Electrochemically actuated microelectrodes for minimally invasive peripheral nerve interfaces.

Electrode arrays that interface with peripheral nerves are used in the diagnosis and treatment of neurological disorders; however, they require complex placement surgeries that carry a high risk of nerve injury. Here we leverage recent advances in soft robotic actuators and flexible electronics to develop highly conformable nerve cuffs that combine electrochemically driven conducting-polymer-based soft actuators with low-impedance microelectrodes. Driven with applied voltages as small as a few hundreds of millivolts, these cuffs allow active grasping or wrapping around delicate nerves. We validate this technology using in vivo rat models, showing that the cuffs form and maintain a self-closing and reliable bioelectronic interface with the sciatic nerve of rats without the use of surgical sutures or glues. This seamless integration of soft electrochemical actuators with neurotechnology offers a path towards minimally invasive intraoperative monitoring of nerve activity and high-quality bioelectronic interfaces.

Socioeconomic and ethnic disparities associated with access to cochlear implantation for severe-to-profound hearing loss: A multicentre observational study of UK adults.

BACKGROUND: Patients with severe-to-profound hearing loss may benefit from management with cochlear implants. These patients need a referral to a cochlear implant team for further assessment and possible surgery. The referral pathway may result in varied access to hearing healthcare. This study aimed to explore referral patterns and whether there were any socioeconomic or ethnic associations with the likelihood of referral. The primary outcome was to determine factors influencing referral for implant assessment. The secondary outcome was to identify factors impacting whether healthcare professionals had discussed the option of referral. METHODS AND FINDINGS: A multicentre multidisciplinary observational study was conducted in secondary care Otolaryngology and Audiology units in Great Britain. Adults fulfilling NICE (2019) audiometric criteria for implant assessment were identified over a 6-month period between 1 July and 31 December 2021. Patient- and site-specific characteristics were extracted. Multivariable binary logistic regression was employed to compare a range of factors influencing the likelihood of implant discussion and referral including patient-specific (demographics, past medical history, and degree of hearing loss) and site-specific factors (cochlear implant champion and whether the hospital performed implants). Hospitals across all 4 devolved nations of the UK were invited to participate, with data submitted from 36 urban hospitals across England, Scotland, and Wales. Nine hospitals (25%) conducted cochlear implant assessments. The majority of patients lived in England (n = 5,587, 86.2%); the rest lived in Wales (n = 419, 6.5%) and Scotland (n = 233, 3.6%). The mean patient age was 72 ± 19 years (mean ± standard deviation); 54% were male, and 75·3% of participants were white, 6·3% were Asian, 1·5% were black, 0·05% were mixed, and 4·6% were self-defined as a different ethnicity. Of 6,482 submitted patients meeting pure tone audiometric thresholds for cochlear implantation, 311 already had a cochlear implant. Of the remaining 6,171, 35.7% were informed they were eligible for an implant, but only 9.7% were referred for assessment. When adjusted for site- and patient-specific factors, stand-out findings included that adults were less likely to be referred if they lived in more deprived area decile within Indices of Multiple Deprivation (4th (odds ratio (OR): 2·19; 95% confidence interval (CI): [1·31, 3·66]; p = 0·002), 5th (2·02; [1·21, 3·38]; p = 0·05), 6th (2·32; [1·41, 3·83]; p = 0.05), and 8th (2·07; [1·25, 3·42]; p = 0·004)), lived in London (0·40; [0·29, 0·57]; p < 0·001), were male (females 1·52; [1·27, 1·81]; p < 0·001), or were older (0·97; [0·96, 0·97]; p < 0·001). They were less likely to be informed of their potential eligibility if they lived in more deprived areas (4th (1·99; [1·49, 2·66]; p < 0·001), 5th (1·75; [1·31, 2·33], p < 0·001), 6th (1·85; [1·39, 2·45]; p < 0·001), 7th (1·66; [1·25, 2·21]; p < 0·001), and 8th (1·74; [1·31, 2·31]; p < 0·001) deciles), the North of England or London (North 0·74; [0·62, 0·89]; p = 0·001; London 0·44; [0·35, 0·56]; p < 0·001), were of Asian or black ethnic backgrounds compared to white patients (Asian 0·58; [0·43, 0·79]; p < 0·001; black 0·56; [0·34, 0·92]; p = 0·021), were male (females 1·46; [1·31, 1·62]; p < 0·001), or were older (0·98; [0·98, 0·98]; p < 0·001). The study methodology was limited by its observational nature, reliance on accurate documentation of the referring service, and potential underrepresentation of certain demographic groups. CONCLUSIONS: The majority of adults meeting pure tone audiometric threshold criteria for cochlear implantation are currently not appropriately referred for assessment. There is scope to target underrepresented patient groups to improve referral rates. Future research should engage stakeholders to explore the reasons behind the disparities. Implementing straightforward measures, such as educational initiatives and automated pop-up tools for immediate identification, can help streamline the referral process.

