Cochlear Implant Research Articles

Single-Sided Deafness: A Narrative Review

Background and Aims: Single-sided deafness (SSD) is a severe type of hearing loss affecting one ear, and it frequently presents social difficulties for those affected. Head shadow effect and sound localisation play an important role in speech perception. Methods: Research articles on SSD were identified through an online search of PubMed, Scopus, Medline, and Google Scholar databases. Results: SSD affects daily activities and emotional or social well-being. It is necessary to get the early identification of the aetiology of SSD for prompt intervention. The aetiology of SSD can be determined with the use of investigations such as as genetic testing, serological testing, computed tomography (CT) scan, magnetic resonance imaging, and DNA testing for viral infections. Rehabilitation options for patients with SSD include cochlear implants, bone-anchored hearing aids, and contralateral routing of sound. Individuals with SSD cochlear implants have strong auditory perception. The objective of this review article is to provide aetiology, clinical presentations, diagnosis and current treatment of SSD. Conclusion: Individuals with SSD commonly experience communication issues that have a substantial negative effect on their quality of life. Word discrimination is hampered by SSD, and this impairment varies depending on the affected ear’s residual hearing. Speech comprehension is frequently difficult for patients with severe SSD, especially in noisy environments.

Effects of Number of Filters and Frequency Cutoff in Continuous Interleaved Sampling and Frequency Amplitude Modulation Encoding Schemes in Cochlear Implant

Cochlear implants are devices designed to transform sound into electrical signals perceived by the brain, making them vital prostheses for deaf individuals. This study examines two schemes used in cochlear implants, namely Continuous Interleaved Sampling (CIS) and Frequency Amplitude Modulation Encoding (FAME), to compare their performance while varying the number of bandpass filters and cutoff frequencies used. Both schemes were simulated using 8 and 5 bandpass filters, and cutoff frequencies of 2000 Hz and 200 Hz. Results show that the CIS scheme can maintain signal intelligibility despite the loss of some frequency components when the number of bandpass filters is lowered. Conversely, FAME retains more frequency details but presents perceptible delays. With a cut off frequency of 200 Hz, signals processed with CIS loses intelligibility significantly, whereas FAME-processed signals remain intelligible both at 200 Hz and 2000 Hz cut off frequencies. It is therefore concluded that FAME can provide better cochlear implant performance despite the lower number of bandpass filters and lower frequency cutoff.

The Indian context: an investigative study of assistive listening device usage and experiences among hearing aid users

Background: Assistive Listening Devices (ALDs) augment the functionality of hearing aids and cochlear implants, facilitating enhanced auditory communication for individuals with hearing impairment and potentially improving their life quality. The limited popularity of ALDs within the Indian context necessitates an investigation into the factors influencing their underutilization. Methods: To address this, a survey assessing ALD awareness among Indian hearing aid users with at least one year of device usage was administered using a questionnaire. A total of 42 responses were collected and subjected to descriptive analysis. Results: The findings of the study revealed a predominant willingness among hearing aid users to discover ALDs and their advantages in daily activities. A segment of the cohort was already conversant with ALDs, whereas a minor fraction showed reluctance towards acquiring additional information. Conclusions: The obtained data indicates a requirement for further comprehensive research with a larger pool of data to understand the breadth of user dispositions and the motivation for the indifferent reception of ALDs in the Indian context.

Hearing loss in children with congenital heart disease

Background : Congenital heart disease (CHD) is a dangerous disease, about 50% of deaths will occur in the first month of life. In developed countries almost all types of congenital heart disease have been detected in infancy even at less than 1 month of age, whereas in developing countries many are only detected after the child is older, so in some severe CHD types may have died before being detected. Rubella infection in pregnancy or congenital rubella syndrome (CRS) can cause miscarriage, fetal death, or congenital abnormalities after birth. CRS is characterized by sensorineural hearing loss (SNHL), congenital cataracts or glaucoma, congenital heart disease, and developmental delays. Purpose : This case report was submitted in order to find out how to properly treat patients with hearing loss with sensory deafness and congenital heart disease. Case : Reported a 3-year-old 6-month-old boy diagnosed with very severe degree sensorineural deafness and congenital heart disease based on anamnesis, physical examination and examination of OAE, BERA and ASSR for examination of auditory function) and echocardiography examination for examination of cardiac function. Conclusion : From the history, physical examination and examination of OAE, BERA, ASSR showed patients with very severe sensorineural hearing loss of the left and right ear and congenital heart disease, planned use of hearing aids or cochlear implantation and cardiac consul for CHD treatment.

