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1) To determine the relationship of electrocochleography (ECochG) responses measured on the promontory with responses measured at the round window (RW) and various intracochlear sites. 2) To evaluate if promontory ECochG responses correlate with postoperative speech-perception performance using the cochlear implant (CI).Prospective cohort study.Tertiary referral center.Ninety-six adult CI recipients with no cochlear malformations or previous otologic surgery.Acoustically evoked ECochG responses were measured intraoperatively at both extracochlear and intracochlear locations. ECochG total response (ECochG-TR), a measure of residual cochlear function, was calculated by summing the fast Fourier transformation amplitudes in response to 250-Hz to 2-kHz acoustic stimuli. Speech-perception performance was measured at 3 months.There were strong linear correlations for promontory ECochG-TR with the ECochG-TRs measured at the RW ( r = 0.95), just inside scala tympani ( r = 0.91), and after full insertion ( r = 0.83). For an individual subject, the morphology of the ECochG response was similar in character across all positions; however, the response amplitude increased from promontory to RW (~1.6-fold) to just inside scala tympani (~2.6-fold), with the largest response at full insertion (~13.1-fold). Promontory ECochG-TR independently explained 51.8% of the variability ( r2 ) in consonant-nucleus-consonant at 3 months.Promontory ECochG recordings are strongly correlated with responses previously recorded at extracochlear and intracochlear sites and explain a substantial portion of the variability in CI performance. These findings are a critical step in supporting translation of transtympanic ECochG into the clinic preoperatively to help predict postoperative CI performance.

Characterize the contribution of the auditory nerve neurophonic (ANN) to electrocochleography (ECochG) of pediatric cochlear implant (CI) recipients with and without auditory nerve spectrum disorder (ANSD).ECochG is an emerging technique for predicting outcomes in CI recipients. Its utility may be increased by separating the cochlear microphonic (CM), produced by hair cells, from the ANN, the evoked potential correlate of neural phase-locking, which are mixed in the ongoing portion of the response to low frequency tone bursts.Responses to tone bursts of different frequency and intensities were recorded from the round window of pediatric CI recipients. Separation of the CM and ANN was performed using a model of the underlying processes that lead to the shapes of the observed waveforms.Preoperative mean pure tone amplitudes of the included ANSD (n = 36) and non-ANSD subjects (n = 123), were similar (89.5 and 93.5, p = 0.1). Total of 1,024 ECochG responses to frequency and intensity series were recorded. The mean correlation ( r ) between the input and the modeled signals was 0.973 ± 0.056 (standard deviation). The ANN magnitudes were higher in the ANSD group (ANOVAs, F = 26.5 for frequency and 21.9 for intensity, df's = 1, p 's0.001). However, its relative contribution to the overall signal was lower (ANOVAs, F = 25.8 and 12.1, df = 1, p 's0.001).ANN was detected in low frequency ECochG responses but not high frequency responses in both ANSD and non-ANSD subjects. ANSD subjects, evidence of neural contribution in responses to low frequency stimuli was highly variable and often comparable to signals recorded in non-ANSD subjects. The computational model revealed that on average the ANN comprised a lower proportion of the overall signal than in non-ANSD subjects.

Accumulating evidence suggests that cochlear deafferentation may contribute to suprathreshold deficits observed with or without elevated hearing thresholds, and can lead to accelerated age-related hearing loss. Currently there are no clinical diagnostic tools to detect human cochlear deafferentation in vivo. Preclinical studies using a combination of electrophysiological and post-mortem histological methods clearly demonstrate cochlear deafferentation including myelination loss, mitochondrial damages in spiral ganglion neurons (SGNs), and synaptic loss between inner hair cells and SGNs. Since clinical diagnosis of human cochlear deafferentation cannot include post-mortem histological quantification, various attempts based on functional measurements have been made to detect cochlear deafferentation. So far, those efforts have led to inconclusive results. Two major obstacles to the development of in vivo clinical diagnostics include a lack of standardized methods to validate new approaches and characterize the normative range of repeated measurements. In this overview, we examine strategies from previous studies to detect cochlear deafferentation from electrocochleography and auditory brainstem responses. We then summarize possible approaches to improve these non-invasive functional methods for detecting cochlear deafferentation with a focus on cochlear synaptopathy. We identify conceptual approaches that should be tested to associate unique electrophysiological features with cochlear deafferentation.

