Evaluating cochlear insertion trauma and hearing preservation after cochlear implantation (CIPRES): a study protocol for a randomized single-blind controlled trial

Background In order to preserve residual hearing in patients with sensorineural hearing loss (SNHL) who receive a cochlear implant (CI), insertion trauma to the delicate structures of the cochlea needs to be minimized. The surgical approach comprises the conventional mastoidectomy-posterior tympanotomy (MPT) to arrive at the middle ear, followed by either a cochleostomy (CO) or the round window (RW) approach. Both techniques have their benefits and disadvantages. Another important aspect in structure preservation is the design of the electrode array. Two different designs are used: a “straight” lateral wall lying electrode array (LW) or a “pre-curved” perimodiolar lying electrode array (PM). Interestingly, until now, the best surgical approach and design of the implant is uncertain. Our hypothesis is that there is a difference in hearing preservation outcomes between the four possible treatment options. Methods We designed a monocenter, multi-arm, randomized controlled trial to compare insertion trauma between four groups of patients, with each group having a unique combination of an electrode array type (LW or PM) and surgical approach (RW or CO). In total, 48 patients will be randomized into one of these four intervention groups. Our primary objective is the comparison of postoperative hearing preservation between these four groups. Secondly, we aim to assess structure preservation (i.e., scalar translocation, with basilar membrane disruption or tip fold-over of array) for each group. Thirdly, we will compare objective outcomes of hearing and structure preservation by way of electrocochleography (ECochG). Discussion Cochlear implantation by way of a cochleostomy or round window approach, using different electrode array types, is the standard medical care for patients with severe to profound bilateral sensorineural hearing loss, as it is a relatively simple and low-risk procedure that greatly benefits patients. However, loss of residual hearing remains a problem. This trial is the first randomized controlled trial that evaluates the effect of cochlear insertion trauma of several CI treatment options on hearing preservation. Trial registration Netherlands Trial Register (NTR) NL8586. Registered on 4 May 2020. Retrospectively registered; 3/48 participants were included before registration.

The Limitations of FDA Criteria: Inconsistencies with Clinical Practice, Findings, and Adult Criteria as a Barrier to Pediatric Implantation

Children require greater access to sound than adults as they are learning to communicate using hearing and spoken language. Yet when it comes to cochlear implant candidacy, currently approved Food and Drug Administration (FDA) criteria for adults are much less restrictive than those for children, allowing for greater levels of residual hearing and aided speech recognition in adults. Cochlear implant guidelines for children have changed very little in the 30 years since cochlear implants have been approved for pediatrics, and this lack of change has proven to be a barrier to implantation. Using evidence-based practice, centers have been providing off-label implantation for children who fall outside of current FDA criteria, including children with more residual hearing, children with single-side deafness younger than 5 years, and infants with bilateral profound loss younger than 9 months. The purpose of this article is to outline how these restrictions impede access to implants for children and describe the evidence supporting cochlear implantation in children who fall outside of current criteria.

Mythbusters! The Truth about Common Misconceptions in Cochlear Implantation

Cochlear implantation (CI) is the preferred method of hearing rehabilitation when patients cannot perform well with traditional amplification. Unfortunately, there are still significant misconceptions around this life-changing intervention. The goal of this article is to address some of the most common myths around CI surgery. After reading this article, the learner will be able to explain the utility of CI in patients with residual hearing and recognize that insurance coverage is widespread. The reader will be able to list common risks associated with this well-tolerated procedure including anesthetic risk and the risk of vestibular dysfunction. Additionally, the reader will be able to identify the significant positive impact of CI on patients' quality of life. Finally, the reader will identify that many patients can safely have an MRI scan after implantation, including nearly all contemporary recipients.

Explanation of Frequency Distinguishing in Human Ear (Using Computer Model)

The inspiration for this model ware possibilities of the human ear to distinguish the frequency of sounds and a diffraction grating. Detection takes place after max. 15 length of the wave (arbitrary choice). The range of frequencies to detect for tests – 800-3200 Hz: detection every 5 Hz in the range 800-1600 Hz and 10 Hz in the range 1600-3200 Hz (arbitrary choice). It can explain the residual hearing effect (missing tone f is heard when harmonic tones 2f, 3f and 4f are played). The algorithm can be used as an alternative for FFT. Model uses only memory for delay line end for results, and adding operation, so it should be fast and cheep, and can work on-line in real-time. Testing program was written in Perl.

Explanation of frequency distinguishing in human ear (using computer model)

The inspiration for this model ware possibilities of the human ear to distinguish the frequency of sounds and a diffraction grating. Detection takes place after max. 15 length of the wave (arbitrary choice). The range of frequencies to detect for tests – 800-3200 Hz: detection every 5 Hz in the range 800-1600 Hz and 10 Hz in the range 1600-3200 Hz (arbitrary choice). It can explain the residual hearing effect (missing tone f is heard when harmonic tones 2f, 3f and 4f are played). The algorithm can be used as an alternative for FFT. Model uses only memory for delay line end for results, and adding operation, so it should be fast and cheep, and can work on-line in real-time. Testing program was written in Perl.

