Advanced Bionics Research Articles

The Relationship Between eSRTs and Upper Stimulation Levels in a Large Cohort of Adult Cochlear Implant Recipients.

To compare electrically evoked stapedial reflex thresholds (eSRTs) measured at 1 month post-activation to upper stimulation levels used for programming adult cochlear implant (CI) recipients over time in a large clinical population. Review of prospectively collected clinical database. Large CI program at an academic medical center. Postlingually deafened adult CI recipients (n = 439). eSRTs recorded in the medical record and upper stimulation levels derived from the programming software at 1 and 6 months post-activation. The correlation between eSRTs and upper stimulation levels was strong for all three manufacturers (r = 0.80-0.86). On average, upper stimulation levels were set 15.4 clinical levels below eSRT for Cochlear using a pulse width of 25 microseconds, 13.4 clinical levels below eSRT for Cochlear using a pulse width of 37 microseconds, 11.3 clinical units below eSRT for Advanced Bionics, and 0.1 charge unit above eSRT for MED-EL. eSRTs were found to be elicited at similar levels for different electrodes/frequencies across the array. After upper stimulation levels were set based on eSRT at 1 month post-activation, there was no significant change in upper stimulation levels between 1 and 6 months post-activation. eSRTs and upper stimulation levels are highly correlated. Average differences between eSRTs and upper stimulation levels reported herein can be used to guide programming in the clinic. Further, when eSRTs are used to program upper stimulation levels, upper stimulation levels should be relatively similar across channels and stable over time.

Early experiences with the Advanced Bionics cochlear implant

Early experiences with the Advanced Bionics cochlear implant

Investigating the Effect of Blurring and Focusing Current in Cochlear Implant Users with the Panoramic ECAP Method.

For some cochlear implants (CIs), it is possible to focus electrical stimulation by partially returning current from the active electrode to nearby, intra-cochlear electrodes (partial tripolar (pTP) stimulation). Another method achieves the opposite: "blurring" by stimulating multiple electrodes simultaneously. The Panoramic ECAP (PECAP) method provides a platform to investigate their effects in detail by measuring electrically evoked compound action potentials and estimating current spread and neural responsiveness along the length of the CI electrode array. We investigate how sharpening and broadening the electrical current spread are reflected in PECAP estimates. PECAP measurements were recorded at most comfortable level in 12 ears of Advanced Bionics CI users. Focused thresholds were also determined. For the electrodes with the highest and lowest focused thresholds, additional PECAP measurements were recorded while stimulating in pTP mode and in "blurred" mode with 3 or 5 adjacent electrodes simultaneously stimulated. Current spread and neural responsiveness were then estimated along the electrode array using PECAP. PECAP revealed increased current spread estimates across participants for blurred stimulation of the targeted electrodes towards the apex of the cochlea. Variable results for pTP stimulation were found, with two of eight ears appearing to drive a small group-level effect of increased current spread. When stimulating multiple electrodes simultaneously, PECAP detected localized increases in current spread towards the apex (but not the base) of the cochlea. pTP stimulation showed mixed effects on PECAP current spread estimates. These findings are in line with behavioral speech perception studies and have implications for cochlear implant optimization.

Impact of Cochlear Implant Electrode Array Design on Post-Op Speech Perception.

Electrode array design may impact hearing outcomes in patients who receive cochlear implants. The goal of this work was to assess differences in post operative speech perception among patients who received cochlear implants of differing designs and lengths. Retrospective chart review. Tertiary Care Hospital. Patients (n = 129) received 1 of 9 electrode arrays, which were categorized by design: Lateral wall electrodes (n = 36) included CI522, CI622 (Cochlear Americas), Flex24, and Flex28 (Med El). Midscala electrodes (n = 16) included HiRes Ultra 3D (Advanced Bionics). Perimodiolar electrodes (n = 77) included CI512, CI532, CI612, and CI632 (Cochlear Americas). Speech perception was evaluated using consonant-nucleus-consonant (CNC) tests and at 3, 6, 12, and 24 months postimplantation. Perimodiolar electrodes showed significantly higher CNC scores compared to lateral wall electrodes at 6 and 24 months. Perimodiolar electrodes also outperformed midscala electrodes at 12 months. An inverse relationship was observed between electrode length and CNC scores noted at 6, 12, and 24 months. Perimodiolar electrode arrays, which tend to be shorter, demonstrated better speech perception outcomes compared to the longer lateral wall and midscala arrays at some timepoints. These findings suggest a potential advantages of perimodiolar electrodes for optimizing hearing outcomes.