OBJECTIVE: Describe early hearing preservation (HP) cochlear implantation (CI) outcomes using a new slim lateral wall electrode (SLWE). STUDY DESIGN: Prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Adult CI candidates with preoperative low-frequency pure tone average (LFPTA; 125, 250, 500Hz) ≤60 dB HL INTERVENTION(S): CI with and without intracochlear real-time electrocochleography (RT-ECochG) MAIN OUTCOME MEASURE(S): HP (LFPTA ≤80dB HL), LFPTA shift, speech-perception performance measures, postoperative CT reconstruction RESULTS: Forty-two subjects were implanted with the SLWE. Thirty patients underwent full insertion without RT-ECochG feedback, and HP was maintained at 3-months postactivation for 7 (23.3%) patients with mean LFPTA shift of 57.5 ± 25.6 dB HL. RT-ECochG feedback was utilized on 12 patients, of which 6 patients had full insertions and 6 patients had anywhere from 1–3 electrodes left outside of the cochlea based on RT-ECochG feedback. At 3-months postoperatively, HP was achieved on 10 (83.3%) patients and mean LFPTA shift was 18.9 c 11.7 dB HL. Mean difference between LFPTA threshold shift at 3-months postactivation with and without RT-ECochG was 38.6 dB HL (95% CI, 25.6 – 51.67). There was an improvement in delta CNC from preoperative to 3-months postactivation when using RT-ECochG, with mean difference 20.7% (95% CI, 3.3 to 38.1). CONCLUSIONS: Use of RT-ECochG monitoring during SLWE placement results in fewer full electrode insertions and significantly better HP rates and speech-perception outcomes when compared to unmonitored insertions. Further investigation is needed to evaluate long-term audiologic outcomes to better understand the relationships among ECochG, cochlear trauma, functional outcomes, and HP.

Intraoperative electrocochleography (ECochG) has been proposed for cochlear monitoring to minimize trauma during the insertion of the electrode of a cochlear implant (CI). CI surgery is normally performed under general anesthesia, which is why intraoperative ECochG measurements have never been validated against the patient's subjective sound perception. The main objectives of this study were to investigate the feasibility of cochlear monitoring based on the patients hearing and to validate it against intraoperative ECochG measurements during CI surgery under local anesthesia.Prospective case series study.Tertiary referral center.Patients eligible for cochlear implantation with residual hearing (pure-tone threshold averages [PTA] 2501000 Hz ≤ 75 dB HL). Additionally, patients should be able to hear ECochG stimuli at 250, 500, or 1000 Hz at less than or equal to 100 dB (HL).Cochlear implantation under local anesthesia without conscious sedation. Intraoperative ECochG monitoring.The development of ECochG amplitudes and the patients' subjective perception to the sound stimuli.In all patients, monitoring based on their subjective sound perception was feasible, whereas, reliable ECochG responses could be measured in seven patients. Sixty percent of the registered declines in ECochG amplitude were associated with a concomitant attenuation of the subjectively perceived sound.The developments in the ECochG responses matched well with the changes of the sound stimulus perceived by the patients, which supports the applicability of ECochG for preventing insertion trauma. Monitoring of the patients subjective hearing appears to be more reliable than ECochG but requires surgery under local anesthesia without conscious sedation.

OBJECTIVES. To compare intraoperative intracochlear electrocochleography (ECochG) with hearing preservation outcomes in cochlear implant (CI) subjects. DESIGN. Intraoperative electrocochleography was performed in adult CI subjects who were recipients of Advanced Bionics’ Bionics LLC precurved HiFocus(™) MidScala or straight HiFocus(™) SlimJ electrode arrays. ECochG responses were recorded from the most apical electrode contact during insertion. No changes to the insertions were made due to ECochG monitoring. No information about insertion resistance was collected. ECochG drops were estimated as the change in amplitude from peak (defined as maximum amplitude response) to drop (largest drop) point after the peak during insertion was measured following the peak response. .Audiometric thresholds from each subject were obtained before and approximately one month after CI surgery. The change in pure tone average (PTA) for frequencies between 125 Hz and 500 Hz was measured after surgery. No post-operative CT scans were collected as part of this study. RESULTS. A total of 68 subjects from 5 surgical centers participated in the study. The study sample included 30 MidScala and 38 SlimJ electrodes implanted by approximately 20 surgeons who contributed to the study. Although a wide range of results were observed, there was a moderate positive correlation (Pearson Correlation coefficient r = 0.56, p < 0.01) between the size of the ECochG drop and the magnitude of PTA change. This trend was present for both the MidScala and SlimJ arrays. The SlimJ and MidScala arrays produced significantly different hearing loss after surgery. CONCLUSION. Large ECochG amplitude drops observed during electrode insertion indicated poorer hearing preservation. Although the outcomes were variable, this information may be helpful to guide surgical decision-making when contemplating full electrode insertion and the likelihood of hearing preservation.

