dB Shift Research Articles

Hearing impairment following surgically repaired congenital heart disease in children: a prospective study

ObjectivesTo determine the prevalence of sensorineural hearing loss (SNHL) in children who underwent congenital cardiac surgery (CCS) by using a pre- and postoperative hearing test, a conventional audiometry, an extended...

Complications of Cochleostomy Versus Round Window Surgical Approaches: A Systematic Review and Meta-Analysis.

We conducted a systematic review and meta-analysis to compare round window (RW) and cochleostomy (C) surgical approaches for the placement of cochlear implants (CIs). After obtaining the Institutional Review Board (IRB) approval, 213 peer-reviewed articles published between January 1, 2000, and August 1, 2021, comparing RW and C approaches were identified via a search on Google Scholar, Cochrane, and PubMed. The inclusion criteria were articles having an English version and involving only human subjects (cadaveric or alive). Statistical analysis of compiled electrode-to-modiolus distances was performed with two-sample independent t-tests. Live patients were categorized as having complete hearing preservation (<10 dB threshold shift), partial hearing preservation (10-20 dB shift), or minimal hearing preservation (>20 dB shift). Chi-squared testing was used to compare the distribution of hearing preservation categories between surgical approaches. Due to the heterogeneous nature of the data, only summative information was provided on the effects of approaches on trauma, electrical impedance, speech perception, vestibular dysfunction, ease of scala tympani insertion, and scalar shift. A total of 3,797 CI patients were evaluated. The RW approach resulted in a smaller (0.15 mm smaller on average, p<0.05) electrode-to-modiolus distance when compared to the C approach. The RW approach (93.0%) led to statistically better hearing preservation than the C approach (84.3%) (p<0.05). The RW approach was also associated with better outcomes in terms of speech perception, ease of scala tympani insertion, and reduced scalar shift. No difference between approaches was found with regard to trauma, electrical impedance, and vestibular dysfunction. Based on our findings, the RW approach appears to have several benefits compared to the C approach.

Effect of alternate definitions of "high" annoyance on exposure-response functions.

The International Standards Organization (ISO) published Technical Specification (TS) 15666 in 2003 to facilitate the comparison of results from surveys on noise annoyance. This document recommends including two standardized questions with two standardized response scales in all surveys of long-term noise annoyance. A recently revised version of the TS proposes a weighting procedure for the response data to achieve a better similarity between the results from the two questions. This paper analyses the results from 43 surveys conducted according to the ISO/TS 15666 recommendations. It is shown that the average difference in the response to the two annoyance questions is equivalent to a 6 dB shift in the exposure level. The proposed weighting of the verbal response whereby response category 5 (extremely) is counted in full, and category 4 (very) is weighted by a factor 0.4 creates a greater similarity between the two responses. It is important to use a definition of prevalence of high annoyance which matches the one used for the development of the relevant noise regulations.

High-Frequency TiO2 Nanotube-Adapted Microwave Coplanar Waveguide Resonator for High-Sensitivity Ultraviolet Detection.

Ultraviolet (UV) sensors are a key component in growing applications such as water quality treatment and environmental monitoring, with considerable interest in their miniaturization and enhanced operation. This work presents a passive gold coplanar waveguide split ring resonator integrated with anodic self-organized TiO2 nanotube (TNT) membranes with a thickness of 20 μm to provide real-time UV detection. The resonator operated as a one-port device to capture the reflection coefficient (S11) signal, with a center frequency of 16 GHz and a notch amplitude of -88 dB. It was experimentally analyzed for its UV sensing capability in the range of 36.5-463 μW/cm2. The high-frequency resonator was improved through design choices including the addition of a tapered input transmission line, wire bonding for practical device design, and an interdigitated capacitive ring gap. The high frequency also helped mitigate noise due to water vapor or environmental contaminants. S11 amplitude variation was found through both experiments and modeling to follow a linear trend with UV illumination intensity. The resonator exhibited over 45 ± 2 dB shift in the resonant amplitude under the highest UV illumination conditions, with a sensitivity of 0.084 dB/μW cm-2 and the potential to sense UV intensity as low as 2.7 μW/cm2. The presented device enabled a repeatable and accurate microwave response under UV illumination with very high sensitivity, entirely through the use of passive circuit elements.