Removal of Koos IV acoustic neuroma and auditory brainstem implant in NF2 patient

The authors present the case of removal of a Koos grade IV right acoustic neuroma in a neurofibromatosis type 2 (NF2) patient, already operated on for left cerebellopontine angle meningioma at 7 years of age and a left acoustic neuroma at 16 years of age. A transpetrosal approach allowed cochlear sensor implantation to detect residual hearing. An enlarged retrosigmoid approach then allowed subtotal microsurgical removal of the lesion; consequently, the authors illustrate the technical nuances of an auditory brainstem implant (ABI). One month after surgery, the ABI was successfully switched on, giving back hearing perception to the patient. The video can be found here: https://stream.cadmore.media/r10.3171/2021.7.FOCVID2188

Cochlear Implantation in Elderly Patients with Residual Hearing

This retrospective study aimed to investigate the range of hearing levels in a cochlear implant (CI) elderly population receiving electric-acoustic-stimulation (EAS) or electric-stimulation (ES) alone. The investigation evaluates the degree of hearing preservation (HP) and the speech comprehension resulting from EAS or ES-only to identify audiometric factors that predict adequate EAS and ES use. We analyzed the pure tone audiometry and speech perception in quiet and noise preoperatively and 12-months after activation of 89 elderly adults (age of 65 years old or older), yielding in total 97 CIs. Thirty-two (33.1%) patients were potential EAS candidates preoperatively, of which 18 patients used EAS at the time of first fitting and the other 14 patients continued to use their residual hearing for EAS at 12-months. Post-treatment, patients with EAS system and ES-only users’ with longer electrodes showed better results in monosyllable word scores in quiet than ES-only users with shorter electrodes. A similar trend was revealed for the speech recognition in noise. Patients with an EAS system benefit from maintaining their natural residual hearing. Nevertheless, strict preoperative patient selection is warranted particularly in elderly patients, in whom the hearing thresholds for EAS indication differ slightly from that in younger adults.

Bimodal Fitting and Bilateral Cochlear Implants in Children With Significant Residual Hearing: The Impact of Asymmetry in Spatial Release of Masking on Localization

Purpose This study aimed to gain more insight into the primary auditory abilities of children with significant residual hearing in order to improve decision making when choosing between bimodal fitting or sequential bilateral cochlear implantation. Method Sound localization abilities, spatial release of masking, and fundamental frequency perception were tested. Nine children with bimodal fitting and seven children with sequential bilateral cochlear implants were included in the study. As a reference, 15 children with normal hearing and two children with simultaneous bilateral cochlear implants were included. Results On all outcome measures, the implanted children performed worse than the normal hearing children. For high-frequency localization, children with sequential bilateral cochlear implants performed significantly better than children with bimodal fitting. Compared to children with normal hearing, the left–right asymmetry in spatial release of masking was significant. When the implant was hindered by noise, bimodally fitted children obtained significantly lower spatial release of masking compared to when the hearing aid was hindered by noise. Overall, the larger the left–right asymmetry in spatial release of masking, the poorer the localization skills. No significant differences were found in fundamental frequency perception between the implant groups. Conclusions The data hint to an advantage of bilateral implantation over bimodal fitting. The extent of asymmetry in spatial release of masking is a promising tool for decision making when choosing whether to continue with the hearing aid or to provide a second cochlear implant in children with significant residual hearing.

Comparison of residual hearing preservation and auditory based performance after paediatric cochlear implantation by round window insertion versus cochleostomy technique: an ambispective cohort study

<p class="abstract"><strong>Background:</strong> Cochlear implantation (CI) has revolutionized the treatment of sensorineural deafness. The aim of the study was to compare auditory based performance in cochlear implants who underwent round window insertion and cochleostomy.</p><p class="abstract"><strong>Methods:</strong> Ambispective cohort study was done among the children who underwent perilingual cochlear implant in a tertiary care hospital for period of 1 year. Children who satisfied the inclusion criteria were selected and randomly subdivided into 2 groups: group A- round window insertion and group B-cochleostomy. Pre- and post-operative pure tone average (PTA) and residual hearing preserved were evaluated among the cochleostomy and round window insertion groups separately. Post-operatively, children were evaluated, from three months to 1 year from the activation of cochlear implant, with the use of scores such as Category of Auditory Performance (CAP), Meaningful Auditory Integration Scale (MAIS), Speech Intelligibility rating (SIR) and Meaningful use of speech scale (MUSS score) to measure speech production skills by auditory verbal therapist. </p><p class="abstract"><strong>Results:</strong> A total of 80 patients were included in the study. Complete hearing preservation (within 10 dB) was significantly high in round window insertion group compared to cochleostomy technique (p&lt;0.001). None the subjects had complete loss of residual hearing. On evaluating the post CI performance, MAIS score in the round window insertion group (9.34, 18.21, 27.79) were significantly better compared to cochleostomy group during the 3 months, 6 months and 12 months follow-up.</p><p class="abstract"><strong>Conclusions:</strong> Round window insertion technique is significantly more successful in complete hearing preservation at low frequencies compared to cochleostomy technique. Among the auditory scores, only MAIS in the round window insertion group was found to be significantly better compared to cochleostomy group.</p>