Correlation of Electrophysiological and Behavioral Response in Cochlear Implant Candidates

Correlation of Electrophysiological and Behavioral Response in Cochlear Implant Candidates

Evaluating Wideband Tympanometry Absorbance Changes in Cochlear Implant Recipients: Mechanical Insights and Influencing Parameters.

Background: Cochlear implant (CI) electrode insertion can change the mechanical state of the ear whereby wideband tympanometry absorbance (WBTA) may serve as a sensitive tool to monitor these mechanical changes of the peripheral auditory pathway after CI surgery. In WBTA, the amount of acoustic energy reflected by the tympanic membrane is assessed over a wide frequency range from 226 Hz to 8000 Hz. The objective of this study was to monitor changes in WBTA in CI recipients before and after surgery. Methods: Following otoscopy, WBTA measurements were conducted twice in both ears of 38 standard CI recipients before and in the range of 4 to 15 weeks after CI implantation. Changes from pre- to postoperative absorbance patterns were compared for the implanted as well as the contralateral control ear for six different frequencies (500 Hz, 750 Hz, 1000 Hz, 2000 Hz, 3000 Hz, 4000 Hz). Furthermore, the influence of the time point of the measurement, surgical access, electrode type, sex and side of the implantation were assessed for the implanted and the control ear in a linear mixed model. Results: A significant decrease in WBTA could be observed in the implanted ear when compared with the contralateral control ear for 750 Hz (p < 0.01) and 1000 Hz (p < 0.05). The typical two-peak pattern of WBTA measurements was seen in both ears preoperatively but changed to a one-peak pattern in the newly implanted ear. The linear mixed model showed that not only the cochlear implantation in general but also the insertion through the round window compared to the cochleostomy leads to a decreased absorbance at 750 and 1000 Hz. Conclusions: With WBTA, we were able to detect mechanical changes of the acoustical pathway after CI surgery. The implantation of a CI led to decreased absorbance in the lower frequencies and the two-peak pattern was shifted to a one-peak pattern. The result of the linear mixed model indicates that WBTA can detect mechanical changes due to cochlear implantation not only in the middle ear but also in the inner ear.

Cochlear implants for hereditary ATTR amyloidosis: a case report of two cases.

To analyze the clinical presentation, management, and outcome of two sisters affected by hereditary transthyretin related amyloidosis (ATTRv) and bilateral severe-to-profound hearing loss treated with cochlear implant. A description of two patients underwent three cochlear implant (CI) surgery was performed. Age at time of implantation ranged from 48 to 53years. Both patients were initially equipped with a bilateral hearing aid and subsequently underwent cochlear implant. A bimodal stimulation was maintained thereafter. One case underwent bilateral surgery. Hearing outcomes were assessed by comparing pre- and post-operatively tonal and vocal hearing thresholds and speech perception tests (Common Evaluation Protocol Results in Rehabilitation Audiology). In both patients, a significant and stable improvement of hearing threshold and speech perception was observed up to the last follow-up. No post-operative complication were observed during the follow-up. ATTRv amyloidosis may be the cause of cochlear function impairment. Restoring the hearing in these group of patients is of paramount importance since the vision is often compromised too. Cochlear implant could be a viable strategy of rehabilitation for selected patients affected by severe-to-profound sensorineural hearing loss caused by ATTRv amyloidosis.

Benefits of Cochlear Implantation for Older Adults With Asymmetric Hearing Loss.

