Audiometric Thresholds Research Articles

A Novel Method to Determine the Maximum Output of Individual Patients for an Active Transcutaneous Bone Conduction Implant Using Clinical Routine Data.

The maximum output provided by a bone conduction (BC) device is one of the main factors that determines the success when treating patients with conductive or mixed hearing loss. Different approaches such as sound pressure measurements using a probe microphone in the external auditory canal or a surface microphone on the forehead have been previously introduced to determine the maximum output of active transcutaneous BC devices that are not directly accessible after implantation. Here, we introduce a method to determine the maximum output hearing level (MOHL) of a transcutaneous active BC device using patients' audiometric data. We determined the maximum output in terms of hearing level MOHL (dB HL) of the Bonebridge using the audiometric and direct BC threshold of the patient together with corresponding force levels at hearing threshold and the maximum force output of the device. Seventy-one patients implanted with the Bonebridge between 2011 and 2020 (average age 45 ± 19 years ranging from 5 to 84 years) were included in this study. The analyses of MOHLs were performed by (1) dividing patients into two groups with better or worse average audiometric BC threshold (0.5, 1, 2, 4 kHz), on the ipsilateral side or (2) by separating the MOHLs based on better or worse frequency-by-frequency specific audiometric BC thresholds on the ipsilateral (implanted) side. When using a frequency-by-frequency analysis obtained average ipsilateral MOHLs were in the range between 51 and 73 dB HL for frequencies from 0.5 to 6 kHz in the group with better audiometric BC threshold on the ipsilateral ears. The average contralateral MOHLs in the group with better contralateral hearing were in the range from 43 to 67 dB HL. The variability of the data was approximately 6 to 11 dB (SDs) across measured frequencies (0.5 to 6 kHz). The average MOHLs were 4 to 8 dB higher across frequencies in the group with better audiometric BC threshold on the ipsilateral ears than in the group with better audiometric BC threshold on the contralateral ears. The differences between groups were significant across measured frequencies ( t test; p < 0.05). Our proposed method demonstrates that the individual frequency-specific MOHL on the ipsilateral and contralateral side of individual patients with a transcutaneous BC device can be determined mainly using direct and audiometric BC threshold data of the patients from clinical routine. The average MOHL of the implant was found 4 to 8 dB higher on the ipsilateral (implanted) side than on the contralateral side.

Objective evaluation of intracochlear electrocochleography: repeatability, thresholds, and tonotopic patterns.

Intracochlear electrocochleography (ECochG) is increasingly being used to measure residual inner ear function in cochlear implant (CI) recipients. ECochG signals reflect the state of the inner ear and can be measured during implantation and post-operatively. The aim of our study was to apply an objective deep learning (DL)-based algorithm to assess the reproducibility of longitudinally recorded ECochG signals, compare them with audiometric hearing thresholds, and identify signal patterns and tonotopic behavior. We used a previously published objective DL-based algorithm to evaluate post-operative intracochlear ECochG signals collected from 21 ears. The same measurement protocol was repeated three times over 3 months. Additionally, we measured the pure-tone thresholds and subjective loudness estimates for correlation with the objectively detected ECochG signals. Recordings were made on at least four electrodes at three intensity levels. We extracted the electrode positions from computed tomography (CT) scans and used this information to evaluate the tonotopic characteristics of the ECochG responses. The objectively detected ECochG signals exhibited substantial repeatability over a 3-month period (bias-adjusted kappa, 0.68; accuracy 83.8%). Additionally, we observed a moderate-to-strong dependence of the ECochG thresholds on audiometric and subjective hearing levels. Using radiographically determined tonotopic measurement positions, we observed a tendency for tonotopic allocation with a large variance. Furthermore, maximum ECochG amplitudes exhibited a substantial basal shift. Regarding maximal amplitude patterns, most subjects exhibited a flat pattern with amplitudes evenly distributed over the electrode carrier. At higher stimulation frequencies, we observed a shift in the maximum amplitudes toward the basal turn of the cochlea. We successfully implemented an objective DL-based algorithm for evaluating post-operative intracochlear ECochG recordings. We can only evaluate and compare ECochG recordings systematically and independently from experts with an objective analysis. Our results help to identify signal patterns and create a better understanding of the inner ear function with the electrode in place. In the next step, the algorithm can be applied to intra-operative measurements.