The non-invasive tympanic electrocochleography (TM-ECochG) is useful for clinical diagnoses. Nevertheless, the influence of the electrode location on tympanic membrane (TM) on ECochG results needs to be studied.The aim of the present study was to compare the TM-ECochG results obtained when the electrode was placed on the superior region versus the inferior region of TM.Forty healthy adults (aged 29 to 50 years) participated in this comparative study. The TM-ECochG testing was conducted with the electrode placed on the superior and inferior regions of TM.SP and AP amplitudes were statistically higher for the inferior region of TM (In TM-ECochG recording, when the electrode was placed on the inferior region of TM, SP and AP amplitudes were greater than when the electrode was placed on the superior region of TM. On the other hand, SP/AP amplitude ratio was not affected by the location of electrode on TM. The findings from the present study could be useful to guide clinicians in optimizing TM-ECochG recording when testing their respective patients.

Electrocochleography (ECochG) is increasingly being used during cochlear implant (CI) surgery to detect and mitigate insertion-related intracochlear trauma, where a drop in ECochG signal has been shown to correlate with a decline in hearing outcomes. In this study, an ECochG-guided robotics-assisted CI insertion system was developed and characterized that provides controlled and consistent electrode array insertions while monitoring and adapting to real-time ECochG signals.Experimental research.A research laboratory and animal testing facility.A proof-of-concept benchtop study evaluated the ability of the system to detect simulated ECochG signal changes and robotically adapt the insertion. Additionally, the ECochG-guided insertion system was evaluated in a pilot in vivo sheep study to characterize the signal-to-noise ratio and amplitude of ECochG recordings during robotics-assisted insertions. The system comprises an electrode array insertion drive unit, an extracochlear recording electrode module, and a control console that interfaces with both components and the surgeon.The system exhibited a microvolt signal resolution and a response time100 milliseconds after signal change detection, indicating that the system can detect changes and respond faster than a human. Additionally, animal results demonstrated that the system was capable of recording ECochG signals with a high signal-to-noise ratio and sufficient amplitude.An ECochG-guided robotics-assisted CI insertion system can detect real-time drops in ECochG signals during electrode array insertions and immediately alter the insertion motion. The system may provide a surgeon the means to monitor and reduce CI insertion-related trauma beyond manual insertion techniques for improved CI hearing outcomes.

Hearing is one of the five sensory organs that allows us to interact with society and our environment. However, one in eight Americans suffers from sensorineural hearing loss that is great enough to adversely impact their daily life. There is an urgent need to identify what part/degree of the auditory pathway (sensory or neural) is compromised so that appropriate treatment/intervention can be implemented. Single- or two-tone evoked potentials, the electrocochleography (eCochG), were measured along the auditory pathway, i.e., at the round window and remotely at the vertex, with simultaneous recordings of ear canal distortion product otoacoustic emissions. Sensory (cochlear) and neural components in the (remote-) eCochG responses showed distinct level- and frequency-dependent features allowing to be differentiated from each other. Specifically, the distortion products in the (remote-)eCochGs can precisely localize the sensory damage showing that they are effective to determine the sensory or neural damage along the auditory pathway.