International Consensus Statements on Intraoperative Testing for Cochlear Implantation Surgery.

OBJECTIVES: A wide variety of intraoperative tests are available in cochlear implantation. However, no consensus exists on which tests constitute the minimum necessary battery. We assembled an international panel of clinical experts to develop, refine, and vote upon a set of core consensus statements. DESIGN: A literature review was used to identify intraoperative tests currently used in the field and draft a set of provisional statements. For statement evaluation and refinement, we used a modified Delphi consensus panel structure. Multiple interactive rounds of voting, evaluation, and feedback were conducted to achieve convergence. RESULTS: Twenty-nine provisional statements were included in the original draft. In the first voting round, consensus was reached on 15 statements. Of the 14 statements that did not reach consensus, 12 were revised based on feedback provided by the expert practitioners, and 2 were eliminated. In the second voting round, 10 of the 12 revised statements reached a consensus. The two statements which did not achieve consensus were further revised and subjected to a third voting round. However, both statements failed to achieve consensus in the third round. In addition, during the final revision, one more statement was decided to be deleted due to overlap with another modified statement. CONCLUSIONS: A final core set of 24 consensus statements was generated, covering wide areas of intraoperative testing during CI surgery. These statements may provide utility as evidence-based guidelines to improve quality and achieve uniformity of surgical practice.

Outcomes of cochlear implantation in Usher syndrome: a systematic review.

PURPOSE: This study is a systematic review of the literature which seeks to evaluate auditory and quality of life (QOL) outcomes of cochlear implantation in patients with Usher syndrome. METHODS: Systematic review of studies indexed in Medline via PubMed, Ovid EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to March 9th 2022, conducted in accordance with the PRISMA statement. Patient demographics, comorbidity, details of cochlear implantation, auditory, and QOL outcomes were extracted and summarized. RESULTS: 33 studies reported over 217 cochlear implants in 187 patients with Usher syndrome, comprising subtypes 1 (56 patients), 2 (9 patients), 3 (23 patients), and not specified (99 patients). Auditory outcomes included improved sound detection, speech perception, and speech intelligibility. QOL outcomes were reported for 75 patients, with benefit reported in the majority. CONCLUSIONS: Many patients with Usher syndrome develop improved auditory outcomes after cochlear implantation with early implantation being an important factor.

Minimum intraoperative testing battery for cochlear implantation: the international practice trend.

PURPOSE: In cochlear implantation (CI) surgery, there are a wide variety of intraoperative tests available. However, no clear guide exists on which tests must be performed as the minimum intraoperative testing battery. Toward this end, we studied the usage patterns, recommendations, and attitudes of practitioners toward intraoperative testing. METHODS: This study is a multicentric international survey of tertiary referral CI centers. A survey was developed and administered to a group of CI practitioners (n = 34) including otologists, audiologists and biomedical engineers. Thirty six participants were invited to participate in this study based on a their scientific outputs to the literature on the intraoperative testing in CI field and based on their high load of CI surgeries. Thirty four, from 15 countries have accepted the invitation to participate. The participants were asked to indicate the usage trends, perceived value, influence on decision making and duration of each intraoperative test. They were also asked to indicate which tests they believe should be included in a minimum test battery for routine cases. RESULTS: Thirty-two (94%) experts provided responses. The most frequently recommended tests for a minimum battery were facial nerve monitoring, electrode impedance measurements, and measurements of electrically evoked compound action potentials (ECAPs). The perceived value and influence on surgical decision-making also varied, with high-resolution CT being rated the highest on both measures. CONCLUSION: Facial nerve monitoring, electrode impedance measurements, and ECAP measurements are currently the core tests of the intraoperative test battery for CI surgery.