Temporary Unilateral Hearing Loss Impairs Spatial Auditory Information Processing in Neurons in the Central Auditory System.

Temporary conductive hearing loss (CHL) can lead to hearing impairments that persist beyond resolution of the CHL. In particular, unilateral CHL leads to deficits in auditory skills that rely on binaural input (e.g., spatial hearing). Here, we asked whether single neurons in the auditory midbrain, which integrate acoustic inputs from the two ears, are altered by a temporary CHL. We introduced 6 weeks of unilateral CHL to young adult chinchillas via foam earplug. Following CHL removal and restoration of peripheral input, single-unit recordings from inferior colliculus (ICC) neurons revealed the CHL decreased the efficacy of inhibitory input to the ICC contralateral to the earplug and increased inhibitory input ipsilateral to the earplug, effectively creating a higher proportion of monaural responsive neurons than binaural. Moreover, this resulted in a ∼10 dB shift in the coding of a binaural sound location cue (interaural-level difference, ILD) in ICC neurons relative to controls. The direction of the shift was consistent with a compensation of the altered ILDs due to the CHL. ICC neuron responses carried ∼37% less information about ILDs after CHL than control neurons. Cochlear peripheral-evoked responses confirmed that the CHL did not induce damage to the auditory periphery. We find that a temporary CHL altered auditory midbrain neurons by shifting binaural responses to ILD acoustic cues, suggesting a compensatory form of plasticity occurring by at least the level of the auditory midbrain, the ICC.

Auditory Brainstem Responses Predict Behavioral Deficits in Rats with Varying Levels of Noise-Induced Hearing Loss

Intense noise exposure is a leading cause of hearing loss, which results in degraded speech sound discrimination ability, particularly in noisy environments. The development of an animal model of speech discrimination deficits due to noise induced hearing loss (NIHL) would enable testing of potential therapies to improve speech sound processing. Rats can accurately detect and discriminate human speech sounds in the presence of quiet and background noise. Further, it is known that profound hearing loss results in functional deafness in rats. In this study, we generated rats with a range of impairments which model the large range of hearing impairments observed in patients with NIHL. One month after noise exposure, we stratified rats into three distinct deficit groups based on their auditory brainstem response (ABR) thresholds. These groups exhibited markedly different behavioral outcomes across a range of tasks. Rats with moderate hearing loss (30 dB shifts in ABR threshold) were not impaired in speech sound detection or discrimination. Rats with severe hearing loss (55 dB shifts) were impaired at discriminating speech sounds in the presence of background noise. Rats with profound hearing loss (70 dB shifts) were unable to detect and discriminate speech sounds above chance level performance. Across groups, ABR threshold accurately predicted behavioral performance on all tasks. This model of long-term impaired speech discrimination in noise, demonstrated by the severe group, mimics the most common clinical presentation of NIHL and represents a useful tool for developing and improving interventions to target restoration of hearing.

Enlarged Vestibular Aqueduct: Hearing Progression and Cochlear Implant Candidacy in Pediatric Patients.

Investigate the rate of hearing loss progression and incidence of cochlear implant candidacy in children with enlarged vestibular aqueduct (EVA). EVA is the most common congenital malformation of the inner ear, is responsible for a large percentage of children with hearing loss, and is associated with hearing loss progression. Rates and degree of progression of hearing loss to cochlear implantation candidacy have not been well described. Review of children with EVA who presented to a single academic medical center. Audiometric data were reviewed to determine subjects who met criteria for cochlear implantation (≥75 dB pure-tone average) at presentation. For those not meeting criteria, serial audiometric data were reviewed for progression to candidacy. A total of 257 ears met inclusion criteria. One hundred ninety-two (74.7%) met cochlear implant candidacy criteria by age 12, yet only 117 ears (60.9%) actually received implants before turning 13. One hundred fifty-three ears (59.5%) met implant candidacy criteria at presentation. Nearly 50% of those not initially meeting implantation criteria had a ≥15 dB shift in pure-tone average by age 12, with 37.5% of this subgroup meeting implant candidacy criteria before their teen years at an average age of 7.10 years. The majority of children with EVA reach cochlear implant candidacy before reaching adulthood, yet implantation rates for candidate ears remain at 60% and delay in implantation persist. Parents of children with EVA should be counseled on the likelihood of progression and closely monitored for cochlear implant candidacy.