Development of an Optimized Protocol for Cochlear Implant Care to Increase Cochlear Implant Access.

To develop an evidence-based protocol for audiology-based, cochlear implant (CI) programming in the first year after activation. Retrospective case review. CI program at a tertiary medical center. One-hundred seventy-one patients (178 ears; mean age at implantation, 62.3 yr; 44.4% female) implanted between 2016 and 2021 with postlingual onset of deafness and no history of CI revision surgery. Patients included here had confirmed CI programming optimization based on CI-aided thresholds in the 20- to 30-dB-HL range as well as upper stimulation levels guided by electrically evoked stapedial reflex thresholds. Consonant-nucleus-consonant monosyllabic word recognition scores in the CI-alone and bilateral best-aided conditions at five time points: preoperative evaluation, and 1, 3, 6, and 12 months after activation. For both the CI-alone and bilateral best-aided conditions, consonant-nucleus-consonant word recognition significantly improved from preoperative evaluation to all postactivation time points. For the CI-alone condition, no significant differences were observed between 3 and 6 months, or from 6 to 12 months after activation. In contrast, for the bilateral best-aided condition, significant differences were observed between 1 and 3 months, and 3 and 6 months, but no difference in scores between 6 and 12 months. Based on the current data set and associated analyses, CI centers programming adult patients could eliminate either the 3- or 6-month visit from their clinical follow-up schedule if patient mapping of lower and upper stimulation levels is validated via CI-aided audiometric thresholds and electrically evoked stapedial reflex thresholds, respectively.

Frequency detection, frequency discrimination, and spectro-temporal pattern perception in older and younger typically hearing adults

Elderly adults often experience difficulties in speech understanding, possibly due to age-related deficits in frequency perception. It is unclear whether age-related deficits in frequency perception differ between the apical or basal regions of the cochlea. It is also unclear how aging might differently affect frequency discrimination or detection of a change in frequency within a stimulus. In the present study, pure-tone frequency thresholds were measured in 19 older (61–74 years) and 20 younger (22–28 years) typically hearing adults. Participants were asked to discriminate between reference and probe frequencies or to detect changes in frequency within a probe stimulus. Broadband spectro-temporal pattern perception was also measured using the spectro-temporal modulated ripple test (SMRT). Frequency thresholds were significantly poorer in the basal than in the apical region of the cochlea; the deficit in the basal region was 2 times larger for the older than for the younger group. Frequency thresholds were significantly poorer in the older group, especially in the basal region where frequency detection thresholds were 3.9 times poorer for the older than for the younger group. SMRT thresholds were 1.5 times better for the younger than for the older group. Significant age effects were observed for SMRT thresholds and for frequency thresholds only in the basal region. SMRT thresholds were significantly correlated with frequency thresholds only in the older group. The poorer frequency and spectro-temporal pattern perception may contribute to age-related deficits in speech perception, even when audiometric thresholds are nearly normal.

Bone Conduction Threshold Measurements in Patients with Bone Conduction Devices: A Comparison of Available Methods.

The semi-implantable bone conduction devices connect the skull to the hearing device by means of an implant. This implant affords us 3 possible methods for conducting bone conduction evaluation, which may produce a different result for the same patient, and comparisons of results from different centers may therefore be interpreted incorrectly. Thus, the authors attempt to quantify the audiometric differences between the obtained auditory results and to check whether the results of standard pure tone audiometry could be replaced with the results obtained by alternative measurement methods. Measurements were conducted in a group of 53 adult patients implanted with bone conduction devices in 3 modes: bone conduction-direct, when the bone conduction device itself is used to assess the audiometric threshold; bone conduction-pure tone audiometry with audiometric oscillator placed over mastoid aside of an implant; and bone conduction-indirect with oscillator placed on an implant. The analysis revealed differences between obtained results, which can reach up to 21.48 dB with a mean of 10 dB across all frequencies. The lowest values, regardless of the type of implant connection ("magnetic"; "snap"), were recorded for bone conduction-indirect mode whereas the highest mean all-frequency thresholds were recorded in the mode defined as bone conduction-direct. The method that provides the most comparable thresholds is when the oscillator is positioned on the mastoid, aside from an implant. It should be the method of choice for any hearing evaluation in patients fitted with bone conduction devices, because of standardized equipment and the availability of preoperative data obtained with the same method.