The Predictive Value of Preoperative Measurements of Cochlear Nerve Diameters From MRT and Postoperative Speech Perception in Adult Patients With Cochlear Implant.

The current study aims to investigate whether objective measurements of the cochlear nerve (CN), derived from preoperative MRI images, correlate with postoperative speech perception in CI patients. Retrospective cohort study. University Medical Center, tertiary academic referral center. Patients undergoing a cochlear implant surgery including MED-EL (Synchrony 2, FLEX electrode series; MED-EL, Innsbruck, Austria) Cochlear (slim straight electrodes; Cochlear Ltd., Sydney, Australia), Advanced Bionics (HiRes Ultra 3D CI, HiFocus SlimJ electrodes; Sonova, Zürich, Switzerland), and Oticon (Neuro Zti EVO; Oticon A/S, Smørum, Denmark) between 2020 and 2023. Preoperative MRI images were utilized to measure the volume of the modiolus (VM), the cross-sectional areas of the CN (ACN), and for normalization, the area of the facial nerve (AFN) and the area of the internal ear canal (AIEC). Postoperative speech perceptions were assessed through word recognition scores (WRS) at several stages following the first fitting (FF) of the CI processor: immediately after FF, 1 month, 3 months, and 6 months after FF. Sixty-eight patients were enrolled in this study. A statistically significant positive correlation between the ratio between ACN and AFN (ACN/AFN) and WRSFF was identified (R = 0.36, p < 0.003). However, this correlation disappeared in subsequent follow-up tests. Moreover, upon grouping patients based on their degree of asymmetrical hearing loss, it was observed that the correlation was primarily driven by patients with moderate to severe asymmetrical hearing loss (AHLm) on the contralateral side (R = 0.62, p = 0.0003). The present results suggest that assessing the size of the CN through MRI has limited predictive utility for postoperative speech perceptions during CI consultations. This limitation seems to be particularly relevant for AHLm patients and is confined to the initial activation period.

Remote self-testing for adult cochlear implant users: the effect of wireless streaming on speech recognition in noise

Objectives Wireless sound transfer methods for cochlear implant sound processors have become popular for remote self-assessed hearing tests. The aim of this study was to determine (1) spectral differences in stimuli between different wireless sound transfer options and (2) the effect on outcomes of speech recognition tests in noise. Design In study 1, the frequency response of different streaming options (Phonak Roger Select, Cochlear Mini Mic 2+, telecoil and Bluetooth connection) was measured by connecting headphones to CI sound processors. Study 2 followed a repeated measures design in which digits-in-noise (DIN) tests were performed using wireless streaming to sound processors from Cochlear, Advanced Bionics, and MED-EL. Study Sample 20 normal hearing participants. Results Differences in frequency response between loudspeaker and wireless streaming conditions were minimal. We did not find significant difference in DIN outcome (F4,194 = 1.062, p = 0.376) between the wireless transfer options with the Cochlear Nucleus 7 processor. No significant difference in DIN outcomes was found between Bluetooth streaming and the loudspeaker condition for all of the three tested brands. The mean standard error of measurement was 0.72 dB. Conclusions No significant differences in DIN test outcomes between wireless sound transfer and the reference method were found.

Multiresponse Liquid Metal Bionic Flexible Actuator.

The flexible actuator has attracted significant interest for its ability to respond flexibly to external stimuli, especially for renewable natural energy sources. However, the flexible actuator faces issues such as inadequate sensitivity and inability to achieve synergistic responses. Therefore, we prepared a highly sensitive flexible actuator by mixing liquid metal (LM) with poly(vinylpyrrolidone) (PVP), graphene oxide (GO), and coating the resulting mixtures onto poly(ethylene terephthalate) (PET) substrate materials using the rod coating process. The flexible actuator responds quickly to near-infrared light and humidity and can be rapidly transformed from flat to curved with a maximum angular change of 540°. By demonstrating the flexible actuator in action, it can be used to create a crawling robot that mimics the movement of an inchworm on a leaf, as well as a gripper capable of lifting objects 5 times its weight, and a crawling robot that moves forward, turns left, and then right. Flexible actuators hold significant promise for applications in emerging fields such as advanced bionics and artificial intelligence.