Altered brain-wide auditory networks in a zebrafish model of fragile X syndrome

BackgroundLoss or disrupted expression of the FMR1 gene causes fragile X syndrome (FXS), the most common monogenetic form of autism in humans. Although disruptions in sensory processing are core traits of FXS and autism, the neural underpinnings of these phenotypes are poorly understood. Using calcium imaging to record from the entire brain at cellular resolution, we investigated neuronal responses to visual and auditory stimuli in larval zebrafish, using fmr1 mutants to model FXS. The purpose of this study was to model the alterations of sensory networks, brain-wide and at cellular resolution, that underlie the sensory aspects of FXS and autism.ResultsCombining functional analyses with the neurons’ anatomical positions, we found that fmr1−/− animals have normal responses to visual motion. However, there were several alterations in the auditory processing of fmr1−/− animals. Auditory responses were more plentiful in hindbrain structures and in the thalamus. The thalamus, torus semicircularis, and tegmentum had clusters of neurons that responded more strongly to auditory stimuli in fmr1−/− animals. Functional connectivity networks showed more inter-regional connectivity at lower sound intensities (a − 3 to − 6 dB shift) in fmr1−/− larvae compared to wild type. Finally, the decoding capacities of specific components of the ascending auditory pathway were altered: the octavolateralis nucleus within the hindbrain had significantly stronger decoding of auditory amplitude while the telencephalon had weaker decoding in fmr1−/− mutants.ConclusionsWe demonstrated that fmr1−/− larvae are hypersensitive to sound, with a 3–6 dB shift in sensitivity, and identified four sub-cortical brain regions with more plentiful responses and/or greater response strengths to auditory stimuli. We also constructed an experimentally supported model of how auditory information may be processed brain-wide in fmr1−/− larvae. Our model suggests that the early ascending auditory pathway transmits more auditory information, with less filtering and modulation, in this model of FXS.

Kirigami-Enabled Microwave Resonator Arrays for Wireless, Flexible, Passive Strain Sensing.

Wireless and highly sensitive flexible strain sensors would have widespread application across a number of different fields. Here, the novel combination of two different metamaterials, one mechanical and one electronic, is demonstrated for its potential as such a sensor. An array of split-ring resonators (SRRs) were mounted on a bespoke kirigami sheet. The hybrid kirigami structure was designed specifically for the resonator array, in terms of both its physical dimensions and elastic response. Mechanical tests in concert with finite element modeling confirmed that the hybrid kirigami structure, containing two disparate kirigami motifs, exhibited a high range of strain and out-of-plane rotation without plastic deformation. The microwave sensing was designed to monitor variations in the S11 response of the resonators as a function of out-of-plane kirigami hinge rotation. The mounted array of SRRs on the hybrid kirigami sheet could wirelessly detect changes in strain with high sensitivity (>30 MHz shift in resonant frequency; >30 dB shift in resonant amplitude) over a large range of strain, from 0.6 to 21.3%.

Fabrication of three‐dimensional printed rectangular waveguide T‐junction with in‐phase and equal power division

AbstractThree‐dimensional (3D) printed rectangular waveguide T‐junction is presented with in‐phase and equal power division by means of iris and septum at 10–15 GHz frequency range to use the waveguide feed network for array antenna. The proposed T‐junction structure is designed and fabricated with 3D printing, as novelty, that is a good alternative to traditional methods in terms of reduced‐weight, cost, flexible applicability, and being monolithic for complex geometry. After making the skeleton of T‐junction from acrylonitrile butadiene styrene, metal plating process is applied over the all surfaces with copper. Transmission and reflection characteristics and electric‐field distribution of the structure are obtained with CST Microwave Studio software. Qualitative agreement is obtained between measurement and simulation with ∼7 dB shift and that shift is because of high precision and low surface roughness on 3D printed junctions. Unlike studies in the literature, the proposed study provides two points, as a novelty: First is that the fabrication of rectangular waveguide T‐junction with 3D printing is made. Second is that the return loss of T‐junction is improved by changing the geometry of iris and septum.

