Cochlear Implant Electrode Placement and Music Perception.

Importance: Cochlear implants enable improvements in speech perception, but music perception outcomes remain variable. Image-guided cochlear implant programming has emerged as a potential programming strategy for increasing the quality of spectral information delivered through the cochlear implant to improve outcomes.

Objectives: To perform 2 experiments, the first of which modeled the variance in music perception scores as a function of electrode positioning factors, and the second of which evaluated image-guided cochlear implant programming as a strategy to improve music perception with a cochlear implant.

The relationship between channel interaction, electrode placement, and speech perception in adult cochlear implant users.

This study (1) characterized the effects of channel interaction using spectral blurring, (2) evaluated an image-guided electrode selection (IGES) method aiming to reduce channel interaction, and (3) investigated the impact of electrode placement factors on the change in performance by condition. Twelve adult MED-EL (Innsbruck, Austria) cochlear implant recipients participated. Performance was compared across six conditions: baseline (no blurring), all blurred, apical blurred, middle blurred, basal blurred, and IGES.

Frequency-to-Place Mismatch and Cochlear Implant Outcomes by Electrode Type.

Importance: Speech recognition outcomes with a cochlear implant (CI) are highly variable. One factor suggested to correlate with CI-aided speech recognition is frequency-to-place mismatch, or the discrepancy between the natural tonotopic organization of the cochlea and the electric frequency allocation of the CI electrodes within the patient's cochlea.

Objective: To evaluate the association between frequency-to-place mismatch and speech recognition outcomes in a large cohort of postlingually deafened adult CI users, while controlling for various clinical factors known to be associated with those outcomes.

Super-resolution segmentation network for inner-ear tissue segmentation.

Cochlear implants (CIs) are considered the standard-of-care treatment for profound sensory-based hearing loss. Several groups have proposed computational models of the cochlea in order to study the neural activation patterns in response to CI stimulation. However, most of the current implementations either rely on high-resolution histological images that cannot be customized for CI users or CT images that lack the spatial resolution to show cochlear structures.

A Unified Deep-Learning-Based Framework for Cochlear Implant Electrode Array Localization.

Cochlear implants (CIs) are neuroprosthetics that can provide a sense of sound to people with severe-to-profound hearing loss. A CI contains an electrode array (EA) that is threaded into the cochlea during surgery. Recent studies have shown that hearing outcomes are correlated with EA placement.

Cochlear Implant Fold Detection in Intra-operative CT Using Weakly Supervised Multi-task Deep Learning.

In cochlear implant (CI) procedures, an electrode array is surgically inserted into the cochlea. The electrodes are used to stimulate the auditory nerve and restore hearing sensation for the recipient. If the array folds inside the cochlea during the insertion procedure, it can lead to trauma, damage to the residual hearing, and poor hearing restoration.

Electrode array positioning after cochlear reimplantation from single manufacturer.

Objective: To investigate whether revision surgery with the same device results in a change in three key indicators of electrode positioning: scalar location, mean modiolar distance (), and angular insertion depth (AID).

Methods: Retrospective analysis of a cochlear implant database at a university-based tertiary medical center. Intra-operative CT scans were obtained after initial and revision implantation.

Validation of active shape model techniques for intracochlear anatomy segmentation in computed tomography images.

Purpose: Cochlear implants (CIs) have been shown to be highly effective restorative devices for patients suffering from severe-to-profound hearing loss. Hearing outcomes with CIs depend on electrode positions with respect to intracochlear anatomy. Intracochlear anatomy can only be directly visualized using high-resolution modalities, such as micro-computed tomography (), which cannot be used .

Endoscope-Assisted Visualization of the Internal Auditory Canal Using the Middle Fossa Approach.

Hypothesis: Angled endoscopes have been postulated to increase visualization of the internal auditory canal (IAC); however, few studies have quantified the extent of IAC visualization using endoscopes of varying angles.

Background: Preservation of the bony labyrinth in middle fossa (MF) vestibular schwannoma surgery may limit visualization of the lateral IAC. We sought to determine the extent to which IAC visualization is increased with endoscopes in these situations.

Effects of the Number of Channels and Channel Stimulation Rate on Speech Recognition and Sound Quality Using Precurved Electrode Arrays.