The Value of Endoscopic Exposure of Round Window in Cochlear Implant via Facial Recess

Abstract Background Cochlear implantation (CI) has been considered as the best treatment in patients with severe to profound hearing loss unaidable with hearing aids. The main value of endoscope-assisted cochlear implantation is improved visibility of the RW and reduced risk of complications, especially in patients with congenital malformations. Aim of the Work The aim of the present study was to assess the value of endoscopic assisted CI surgery via facial recess approach without elevating tympanic anulus. Methods This Prospective case series study non-randomized sample was performed on a total of 50 patients with severe to profound hearing loss unaidable with hearing aids undergoing unilateral endoscopic assisted cochlear implant surgery with round window electrode insertion at Ain Shams University hospitals from April 2020 till March 2022 and approved 94/2020MD by an ethical committee before the start of the recruitment. Results 50 CI operations with endoscopic assistance were prospectively evaluated. There were 23 male (46%) and 27 female (54%) patients. The majority of the cases were children (41 cases, 82%). Of those 50 patients, 39 (78%) were prelingually hearing impaired. Four cases (8%) had various inner ear abnormalities. The standard mastoidectomy and Posterior Tympanotomy (PT) approach were used for all cases. Med-El (FLEX28TM; FLEX24TM Med-El, Innsbruck, Australia), Advanced Bionics (AB)Mid-Scala Electrode and CochlearTM (NUCLEUS® CI422 WITH SLIM STRAIGHT, NUCLEUS® CI24RE CONTOUR ADVANCETM, Sydney, Australia) implants were used. Endoscope-assisted visualization of the RW region through the PT was performed in all cases Rigid endoscopes with 0o and 30o (1.9, 2.7 and 4 mm in width, 11 and 6 cm in length) and an HD (high-definition) camera system (Karl Storz, Tuttlingen, Germany) were used for the endoscopic evaluation. The RW region was visualized and identified by inserting the endoscope through the PT without elevating the tympanic annulus. Then we switched to the microscope and drilled the RW niche (tegmen) using both hands until a circumferential view of the RW membrane is obtained. After proper exposure, the electrode was inserted through an opening in the RW membrane mostly under microscopical vision. Endoscopic identification of the RW through the PT enabled us to perform regular surgery in all cases. The current study concludes the difference between microscopic exposure and endoscopic exposure represented by Saint Tomas classification regarding round window exposure found that endoscopic exposure of round window classification is better represented by downgrading in the classification of round window exposure as type I 29(58%), type IIa 18(36%) type IIb 3 (6%) Non were type III by endoscopic exposure compared to microscopic exposure of round window is a type I 7(14%), type II 14(28%), type IIb 22(44%) and type III 7 (14%). Conclusion As evident from the current study, Endoscopy proved a great value in exposure and identification of RW in CI surgery through posterior tympanotomy approach, especially in difficult cases. Endoscopic-assisted CI through facial recess could be easily done using 1.9mm 0-degree endoscopy even in cases e narrow PT or rotated cochlea

Worldwide differences in surgeon intraoperative practices for cochlear implantation

Objective To characterize practice patterns of intraoperative imaging and/or functional confirmation of cochlear implant electrode location worldwide. Methods A cross-sectional survey of otolaryngologists performing cochlear implantation was conducted between March 1 and May 6, 2023. Participants were recruited worldwide using an international otologic society membership email list and at professional meetings. Ninety-seven of the 125 invited participants (78%) completed the survey. Participants were categorized by continent. Results North American surgeons use intraoperative X-rays more frequently than surgeons in Europe and Asia (p < 0.001). Otolaryngologists in Europe and Asia more frequently use no intraoperative imaging (p = 0.02). There is no regional difference between the intraoperative use of electrophysiologic instruments. European and Asian surgeons implant MED-EL devices (p = 0.012) more frequently than North American surgeons, who more frequently use Cochlear Corporation devices (p = 0.003). MED-EL use is related to less frequent intraoperative X-ray use (p = 0.02). Advanced Bionics use is related to more frequent intraoperative CT use (p = 0.03). No significant association existed between years of practice, number of cochlear implantation surgeries performed yearly, volume of pediatric CI practice, and use of intraoperative tools. Conclusion Intraoperative practice for radiologic and functional verification of cochlear implant electrode positioning varies worldwide. Practice guidelines may help establish a standard of care for cochlear implantation.