Impact of Insertion Speed, Depth, and Robotic Assistance on Cochlear Implant Insertion Forces and Intracochlear Pressure: A Scoping Review.

Cochlear implants are crucial for addressing severe-to-profound hearing loss, with the success of the procedure requiring careful electrode placement. This scoping review synthesizes the findings from 125 studies examining the factors influencing insertion forces (IFs) and intracochlear pressure (IP), which are crucial for optimizing implantation techniques and enhancing patient outcomes. The review highlights the impact of variables, including insertion depth, speed, and the use of robotic assistance on IFs and IP. Results indicate that higher insertion speeds generally increase IFs and IP in artificial models, a pattern not consistently observed in cadaveric studies due to variations in methodology and sample size. The study also explores the observed minimal impact of robotic assistance on reducing IFs compared to manual methods. Importantly, this review underscores the need for a standardized approach in cochlear implant research to address inconsistencies and improve clinical practices aimed at preserving hearing during implantation.

The effect of photobiomodulation on hearing loss: A systematic review.

OBJECTIVES: To assess outcomes associated with photobiomodulation therapy (PBMT) for hearing loss in human and animal studies. DESIGN: Systematic review and narrative synthesis in accordance with PRISMA guidelines. SETTING: Data bases searched: MEDLINE, EMBASE, CENTRAL, ClinicalTrials.gov and Web of Science. No limits were placed on language or year of publication. Review conducted in accordance with the PRISMA 2020 statement. PARTICIPANTS: All human and animal subjects treated with PBMT for hearing loss. MAIN OUTCOME MEASURES: Pre- and post-PBMT audio metric outcomes. RESULTS: Searches identified 122 abstracts and 49 full text articles. Of these, 17 studies met the inclusion criteria, reporting outcomes in 327 animals (11 studies), 30 humans (1 study), and 40 animal specimens (5 studies). PBMT parameters included 6 different wavelengths: 908 nm (1 study), 810 nm (1 study), 532 & 635 nm (1 study), 830 nm (3 studies), 808 nm (11 studies). The duration ranged from 4 to 60 minutes in a session, and the follow-up ranged from 5-28 days. Outcomes improved significantly when wavelengths within the range of 800-830 nm were used, and with greater duration of PBMT exposure. Included studies predominantly consisted of non-randomized controlled trials (10 studies). CONCLUSIONS: Hearing outcomes following PBMT appear to be superior to no PBMT for subjects with hearing loss, although higher level evidence is required to verify this. PBMT enables concentrated, focused delivery of light therapy to the inner ear through a non-invasive manner with minimal side effects. As a result of heterogeneity in reporting PBMT parameters and outcomes across the included studies, direct comparison is challenging.

SpeedCAP: An Efficient Method for Estimating Neural Activation Patterns Using Electrically Evoked Compound Action-Potentials in Cochlear Implant Users.

