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Objective: Jugular bulb abnormalities (JBA), including high-riding jugular bulb (HRJB) and jugular bulb diverticulum (JBD), can erode into the inner ear. In this study, the authors investigate the prevalence and consequences of JBA and their erosion into inner ear structures using temporal bone histopathology and computed tomography (CT). Study Design: Cross-sectional study of temporal bone histopathology and radiology. Setting: Academic medical center. Subjects and Methods: In total, 1579 temporal bone specimens and 100 CT of the temporal bones (200 ears) were examined for JBA and any associated dehiscence of inner ear structures. Temporal bone specimens were examined for histological consequences of inner ear erosion. Jugular bulb dimensions were measured on axial CT scans and compared across groups. Accompanying demographic and clinical information were reviewed. Results: High jugular bulbs were noted in 8.2% (130/1579) of temporal bone specimens and in 8.5% (17/200) of temporal bone CT. The prevalence of JBA increases during the first 4 decades of life and stabilizes thereafter. High-riding jugular bulbs eroded inner ear structures such as the vestibular aqueduct, vertical facial nerve, or posterior semicircular canal in 2.8% (44/1579) of cases histologically and 1.5% (3/200) radiologically. In most, jugular bulb-mediated inner ear dehiscence was clinically and radiologically silent. Conclusion: Jugular bulb abnormalities are common. They are present in 10% to 15% individuals and are primarily acquired by the fourth decade of life. In 1% to 3% of cases, the HRJB erodes into the inner ear and most frequently involves the vestibular aqueduct. [ABSTRACT FROM AUTHOR]

The endolymphatic hydrops seen in Ménière's disease (MD) results from an inner ear fluid disequilibrium that has a suspected inherited component. Aquaporin-2 and aquaporin-4 (AQP2 and AQP4) water transport proteins may contribute to abnormal fluid homeostasis seen in MD. Our objective was to screen for sequence alterations in AQP2 and AQP4 genes in a northern European population with MD. Amplification for AQP2 ( n = 18) and AQP4 ( n = 30) was performed for patients with MD. Sequences were screened with denaturing high powered liquid chromatography (DHPLC) and confirmed with sequencing. Allele frequencies were compared with previously reported normal populations. We found that DHPLC failed to identify sequence alterations in any sample. Sequencing identified three intronic and one 3' untranslated region polymorphism in AQP2, and one polymorphism upstream from the start codon in AQP4 . Two of the AQP2 intronic allele frequencies showed an A and C allele enrichment, respectively, compared with a reported mixed population (0.389 A vs. 0.00 A; 0.389 C vs. 0.00 C, p < 0.001). The remaining polymorphism showed statistical difference from three non- Caucasian populations (0.611 A vs. 0.389 A, 0.375 A, and 0.280 A, p <0.05). The AQP4 allele frequency in the MD population was statistically different from a previously published Japanese population (0.800 G vs. 0.620 G, p = 0.0053) but not from a reported Caucasian population. We concluded that aquaporin polymorphisms may contribute to MD. Additional studies are needed to confirm these findings in well-defined population isolates and to determine if these polymorphisms lead to altered AQP protein function or levels. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: The objectives of this prospective study were to assess the reproducibility of the measurements of the cochlea and lateral semicircular canal (LSCC) and to determine if abnormal measurements predict sensorineural hearing loss (SNHL). Methods: Two readers independently measured the cochlear height on coronal section and the LSCC bony island width on axial section on 109 temporal bone computed tomography scans; audiologic data on these patients were collected independently from medical records. Inter- and intrareader variability was evaluated using intraclass correlation coefficients (ICCs) based on a random-effects model. The positive and negative predictive values of abnormal measurement for hearing loss were determined. Results: There was excellent inter- and intraobserver agreement for both measurements (ICC >80%). The average cochlear height was 5.1 mm (normal range, 4.4-5.9 mm) and average LSCC bony island width was 3.7 mm (normal range, 2.6-4.8 mm). Review of the original radiology reports demonstrated that both cochlear hypoplasia and LSSC dysplasia were overlooked in >50% of patients with both abnormal measurements and SNHL. Cochlear hypoplasia (< 4.4 mm) had a positive predictive value of 100% for SNHL, whereas cochlear hyperplasia and bony island dysplasia were less predictive. Conclusion: The measurements of coronal cochlear height and axial LSCC bony width have excellent reproducibility and identify bony labyrinth abnormalities missed by visual inspection alone. In addition, cochlear hypoplasia is highly predictive of SNHL. To reliably identify inner ear malformations, measurement of the cochlear height and LSCC bony island width, in addition to the vestibular aqueduct, should be routinely performed on all temporal bone studies. [ABSTRACT FROM AUTHOR]