Objectives Histologic reports of temporal bones of ears with vestibular schwannomas (VSs) have indicated findings of endolymphatic hydrops (ELH) in some cases. The main goal of this investigation was to test ears with VSs to determine if they exhibit electrophysiological characteristics similar to those of ears expected to experience ELH. Design Fifty-three subjects with surgically confirmed VS aged ≥18 and with normal middle ear status were included in this study. In addition, a second group of adult subjects (n = 24) undergoing labyrinthectomy (n = 6) or endolymphatic sac decompression and shunt (ELS) placement (n = 18) for poorly controlled vestibular symptoms associated with Meniere's disease (MD) participated in this research. Intraoperative electrocochleography (ECochG) from the round window was performed using tone burst stimuli. Audiometric testing and word recognition scores (WRS) were performed preoperatively. ECochG amplitudes, cochlear microphonic/auditory nerve neurophonic (ANN) in the form of the "ongoing" response and summation potential, were analyzed and compared between the two groups of subjects. In addition, to evaluate any effect of auditory nerve function, the auditory nerve score was calculated for each subject. Pure-tone averages were obtained using the average air conduction thresholds at 0.5, 1, and 2 kHz while WRS was assessed using Northwestern University Auditory Test No. 6 word lists. Results In the VS group the average pure-tone averages and WRS were 59.6 dB HL and 44.8%, respectively, while in the MD group they were 52.3 dB HL and 73.8%. ECochG findings in both groups revealed a reduced trend in amplitude of the ongoing response with increased stimulus frequency. The summation potential amplitudes of subjects with VS were found to be less negative than the MD subjects for nearly all test frequencies. Finally, the VS group exhibited poorer amounts of auditory nerve function compared to the MD group. Conclusions The current findings suggest cochlear pathology (e.g., hair cell loss) in both groups but do not support the hypothesis that VSs cause ELH.

OBJECTIVE To determine the degree to which electrocochleography (ECoG) correlates with auditory and vestibular outcomes after repair of superior semicircular canal dehiscence (SSCD) via transmastoid (TM) and middle cranial fossa (MCF) approaches. STUDY DESIGN Retrospective review. SETTING Academic tertiary referral center. PATIENTS Adults with SSCD who underwent repair between 2005 and 2019. INTERVENTION Pre-, intra-, and postoperative ECoG. MAIN OUTCOME MEASURES Patient-reported vestibular and auditory symptoms; pre-, intra-, and postoperative ECoG measures, dizziness handicap inventory (DHI) scores. RESULTS Forty-six patients underwent SSCD repair (40 unilateral, six bilateral) between 2005 and 2019, including 24 MCF and 28 TM approaches. There were no differences in preoperative, intraoperative, or postrepair ECoG SP/AP values between the MCF and TM groups (p 0.12, 0.77, 0.58). Patients had subjective improvement in vestibular symptoms (or stable vestibular function in patients operated for predominantly auditory manifestations) with both approaches (MCF: 87.5%; TM: 92.3%; p 0.64). A successful outcome correlated with intraoperative SP/AP ratio normalization (p 0.0005). Similarly, DHI scores were similar in both groups preoperatively (p 0.66) and returned to their preoperative baseline postoperatively with both (p 0.52). Reported vestibular symptoms persisted or worsened more often in patients with migraine (66.6% vs. 28.9%, p 0.03), and with persistently abnormal ECoG measures, though the latter was not statistically significant in this population (38% vs. 15%, p 0.10). Patients had subjective improvement or stability in auditory symptoms using either approach (MCF: 96%; TM: 100%; p 0.62), also correlating with SP/AP ratio normalization (p 0.008). CONCLUSIONS Correction of abnormal preoperative ECoG reliably correlates to patient symptom improvement after SSCD repair. No significant differences in postoperative outcomes were noted between patients undergoing TM versus MCF repair. Circumspection regarding the likelihood of an ideal outcome after SSCD repair should be exercised when counseling patients with concomitant migraine. DEFINE PROFESSIONAL PRACTICE GAP AND EDUCATIONAL NEED It is not certain whether outcomes differ between the two dominant approaches for SSCD repair. Surgeons and patients would benefit from an intraoperative metric that reflects satisfactory plugging of SSCD. LEARNING OBJECTIVE To highlight the reliability and unique utility of intraoperative ECoG and demonstrate the correlation between ECoG correction and symptom improvement for SSCD repair. DESIRED RESULT To report subjective and objective outcomes following SSCD repair and encourage adoption of intraoperative ECoG monitoring. LEVEL OF EVIDENCE Level V. INDICATE IRB OR IACUC IRB review considers this study exempt (HUM00169949).