Detection of biological abnormalities using a near-field microwave microscope

Microwave and millimeter-wave reflectometry is one of the potential techniques for the diagnosis and detection of biological abnormalities, such as subcutaneous masses or cancerous tumors in human body. In this paper, a high-quality microwave sensor based on planar misrostrip resonator is designed, fabricated, and successfully tested with different kinds of biological samples. The proposed sensor has unique properties such as small size, simple fabrication, non-contact with a sample, excellent de-coupling from surroundings, and high microwave power is directly coupled into the tissue. Two experiments are performed for the detection of visible and hidden “lipoma” (fat masses), and minimum size of “lipoma” that is diagnosed by the sensor is obtained as well. In this regard, a two-dimensional image of hidden “lipomas” with amplitude contrast about 30 dB and frequency shifts contrast about 60 MHz at aλ/10 (at 13.5 GHz) stand-off distance is provided. Finally, a measurement scenario for the detection of skin cancer based on the artificial model using different layers of raw chicken with different water content is described. Results show that the proposed microscope is easy to fabricate and provide a low-cost solution for fast and accurate skin cancer detection.

Chronic lead exposure induces cochlear oxidative stress and potentiates noise-induced hearing loss

Acquired hearing loss is caused by complex interactions of multiple environmental risk factors, such as elevated levels of lead and noise, which are prevalent in urban communities. This study delineates the mechanism underlying lead-induced auditory dysfunction and its potential interaction with noise exposure. Young-adult C57BL/6 mice were exposed to: 1) control conditions; 2) 2 mM lead acetate in drinking water for 28 days; 3) 90 dB broadband noise 2 h/day for two weeks; and 4) both lead and noise. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS) lead-induced cochlear oxidative stress signaling was assessed using targeted gene arrays, and the hearing thresholds were assessed by recording auditory brainstem responses. Chronic lead exposure downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. Isolated exposure to lead or noise induced 8–12 dB and 11–25 dB shifts in hearing thresholds, respectively. Combined exposure induced 18–30 dB shifts, which was significantly higher than that observed with isolated exposures. This study suggests that chronic exposure to lead induces cochlear oxidative stress and potentiates noise-induced hearing impairment, possibly through parallel pathways.

92 - Chronic Lead Exposure Induces Cochlear Oxidative Stress and Impairs Hearing

Oxidative stress plays a pivotal role in mediating hearing loss induced by exposure to a number of environmental risk factors. Elevated levels of lead is one of the commonly encountered risk factor in the urban environment. Though lead exposure damages the sensory, vascular, and neuronal components of the cochlea, it is not known whether oxidative stress mediates its ototoxic effects. The aim of this study is to delineate the redox mechanism underlying lead-induced auditory dysfunction. Young-adult C57BL/6 mice were exposed to: 1) control conditions or 2) 2 mM lead acetate in drinking water for 28 days. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS), lead-induced cochlear oxidative stress was assessed using targeted gene arrays, and hearing thresholds were assessed by recording auditory brainstem responses. Lead exposure significantly increased the blood lead levels to 293 ± 67 ppb. However, the body weight, appearance, and behavior of the lead-exposed mice were similar to that of the controls. This suggested that the exposure level was probably moderate for young-adult mice, and was not capable of inducing severe toxic effects. Nevertheless, lead exposure at this level downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. In addition, exposure to lead induced 8-12 dB shifts in hearing thresholds. Collectively, these findings suggest that chronic exposure to even moderate levels of lead induces cochlear oxidative stress and causes hearing loss.

Effects of Implantation and Reimplantation of Cochlear Implant Electrodes in an In Vivo Animal Experimental Model (Macaca fascicularis).