Purpose: This study investigated the relationship between the number of active electrodes, channel stimulation rate, and their interaction on speech recognition and sound quality measures while controlling for electrode placement. Cochlear implant (CI) recipients with precurved electrode arrays placed entirely within scala tympani and closer to the modiolus were hypothesized to be able to utilize more channels and possibly higher stimulation rates to achieve better speech recognition performance and sound quality ratings than recipients in previous studies.

Method: Participants included seven postlingually deafened adult CI recipients with Advanced Bionics Mid-Scala electrode arrays confirmed to be entirely within scala tympani using postoperative computerized tomography.

Min-Max Similarity: A Contrastive Semi-Supervised Deep Learning Network for Surgical Tools Segmentation.

A common problem with segmentation of medical images using neural networks is the difficulty to obtain a significant number of pixel-level annotated data for training. To address this issue, we proposed a semi-supervised segmentation network based on contrastive learning. In contrast to the previous state-of-the-art, we introduce Min-Max Similarity (MMS), a contrastive learning form of dual-view training by employing classifiers and projectors to build all-negative, and positive and negative feature pairs, respectively, to formulate the learning as solving a MMS problem.

Dynamic Behavior and Insertional Forces of a Precurved Electrode Using the Pull-Back Technique in a Fresh Microdissected Cochlea.

Hypothesis: This study evaluated the utility of the pull-back technique in improving perimodiolar positioning of a precurved cochlear implant (CI) electrode array (EA) with simultaneous insertion force profile measurement and direct observation of dynamic EA behavior.

Background: Precurved EAs with perimodiolar positioning have improved outcomes compared with straight EAs because of lowered charge requirements for stimulation and decreased spread of excitation. The safety and efficacy of the pull-back technique in further improving perimodiolar positioning and its associated force profile have not been adequately demonstrated.

Activation region overlap visualization for image-guided cochlear implant programming.

. The cochlear implant is a neural prosthesis designed to directly stimulate auditory nerve fibers to induce the sensation of hearing in those experiencing severe-to-profound hearing loss. After surgical implantation, audiologists program the implant's external processor with settings intended to produce optimal hearing outcomes.

The Relationship Between Interaural Insertion-Depth Differences, Scalar Location, and Interaural Time-Difference Processing in Adult Bilateral Cochlear-Implant Listeners.

Sensitivity to interaural time differences (ITDs) in acoustic hearing involves comparison of interaurally frequency-matched inputs. Bilateral cochlear-implant arrays are, however, only approximately aligned in angular insertion depth and scalar location across the cochleae. Interaural place-of-stimulation mismatch therefore has the potential to impact binaural perception.

Speech recognition as a function of the number of channels for pediatric cochlear implant recipients.

This study investigated the number of channels required for asymptotic speech recognition for ten pediatric cochlear implant (CI) recipients with precurved electrode arrays. Programs with 4-22 active electrodes were used to assess word and sentence recognition in noise. Children demonstrated significant performance gains up to 12 electrodes for continuous interleaved sampling (CIS) and up to 22 channels with 16 maxima.

Cochlear implant spectral bandwidth for optimizing electric and acoustic stimulation (EAS).

Cochlear implantation with acoustic hearing preservation is becoming increasingly prevalent allowing cochlear implant (CI) users to combine electric and acoustic stimulation (EAS) in the implanted ears. Despite a growing EAS population, our field does not have definitive guidance regarding EAS technology optimization and the majority of previous studies investigating hearing aid (HA) and cochlear implant (CI) programming for EAS listeners have been mixed. Thus, the purpose of this exploratory study was to explore the effects of various EAS crossover frequencies-defined as the low-frequency (LF) CI cutoff-relative to the underlying spiral ganglion (SG) characteristic frequency associated with the most distal or apical electrode in the array.

Speech recognition as a function of the number of channels for Mid-Scala electrode array recipients.

This study investigated the number of channels needed for maximum speech understanding and sound quality in 15 adult cochlear implant (CI) recipients with Advanced Bionics (AB) Mid-Scala electrode arrays completely within scala tympani. In experiment I, CI programs used a continuous interleaved sampling (CIS)-based strategy and 4-16 active electrodes. In experiment II, CI programs used an n-of-m strategy featuring 16 active electrodes with either 8- or 12-maxima.