High-frequency audiometry in the diagnosis of tinnitus

BackgroundSubjective tinnitus is an unpleasant perception of sound without any external acoustic stimulus. It can be manifested in the form of various phantom sounds, which most often resemble ringing, whistling, squeaking, noise, chirping, or buzzing. The sounds are heard solely by the sufferer and can occur in the middle of the head, but also in the ears—on one or both sides.AimThe aim of the study was to evaluate the hearing capacity based on audiometric threshold measurements in the frequency range of 0.125–16 kHz in patients with tinnitus. In addition, we investigated the following questions:Can high-frequency audiometry be useful in the diagnosis of tinnitus?Does hearing loss occur in an increasingly wide frequency range with age compared to the control group?Can tinnitus be considered the first symptom of the onset of high-frequency hearing loss?MethodsThe study included 99 patients, all of whom underwent pure-tone audiometry (PTA) and extended high-frequency audiometry (HFA) in the ranges of 0.125–8 kHz and 8–16 kHz, respectively. In each patient (excluding the control group), tinnitus was characterized in terms of its frequency and intensity.Results and conclusionThe study concluded that tinnitus may be a symptom indicating the presence of high-frequency hearing loss as hearing loss occurs in an increasingly wider frequency range with age, so HFA should be a routine audiological test in patients with tinnitus.

Correlates of hearing loss among adults with schizophrenia.

Hearing loss (HL) is associated with adverse cognitive, mental, and physical health outcomes. There is evidence that across age groups HL is more prevalent in people with schizophrenia than the general population. Given that people with schizophrenia may already be vulnerable to cognitive and psychosocial disability, we sought to examine how hearing ability relates to concurrent levels of cognitive, mental and daily functioning. Community-dwelling adults with schizophrenia (N=84) ages 22-50 completed pure tone audiometry assessments. Hearing threshold (in decibels) was defined as the lowest detectable pure tone at 1000Hz. Pearson correlation was used to test the hypothesis that higher hearing thresholds (worse hearing) would be significantly associated with poorer performance on the Brief Assessment of Cognition in Schizophrenia (BACS). Additional analyses explored the relationships between audiometric threshold and functional capacity measured with the Virtual Reality Functional Capacity Assessment Tool (VRFCAT) and symptoms severity rated on the Positive and Negative Syndrome Scale (PANSS). Hearing threshold was inversely and significantly correlated with the BACS composite score (r=-0.27, p=0.017). This relationship was reduced but remained significant after controlling for age (r=-0.23, p=0.04). Hearing threshold was not associated with VRFCAT or psychiatric symptom measures. While schizophrenia and HL are independently associated with cognitive impairment, the magnitude of impairment in this sample was greater among those with poorer hearing. Findings warrant further mechanistic study of the relationship between hearing impairment and cognition and have implications for addressing modifiable health risk factors for higher morbidity and mortality in this vulnerable population.

Evaluation of Subtle Auditory Impairments with Multiple Audiological Assessments in Normal Hearing Workers Exposed to Occupational Noise.

Recent studies involving guinea pigs have shown that noise can damage the synapses between the inner hair cells and spiral ganglion neurons, even with normal hearing thresholds-which makes it important to investigate this kind of impairment in humans. The aim was to investigate, with multiple audiological assessments, the auditory function of normal hearing workers exposed to occupational noise. Altogether, 60 workers were assessed (30 in the noise-exposure group [NEG], who were exposed to occupational noise, and 30 in the control group [CG], who were not exposed to occupational noise); the workers were matched according to age. The following procedures were used: complete audiological assessment; speech recognition threshold in noise (SRTN); speech in noise (SN) in an acoustic field; gaps-in-noise (GIN); transient evoked otoacoustic emissions (TEOAE) and inhibitory effect of the efferent auditory pathway; auditory brainstem response (ABR); and long-latency auditory evoked potentials (LLAEP). No significant difference was found between the groups in SRTN. In SN, the NEG performed worse than the CG in signal-to-noise ratio (SNR) 0 (p-value 0.023). In GIN, the NEG had a significantly lower percentage of correct answers (p-value 0.042). In TEOAE, the NEG had smaller amplitude values bilaterally (RE p-value 0.048; LE p-value 0.045) and a smaller inhibitory effect of the efferent pathway (p-value 0.009). In ABR, the NEG had greater latencies of wave V (p-value 0.017) and interpeak intervals III-V and I-V in the LE (respective p-values: 0.005 and 0.04). In LLAEP, the NEG had a smaller P3 amplitude bilaterally (RE p-value 0.001; LE p-value 0.002). The NEG performed worse than the CG in most of the assessments, suggesting that the auditory function in individuals exposed to occupational noise is impaired, even with normal audiometric thresholds.