FDA-approved indications for cochlear implantation include patients with severe-to-profound unilateral hearing loss (UHL) or asymmetric hearing loss (AHL); however, these indications are not covered for Medicare beneficiaries. We assessed the outcomes of cochlear implant (CI) use for older adults with UHL or AHL. Eighteen older adults (≥65 years of age at surgery) with UHL/AHL participated in a prospective, longitudinal investigation evaluating outcomes of CI use. Speech recognition for the affected ear was evaluated with consonant-nucleus-consonant (CNC) words. Spatial hearing was assessed with measures of sound source localization and sentence recognition in noise. The target sentence was presented from the front and the masker was either co-located with the target (SoNo), presented toward the affected ear (SoNci) or contralateral ear (SoNcontra). Perceived benefit was assessed with the Speech, Spatial, and Qualities of Hearing scale (SSQ) and the Tinnitus Handicap Inventory (THI). Participants experienced significant improvements with CI use for CNC words (mean [SD]; preop: 8% [10%], 1 yr: 51% [22%], 5 yr: 50% [19%]), masked sentence recognition (SoNcontra preop: 5% [6%], 1 yr: 22% [15%], 5 yr: 41% [14%]), and localization (preop: 76° [18°], 1 yr: 40° [11°], 5 yr: 41° [14°]),and reported significant improvements in hearing abilities (SSQ Spatial Hearing preop: 3 [1], 1 yr: 6 [2], 5 yr: 6 [2]) and tinnitus severity (THI preop: 16 [18], 1 yr: 4 [14], 5 yr: 6 [12]). Older adults with UHL/AHL experience significant improvements in speech recognition, spatial hearing, and subjective perceptions (e.g., hearing abilities and tinnitus severity) with a CI as compared to pre-operative abilities. IV Laryngoscope, 2024.

Cochlear implantation in syndromic patients: difficulties and lessons learnt.

Identify the prevalence of syndromes in a cohort of patients who underwent cochlear implantation, to report on the presence of inner and middle ear malformations and highlight the surgical difficulties encountered. Observational, retrospective study. Tertiary referral children's hospital pediatric cochlear implant program. An IRB-approved retrospective chart review of children undergoing cochlear implantation at a tertiary academic medical center, from 2018 to 2023. Preoperative imaging data of syndromic patients in that cohort with special attention to the presence of inner ear or middle ear malformations were collected. Abnormal intraoperative findings and difficulties reported by the surgeons were also noted. 1024 children were unilaterally implanted for bilateral profound hearing loss. There were 45 cases diagnosed with associated syndromes (4.3%). The commonest syndromes were Jervell and Lange Nielsen (JLN) syndrome followed by Waardenberg syndrome (WS), in a prevalence of 34% and 32% respectively. These syndromes had no associated inner ear malformations (IEM). Less common syndromes included Branchio-oto-renal (BOR) syndrome, CHARGE association and Treacher Collins syndrome, 3 cases each, and keratosis icthyosis deafness syndrome (KID), Usher syndrome and Albino, 2 cases each and an H syndrome case. There were 9 cases (20%) with IEM, with 6 cases of perilymph gusher. Two cases had middle ear anomalies and one case had a facial nerve course abnormality. The outcome of these cases was similar to non-syndromic cases. Children with syndromic HL should be dealt with on a case by case scenario to diagnose inner and middle ear malformations. Additional disabilities can affect the rehabilitation procedures. All children with congenital hearing loss should undergo pediatric, cardiologic, ophthalmologic and nephrologic examination in order to exclude the syndromic etiology of hearing loss.

FOXO1-NCOA4 Axis Contributes to Cisplatin-Induced Cochlea Spiral Ganglion Neuron Ferroptosis via Ferritinophagy.