Mhatre AN, Li Y, Feng L, Gasperin A, Lalwani AK.SDHB, SDHC, andSDHDmutation screen in sporadic and familial head and neck paragangliomas.Mutations within three genes,SDHB,SDHC, andSDHD, encoding distinct subunits of a hetero-oligomeric protein known as the mitochondrial complex II, a component of the mitochondrial electron transport chain and the Krebs cycle have been implicated in the pathogenesis of hereditary paraganglioma (PGL). This study describes a mutation screen ofSDHB,SDHC, andSDHDin blood and tumor samples of 14 sporadic and three familial cases of head and neck PGL (HNP). Germline mutations inSDHBandSDHDwere identified in two of the three affected individuals with familial HNP. TheSDHBmutation was a novel 3 base pair, in-frame deletion of AGC at nucleotide 583–585 encoding serine (delS195). TheSDHDmutation was a C to T transition within codon 81 causing substitution of proline with leucine (P81L). In contrast to familial cases, no germline or somatic mutations were identified in the 14 sporadic cases of HNP. The presence of mutations withinSDHBandSDHDin two of the three samples of familial PGLs and absence of mutations in sporadic cases is consistent with the significant contribution of these genes to familial but not sporadic PGL. The etiology of sporadic PGL remains to be elucidated. [ABSTRACT FROM AUTHOR]

Background: In patients with congenital sensorineural hearing loss (SNHL), a computed tomography (CT) scan of the temporal bone identifies inner ear malformations in approximately 25%, whereas the inner ear is grossly normal to visual inspection in the remaining 75% of the patients. In the latter group, the hearing loss is often attributed to radiologically undetectable abnormalities of the membranous labyrinth. However, subtle bony malformations may be missed because visual inspection alone is insensitive for detection.Objective: To test the hypothesis that there are subtle bony abnormalities of the inner ear in patients with SNHL who are radiologically deemed to have normal otic bone, using standardized measurements of the inner ear.Study Design: Retrospective review.Methods: Measurements of the cochlea, vestibule, and semicircular canals (SCCs) were made on axial and coronal temporal bone CT scans on 15 patients with normal hearing and 15 patients with congenital SNHL and grossly normal temporal bone CT scans. Student's t-test was performed to compare the measurements of the two groups. RESULTS All studies from the SNHL group were deemed normal by visual inspection and standardized measurements (+/-2 SD from normal). Surprisingly, there were significant differences in the measurements of the cochlea and of the SCCs between patients with and without SHNL (P <.05).Conclusions: As a group, patients with SNHL and a "normal CT scan" have significant differences in the dimensions of the inner ear. This suggests that these patients have disturbed morphogenesis of both membranous and bony labyrinth. This novel observation has important implications for understanding the etiology of SNHL. [ABSTRACT FROM AUTHOR]