The Influence of Cochlear Volume on Temporal Changes of Impedance among Cochlear Implant Patients

Background: There is evidence that the cochlear volume may influence audiometric thresholds and CI electrodes’ impedance. The aim of the present study was to evaluate the impedance changes over time and correlate them to the residual volume of the cochlea. Methods: An MRI scan was performed via 3-D reconstruction before every surgery to obtain a residual volume for each ear. We performed repeated assessments of electrode impedance, both intra-operatively and post-implant, at the following intervals: 3 months, 6 months, and one year. The same type of perimodiolar array was implanted for each. Results: Thirty-four patients (10 (29.41%) male patients and 24 (70.59%) female patients) were evaluated. Patients received the implants between 2008 and 2017. The mean age of implantation was 13 ± 17.17 years, and the average of hearing thresholds improved after one year of the surgery. The mean cochlear volumes of the implanted ears were 68.16 ± 10.74 mm3 (right ear) and 56.54 ± 13.75 mm3 (left ear). We observed an increase in the basal electrodes’ impedance at the 3rd month. Yet, for the apical electrodes’ impedance, there was a decrease in averaged values. Conclusions: Post-operative impedance measurements were increased when compared to the intraoperatively measured basal values. Newly formed connective tissue is thought to be the cause of the higher impedance values.

Long-term follow-up of children with hearing loss that is minimally progressive

Objectives The purpose of this study was to describe changes in audiometric thresholds over time in children whose hearing loss demonstrated early mild progression. Design This was a retrospective follow-up study to examine long-term audiologic results in children with progressive loss. Study sample We examined audiologic data for 69 children, (diagnosed from 2003 to 2013), who had been previously categorised as having “minimal” progressive hearing loss. Results Children had a median of 10.0 (7.5, 12.1) years of follow-up and a median age of 12.5 (IQR: 11.0, 14.5) years; 92.8%; 64 of 69) of children continued to show progressive hearing loss (defined as a decrease of ≥10 dB at two or more adjacent frequencies between 0.5 and 4 kHz or a decrease in 15 dB at one frequency) in at least one ear since diagnosis. Further examination showed that 82.8% of ears (106 of 128) had deterioration in hearing. Of the 64 children, 29.7% (19/64) showed further deterioration since the first analysis. Conclusion More than 90% of children identified as having minimal progressive hearing loss continued to show deterioration in hearing. Ongoing audiological monitoring of children with hearing loss is indicated to ensure timely intervention and to better counsel families.

Symptoms: Sudden Sensorineural Hearing Loss and Aural Fullness

Symptoms: Sudden Sensorineural Hearing Loss and Aural Fullness

Auditory function in symptomatic patients recovered from SARS-CoV-2 and unexposed patients: An analytical cross-sectional study

ObjectiveTo describe audiological symptoms, audiometric profile, and distortion product otoacoustic emission in symptomatic patients recovering from SARS-CoV-2 infection (positive RT-PCR test) and asymptomatic patients (negative RT-PCR test). MethodsAn analytical cross-sectional study was conducted using data obtained from clinical charts, physical examination, audiometry, and distortion product otoacoustic emission on 40 patients [case patients (CP)] recovering from SARS-CoV-2 infection diagnosed by a positive RT-PCR test and 22 asymptomatic participants with a negative RT-PCR test [non-case (NC)]. ResultsSixty-two patients (mean age: 31.1 and 28.2 years in the CP and NC groups, respectively) were included. All participants were young without significant comorbidities, risk factors for hearing loss or otological history. Vertigo (5%), tinnitus (17.5%) and aural fullness/hearing loss (35%) were found in the CP group. A statistically significant difference was found in specific frequencies (1000, 4000, and 8000 Hz) and pure tone average (low and high conversational frequencies with increased threshold in the PC group compared with the NC group), which was not found in distortion product otoacoustic emission. ConclusionAudiovestibular symptoms are frequent in symptomatic patients recovering from SARS-CoV-2 infection. SARS-CoV-2 infection was consistently associated with an increased audiometric hearing threshold at specific frequencies and low tone average.