This study aimed to validate the existence and investigate the characteristics of the transient responses from conventional auditory steady-state responses (ASSRs) using deconvolution methods capable of dealing with amplitude modulated (AM) stimulation. Conventional ASSRs to seven stimulus rates were recorded from 17 participants. A deconvolution method was selected and modified to accommodate the AM stimulation. The calculated responses were examined in terms of temporal features with respect to different combinations of stimulus rates. Stable transient responses consisting of early stage brainstem responses and middle latency responses were reconstructed consistently for all rate combinations, which indicates that the superposition hypothesis is applicable to the generation of approximately 80 Hz ASSRs evoked by AM tones (AM-ASSRs). The new transient responses are characterized by three pairs of peak-troughs named as n(0)p(0), n(1)p(1), and n(2)p(2) within 40 ms. Compared with conventional ABR-MLRs, the n(0)p(0) indicates the first neural activity where p(0) might represent the main ABR components; the n(1) is the counterpart of N10; the p(2) is corresponding to the robust Pa at about 30 ms; the p(1) and n(2) are absent of real counterparts. The peak–peak amplitudes show a slight decrease with increasing stimulation rate from 75 to 95 Hz whereas the peak latencies change differently, which is consistent with the known rate-effect on AEPs. This is direct evidence for a transient response derived from AM-ASSRs for the first time. The characteristic components offer insight into the constitution of AM-ASSRs and may be promising in clinical applications and fundamental studies.

Studies have shown that hearing preservation is possible in the context of reimplantation, but residual hearing could not be predicted or expected in these cases. We describe a case in which a patient with mild to profound sensorineural hearing loss who underwent cochlear implantation with a lateral wall array and had hearing preserved postoperatively. She developed facial nerve stimulation which was unresponsive to reprogramming. Using electrocochleography to measure intracochlear trauma during the insertion process, the patient underwent reimplantation with a perimodiolar electrode and hearing was preserved postoperatively. This case demonstrates the potential to use electrocochleography for hearing preservation during reimplantation. Laryngoscope, 131:2348-2351, 2021.

Background Various extratympanic recording electrodes have been used to make electrocochleography (ECochG) and auditory brainstem response (ABR) measurements in clinics, translational research, and basic science laboratories. However, differences may exist in ECochG and ABR measurements depending on the different types of extratympanic electrodes that are used. Purpose The purpose of this research is to compare simultaneously recorded ECochG and ABR responses using three different extratympanic electrodes. This research helps clinicians and researchers to understand how electrode types and recording sites influence EcochG and ABR results. In addition, our findings could provide more normative data to the ECochG and ABR literature as well as give perspective on a preferred electrode approach when performing simultaneous ECochG and ABR testing. Research Design Ours was a repeated-measures study with measurements being made from individual participants on two separate sessions. Study Sample Twenty young adult females with normal hearing. Procedure A three-channel recording system was used to simultaneously record ECochG and ABR measurements in response to alternating polarity click stimuli. In each session, measurements were simultaneously recorded with a TipTrode electrode and one of the tympanic membrane (TM) electrodes. Data Collection and Analysis Suprathreshold summating potential (SP) and action potential (AP) of the ECochG and waves I, III, and V of the ABR, and threshold responses (AP and wave V) were identified. Results Compared with the ear canal TipTrode electrode, TM electrodes yielded suprathreshold amplitudes that were larger than those from the ear canal electrode, smaller SP–AP ratios, lower AP thresholds, and less variability. These findings can help guide choices made by clinicians, translational investigators, and basic science researchers on which type of extra-tympanic electrode to use for their intended purpose.

The progressive degeneration of the excitable cells of the ear depends on the sustained excitation of the voltage-sensitive sodium channels, so the negative pharmacological modulation could be a rational therapeutic strategy against the damage of these cells. The objective was to demonstrate the effectiveness of Vinpocetine (VPC), a potent sodium channel blocker, as a treatment for acquired sensorineural hearing loss. A phase II, longitudinal and prospective open clinical study, was conducted over a period of 12 months with patients older than 18 years, to demonstrate the effectiveness of Vinpocetine (VPC) as a treatment for acquired sensorineural hearing loss, using evoked potentials, otoacoustic emissions, audiometry and logoaudiometry, analyzing the results at 6 and 12 months of treatment with Vinpocetine (30 mg/day in 3 doses). It was observed that from 0 to 6 months there was hearing impairment (which was already expected due to the age of the patients). From 6 to 12 months and from 0 to 12 months there were significant differences with a tendency towards improvement, indicating that the aforementioned deterioration not only stopped, but that with the use of vinpocetine, the hearing capacity improved. It is concluded that Vinpocetine helps to stop hearing impairment and even improve hearing.