Self-Assessment of Cochlear Health by New Cochlear Implant Recipients: Daily Impedance, Electrically Evoked Compound Action Potential and Electrocochleography Measurements Over the First Three Postoperative Months.

In newly implanted cochlear implant (CI) users, electrically evoked compound action (eCAPs) and electrocochleography (ECochGs) will remain stable over time. Electrode impedances will increase immediately postimplantation due to the initial inflammatory response, before decreasing after CI switch-on and stabilizing thereafter. The study of cochlear health (CH) has several applications, including explaining variation in CI outcomes, informing CI programming strategies, and evaluating the safety and efficacy of novel biological treatments for hearing loss. Very early postoperative CH patterns have not previously been intensively explored through longitudinal daily testing. Thanks to technological advances, electrode impedances, eCAPs, and ECochGs can be independently performed by CI users at home to monitor CH over time. A group of newly implanted CI users performed daily impedances, eCAPs, and ECochGs for 3 months at home, starting from the first day postsurgery (N = 7) using the Active Insertion Monitoring system by Advanced Bionics. Measurement validity of 93.5, 93.0, and 81.6% for impedances, eCAPs, and ECochGs, respectively, revealed high participant compliance. Impedances increased postsurgery before dropping and stabilizing after switch-on. eCAPs showed good stability, though statistical analyses revealed a very small but significant increase in thresholds over time. Most ECochG thresholds did not reach the liberal signal-to-noise criterion of 2:1, with low threshold stability over time. Newly implanted CI recipients can confidently and successfully perform CH recordings at home, highlighting the valuable role of patients in longitudinal data collection. Electrode impedances and eCAPs are promising objective measurements for evaluating CH in newly implanted CI users.

Failure in HiRes Ultra Series Recall Devices Does Not Necessarily Lead to Decrement in Performance.

To understand the impact on speech perception for patients experiencing Advanced Bionics V1 series Ultra and Ultra 3D cochlear implant failure. Retrospective cohort study. Tertiary academic center. Adult patients implanted with V1 series devices. Device integrity and speech perception testing. consonant-nucleus-consonant and AzBio in quiet speech recognition scores. At our institution, 116 V1 series cochlear implants were placed in 114 patients. Thirteen devices in prelingual patients were excluded, leaving 103 (89%) for final analysis. Forty-eight (46.6%) devices were considered as failed using the company provided EFI analysis tool. There were 36 (65.5%) of the remaining 55 devices that consistently tested within normal range; the remainder lost to follow-up with unknown status. Among the 48 device failures, 29 were revised and 19 patients were not revised. Among those not revised, 11 self-opted for observation (57.9%). Observed patients, despite impedance changes meeting failure criteria, had no subjective or objective changes in speech perception. Sentence testing scores for failure patients who elected observation (82.9 ± 11.4%) were significantly higher at failure compared with those opting for revision (55 ± 22.8%, p = 0.006). For those undergoing revision surgery, significant improvement in post-activation scores was noted as compared with time of failure with a mean improvement of 12.9% (p = 0.002, n = 24) for consonant-nucleus-consonant word scores and 17.2% (p = 0.001, n = 19) for AzBio in quiet scores. Proactive monitoring using EFI identifies a higher rate of Ultra Series V1 device failure than previously reported. However, about 20% of these patients may not have subjective change in hearing or objective decline in test scores and could be observed. Should performance worsen, reimplantation provides significant improvement in speech recognition.

Revision Cochlear Implantation With Device Manufacturer Conversion: Surgical Outcomes and Speech Perception Performance.