The objectives of this study were to evaluate the effect of reimplanting a cochlear implant electrode in animal normal-hearing cochlea to propose measures that may prevent cochlear injury and, given its close phylogenetic proximity to humans, to evaluate the macaque as a model for electroacoustic stimulation. Simultaneous, bilateral surgical procedures in a group of 5 normal-hearing specimens (Macaca fascicularis) took place in a total of 10 ears. Periodic bilateral auditory testing (distortion product otoacoustic emissions and auditory brainstem evoked responses [ABR]) took place during a 6-month follow-up period. Subsequently, unilateral explantation and reimplantation was performed. Auditory follow-up continued up to 12 months, after which animals were sacrificed and both temporal bones extracted for histological analysis. Implantation and reimplantation surgeries were performed without complications in 9 of 10 cases. Full insertion depth was achieved at reimplantation in four of five ears. Auditory evaluation: Statistically significant differences between implanted and reimplanted were observed for the frequencies 2000 and 11,000 Hz, the remaining frequencies showed no differences for distortion product otoacoustic emission. Before the procedure, average thresholds with click-stimuli ABR of the five animals were 40 dB SPL (implanted group) and 40 dB SPL (reimplanted group). One week after first implantation, average thresholds were 55 dB SPL and 60 dB, respectively. After 12 months of follow-up, the average thresholds were 72.5 dB SPL (implanted group) and 65 dB SPL (reimplanted group). Hearing loss appeared during the first weeks after the first implantation and no deterioration was observed thereafter. Differences for ABR under click stimulus were not significant between the two ear groups. Similar results were observed with tone-burst ABR. A 15 dB shift was observed for the implanted group preoperatively versus 1-week post surgery and an additional 17.5 dB shift was seen after 12-month follow-up. For the reimplanted group, a 20 dB shift was observed within the first week post reimplantation surgery and an additional 5 dB after 6 months follow-up. Statistical analysis revealed significant differences between the implanted and reimplanted ear groups for frequencies 4000 Hz (p = 0.034), 12000 Hz (p = 0.031), and 16,000 Hz (p = 0.031). The histological analysis revealed that the electrode insertion was minimally traumatic for the cochlea, mainly indicating rupture of the basilar membrane in the transition area between the basal turn and the first cochlear turn only in Mf1 left ear. With application of minimally traumatic surgical techniques, it is possible to maintain high rates of hearing preservation after implantation and even after reimplantation. Partial impairment of auditory thresholds may occur during the first weeks after surgery, which remains stable. Considering the tonotopic distribution of the cochlea, we found a correlation between the histological lesions sites and the auditory findings, suggesting that a rupture of the basilar membrane may impact hearing levels. The macaque was observed to be a functionally and anatomically an excellent animal model for cochlear implantation.

Safety of the HyperSound® Audio System in Subjects with Normal Hearing.

The objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered pre-exposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

Low insertion loss, high power handling and good performance 90o phase shifter for X-band radar application

In this paper, a monolithic microwave integrated circuit 90° phase shifter circuit for X band radar application is designed and fabricated using 0.1 μm pseudomorphic high electron mobility transistor technology based on GaAs with f t = 85 GHz. This block is used in passive phase shifters. The structure of 90° used double single port double throw (SPDT) in both input/output. The SPDT used a high yield and good performance switch. The switches have low insertion loss and phase variation. The measurement results of 90° block with ?6 V control voltage indicate that the insertion loss is less than ?1.6 dB and phase shift is 87 ± 3.5° over 8---12 GHz. The 1 dB compression point (P1dB) is more than 25 dBm. The die size is 1 mm2. The measurements show good correlation between simulation and measurement results. So, the result demonstrates the great potential of the proposed block for high performance phased array radar systems.

Uncooled resonant infrared detector based on aluminum nitride piezoelectric film through charge generations and lattice absorptions

This Letter demonstrates an aluminum nitride (AlN) based uncooled resonant infrared (IR) detector utilizing the photo-sensitive and piezoelectric properties of polycrystalline AlN. The AlN Lamb wave mode resonator is found responsive to IR illuminations by showing a decrease in the S21 magnitude instead of a resonant frequency shift. A −0.08 dB shift of S21 magnitude was observed for an IR incident power of 647 nW, which translates to a responsivity of 124 kdB/W. Photoresponse is proposed for the IR sensing mechanism through additional charge carriers generation rather than thermal effects.