Mammalian cochlea spiral ganglion neurons (SGNs) are crucial for sound transmission, they can be damaged by chemotherapy drug cisplatin and lead to irreversible sensorineural hearing loss (SNHL), while such damage can also render cochlear implants ineffective. However, the mechanisms underlying cisplatin-induced SGNs damage and subsequent SNHL are still under debate and there is no currently effective clinical treatment. Here, this study demonstrates that ferroptosis is triggered in SGNs following exposure to cisplatin. Inhibiting ferroptosis protects against cisplatin-induced SGNs damage and hearing loss, while inducing ferroptosis intensifies these effects. Furthermore, cisplatin prompts nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy in SGNs, while knocking down NCOA4 mitigates cisplatin-induced ferroptosis and hearing loss. Notably, the upstream regulator of NCOA4 is identified and transcription factor forkhead box O1 (FOXO1) is shown to directly suppress NCOA4 expression in SGNs. The knocking down of FOXO1 amplifies NCOA4-mediated ferritinophagy, increases ferroptosis and lipid peroxidation, while disrupting the interaction between FOXO1 and NCOA4 in NCOA4 knock out mice prevents the cisplatin-induced SGN ferroptosis and hearing loss. Collectively, this study highlights the critical role of the FOXO1-NCOA4 axis in regulating ferritinophagy and ferroptosis in cisplatin-induced SGNs damage, offering promising therapeutic targets for SNHL mitigation.

Reading achievement and deaf students with cochlear implants

Objectives The purpose of this study was to investigate the reading outcomes of a Canadian cohort of school-aged deaf learners with cochlear implants (CIs). The goal was to investigate whether achievement approached that of hearing age peers and identify demographic factors influencing performance. Methods Participants represent a subset of 13 students with CIs from a larger sample of 70 deaf students in grades four through 12 educated in inclusive settings within a large school board in central Canada. Data sources included demographic information, teachers’ ratings on the Categories of Auditory Performance (CAP), and scores from the Woodcock-Johnson III Diagnostic Reading Battery [WJ III-DRB]. Results/Discussion: Participants performed within the low average range in all areas except for Phonological Awareness, which was in the low range; however, there was wide variability in scores across participants. None of the demographic variables (e.g. home language, additional disabilities) had a statistically significant association with performance, although older students had higher mean scores on the Phonological Awareness cluster. Conclusion These findings add to the body of research on literacy achievement and cochlear implantation, providing evidence that this technology has a significant positive effect on outcomes for a population that has heretofore underperformed in this area.

Rehabilitation with cochlear implants in children with malformations of the inner ear

Cochlear implants (CIs) are the treatment of choice for hearing rehabilitation in children with congenital or acquired profound hearing loss or deafness in order to ensure appropriate speech development and avoid social deprivation. However, in the case of aradiologically detectable malformation of the inner ear structures and potentially associated hypo- or aplasia of the vestibulocochlear nerve, application of aCI is either not possible, or the functional outcome may be of limited predictability. In addition, the risk of surgical complications is also increased in these patients. Counseling parents and developing an appropriate individual therapeutic decision can therefore be amajor challenge for the medical team. The current paper is intended to provide support in this regard. It presents criteria for various inner ear malformations and discusses possible treatment options.

Noise exposure of the inner ear during robotic drilling.

Preserving the cochlear structures and thus hearing preservation, has become a prominent topic of discussion in cochlear implant (CI) surgery. Various approaches and soft surgical techniques have been described when approaching the inner ear. Robot-assisted cochlear implant surgery (RACIS) reaches the round window in a minimally invasive manner by following a trajectory of minimal trauma. This involves the drilling of a keyhole trajectory to the round window, through the facial recess, with no need for a complete mastoidectomy. It involves less drilling, less drilling time and less structural damage. A lot of attention has been paid to the structural traumatic causes of hearing loss but acoustic trauma during the exposure of the inner ear appears to be neglected topic. The aim was to measure the noise exposure of the inner ear during the robotic drilling of the mastoid and bony overhang of the round window. The results were compared with the milling in conventional cochlear implantation surgery. RACIS on fresh frozen human cadavers. The equivalent frequency-weighted and time-averaged sound pressure level LAF in dB and the noise dose in % derived from a noise damage model, both obtained during RACIS. The robotic drilling of 6 trajectories towards the inner ear were performed, including 4 trajectories through round window access and 2 trajectories through cochleostomy. The results were compared with the data of 7 cases of conventional CI surgery that have been described in literature. The induced equivalent sound pressure level LAF was determined via an accelleration sensor at the zygomatic arch and a calibration according to bone conduction audiometry. A noise dose for the whole procedure was calculated from the equivalent sound pressure level LAF and the exposure time using a noise damage model. A noise dose of 100% is considered a critical exposure limit and values above are considered potentially harmful, with the risk of hearing impairment. The maximum LAF was 82 dB during fiducial screw placement; 87 dB during middle ear access; 95 dB for the accesses through the round window and 88 dB for the accesses through cochleostomy. The noise dose due to the HEARO®-procedure was always far below the critical value of 100%. There was no acoustic trauma of the inner ear in all cases with the noise dose being smaller than 0.1% in five out of the six cases. The maximum LAF in the seven cases of conventional CI surgery was 118 dB with a maximum cumulative noise dose of 172.6%. The critical exposure limit of 100% was exceeded in three cases of conventional CI surgery. RACIS provokes significantly less acoustic trauma than conventional mastoid surgery in our findings. There were no observable differences in noise exposure levels between a cochleostomy or a round window approach where the bony overhang needed to be drilled.