Describe the clinical profile of revision cochlear implantation (RCI) cases involving device manufacturer conversion (RCImc+), compare them to cases without manufacturer conversion (RCImc-), and classify the reasons for manufacturer conversion (MC). Retrospective case review. Tertiary academic center. Data on demographics, RCI indications, medical background, surgical details, and the reasons for MC were collected for all RCIs from 1989 to 2020. Post-RCI speech perception performance was categorized as unchanged, improved, or declined, according to clinically based criteria. Of 185 RCIs, 39 (21%) involved MC, mostly in pediatric patients (67%). The leading RCImc+ indications were device-related (59%) and medical (31%) failures. Initial implant manufacturers were Advanced Bionics (49%), Cochlear (25.5%), or Medel (25.5%). Most MC reasons were patient-driven (64%) versus CI team recommendations (36%). The RCImc+ group demonstrated a 3-fold higher rate of medical indications than RCImc- (31% vs11.5%, P = .007). The time interval from symptom onset to RCI was longer in RCImc+ (43 vs20.3 months, P = .001), and the rate of multiple revisions in the same ear was higher (25.6% vs8.2%, P = .009). Complete reinsertion rates were high in both RCImc+ and RCImc- (94.8% vs94.5%, P = 1) without any complications. Speech perception improved or remained unchanged in most (84%) cases, with no significant difference between the groups (P = .183). This retrospective study showed that RCI involving MC is safe and beneficial. Although RCImc+ patients exhibited distinct clinical characteristics, MC did not impact surgical or speech perception outcomes. This provides evidence-based data to support informed decision-making by CI teams and patients.

Seven-Year Revision Rates for Cochlear Implants in Pediatric and Adult Populations of an Integrated Healthcare System.

We assessed three cochlear implant (CI) suppliers: Advanced Bionics, Cochlear Limited, and MED-EL, for implant revision requiring reoperation after CI placement. Retrospective cohort study of integrated-health-system database between 2010 and 2021. Separate models were created for pediatric (age <18) and adult (age ≥18) cohorts. Pediatric (age <18) and adult (age ≥18) patients undergoing cochlear implantation within our integrated healthcare system. Revision after CI placement. Cox proportional hazard regression was used to evaluate revision risk and adjust for confounding factors. Hazard ratios (HRs) and 95% confidence intervals (CIs) are presented. A total of 2,347 patients underwent a primary CI placement, and Cochlear Limited was most implanted (51.5%), followed by Advanced Bionics (35.2%) and MED-EL (13.3%). In the pediatric cohort, the 7-year crude revision rate was 10.9% for Advanced Bionics and 4.8% for Cochlear Limited, whereas MED-EL had insufficient cases. In adults, the rates were 9.1%, 4.5%, and 3.3% for Advanced Bionics, MED-EL, and Cochlear Limited, respectively. After 2 years of postoperative follow-up, Advanced Bionics had a significantly higher revision risk (HR = 8.25, 95% CI = 2.91-23.46); MED-EL had no difference (HR = 2.07, 95% CI = 0.46-9.25). We found an increased revision risk after 2 years of follow-up for adults with Advanced Bionics CI devices. Although we found no statistical difference between manufacturers in the pediatric cohort, after 2 years of follow-up, there were increasing trends in the revision probability for Advanced Bionics. Further research may determine whether patients are better suited for some CI devices.

Hearing outcomes following reimplantation of functional legacy cochlear implants

ObjectivesRecently, patients with certain legacy cochlear implants (CIs) have sought out reimplantation to enjoy the benefits offered by newer processor technology. This decision can be difficult, especially when the individual relies exclusively on the device for communication and scores at the ceiling of performance metrics. To date, most outcome data is derived from reimplantation of a non-functioning CI—a relatively easy decision. The aim of this study is to report hearing outcomes following reimplantation of legacy implants to guide surgeons and patients approaching this high-stakes clinical situation. Patients and interventionFour patients implanted with Advanced Bionics Clarion C1 devices over 20 years ago underwent reimplantation. ResultsThree reimplanted patients demonstrated a maintenance or improvement in their audiometric performance with one patient experiencing only a 5 % decrease in AzBioQ score. Each patient expressed satisfaction with the expansion of technological capabilities including improved battery life, and device connectivity. There were no failed reimplantations or other adverse effects. ConclusionsReimplantation of a functioning legacy CI result in stability or improvement in auditory performance. All individuals in this series report that they enjoy the new connectivity and programming technologies. As the rate advancement in CI technology continues to increase and newer device architectures emerge, these data will help to inform the decision to reimplant functioning devices.