Effects of sensorineural hearing loss on formant-frequency discrimination: Measurements and models

This study concerns the effect of hearing loss on discrimination of formant frequencies in vowels. In the response of the healthy ear to a harmonic sound, auditory-nerve (AN) rate functions fluctuate at the fundamental frequency, F0. Responses of inner-hair-cells (IHCs) tuned near spectral peaks are captured (or dominated) by a single harmonic, resulting in lower fluctuation depths than responses of IHCs tuned between spectral peaks. Therefore, the depth of neural fluctuations (NFs) varies along the tonotopic axis and encodes spectral peaks, including formant frequencies of vowels. This NF code is robust across a wide range of sound levels and in background noise. The NF profile is converted into a rate-place representation in the auditory midbrain, wherein neurons are sensitive to low-frequency fluctuations. The NF code is vulnerable to sensorineural hearing loss (SNHL) because capture depends upon saturation of IHCs, and thus the interaction of cochlear gain with IHC transduction. In this study, formant-frequency discrimination limens (DLFFs) were estimated for listeners with normal hearing or mild to moderate SNHL. The F0 was fixed at 100 Hz, and formant peaks were either aligned with harmonic frequencies or placed between harmonics. Formant peak frequencies were 600 and 2000 Hz, in the range of first and second formants of several vowels. The difficulty of the task was varied by changing formant bandwidth to modulate the contrast in the NF profile. Results were compared to predictions from model auditory-nerve and inferior colliculus (IC) neurons, with listeners’ audiograms used to individualize the AN model. Correlations between DLFFs, audiometric thresholds near the formant frequencies, age, and scores on the Quick speech-in-noise test are reported. SNHL had a strong effect on DLFF for the second formant frequency (F2), but relatively small effect on DLFF for the first formant (F1). The IC model appropriately predicted substantial threshold elevations for changes in F2 as a function of SNHL and little effect of SNHL on thresholds for changes in F1.

The Effect of Tinnitus and Related Characteristics on Subcortical Auditory Processing.

The primary aim of this study was to evaluate whether individuals with tinnitus exhibited evidence of reduced inhibition and increased excitation at the subcortical auditory processing level. Based on the proposed mechanism of tinnitus generation, including peripheral auditory insult that triggers reduced inhibition and subcortical hyperactivity, it was hypothesized that a tinnitus group would yield reduced amplitudes for the most peripheral auditory brainstem response (ABR) component (wave I) and larger amplitudes for the most central ABR component (wave V) relative to controls matched on factors of age, sex, and hearing loss. Further, this study assessed the relative influence of tinnitus presence versus other related individual characteristics, including hearing loss, age, noise exposure history, and speech perception in noise on these ABR outcomes. Subcortical processing was examined using click-evoked ABR in an independent groups experimental design. A group of adults who perceived daily unilateral or bilateral tinnitus were matched with a control group counterpart without tinnitus by age, hearing, and sex (in each group n = 18; 10 females, 8 males). Amplitudes for ABR waves I, III, V, and the V/I ratio were compared between groups by independent t-tests. The relative influence of tinnitus (presence/absence), age (in years), noise exposure history (subjective self-report), hearing loss (audiometric thresholds), and speech perception in noise (SNR-50) was determined based on the proportional reduction in error associated with accounting for each variable of interest using multiple regression. Between-group trends were consistent with smaller amplitudes for all ABR components in individuals with tinnitus. Contrary to our hypotheses, however, none of the tinnitus compared with control group differences in ABR outcomes were statistically significant. In the multiple regression models, none of the factors including tinnitus presence, age, noise exposure history, hearing loss, and speech perception in noise significantly predicted ABR V/I ratio outcomes. The presence of reduced inhibition and subcortical hyperactivity in the tinnitus group was not supported in the current study. There were trends in ABR outcomes consistent with reduced peripheral to central brainstem auditory activity in the tinnitus group, but none of the group differences reached significance. It should also be noted that the tinnitus group had poorer extended high-frequency thresholds compared with controls. Regardless, neither tinnitus presence nor any of the proposed related characteristics were found to significantly influence the ABR V/I ratio. These findings suggest that either reduced subcortical inhibition was not a primary underlying mechanism for the tinnitus perceived by these subjects, or that ABR was not a reliable indicator of reduced subcortical inhibition possibly due to characteristics of the sample including a skewed distributions toward young and normal hearing individuals with little tinnitus distress.