Hearing loss secondary to variants in the OTOF gene

ObjectiveGenetic variants in the OTOF gene are responsible for non-syndromic hearing loss with an autosomal recessive inheritance pattern. The objective of our work was to evaluate the clinical characteristics of patients with biallelic pathogenic variants in OTOF and their evolution after treatment. MethodsA cohort of 124 patients with prelingual hearing loss, studied from 1996 to 2023, was included in this study. A genetic analysis was conducted to identify the type and frequency of variants in the OTOF gene and their relation to the clinical characteristics of the patients. ResultsThe homozygous p. Gln829* variant in the OTOF gene was detected in 3 probands (2.4 %) of a group of 124 individuals with prelingual hearing loss. Another 6 family members to a total of 9 individuals were finally included. All presented with severe/profound bilateral sensorineural hearing loss of congenital onset. Three of these individuals were diagnosed with auditory neuropathy spectrum disorder. One individual passed the OAE test during the screening program, and since he did not have risk factors for hearing loss that would warrant ABR testing, this led to a delay in his hearing loss diagnosis. Four individuals underwent cochlear implants (three bilateral) with good functional outcomes in three of them. However, in 17 familial cases with heterozygous variants, either no hearing loss was observed or it was within the expected range for their age. ConclusionsHearing loss secondary to the p.Gln829* variant of the OTOF gene is relatively rare in our medical area. Its presence in homozygosity is the cause of severe/profound bilateral prelingual sensorineural hearing loss, responsible for auditory neuropathy with a good response to cochlear implantation.

What Do People Want to Know About Cochlear Implants: A Google Analytic Study.

Identify the questions most frequently asked online about cochlear implants (CI) and assess the readability and quality of the content. A Google search engine observational study was conducted via a search response optimization (SEO) tool. The SEO tool listed the questions generated by Google's "People Also Ask" (PAA) feature for the search queries "cochlear implant" and "cochlear implant surgery." The top 50 PAA questions for each query were conceptually classified. Sourced websites were evaluated for readability, transparency and information quality, and ability to answer the question. Readability and accuracy in answering questions were also compared to the responses from ChatGPT 3.5. The PAA questions were commonly related to technical details (21%), surgical factors (18%), and postoperative experiences (12%). Sourced websites mainly were from academic institutions, followed by commercial companies. Among all types of websites, readability, on average, did not meet the recommended standard for health-related patient education materials. Only two websites were at or below the 8th-grade level. Responses by ChatGPT had significantly poorer readability compared to the websites (p < 0.001). These online resources were not significantly different in the percentage of accurately answering the questions (websites: 78%, ChatGPT: 85%, p = 0.136). The most searched topics were technical details about devices, surgical factors, and the postoperative experience. Unfortunately, most websites did not meet the ideal criteria of readability, quality, and credibility for patient education. These results highlight potential knowledge gaps for patients, deficits in current online education materials, and possible tools to better support CI candidate decision-making. NA Laryngoscope, 2024.

Pediatric Failure Rates and Speech Outcomes in the HiRes Ultra and Ultra 3D Series Recall.