Postnatal Refinement of Auditory Hair Cell Planar Polarity Deficits Occurs in the Absence of Vangl2

The distinctive planar polarity of auditory hair cells is evident in the polarized organization of the stereociliary bundle. Mutations in the core planar cell polarity gene Van Gogh-like 2 (Vangl2) result in hair cells that fail to properly orient their stereociliary bundles along the mediolateral axis of the cochlea. The severity of this phenotype is graded along the length of the cochlea, similar to the hair cell differentiation gradient, suggesting that an active refinement process corrects planar polarity phenotypes in Vangl2 knock-out (KO) mice. Because Vangl2 gene deletions are lethal, Vangl2 conditional knock-outs (CKOs) were generated to test this hypothesis. When crossed with Pax2-Cre, Vangl2 is deleted from the inner ear, yielding planar polarity phenotypes similar to Vangl2 KOs at late embryonic stages except that Vangl2 CKO mice are viable and do not have craniorachischisis like Vangl2 KOs. Quantification of planar polarity deficits through postnatal development demonstrates the activity of a Vangl2-independent refinement process that rescues the planar polarity phenotype within 10 d of birth. In contrast, the Pax2-Cre;Vangl2 CKO has profound changes in the shape and distribution of outer pillar cell and Deiters' cell phalangeal processes that are not corrected during the period of planar polarity refinement. Auditory brainstem response analyses of adult mice show a 10-15 dB shift in auditory threshold, and distortion product otoacoustic emission measurements indicate that this mild hearing deficit is of cochlear origin. Together, these data demonstrate a Vangl2-independent refinement mechanism that actively reorients auditory stereociliary bundles and reveals an unexpected role of Vangl2 during supporting cell morphogenesis.

High Bandwidth Resonant Radio Frequency Circuit for Lipid Bilayer Detection

Research on ion channels are traditionally performed in the DC regime. Only a few attempts having been made to conduct RF measurements for probing ion channel properties. We present here simulations and subsequent measurements of an integrated coplanar waveguide and microfluidic tank circuit detecting bilayer formation. We observe a 5 MHz shift in resonant frequency and a 1.4 dB shift in amplitude when a lipid bilayer is formed. These measurements allow for in-vitro radio frequency recordings with nanosecond readout times. The designed structure also enables the incorporation of simultaneous RF and DC recordings from lipid bilayer embedded proteins such as ion channels.

Hearing Loss and Cochlear Pathology in a Type II Diabetic Mouse Model

Objective: 1) Determine whether a type II diabetic mouse model demonstrates hearing loss. 2) Examine cochlear ultrastructure of a type II diabetic mouse model for evidence of pathology. Method: The Leprdb/Leprdb (db/db) mouse has a leptin receptor point mutation which manifests as polyphagia, hyperglycemia, and obesity, mimicking type II diabetes. Db/db and wild type mice from the parent strain underwent auditory brainstem response measurements followed by cochlear ultrastructure analysis using scanning and transmission electron microscopy. Results: At 12 weeks of age, the mutant animals demonstrate a profound hearing loss from 8 to 32 kHz, which is in contrast to published data of a 10 dB shift at 8 kHz and 30 dB shift at 16 to 32 kHz for age-matched, wild type C57BL/6J counterparts. In addition, fine structure analysis reveals evidence of morphological alterations in multiple locations within the cochlea, including loss of neuron density in the spiral ganglion, stria vascularis edema, and endothelial abnormalities within strial capillaries. Age-matched controls are without similar ultrastructural changes. Scanning electron microscopy reveals no evidence of hair cell loss or other identifiable abnormalities. Conclusion: This is the first demonstration of cochlear pathophysiology in a genetically derived type II diabetic mouse model. Use of the db/db mouse provides an opportunity to investigate the underlying mechanism of type II diabetes associated hearing loss.