit communicating with the fourth ventricle and upward shift of the transverse sinuses, tentorium and dyes. Among the clinical signs are occipital protuberances, a progressive increase of the skull, bowing before the fontanels, papilledema, ataxia, gait disturbances, nystagmus, and intellectual impairment. Objectives: To describe a case of female patient, 13 years old with a diagnosis of this syndrome and bilateral hearing loss underwent cochlear implant surgery under local anesthesia and sedation. Case Report: CGS, 13 years old female was referred to the Otolaryngological Department of Otolaryngology Institute of Parana with a diagnosis of "Dandy-Walker syndrome" for Otolaryngological evaluation for bilateral hearing loss with no response to the use of hearing aids. Final Comments: The field of cochlear implants is growing rapidly. We believe that the presence of Dandy-Walker syndrome cannot be considered a contraindication to the performance of cochlear implant surgery, and there were no surgical complications due to neurological disorders with very favorable results for the patient who exhibits excellent discrimination. It has less need for lip reading with improvement in speech quality...

Effect of cochlear implant technology in sequentially bilaterally implanted adults.

OBJECTIVE: Bilateral sequential cochlear implantation outcomes are dependent on many different factors. Newer technology in the second implanted ear may also contribute to outcome. This study examines the effect of cochlear implant technology on speech recognition outcomes in a population of adult patients who have undergone bilateral sequential implantation using different technologies in each ear. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Twenty adults who underwent bilateral sequential cochlear implantation with different technologies and processing strategies in each ear were patients for this study. Control Group A included patients (n = 8) who were simultaneously implanted, and Control Group B (n = 3) were patients who were sequentially implanted with the same technology. INTERVENTION: Bilateral sequential cochlear implantation. OUTCOME MEASURES: The outcome measure was the Consonant-Nucleus-Consonant monosyllabic word test administered in each implanted ear and in the binaural condition before and 1 year after operation. A multivariate analysis was performed to account for factors including duration of deafness, length of device usage, and severity of deafness. RESULTS: There was significant improvement from before to 1 year after the operation in word scores for the individual ears and in the binaural condition for all groups. All patients were consistent users of both devices, and the use of different technology in the second implanted ear did not affect the patients' ability to benefit from bilateral implantation despite the use of different devices and processing strategies. CONCLUSION: Bilateral sequential implantation with newer and/or differing technology in the second implanted ear did not reduce the benefits of bilateral stimulation and should not be considered a deterrent to second-sided implantation.

Cochlear implant and hearing aid: a new approach to optimizing the fitting in this bimodal situation.

More and more patients with residual hearing on the contralateral side are becoming candidates for cochlear implants (CI) surgery due to increasing CI. The major benefits of regular binaural hearing are spatial hearing, localization, and signal source discrimination in both quiet and noisy surroundings. In most of the reports, hearing aid fitting was carried out without balancing both the devices. Twelve children and eight adults with residual hearing on the non-operated side were binaurally fitted. Our fitting procedure for the hearing aid was based on the desired sensation level [i/o] method. A loudness scaling was used to adjust the loudness perception monaurally and to balance the volume of both devices. Speech audiometry in quiet and noisy surroundings was conducted both monaurally and in the bimodal mode. The fitting was modified according to the respective test results. In all children and six adults, a measurable gain and/or a subjective improvement of speech perception was achieved. Two adult patients did not accept the new fitting. In seven younger children, loudness scaling was impossible to perform because of age. This was also the case with speech audiometry for two children. A structured bimodal fitting using loudness scaling for both the cochlear implant and the hearing aid results in a subjective and objective amelioration of the patient's hearing and speech perception.

Cochlear nucleus auditory prostheses.