Multi-Magnet Cochlear Implant Technology and Magnetic Resonance Imaging: The Safety Issue.

Despite the spread of novel-generation cochlear-implant (CI) magnetic systems, access to magnetic resonance imaging (MRI) for CI recipients is still limited due to safety concerns. The aim of this study is to assess and record the experiences of Hires Ultra 3D (Advanced Bionics) recipients who underwent an MRI examination. A multicentric European survey about this topic was conducted focusing on safety issues, and the results were compared with the current literature. We collected a total of 65 MRI scans performed in 9 otologic referral centers for a total of 47 Hires Ultra 3D recipients, including, for the first time, 2 children and 3 teenagers. Preventive measures were represented by scanning time and sedation for children. Head wrapping was used in eight cases, and six of the eight cases received local anesthesia, even if both measures were not needed. Only three patients complained of pain (3/65 examinations, 4.6%) due to the tight head bandage, and one of the three cases required MRI scan interruption. No other adverse events were reported. We believe that these results should encourage MRI execution in accordance with manufacturer recommendations for Ultra 3D recipients.

Predicting Matrix Test Effectiveness for Evaluating Auditory Performance in Noise Using Pure-Tone Audiometry and Speech Recognition in Quiet in Cochlear Implant Recipients

Introduction: Auditory performance in noise of cochlear implant recipients can be assessed with the adaptive Matrix test (MT); however, when the speech-to-noise ratio (SNR) exceeds 15 dB, the background noise has any negative impact on the speech recognition. Here, we aim to evaluate the predictive power of aided pure-tone audiometry and speech recognition in quiet and establish cut-off values for both tests that indicate whether auditory performance in noise can be assessed using the Matrix sentence test in a diffuse noise environment. Methods: Here, we assessed the power of pure-tone audiometry and speech recognition in quiet to predict the response to the MT. Ninety-eight cochlear implant recipients were assessed using different sound processors from Advanced Bionics (n = 56) and CochlearTM (n = 42). Auditory tests were performed at least 1 year after cochlear implantation or upgrading the sound processor to ensure the best benefit of the implant. Auditory assessment of the implanted ear in free-field conditions included: pure-tone average (PTA), speech discrimination score (SDS) in quiet at 65 dB, and speech recognition threshold (SRT) in noise that is the SNR at which the patient can correctly recognize 50% of the words using the MT in a diffuse sound field. Results: The SRT in noise was determined in 60 patients (61%) and undetermined in 38 (39%) using the MT. When cut-off values for PTA <36 dB and SDS >41% were used separately, they were able to predict a positive response to the MT in 83% of recipients; using both cut-off values together, the predictive value reached 92%. Discussion: As the pure-tone audiometry is standardized universally and the speech recognition in quiet could vary depending on the language used; we propose that the MT should be performed in recipients with PTA <36 dB, and in recipients with PTA >36 dB, a list of Matrix sentences at a fixed SNR should be presented to determine the percentage of words understood. This approach should enable clinicians to obtain information about auditory performance in noise whenever possible.

A frequency peak at 3.1 kHz obtained from the spectral analysis of the cochlear implant electrocochleography noise.

The functional evaluation of auditory-nerve activity in spontaneous conditions has remained elusive in humans. In animals, the frequency analysis of the round-window electrical noise recorded by means of electrocochleography yields a frequency peak at around 900 to 1000 Hz, which has been proposed to reflect auditory-nerve spontaneous activity. Here, we studied the spectral components of the electrical noise obtained from cochlear implant electrocochleography in humans. We recruited adult cochlear implant recipients from the Clinical Hospital of the Universidad de Chile, between the years 2021 and 2022. We used the AIM System from Advanced Bionics® to obtain single trial electrocochleography signals from the most apical electrode in cochlear implant users. We performed a protocol to study spontaneous activity and auditory responses to 0.5 and 2 kHz tones. Twenty subjects including 12 females, with a mean age of 57.9 ± 12.6 years (range between 36 and 78 years) were recruited. The electrical noise of the single trial cochlear implant electrocochleography signal yielded a reliable peak at 3.1 kHz in 55% of the cases (11 out of 20 subjects), while an oscillatory pattern that masked the spectrum was observed in seven cases. In the other two cases, the single-trial noise was not classifiable. Auditory stimulation at 0.5 kHz and 2.0 kHz did not change the amplitude of the 3.1 kHz frequency peak. We found two main types of noise patterns in the frequency analysis of the single-trial noise from cochlear implant electrocochleography, including a peak at 3.1 kHz that might reflect auditory-nerve spontaneous activity, while the oscillatory pattern probably corresponds to an artifact.