A large American family has been mapped to the DFNA2 locus. However, mutation screening of CX31 and KCNQ4, the two genes associated with deafness at this locus, did not identify any mutations. The purpose of this report was to characterize the otologic and audiometric phenotype of this large American family with non-syndromic, autosomal-dominant sensorineural hereditary hearing impairment (HHI). Anamnestic data were obtained, pure-tone audiometry was performed and transient-evoked otoacoustic emissions were recorded. The findings in affected family members were compared to those in unaffected family members and to the respective p50 thresholds of the normal age-matched population. Mutational analysis of the CX26 gene was also performed. The affected members of this family demonstrated progressive symmetric sensorineural hearing impairment. The hearing loss was downward sloping, with mild-to-moderate loss in the low and mid frequencies and severe-to-profound loss in frequencies > 4,000 Hz. The onset of disease was predominantly in the first or early in the second decade. Hearing impairment progressed at approximately 1 dB per year across all frequencies. Transient-evoked otoacoustic emissions revealed a minimal response over all frequencies in affected members but robust responses in all unaffected members. Mutation in the CX26 gene was not present. The affected frequencies observed in this family were similar to those in the original family mapped to DFNA2; however, the age of onset of disease was different and the hearing loss progressed at a slower rate. Therefore, this family provides clinical evidence of genetic heterogeneity at the DFNA2 locus and can serve as a model for age-related hearing loss. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: Pulsatile tinnitus in the face of normal findings on otoscopy is a common otological diagnostic dilemma and can be due to serious vascular malformations such as transverse or sigmoid sinus dural arteriovenous fistula (transverse or sigmoid sinus [TS] DAVF). Left untreated, TS DAVF may result in significant morbidity and mortality. TS DAVF can be suspected or diagnosed with computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance angiography (MRA), with the gold standard being angiography. Our objective was to assess the utility of these various diagnostic modalities in the diagnosis of dural arteriovenous fistula. Study Design: Retrospective clinical review. Methods: Between 1986 and 1996, 54 patients were evaluated and treated for TS DAVF. Between 1996 and 1999, an additional 33 patients underwent MRI combined with MRA for the evaluation of pulsatile tinnitus. A retrospective review of the medical records for both groups, with special attention to clinical presentation, diagnostic evaluation, therapy, and outcome, was performed. Results: All patients had pulsatile tinnitus with normal findings on otoscopy. CT scan was relatively insensitive in the detection of TS DAVF. MRI and MR/MRA were significantly more sensitive than CT. In the evaluation of patients with subjective pulsatile tinnitus, MRI/MRA defined anatomical abnormalities that may contribute to pulsatile tinnitus in 63% of patients. Conclusions: In the absence of objective pulsatile tinnitus, MRI/MRA is an appropriate initial diagnostic step. When a patient has an objective bruit, the clinician may choose to proceed directly to angiography to make certain that a TS DAVF is not missed. [ABSTRACT FROM AUTHOR]

Objective: Lateral semicircular canal (LSCC) malformation is one of the most common radiological inner ear malformations. Traditionally, inner ear malformations are thought to be associated with sensorineural hearing loss (SNHL). Recent experience with patients with LSCC malformation suggested that LSCC malformation may be associated with both SNHL and conductive hearing loss (CHL). The auditory phenotype associated with LSCC malformation is not well delineated. The objective of this study is to define the nature of the hearing loss associated with LSCC malformation. Study Design: Retrospective review Methods: Retrospective review of clinical records, audiological evaluation, and imaging studies. Results: Two patients with unilateral and 13 patients with bilateral LSCC malformation were identified. LSCC malformation was associated with CHL in 14% (4 ears), SNHL in 71% (20 ears), normal hearing in 11% (3 ears) and CHL due to atresia in one ear. Hearing loss varied from mild to profound but did not correlate with the severity of LSCC malformation. In bilateral malformation, the hearing loss was asymmetric in half of the cases. Malformation of the posterior limb of the LSCC was always associated with a large vestibular aqueduct. An absent or rudimentary LSCC was invariably associated with a cochlear abnormality. Conclusions: LSCC malformation, like other inner ear malformations such as large vestibular aqueduct and X-linked mixed deafness with perilymph gusher, can be associated with CHL, SNHL, or normal hearing. Children with unexplained conductive hearing loss often undergo exploratory surgery to improve hearing. Given that inner ear malformations may be associated with a pure CHL, it is critical that children undergo computed tomography scan of the temporal bone prior to undergoing exploratory surgery. [ABSTRACT FROM AUTHOR]

Objective: Locus DFN4 is an X-linked nonsyndromic hearing loss locus originally mapped to Xp21.2. Recently, we have mapped deafness in a second family from Turkey to the same region, refining the location to within the Duchenne muscular dystrophy (DMD) locus. The objective of this study was to characterize the clinical phenotype of the Turkish family with comprehensive audiovestibular testing and high-resolution temporal bone computerized tomography.Methods: Fourteen members of a three-generation family were studied in detail including two deaf affected males. Members of the family underwent general physical and otologic examination, vestibular testing, pure-tone audiometry, otoacoustic emissions, and immitance testing. An affected male underwent high-resolution computerized tomography of the temporal bone, electroretinogram (ERG), electromyography, electroneurography, and determination of serum creatinine phosphokinase level.Results: Affected males were congenitally deaf with normal vestibular function. Carrier females showed a mild sensorineural hearing loss affecting all frequencies and absent otoacoustic emissions. Otoacoustic emissions in a younger, 3-year-old carrier girl were normal. In an affected male, ERG demonstrated subnormal scotopic b-wave typically seen in DMD. Computerized tomography of the temporal bone was normal. With the exception of the ERG finding, there was no clinical or laboratory evidence of DMD or Becker muscular dystrophy (BMD).Conclusion: The abnormal ERG in the Turkish family in conjunction with mapping of the DFN4 locus to within DMD strongly suggests that a defect in dystrophin is responsible for the hearing loss in this family. Patients with DMD and BMD should be screened systematically for sensorineural hearing loss. This family provides additional evidence for the critical role of cytoskeletal proteins in normal hearing. [ABSTRACT FROM AUTHOR]