OBJECTIVES: Electrically evoked compound action-potentials (ECAPs) can be recorded using the electrodes in a cochlear implant (CI) and represent the synchronous responses of the electrically stimulated auditory nerve. ECAPs can be obtained using a forward-masking method that measures the neural response to a probe and masker electrode separately and in combination. The panoramic ECAP (PECAP) analyses measured ECAPs obtained using multiple combinations of masker and probe electrodes and uses a nonlinear optimization algorithm to estimate current spread from each electrode and neural health along the cochlea. However, the measurement of ECAPs from multiple combinations of electrodes is too time consuming for use in clinics. Here, we propose and evaluate SpeedCAP, a speedy method for obtaining the PECAP measurements that minimizes recording time by exploiting redundancies between multiple ECAP measures. DESIGN: In the first study, 11 users of Cochlear Ltd. CIs took part. ECAPs were recorded using the forward-masking artifact-cancelation technique at the most comfortable loudness level (MCL) for every combination of masker and probe electrodes for all active electrodes in the users' MAPs, as per the standard PECAP recording paradigm. The same current levels and recording parameters were then used to collect ECAPs in the same users with the SpeedCAP method. The ECAP amplitudes were then compared between the two conditions, as were the corresponding estimates of neural health and current spread calculated using the PECAP method previously described by Garcia et al. The second study measured SpeedCAP intraoperatively in 8 CI patients and with all maskers and probes presented at the same current level to assess feasibility. ECAPs for the subset of conditions where the masker and probe were presented on the same electrode were compared with those obtained using the slower approach leveraged by the standard clinical software. RESULTS: Data collection time was reduced from ≈45 to ≈8 minutes. There were no significant differences between normalized root mean squared error (RMSE) repeatability metrics for post-operative PECAP and SpeedCAP data, nor for the RMSEs calculated between PECAP and SpeedCAP data. The comparison achieved 80% power to detect effect sizes down to 8.2% RMSE. When between-participant differences were removed, both the neural-health (r = 0.73) and current-spread (r = 0.65) estimates were significantly correlated ( p < 0.0001, df = 218) between SpeedCAP and PECAP conditions across all electrodes, and showed RMSE errors of 12.7 ± 4.7% and 16.8 ± 8.8%, respectively (with the ± margins representing 95% confidence intervals). Valid ECAPs were obtained in all patients in the second study, demonstrating intraoperative feasibility of SpeedCAP. No significant differences in RMSEs were detectable between post- and intra-operative ECAP measurements, with the comparison achieving 80% power to detect effect sizes down to 13.3% RMSE. CONCLUSIONS: The improved efficiency of SpeedCAP provides time savings facilitating multi-electrode ECAP recordings in routine clinical practice. SpeedCAP data collection is sufficiently quick to record intraoperatively, and adds no more than 8.2% error to the ECAP amplitudes. Such measurements could thereafter be submitted to models such as PECAP to provide patient-specific patterns of neural activation to inform programming of clinical MAPs and identify causes of poor performance at the electrode-nerve interface of CI users. The speed and accuracy of these measurements also opens up a wide range of additional research questions to be addressed.

Aetiology and management options for secondary referred otalgia: a systematic review and meta-analyses.

OBJECTIVES OF REVIEW: To review the literature for the evidence base for the aetiology and management of referred otalgia, looking particularly at non-malignant, neuralgic, structural and functional issues. TYPE OF REVIEW: Systematic review. SEARCH STRATEGY: A systematic literature search was undertaken from the databases of EMBASE, CINAHL, MEDLINE®, BNI, and Cochrane Library according to predefined inclusion and exclusion criteria. EVALUATION METHOD: All relevant titles, abstracts and full text articles were reviewed by three authors who resolved any differences by discussion and consultation with senior author. RESULTS: 44 articles were included in our review. The overall quality of evidence was low, with the vast majority of the studies being case-series with three cohort and four randomised-controlled trials included. The prime causes and management strategies were focussed on temporomandibular joint dysfunction (TMJD), Eagle syndrome and neuralgia. Our meta-analyses found no difference on the management strategies for the interventions found. CONCLUSIONS: Referred otalgia is common and treatment should be aimed at the underlying pathology. Potential aetiologies are vast given the extensive sensory innervation of the ear. An understanding of this and a structured approach to patient assessment is important for optimal patient management.

Exploring patient experiences and concerns in the online Cochlear implant community: A cross-sectional study and validation of automated topic modelling.

OBJECTIVE: There is a paucity of research examining patient experiences of cochlear implants. We sought to use natural language processing methods to explore patient experiences and concerns in the online cochlear implant (CI) community. MATERIALS AND METHODS: Cross-sectional study of posts on the online Reddit r/CochlearImplants forum from 1 March 2015 to 11 November 2021. Natural language processing using the BERTopic automated topic modelling technique was employed to cluster posts into semantically similar topics. Topic categorisation was manually validated by two independent reviewers and Cohen's kappa calculated to determine inter-rater reliability between machine vs human and human vs human categorisation. RESULTS: We retrieved 987 posts from 588 unique Reddit users on the r/CochlearImplants forum. Posts were initially categorised by BERTopic into 16 different Topics, which were increased to 23 Topics following manual inspection. The most popular topics related to CI connectivity (n = 112), adults considering getting a CI (n = 107), surgery-related posts (n = 89) and day-to-day living with a CI (n = 85). Cohen's kappa among all posts was 0.62 (machine vs. human) and 0.72 (human vs. human), and among categorised posts was 0.85 (machine vs. human) and 0.84 (human vs. human). CONCLUSIONS: This cross-sectional study of social media discussions among the online cochlear implant community identified common attitudes, experiences and concerns of patients living with, or seeking, a cochlear implant. Our validation of natural language processing methods to categorise topics shows that automated analysis of similar Otolaryngology-related content is a viable and accurate alternative to manual qualitative approaches.