Persons who lack an auditory nerve cannot benefit from cochlear implants, but a prosthesis utilizing an electrode array implanted on the surface of the cochlear nucleus can restore some hearing. Worldwide, more than 500 persons have received these "auditory brainstem implants," most commonly after removal of the tumors that occur with Type 2 Neurofibromatosis (NF2). Typically, the ABIs provide these individuals with improved speech perception when combined with lip-reading and useful perception of environmental sounds, but little open-set speech recognition. The feasibility of supplementing the array of surface electrodes with penetrating microstimulating electrodes has been investigated in animal studies, and 10 persons with NF2 have received implants that include a surface array and an array of penetrating microelectrodes. Their speech perception is not significantly better than that of the NF2 patients who have only the surface arrays, but the findings do validate the concept of intranuclear stimulation and suggest how such prostheses might be improved by modifying the microstimulating array and also by optimizing the sound processing strategies. Recent publications have described ABI patients with deafness of etiologies other than NF2 who have achieved open-set speech recognition. This suggests that the cochlear nuclei of the NF2 patients are damaged by the disease process or during surgical removal of the tumor.

Hearing aids: a review of what's new.

OBJECTIVE: To review the recent innovations in hearing aid technology. STUDY DESIGN: Review of the literature. SETTING: Private tertiary referral otology/neurotology practice. RESULTS: Recent innovations including digital signal processing (DSP), directional microphone technology, and open mold hearing aid fitting have resulted in improved satisfaction with current hearing aids. CONCLUSION: Current hearing aid technology with its innovations better meet needs of individuals who are hard of hearing. SIGNIFICANCE: The image commonly held of hearing aids by the general public is a negative one that can be improved with greater education.

Chronic depolarization enhances the trophic effects of brain-derived neurotrophic factor in rescuing auditory neurons following a sensorineural hearing loss.

The development and maintenance of spiral ganglion neurons (SGNs) appears to be supported by both neural activity and neurotrophins. Removal of this support leads to their gradual degeneration. Here, we examined whether the exogenous delivery of the neurotrophin brain-derived neurotrophic factor (BDNF) in concert with electrical stimulation (ES) provides a greater protective effect than delivery of BDNF alone in vivo. The left cochlea of profoundly deafened guinea pigs was implanted with an electrode array and drug-delivery system. BDNF or artificial perilymph (AP) was delivered continuously for 28 days. ES induced neural activity in two cohorts (BDNF/ES and AP/ES), and control animals received BDNF or AP without ES (BDNF/- and AP/-). The right cochleae of the animals served as deafened untreated controls. Electrically evoked auditory brainstem responses (EABRs) were recorded immediately following surgery and at completion of the drug-delivery period. AP/ES and AP/- cohorts showed an increase in EABR threshold over the implantation period, whereas both BDNF cohorts exhibited a reduction in threshold (P < 0.001, t-test). Changes in neural sensitivity were complemented by significant differences in both SGN survival and soma area. BDNF cohorts demonstrated a significant trophic or survival advantage and larger soma area compared with AP-treated and deafened control cochleae; this advantage was greatest in the base of the cochlea. ES significantly enhanced the survival effects of BDNF throughout the majority of the cochlea (P < 0.05, Bonferroni's t-test), although there was no evidence of trophic support provided by ES alone. Cotreatment of SGNs with BDNF and ES provides a substantial functional and trophic advantage; this treatment may have important implications for neural prostheses.

Programa de implante coclear de la Fundación Santa fe de Bogotá: 6 años de experiencia / Program of cochlear implants of the Fundation Santa Fe de Bogotá: 6 years of experience

En el presente estudio mostramos la experiencia de nuestro grupo multidisciplinario en el tratamiento quirúrgico y rehabilitación de 92 pacientes a quienes se les realizó un Implante coclear. Este grupo está conformado por 57 niños y 25 adultos entre los 2 y los 68 años de edad. Describimos los resultados obtenidos en las pruebas de discriminación del lenguaje de prosodia, contexto cerrado y contexto abierto en los grupos prelinguales y postlinguales. La mejoría en habilidades auditivas tanto en los pacientes pediátricos, como en los adultos con sordera prelingual o postlingual son estadísticamente significativos. El tiempo en la aparición de la sordera, el promedio tonal con audífonos en 2000 y 3000 Hz previo a la implantación y la asistencia a colegio regular son variables que influyen en el mejor desempeño de los pacientes. Las complicaciones quirúrgicas son infrecuentes y se enfatiza la importancia de un medio multidisciplinario para el éxito de un programa de Implante Coclear