The effect of recreational noise exposure on amplitude-modulation detection, hearing sensitivity at frequencies above 8 kHz, and perception of speech in noise.

Psychoacoustic and speech perception measures were compared for a group who were exposed to noise regularly through listening to music via personal music players (PMP) and a control group without such exposure. Lifetime noise exposure, quantified using the NESI questionnaire, averaged ten times higher for the exposed group than for the control group. Audiometric thresholds were similar for the two groups over the conventional frequency range up to 8 kHz, but for higher frequencies, the exposed group had higher thresholds than the control group. Amplitude modulation detection (AMD) thresholds were measured using a 4000-Hz sinusoidal carrier presented in threshold-equalizing noise at 30, 60, and 90 dB sound pressure level (SPL) for modulation frequencies of 8, 16, 32, and 64 Hz. At 90 dB SPL but not at the lower levels, AMD thresholds were significantly higher (worse) for the exposed than for the control group, especially for low modulation frequencies. The exposed group required significantly higher signal-to-noise ratios than the control group to understand sentences in noise. Otoacoustic emissions did not differ for the two groups. It is concluded that listening to music via PMP can have subtle deleterious effects on speech perception, AM detection, and hearing sensitivity over the extended high-frequency range.

Association of Vitamin D Deficiency in Patients with Tinnitus with Normal Audiogram.

In the present study we aim to evaluate serum vitamin D levels in participants having tinnitus with normal audiometric findings. Total 98 participants in the age range 20-70 year were included in the study. Participants underwent detail case history, ear examination, pure tone audiometry and impedance audiometry. 68 participants with subjective tinnitus for more than 3 months and with normal audiometric thresholds and "A" type tympanogram were included in study group and 30 participants without tinnitus in the control group. The participants fullfillng the inclusion criteria underwent thorough tinnitus evaluation which included administration of tinnitus severity index tinnitus handicap inventory, psychophysical evaluation of tinnitus (pitch matching, loudness matching) and assessment of Vitamin D levels. It was seen that the mean Vitamin D levels were significantly lower in study group, and out of 68 participants only 11 had optimal Vitamin D levels, 57 (83%) had Vitamin D levels less that 30mg/dl. In the control group 20 (66%) had vitamin D deficiency. The difference came out to be statistically significant. Our study suggests that there is a link between vitamin D and tinnitus, in view of these findings we recommend evaluating serum Vitamin D levels in patients of chronic idiopathic tinnitus, especially in adults with normal hearing. Our study suggests vitamin D deficiency may be one of the risk factor for tinnitus in people with normal hearing in the absence of other manifestations.

Acceptance and Benefit of Electroacoustic Stimulation in Children.

Children with high-frequency severe-to-profound hearing loss and low-frequency residual hearing who do not derive significant benefit from hearing aids are now being considered for cochlear implantation. Previous research shows that hearing preservation is possible and may be desirable for the use of electroacoustic stimulation (EAS) in adults, but this topic remains underexplored in children. The goal of this study was to explore factors relating to hearing preservation, acceptance, and benefits of EAS for children. Retrospective review. Tertiary academic medical center. Forty children (48 ears) with preoperative low-frequency pure-tone averages of 75 dB HL or less at 250 and 500 Hz (n = 48). All patients underwent cochlear implantation with a standard-length electrode. Low-frequency audiometric thresholds, speech perception, and EAS usage were measured at initial stimulation, and 3 and 12 months postoperatively. Outcomes were compared between children with and without hearing preservation, and between EAS users and nonusers. Hearing was preserved at similar rates as adults but worse for children with an enlarged vestibular aqueduct. Fewer than half of children who qualified to use EAS chose to do so, citing a variety of audiologic and nonaudiologic reasons. No differences were detected in speech perception scores across the groups for words, sentences, or sentences in noise tests. Neither hearing preservation nor EAS use resulted in superior speech perception in children with preoperative residual hearing; rather, all children performed well after implantation.

The Expression Levels of MicroRNAs Differentially Expressed in Sudden Sensorineural Hearing Loss Patients' Serum Are Unchanged for up to 12 Months after Hearing Loss Onset.