Frequency of electrode migration after cochlear implantation in the early postoperative period. What are associated risk factors?

OBJECTIVES: To estimate the prevalence of, and risk factors associated with electrode migration (EM) in cochlear implant (CI) recipients. DESIGN: Historical cohort study of all CIs performed between 1 January 2018 and 1 August 2021 in a single tertiary adult and paediatric CI centre in the UK. MAIN OUTCOME MEASURES: The primary aim is to determine the prevalence of electrode migration, comparing intraoperative surgeon report and examination of a routine plain radiograph performed 2 weeks after surgery. EM is defined as the detection of movement of two or more electrodes out of the cochlea from the time of surgery. Multivariate analysis was performed to investigate preoperative and intraoperative risk factors that might predispose to migration. RESULTS: Four hundred and sixty-five patients, having 516 distinct surgeries, with 628 implants were analysed. EM occurred following 11.5% of implant operations. Pre-existing cochlear abnormality was an independent associated risk factor for EM (OR: 3.40 ⟨1.20-9.62⟩ p = .021). Demographics, surgical technique, usage of a precurved electrode, CSF leak, surgeon seniority and intraoperative telemetry did not influence risk of migration. There were 5 implants (0.8%) which migrated later than 2 weeks, with a median date of imaging diagnosis (x-ray or CT scan) of 263 days ⟨IQR:198⟩, for which head injury was a common precipitating factor. There were differences in the risk of migration between different lateral wall electrodes. CONCLUSION: EM in the early postoperative period is a common occurrence and is more likely in implant recipients with obstructed or malformed cochleae.

Cochlear Implantation in Elderly Patients: Survival Duration, Hearing Outcomes, Complication Rates, and Cost Utility.

INTRODUCTION: The prevalence of hearing loss and its consequences is increasing as the elderly population grows. As the guidelines for cochlear implantation (CI) expand, the number of elderly CI recipients is also increasing. We report complication rates, survival duration, and audiological outcomes for CI recipients aged 80 years and over and discuss the cost utility of CI in this age group. METHODS: A retrospective cohort study was undertaken of all CI recipients (126 cases), aged 80 years and over at the time of their surgery, implanted at our institution (Cambridge University Hospitals) during a period from January 1, 2001, to March 31, 2019. Data on survival at 1, 3, and 5 years post-implantation, post-operative complications and functional hearing outcomes including audiometric and speech discrimination outcomes (Bamford-Kowal-Bench sentence test) have been reported. RESULTS: The mean age at implantation was 84 years. The mean audiometric score improved from 108 dB HL to 28 dB HL post-implantation. The mean Bamford-Kowal-Bench score improved from 14% to 66% and 73% at 2 and 12 months post-implantation, respectively. The complication rate was 15.3%. The survival probability at 1 year post-implantation was 0.95 for females and 0.93 for males, at 3 years was 0.89 for females and 0.81 for males, and at 5 years was 0.74 for females and 0.54 for males. CONCLUSION: CI is safe and well-tolerated in this age group and elderly patients gain similar audiometric and functional benefit as found for younger age groups.

Prevalence of occult nodal metastases in squamous cell carcinoma of the temporal bone: a systematic review and meta-analysis.

PURPOSE: Primary: To determine the rate of occult cervical metastases in primary temporal bone squamous cell carcinomas (TBSSC). Secondary: to perform a subgroup meta-analysis of the risk of occult metastases based on the clinical stage of the tumour and its risk based on corresponding levels of the neck. METHODS: A systematic review and meta-analysis of papers searched through Medline, Cochrane, Embase, Scopus and Web of Science up to November 2021 to determine the pooled rate of occult lymph node/parotid metastases. Quality assessment of the included studies was assessed through the Newcastle-Ottawa scale. RESULTS: Overall, 13 out of 3301 screened studies met the inclusion criteria, for a total of 1120 patients of which 550 had TBSCC. Out of the 267 patients who underwent a neck dissection, 33 had positive lymph nodes giving a pooled rate of occult metastases of 14% (95% CI 10-19%). Occult metastases rate varied according to Modified Pittsburg staging system, being 0% (0-16%) among 12 pT1, 7% (2-20%) among 43 pT2 cases, 21% (11-38%) among 45 pT3, and 18% (11-27%) among 102 pT4 cases. Data available showed that most of the positive nodes were in Level II. CONCLUSION: The rate of occult cervical metastases in TBSCC increases with pathological T category with majority of nodal disease found in level II of the neck.