Computed-Tomography Estimates of Interaural Mismatch in Insertion Depth and Scalar Location in Bilateral Cochlear-Implant Users.

Hypothesis: Bilateral cochlear-implant (BI-CI) users will have a range of interaural insertion-depth mismatch because of different array placement or characteristics. Mismatch will be larger for electrodes located near the apex or outside scala tympani, or for arrays that are a mix of precurved and straight types.

Background: Brainstem superior olivary-complex neurons are exquisitely sensitive to interaural-difference cues for sound localization.

The Relation of Cochlear Implant Electrode Array Type and Position on Continued Hearing Preservation.

Objective: To analyze the relationship of electrode array (EA) type and position on hearing preservation longevity following cochlear implantation.

Study Design: Retrospective chart review.

Setting: Tertiary referral center.

Upward Shifts in the Internal Representation of Frequency Can Persist Over a 3-Year Period for Cochlear Implant Patients Fit With a Relatively Short Electrode Array.

Patients fit with cochlear implants (CIs) commonly indicate at the time of device fitting and for some time after, that the speech signal sounds abnormal. A high pitch or timbre is one component of the abnormal percept. In this project, our aim was to determine whether a number of years of CI use reduced perceived upshifts in frequency spectrum and/or voice fundamental frequency.

Atlas-based Segmentation of Intracochlear Anatomy in Metal Artifact Affected CT Images of the Ear with Co-trained Deep Neural Networks.

We propose an atlas-based method to segment the intracochlear anatomy (ICA) in the post-implantation CT (Post-CT) images of cochlear implant (CI) recipients that preserves the point-to-point correspondence between the meshes in the atlas and the segmented volumes. To solve this problem, which is challenging because of the strong artifacts produced by the implant, we use a pair of co-trained deep networks that generate dense deformation fields (DDFs) in opposite directions. One network is tasked with registering an atlas image to the Post-CT images and the other network is tasked with registering the Post-CT images to the atlas image.

Automatic Segmentation of Intracochlear Anatomy in MR Images Using a Weighted Active Shape Model.

There is evidence that cochlear MR signal intensity may be useful in prognosticating the risk of hearing loss after middle cranial fossa (MCF) resection of acoustic neuroma (AN), but the manual segmentation of this structure is difficult and prone to error. This hampers both large-scale retrospective studies and routine clinical use of this information. To address this issue, we present a fully automatic method that permits the segmentation of the intra-cochlear anatomy in MR images, which uses a weighted active shape model we have developed and validated to segment the intra-cochlear anatomy in CT images.

Hybrid active shape and deep learning method for the accurate and robust segmentation of the intracochlear anatomy in clinical head CT and CBCT images.

Robust and accurate segmentation methods for the intracochlear anatomy (ICA) are a critical step in the image-guided cochlear implant programming process. We have proposed an active shape model (ASM)-based method and a deep learning (DL)-based method for this task, and we have observed that the DL method tends to be more accurate than the ASM method while the ASM method tends to be more robust. We propose a DL-based U-Net-like architecture that incorporates ASM segmentation into the network.

Interaural Place-of-Stimulation Mismatch Estimates Using CT Scans and Binaural Perception, But Not Pitch, Are Consistent in Cochlear-Implant Users.

Bilateral cochlear implants (BI-CIs) or a CI for single-sided deafness (SSD-CI; one normally functioning acoustic ear) can partially restore spatial-hearing abilities, including sound localization and speech understanding in noise. For these populations, however, interaural place-of-stimulation mismatch can occur and thus diminish binaural sensitivity that relies on interaurally frequency-matched neurons. This study examined whether plasticity-reorganization of central neural pathways over time-can compensate for peripheral interaural place mismatch.

Transeustachian Middle Ear Endoscopy Using a Steerable Distal-Camera Tipped Endoscope.

Objective: Demonstrate the ability of a novel steerable distal chip endoscope to traverse the Eustachian tube and provide diagnostic quality images of the human middle ear.

Patients: Three cadaveric temporal bone specimens were used in this work.

Intervention: Diagnostic transeustachian endoscopy of the middle ear was performed.