Objective/hypothesis: Transverse/sigmoid sinus dural arteriovenous fistula (TSDAVF) is a diagnostically elusive entity that is critical for the otologist to account for, when confronted by pulsatile tinnitus in the face of normal otoscopy. Left untreated, TSDAVF may result in catastrophic outcome. We have previously proposed a grading system specifically for TSDAVF based on venous restrictive disease. Our objective was to assess the validity of this grading system for clinical severity and therapeutic outcome.Methods: Through a retrospective review of 41 patients with TSDAVF, we evaluated clinical presentation, diagnostic evaluation, therapy, and outcome. Patients were classified into four grades based on the severity of venous restrictive disease as determined by superselective angiography. Our treatment algorithm combined compression therapy, transarterial embolization, and for more severe grades, surgery.Results: Pulsatile tinnitus was the chief complaint of all the patients in this series, and of 90% of all cases of TSDAVF treated at our institution. While angiography remains the gold standard, magnetic resonance imaging/magnetic resonance arteriography is far superior to computed tomography scanning in detecting dural arteriovenous fistulas. As normal venous outflow gives way to aberrant cortical venous drainage in higher grades, there is a dramatically increased risk for adverse consequences with therapeutic intervention. Using our treatment algorithm, 82% of patients achieved clinical resolution of symptoms. Half of these patients had complete angiographic obliteration of their TSDAVF.Conclusions: The TSDAVF-specific grading system for the severity of venous restrictive disease is reflective of clinical presentation, fundamental in planning treatment, and predictive of therapeutic outcome. [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: To determine the mode of inheritance of familial nonsyndromic Mondini dysplasia.Study Design: Correlative clinical genetic analysis of a single kindred.Methods: Clinical history, physical examination, audiologic analysis, computed tomography of the temporal bones, and cytogenetic analysis.Results: The male proband, three affected sisters, and an affected brother are offspring of unaffected parents. The mother and an unaffected brother have audiologic findings suggestive of heterozygous carrier status for a recessive hearing loss gene.Conclusions: Pedigree analysis indicates autosomal recessive inheritance in this family. The observed inheritance and clinical, audiologic, and radiologic findings are different from those previously described for another family with nonsyndromic Mondini dysplasia. The phenotype in this study family therefore represents a distinct subtype, indicating clinical and genetic heterogeneity of this disorder. This information should facilitate future molecular linkage analyses and genetic counselling of patients with inner ear malformations. [ABSTRACT FROM AUTHOR]