Detecting and managing partial shorts in Cochlear implants: A validation of scalp surface potential testing.

OBJECTIVE: To investigate the value of scalp surface potentials to identify and manage partial short circuits to ground in cochlear implant electrodes. DESIGN: A retrospective review of patients with suspected partial short circuits. MAIN OUTCOME MEASURE: Electrical output of individual electrodes was measured using scalp surface potentials for patients reporting a change in hearing function. Electrical output was compared to functional performance and impedance measurements to determine if devices with suspected partial short circuits were experiencing a decrease in performance as a result of reduced electrical output. Electrical output was checked in an artificial cochlea for two implants following explant surgery to confirm scalp surface potential results. RESULTS: All patients with suspected partial short circuits (n = 49) had reduced electrical output, a drop in impedances to approximately ½ of previously stable measurements or to below 2 kΩ, an atypical electrical field measurement (EFI) and a decline in hearing function. Only devices with an atypical EFI showed reduced electrical output. Results of scalp based surface potentials could be replicated in an artificial cochlea following explantation of the device. All explant reports received to date (n = 42) have confirmed partial short circuits, with an additional four devices failing integrity tests. CONCLUSION: Surface potential measurements can detect partial shorts and had 100% correlation with atypical EFI measurements, which are characteristic of a partial short to ground in this device. Surface potentials can help determine the degree to which the electrode array is affected, particularly when behavioural testing is limited or not possible.

Eustachian Tube Function in Patients with Symptoms on Baro-Challenge.

OBJECTIVES: To explore the relationship between aural symptoms during baro-challenge and the underlying measured Eustachian tube (ET) function. Two key questions were addressed. (1) In patients who have features of obstructive ET dysfunction, is there a measurable underlying difference in ET function between those who experience severe symptoms on baro-challenge and those that do not? (2) What is the diagnostic value of ET function tests in the identification of patients with severe symptoms on baro-challenge? METHODS: Patients with symptoms of obstructive ET dysfunction were recruited, with the presence of aural symptoms on baro-challenge established via the clinical history and analysis of the Cambridge ET Dysfunction Assessment, a patient-reported outcome measure (PROM). ET function tests were assessed in each patient: 9 objective and semi-objective measures of ET opening, and 2 symptom-based PROMs. The tests' results were grouped by type of ET opening assessed, generating passive and active dysfunction scores. Individual test results were assessed for diagnostic accuracy in reference to features in the history or PROM-based evidence of symptoms on baro-challenge. RESULTS: Both passive and active opening of the ET was significantly reduced in ears with a history of pain on baro-challenge. Some patients had apparent severe obstructive ET dysfunction without symptoms on baro-challenge, whilst others had symptoms but normal test results. No individual test of ET opening was of diagnostic value in predicting those ears likely to experience pain or exacerbated symptoms on baro-challenge. CONCLUSION: The relationship between aural pain during baro-challenge and ET function appears more complex than had been assumed, with pain possibly related to factors other than just ET function.

Detection of Extracochlear Electrodes in Cochlear Implants with Electric Field Imaging/Transimpedance Measurements: A Human Cadaver Study.