Sudden sensorineural hearing loss (SSNHL) is an acquired idiopathic hearing loss. Serum levels of small, non-coding RNAs and microRNAs (miRNAs) miR-195-5p/-132-3p/-30a-3p/-128-3p/-140-3p/-186-5p/-375-3p/-590-5p are differentially expressed in SSNHL patients within 28 days of hearing loss onset. This study determines if these changes persist by comparing the serum miRNA expression profile of SSNHL patients within 1 month of hearing loss onset with that of patients 3-12 months after hearing loss onset. We collected serum from consenting adult SSNHL patients at presentation or during clinic follow-up. We matched patient samples drawn 3-12 months after hearing loss onset (delayed group, n = 9 patients) by age and sex to samples drawn from patients within 28 days of hearing loss onset (immediate group, n = 14 patients). We compared the real-time PCR-determined expression levels of the target miRNAs between the two groups. We calculated the air conduction pure-tone-averaged (PTA) audiometric thresholds in affected ears at the initial and final follow-up visits. We undertook inter-group comparisons of hearing outcome status and initial and final PTA audiometric thresholds. There was no significant inter-group difference in miRNA expression level, hearing recovery status and initial and final affected ear PTA audiometric thresholds.

Characteristics of the Summating Potential Measured Across a Cochlear Implant Array as an Indicator of Cochlear Function.

The underlying state of cochlear and neural tissue function is known to affect postoperative speech perception following cochlear implantation. The ability to assess these tissues in patients can be performed using intracochlear electrocochleography (IC ECochG). One component of ECochG is the summating potential (SP) that appears to be generated by multiple cochlear tissues. Its qualities may be able to detect the presence of functional inner hair cells, but evidence for this is limited in human cochleae. This study aimed to examine the IC SP characteristics in cochlear implantation recipients, its relationship to preoperative speech perception and audiometric thresholds, and to other IC ECochG components. This is a retrospective analysis of 113 patients' IC ECochG recordings across the array in response to a 500 Hz tone burst stimulus. Responses to condensation and rarefaction stimuli were then subtracted from one another to emphasize the cochlear microphonic and added to one another to emphasize the SP, auditory nerve neurophonic, and compound action potential. Patients were grouped based on their maximum SP deflection being large and positive (+SP), large and negative (-SP), or minimal (0 SP) to further investigate these relationships. Patients in the +SP group had better preoperative speech perception (mean consonant-vowel-consonant phoneme score 46%) compared to the -SP and 0 SP groups (consonant-vowel-consonant phoneme scores 34% and 36%, respectively, difference to +SP: p < 0.05). Audiometric thresholds were lowest for +SP (mean pure-tone average 50 dB HL), then -SP (65 dB HL), and highest for 0 SP patients (70 dB HL), but there was not a statistical significance between +SP and -SP groups (p > 0.1). There were also distinct differences between SP groups in the qualities of their other ECochG components. These included the +SP patients having larger cochlear microphonic maximum amplitude, more apical SP peak electrode locations, and a more spatially specific SP magnitude growth pattern across the array. Patients with large positive SP deflection in IC ECochG have preoperatively better speech perception and lower audiometric thresholds than those without. Patterns in other ECochG components suggest its positive deflection may be an indicator of cochlear function.

Examining the feasibility of integrating pupillometry measures of listening effort into clinical audiology assessments

Pure-tone thresholds are often a poor predictor of hearing difficulties experienced by patients in audiology clinics. Approximately 25 million Americans may experience hearing difficulties despite having audiometric thresholds within normal limits. Pupil diameter increases with increasing listening effort and could provide an objective measure for determining the presence of such subclinical hearing problems. However, the cost and technical requirements of research-grade eye trackers have limited their use in audiology clinics. This study aims to determine the feasibility of using a commercially-available head mounted display (HMD) with integrated eye tracking to collect pupillometry measures during audiological testing. Pupillary data were collected for N = 46 younger normal-hearing adults while they completed clinically-relevant tests including pure tone audiometry, gaps-in-noise (GIN), dichotic digits, and speech-in-noise tests. Across tasks, task-evoked pupillary responses were generally sensitive to differences in listening demands. Results suggest audiologic testing with commercial HMD eye trackers is feasible and provides additional objective information related to listening effort that may help clinicians better understand and address patient needs. [The views expressed in this abstract are those of theauthors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]