The recent Field Corrective Action (FCA) for the HiRes Ultra and Ultra 3D (V1) cochlear implants (CIs) triggered much research investigating clinical identification, failure rates, and postrevision outcomes. Pediatric data remain limited, especially with regards to speech outcomes. We aim to characterize the trajectory of children implanted with these devices with specific attention to speech outcomes. Retrospective cohort study of pediatric patients with FCA-affected CIs from March 2017 to January 2020 at a tertiary children's hospital. CI placement, device monitoring, audiologic evaluation, revision surgery. CI failure rates, revision surgery rate, speech recognition outcomes. Forty-one devices were implanted in 27 pediatric patients. Average age at implantation was 4.01 years (range, 0.87-12.75). To date, 30 devices (73%) are known failures with 90% of these having undergone revision surgery. No statically significant difference was noted on open-set speech testing across best prerevision, immediate prerevision, and best postrevision time points. Best postrevision CNC scores had a mean score of 71% ± 26%, n = 16. Pediatric patients implanted with FCA-affected CI devices have a high risk of device failure. Open-set speech recognition was not significantly different from prerevision to postrevision testing, suggesting preserved speech outcomes. This may be partially attributable to limitations of cohort size and the pediatric population with open-set speech testing. However, we suspect that close follow-up with standardized testing and a low threshold for revision surgery provided by our multidisciplinary team may have mitigated these changes. Postrevision open-set speech testing remains positive for these patients.

Consonant and vowel production in children with cochlear implants: acoustic measures and multiple factor analysis

IntroductionThe acoustic limitations of cochlear implants (CIs) can lead to perceptual limitations and consequently to imprecise phonological representations and production difficulties. The aim of the study is to document the phonological and phonetic skills of children with CIs and their typically hearing peers. Phonetically, three types of segments were targeted, each characterized by contrasting acoustic information: nasal/oral vowels, fricative segments, and voiced/voiceless stops.MethodsForty-seven typically hearing children (TH) and 23 children with CIs performed a picture-naming task. Productions were analyzed to obtain phonological measures (percentages of correct phonemes, types of errors), and various acoustic measures were collected to characterize the productions on the three types of segments investigated. Multiple factor analyses were conducted to study productive profiles on the various acoustic measures, and the dimensions were correlated with phonological measures.ResultsThe results showed lower performance in lexical (target word retrieval) and phonological (percentages of correct phonemes) skills among children with CIs (CI group), although with better performances among children exposed to CS. Acoustically, children in the CI group exhibited productions significantly different from those of the TH group in terms of the distinction of fricative consonants, marking nasalization through nasal resonance cues, and in the production of voiceless stops. However, the CI group demonstrated compensatory strategies (lengthening of VOT for voiced stops, marking of nasalization through oropharyngeal configuration cues).ConclusionsThe results indicate that children with CIs are at risk of experiencing difficulties in both phonetic and phonological domains. However, there are opportunities for compensation through the exploitation of acoustic cues better coded by the CI and/or through perceptual means (utilization of visual cues).

Validating an Evoked Potential Platform for Electrocochleography During Cochlear Implantation.

To validate electrocochleography (ECochG) between an auditory evoked potential (AEP) machine and an established cochlear implant (CI) manufacturer ECochG system. Intraoperative validation study at a tertiary referral center. Patients included adults and children undergoing cochlear implantation. Intraoperative ECochG was measured with both the Intelligent Hearing Systems (IHS) Duet AEP machine and Cochlear Corporation (CC) ECochG platform. Recording electrodes captured extracochlear measurements through a standard facial recess. Tone-bursts were presented from 250 Hz to 2 kHz (~110 dB SPL). A fast Fourier transform (FFT) of ECochG waveforms at key frequencies was summed into a total response (ECochG-TR). Pearson's correlation was utilized to evaluate the relationship between IHS-ECochG-TR and CC-ECochG-TR after confirming normality. Thirty patients were enrolled with an average age of 67 years (SD 18.8). In the ear that was implanted, mean preoperative pure-tone average (PTA; 0.5, 1, 2, and 4 kHz) was 87.4 dB HL (SD 19.3) and mean preoperative word-recognition scores (WRS) was 17.0% correct (SD 19.1). There was strong correlation (r = 0.905, 95% confidence interval: 0.809 to 0.954) between IHS-ECochG-TR (median 2.30 μV, range 0.1-148.26) and CC-ECochG-TR (median 3.00 μV, range 0.1-239.63). Four patients underwent transtympanic ECochG with the IHS system for feasibility evaluation and achieved similar responses. Extracochlear ECochG has been predictive of CI speech perception performance. The IHS duet system is a valid measure of extracochlear ECochG for the CI population. Future work will utilize this system for measuring transtympanic ECochG to improve preoperative estimation of CI performance. 3 Laryngoscope, 2024.