OBJECTIVES: Extracochlear electrodes in cochlear implants (CI), defined as individual electrodes on the electrode array located outside of the cochlea, are not a rare phenomenon. The presence of extracochlear electrodes frequently goes unnoticed and could result in them being assigned stimulation frequencies that are either not delivered to, or stimulating neurons that overlap with intracochlear electrodes, potentially reducing performance. The current gold-standard for detection of extracochlear electrodes is computed tomography (CT), which is time-intensive, costly and involves radiation. It is hypothesized that a collection of Stimulation-Current-Induced Non-Stimulating Electrode Voltage recordings (SCINSEVs), commonly referred to as "transimpedance measurements (TIMs)" or electric field imaging (EFI), could be utilized to detect extracochlear electrodes even when contact impedances are low. An automated analysis tool is introduced for detection and quantification of extracochlear electrodes. DESIGN: Eight fresh-frozen human cadaveric heads were implanted with the Advanced Bionics HiRes90K with a HiFocus 1J lateral-wall electrode. The cochlea was flushed with 1.0% saline through the lateral semicircular canal. Contact impedances and SCINSEVs were recorded for complete insertion and for 1 to 5 extracochlear electrodes. Measured conditions included: air in the middle ear (to simulate electrodes situated in the middle ear), 1.0% saline in the middle ear (to simulate intraoperative conditions with saline or blood in the middle ear), and soft tissue (temporal muscle) wrapped around the extracochlear electrodes (to simulate postoperative soft-tissue encapsulation of the electrodes). Intraoperative SCINSEVs from patients were collected, for clinical purposes during slow insertion of the electrode array, as well as from a patient postoperatively with known extracochlear electrodes. RESULTS: Full insertion of the cochlear implant in the fresh-frozen human cadaveric heads with a flushed cochlea resulted in contact impedances in the range of 6.06 ± 2.99 kΩ (mean ± 2SD). Contact impedances were high when the extracochlear electrodes were located in air, but remained similar to intracochlear contact impedances when in saline or soft tissue. SCINSEVs showed a change in shape for the extracochlear electrodes in air, saline, and soft tissue. The automated analysis tool showed a specificity and sensitivity of 100% for detection of two or more extracochlear electrodes in saline and soft tissue. The quantification of two or more extracochlear electrodes was correct for 84% and 81% of the saline and soft tissue measurements, respectively. CONCLUSIONS: Our analysis of SCINSEVs (specifically the EFIs from this manufacturer) shows good potential as a detection tool for extracochlear electrodes, even when contact impedances remain similar to intracochlear values. SCINSEVs could potentially replace CT in the initial screening for extracochlear electrodes. Detecting migration of the electrode array during the final stages of surgery could potentially prevent re-insertion surgery for some CI users. The automated detection tool could assist in detection and quantification of two or more extracochlear electrodes.

Quality of life related to symptomatic outcomes in patients with vestibular schwannomas: A Canadian Centre perspective.

Patients with vestibular schwannomas (VS) typically present with hearing loss and tinnitus as well as variable cranial nerve dysfunctions. Surgical resection, stereotactic radiotherapy and/or conservative management employing serial magnetic resonance or computed tomography imaging serve as the main treatment options. Quality of life (QoL) may be impacted by the extent of tumour burden and exacerbated or relieved by treatment. Subjective assessment and quality of life inventories provide valuable information in client centered approaches with important implications for treatment. The intention of QoL measurements affecting VS patients within a clinical setting is to facilitate discussions regarding treatment options and objectively evaluate patient- centered clinical outcomes in a naturalistic setting.

A systematic review on prevention and management of wound infections from cochlear implantation.

OBJECTIVE OF REVIEW: Surgical site infections are a recognised complication of cochlear implant (CI) surgery with significant morbidity. Our aim was to search for the optimum prevention and management strategy to deal with this issue. TYPE OF REVIEW: Systematic review. SEARCH STRATEGY: A systematic literature search was undertaken from the databases of Embase, CINAHL, MEDLINE® , Web of Science, Scopus and Cochrane Library according to the predefined inclusion and exclusion criteria. EVALUATION METHOD: All relevant titles, abstracts and full-text articles were reviewed by two authors who resolved any differences by discussion and consultation with senior authors. RESULTS: Fourteen articles were included in our review. The overall quality of evidence was low with the vast majority of the studies being retrospective case series and expert opinions. No randomised controlled trials were noted. We found consistent reports that intraoperative prophylactic antibiotics should be given to all patients undergoing CI and that the vast majority of CI wound infections had grown Staphylococcal spp. or Pseudomonas spp. CONCLUSION: Our review has not identified any reliable or reproducible strategies to prevent and deal with wound infections after CI. We strongly encourage further research within this field and would suggest that a consensus of opinions from a multidisciplinary panel of experts may be a pragmatic way forward as an effective guide.

Hearing loss.

Hearing loss affects one in six people in the UK and is a significant disease burden. In addition to communication problems, there is also an association with depression and dementia. Clinical assessment with targeted history and examination can identify the characteristics and cause of hearing loss, and complementary audiological testing can confirm its type and severity. Retrocochlear screening is recommended for sudden, rapidly progressive or asymmetric sensorineural hearing loss. Medical or surgical therapies may be indicated in cases of conductive hearing loss, while hearing assistive devices and hearing aids are the mainstay of rehabilitation for sensorineural hearing loss.