Vestibular schwannoma (VS) may present clinically in one of two forms: sporadic unilateral or hereditary bilateral. Almost all cases of familial transmission have been associated with the diagnosis of neurofibromatosis type II (NF-2). In this report, we describe nine families (18 individuals) presenting with unilateral VS without evidence of NF-2. In four of the nine families, the affected individuals were of parent-offspring relationship, in three families they were cousin-cousin, and in the remaining two families, they were sibling-sibling and aunt-nephew. No other members of the families were diagnosed with NF-2. There was no evidence for gender predilection or genomic imprinting among affected individuals. This study suggests that familial occurrence of unilateral VS may be genetically inherited as it occurs more commonly than would be estimated by chance alone. Future genetic studies will elucidate whether occurrence of unilateral VS in these families represents a variable expression of NF-2, chance occurrence of unilateral VS in families, or a new genetic disorder. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: The potential of contrast-enhanced MRI for diagnosing endolymphatic hydrops is limited by long wait times following intravenous (IV) or intratympanic (IT) delivery, high contrast dosages, and inconsistent signal intensity enhancements. This study investigates microneedle-mediated intracochlear (IC) gadodiamide injection for consistent and efficient contrast delivery with minimal contrast dosage., Materials and Methods: A 100 µm diameter microneedle with 35 µm lumen was used to inject 1 µL of diluted gadodiamide (17.4 mM) into a guinea pig cochlea via the round window membrane. Serial MRI imaging was performed in a post-mortem animal using a 9.4 T small-animal MRI. Maximum intensity projections of MRI scans were generated to visualize diffusion of contrast within cochlea over time; mean intensities in defined regions of interest (ROIs) were calculated. Contrast diffusion time and intensity enhancements were determined., Results: Contrast was observed in the basal turn of scala tympani (ST) and scala vestibuli (SV) in the first MRI scan for all subjects which was acquired as early as 35 min after injection. Two-tailed paired t-tests confirmed that contrast reached the first two turns of ST and SV within 60 min, and the second half of third turns and apical turns of ST and SV within 90 min (p < 0.05). Intensity enhancements, defined as the percentage increase of the ROI mean intensity in the injection side compared to the contralateral side, exceeded 100% in the first turn and ranged from 12% to 32% in the third and apical turns of ST and SV at 90 min after injection., Conclusions: IC gadodiamide enables controllable and efficient contrast delivery with significantly lower contrast dosage, making it a viable alternative for contrast-enhanced cochlear MRI., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Anil K. Lalwani and Jeffrey W. Kysar reports financial support was provided by Department of Defense. Anil K. Lalwani, Jeffrey W. Kysar, and Aykut Aksit reports a relationship with Haystack Medical, Inc. that includes: equity or stocks. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Anil K. Lalwani, MD, Jeffrey W. Kysar, PhD and Aykut Aksit, PhD are the co-founders of and have equity in Haystack Medical, Inc., that will commercialize microneedle and associated technology to facilitate medical access to the middle and inner ear. Chaoqun Zhou, MS: None. Sharon J. Feng, MD, MS: None. Stephen Leong, MD: None. Eugénie Breil, MD: None. François Voruz, MD: None. Chris Valentini, MD: None. Daniella R. Hammer, MS: None. Elizabeth S. Olson, PhD: None. Jia Guo, PhD: None., (Copyright © 2024. Published by Elsevier Inc.)

Several studies have been done to investigate the role of hearing loss (HL) in cognitive decline. A co-existence of these two conditions has been identified. Recently, thanks to the use of functional MRI and EEG it has been shown that untreated HL can expose patients with cognitive decline to a higher risk of developing Alzheimer Disease (AD). This chapter will discuss the difference between central and peripheral HL, the link between HL and cognition and the relationship between HL and AD. At the end of the chapter the available technologies to treat HL will be discussed as well as their impact on memory and cognition., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Hypothesis: Microneedle-mediated intracochlear injection of siRNA-Lipofectamine through the round window membrane (RWM) can be used to transfect cells within the cochlea., Background: Our laboratory has developed 100-μm diameter hollow microneedles for intracochlear injection through the guinea pig RWM. In this study, we test the feasibility of microneedle-mediated injection of siRNA and Lipofectamine, a commonly used reagent with known cellular toxicity, through the RWM for cochlear transfection., Methods: Fluorescently labeled scramble siRNA was diluted into Lipofectamine RNAiMax and OptiMEM. One microliter of 5 μM siRNA was injected through the RWM of Hartley guinea pigs at a rate of 1 μl/min (n = 22). In a control group, 1.0 μl of Lipofectamine, with no siRNA, was diluted into OptiMEM and injected in a similar fashion (n = 5). Hearing tests were performed before and either at 24 hours, 48 hours, or 5 days after injection. Afterward, animals were euthanized, and cochleae were harvested for imaging. Control cochleae were processed in parallel to untreated guinea pigs., Results: Fluorescence, indicating successful transfection, was observed within the basal and middle turns of the cochlea with limited distribution in the apex at 24 and 48 hours. Signal was most intense in the organ of Corti, spiral ligament, and spiral ganglion. Little to no fluorescence was observed at 5 days post-injection. No significant changes in auditory brainstem response (ABR) were noted post-perforation at 5 days, suggesting that siRNA-Lipofectamine at low doses does not cause cochlear toxicity., Conclusions: Small volumes of siRNA and Lipofectamine can be effectively delivered to cochlear structures using microneedles, paving the way for atraumatic cochlear gene therapy., Competing Interests: A.K.L., J.W.K., and A.A. are the co-founders of and hold equity in Haystack Medical, Inc., which will commercialize microneedle and associated technology to facilitate medical access to the middle and inner ear. A conflict of interest committee has reviewed and approved all documents. A.K.L. serves on the Medical Advisory Board of Spiral Therapeutics. S.J.F., F.V., S.L., D.R.H., M.Y., L.C., E.S.O., and E.B. disclose no conflicts of interest., (Copyright © 2024, Otology & Neurotology, Inc.)