Alzheimer's Disease-Related Analytes Amyloid-β and Tau in Perilymph: Correlation With Patient Age and Cognitive Score.

To describe the collection methods for perilymph fluid biopsy during cochlear implantation, detect levels of amyloid β 42 and 40 (Aβ42 and Aβ40), and total tau (tTau) analytes with a high-precision assay, to compare these levels with patient age and Montreal Cognitive Assessment (MoCA) scores, and explore potential mechanisms and relationships with otic pathology. Prospective study. Tertiary referral center. Perilymph was collected from 25 patients using polyimide tubing to avoid amyloid adherence to glass, and analyzed with a single-molecule array advanced digital enzyme-linked immunosorbent assay platform for Aβ40, Aβ42, and tTau. Cognition was assessed by MoCA. Perilymph volumes ranged from ∼1 to 13 µL, with analyte concentrations spanning 2.67 to 1088.26 pg/mL. All samples had detectable levels of tTau, Aβ40, and Aβ42, with a significant positive correlation between Aβ42 and Aβ40 levels. Levels of Aβ42, Aβ40, and tTau were positively correlated with age, while MoCA scores were inversely correlated with age. tTau and Aβ42/Aβ40-ratios were significantly correlated with MoCA scores. Alzheimer's disease-associated peptides Aβ42, Aβ40, and tau analytes are detectable in human perilymph at levels approximately 10-fold lower than those found in cerebrospinal fluid (CSF). These species increase with age and correlate with cognitive impairment indicators, suggesting their potential utility as biomarkers for cognitive impairment in patients undergoing cochlear implantation. Future research should investigate the origin of these analytes in the perilymph and their potential links to inner ear pathologies and hearing loss, as well as their relationships to CSF and plasma levels in individuals.

Characterizing Cochlear Implant Trans-Impedance Matrix Heatmaps in Patients With Abnormal Anatomy.

To characterize transimpedance matrix (TIM) heatmap patterns in patients at risk of labyrinthine abnormality to better understand accuracy and possible TIM limitations. Retrospective review of TIM patterns, preoperative, and postoperative imaging. Tertiary referral center. Patients undergoing cochlear implantation with risk of labyrinthine abnormality. None. Seventy-seven patients were evaluated. Twenty-five percent (n = 19) of patients had a TIM pattern variant identified. These variants were separated into 10 novel categories. Overall, 9% (n = 6) of electrodes were malpositioned on intraoperative x-ray, of which 50% (n = 3) were underinserted, 17% (n = 1) were overinserted, 17% (n = 1) had a tip foldover, and 17% (n = 1) had a coiled electrode. The number of patients with a variant TIM pattern and normal x-ray was 18% (n = 14), and the number of patients with normal TIM pattern and malposition noted on x-ray was 3% (n = 2; both were electrode underinsertions that were recognized due to open circuits and surgical visualization).A newly defined skip heat pattern was identified in patients with IP2/Mondini malformation and interscalar septum width <0.5 mm at the cochlear pars ascendens of the basal turn. This study defines novel patterns for TIM heatmap characterization to facilitate collaborative and comparative research moving forward. In doing so, it highlights a new pattern termed skip heat, which corresponds with a deficient interscalar septum of the cochlea pars ascendens of the basal turn in patients with IP2 malformation. Overall, the data assist the surgeon in better understanding the implications and limitations of TIM patterns within groups of patients with risk of labyrinthine abnormalities.