Tone selection for cochlear implants using peak-finding and frequency bin overlap

The Advanced Bionics cochlear implant devices employ a method of allocating static frequency bins to electrodes based on the natural tonotopic organization of the cochlea. Many studies show that there is a significant frequency-to-place mismatch in many subjects, but that over time the brain adjusts to these mismatches. Also, most of the tonal information in human speech is present in the lower end of the frequency spectrum, where there are few frequency bins and electrodes available to represent this information. Here, adjustments to the frequency bin allocation algorithm used in the crowdsourced CI Hackathon code are made to allow a more accurate representation of the original signal in the lower registers. A peak-finding and selecting method is used to find significant peaks regardless of frequency bin, then bins are overlapped to allow more accurate representation of tones near the borders between channels and peaks which may be near to each other.

Improving the sensitivity of cochlear implant integrity testing by recording electrode voltages with surface electrodes

IntroductionIdentification of faults with the internal, implanted, part of a cochlear implant presents a challenge for the cochlear implant community. Advanced Bionics Ultra V1 devices are vulnerable to moisture ingress, a hard failure, resulting in reduced volume and clarity for the recipient. The manufacturer uses a trans-impedance test “Electrical Field Imaging” to identify faulty Ultra V1 devices but reports the sensitivity of the test to be only 70–90%.MethodsIn our clinic we performed Electrode Voltage measurements with surface electrodes and have compared the two tests. Electrical Field imaging and Electrode Voltage (EV) measurements were available for 65 devices. Surface electrodes were attached to the earlobes and forehead and potentials measured in three montages: ipsilateral earlobe and forehead, contralateral earlobe and forehead, and both earlobes; voltages were extracted and relative voltages across the array were calculated.ResultsRelative EV were compared for the two earlobes montage and fitted to a third order polynomial function. A new criterion for identifying faulty devices was derived, with a deviation of &amp;lt; 6% for individual electrodes for normally functioning devices or ≥6% for faulty devices. All devices which were normal according to the new criterion (N = 15) had a normal electrical field imaging test, whilst 17/50 devices which were abnormal had normal electrical field imaging and 33/50 which were abnormal had abnormal electrical field imaging.DiscussionThe REVs test was well-tolerated and carried out in a routine cochlear implant clinic. Together with test sensitivity and reliability this may make it a new routine assessment tool to aid in distinguishing hard and soft failures.

The impact of the size and angle of the cochlear basal turn on translocation of a pre-curved mid-scala cochlear implant electrode

Scalar translocation is a severe form of intra-cochlear trauma during cochlear implant (CI) electrode insertion. This study explored the hypothesis that the dimensions of the cochlear basal turn and orientation of its inferior segment relative to surgically relevant anatomical structures influence the scalar translocation rates of a pre-curved CI electrode. In a cohort of 40 patients implanted with the Advanced Bionics Mid-Scala electrode array, the scalar translocation group (40%) had a significantly smaller mean distance A of the cochlear basal turn (p < 0.001) and wider horizontal angle between the inferior segment of the cochlear basal turn and the mastoid facial nerve (p = 0.040). A logistic regression model incorporating distance A (p = 0.003) and horizontal facial nerve angle (p = 0.017) explained 44.0–59.9% of the variance in scalar translocation and correctly classified 82.5% of cases. Every 1mm decrease in distance A was associated with a 99.2% increase in odds of translocation [95% confidence interval 80.3%, 100%], whilst every 1-degree increase in the horizontal facial nerve angle was associated with an 18.1% increase in odds of translocation [95% CI 3.0%, 35.5%]. The study findings provide an evidence-based argument for the development of a navigation system for optimal angulation of electrode insertion during CI surgery to reduce intra-cochlear trauma.