Objective: Given the prevalence of neonatal hearing loss (HL) associated with intrauterine viral exposures, the goal of this study is to provide information on neonatal HL in the context of the COVID-19 pandemic., Methods: Data were drawn from the COVID-19 Mother Baby Outcomes (COMBO) Initiative. 1007 participants completed the newborn hearing screen as part of routine clinical care (COMBO-EHR cohort) and 555 completed the National Survey of Children's Health (NSCH) at 2 and/or 3 years of age for research purposes (COMBO-RSCH cohort). Maternal SARS-CoV-2 infection status during pregnancy was determined through electronic health records and maternal-reported questionnaires., Results: In adjusted multivariate logistic regression models covarying for newborn age at assessment, mode of delivery, and gestational age at delivery, there was no significant association between intrauterine SARS-CoV-2 exposure and newborn hearing screening failure (OR = 1.05, 95% CI = 0.39-2.42, p = 0.91) in the COMBO-EHR cohort. In the COMBO-RSCH cohort, there were similar non-significant associations between intrauterine exposure to SARS-CoV-2 and maternal-reported concern for HL on the NSCH (OR = 1.19 [95% CI = 0.30-4.24], p = 0.79)., Conclusion: There is no association between intrauterine exposure to SARS-CoV-2 and failed hearing screen in neonates. Similarly, based on the NSCH, there is no association between intrauterine exposure to SARS-CoV-2 and maternal-reported concern for hearing in toddlers. These results offer reassurance given the widespread nature of this pandemic with tens of millions of fetuses having a history of intrauterine exposure., Level of Evidence: Level 4 Laryngoscope, 2024., (© 2024 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: Cochlear implant (CI) users frequently complain about speech quality perception (SQP). In patients undergoing cochlear implantation for single-sided deafness, there is concern that poor SQP from the implanted ear will negatively impact binaural (CI + normal hearing [NH]) SQP. In this study, we investigate if binaural SQP is measurably different than unimplanted NH alone., Study Design: Cross-sectional study., Setting: Tertiary care center., Methods: Fifteen unilateral CI users with NH in the contralateral ear completed the validated Columbia Speech Quality Instrument. This instrument consists of 9 audio clips rated across 14 specific speech qualities using a 10-point visual analog scale. SQP was assessed in 3 conditions: CI only, NH only, and CI + NH., Results: Median speech quality scores were worse in the CI only condition compared to the NH only (50.0 vs 72.6, P = .0003) and binaural (50.0 vs 71.0, P = .007) conditions. Median speech quality scores were not significantly different between the NH only and binaural conditions (72.6 vs 71, P = .8). Compared to NH, CI speech quality sounded less clear, less natural, and more mechanical., Conclusion: Compared to NH, SQP is poorer with a CI alone. However, in contrast to expectation, there is no significant difference between NH and binaural SQP. This suggests poorer CI speech perception does not negatively impact binaural SQP in patients undergoing cochlear implantation for single-sided deafness., (© 2024 American Academy of Otolaryngology–Head and Neck Surgery Foundation.)

Recent evidence shows that it is possible to identify the elements responsible for sensorineural hearing loss, such as pro-inflammatory cytokines and macrophages, by performing perilymph sampling. However, current studies have only focused on the diagnosis of such as otologic conditions. Hearing loss is a feature of certain neuroinflammatory disorders such as multiple sclerosis, and sensorineural hearing loss (SNHL) is widely detected in Alzheimer's disease. Although the environment of the inner ear is highly regulated, there are several communication pathways between the perilymph of the inner ear and cerebrospinal fluid (CSF). Thus, examination of the perilymph may help understand the mechanism behind the hearing loss observed in certain neuroinflammatory and neurodegenerative diseases. Herein, we review the constituents of CSF and perilymph, the anatomy of the inner ear and its connection with the brain. Then, we discuss the relevance of perilymph sampling in neurology. Currently, perilymph sampling is only performed during surgical procedures, but we hypothesize a simplified and low-invasive technique that could allow sampling in a clinical setting with the same ease as performing an intratympanic injection under direct visual check. The use of this modified technique could allow for perilymph sampling in people with hearing loss and neuroinflammatory/neurodegenerative disorders and clarify the relationship between these conditions; in fact, by measuring the concentration of neuroinflammatory and/or neurodegenerative biomarkers and those typically expressed in the inner ear in aging SNHL, it could be possible to understand if SNHL is caused by aging or neuroinflammation.