Supplemental Digital Content is available in the text., Objectives: The primary objective of this study was to establish the reproducibility of cochlear microphonic (CM) recordings obtained from a cochlear implant (CI) electrode contact during and immediately after insertion. This was achieved by evaluating the insertion angle and calculating the position of the apical electrode contact during insertion, using postoperative cone beam computed tomography (CBCT). The secondary objective was to create individualized patient maps of electrode contacts located within acoustically sensitive regions by correlating the CM amplitude to the electrode position determined using CBCT. Methods: CMs were recorded from a CI electrode contact during and immediately after insertion in 12 patients (n = 14 ears). Intraoperative recordings were made for a 0.5 kHz tone burst stimulus and were recorded from the apical electrode contact. Postinsertion recordings were made from the odd-numbered electrode contacts (1–15) along the array, using a range of stimulus frequencies (from 0.125 to 2 kHz). The time point at which each electrode contact passed through the round window was noted throughout the insertion, and the CM amplitude at this point was correlated to postoperative CBCT. This correlation was then used to estimate the CM amplitude at particular points within the cochlea, which was in turn compared with the amplitudes recorded from each electrode postoperatively to assess the reproducibility of the recordings. Results: Significant correlation was shown between intraoperative insertion and postinsertion angles at two amplitude events (maximum amplitude: 29° mean absolute error, r = 0.77, p = 0.006; 10% of maximum amplitude: 52° mean absolute error, r = 0.85, p = 0.002). Conclusion: We have developed a novel method to demonstrate the reproducibility of the CM responses recorded from a CI electrode during insertion. By correlating the CM amplitude with the postoperative CBCT, we have also been able to create individualized maps of CM responses, categorizing the cochlea into acoustically responsive and unresponsive regions. If the electrode contacts within the acoustically sensitive regions are shown to be associated with improved loudness discrimination, it could have implications for optimal electrode mapping and placement.

ContextThe literature on melatonin as a sedative agent in children is limited.ObjectiveTo conduct a systematic review of studies assessing the efficacy and safety of melatonin for non-operating room sedation in children.MethodsMedline, Embase, Cochrane Library and Cumulative Index to Nursing and Allied Health were searched until 9 April 2020 for studies using melatonin and reporting one of the prespecified outcomes of this review. Two authors independently assessed the eligibility, risk of bias and extracted the data. Studies with a similar study design, comparator and procedure were pooled using the fixed-effect model.Results25 studies (clinical trials=3, observational studies=9, descriptive studies=13) were included. Melatonin was used for electroencephalogram (EEG) (n=12), brainstem evoked response audiometry (n=8) and magnetic resonance imaging (MRI) (n=5). No significant differences were noted on meta-analysis of EEG studies comparing melatonin with sleep deprivation (SD) (relative risk (RR) 1.06 (95% CI 0.99 to 1.12)), melatonin with chloral hydrate (RR 0.97 (95% CI 0.89 to 1.05)) and melatonin alone with melatonin and SD combined (RR 1.03 (95% CI 0.97 to 1.10)) for successful procedure completion. However, significantly higher sedation failure was noted in melatonin alone compared with melatonin and SD combined (RR 1.55 (95% CI 1.02 to 2.33)) for EEG. Additionally, meta-analysis showed lower sleep latency for melatonin compared with SD (mean difference −10.21 (95% CI −11.53 to −8.89) for EEG. No major adverse events were reported with melatonin.ConclusionAlthough several studies were identified, and no serious safety concerns were noted, the evidence was not of high quality to establish melatonin’s efficacy for non-operating room sedation in children.

To determine the relationship between intraoperative electrocochleography (ECochG) measurements and residual hearing preservation after cochlear implant (CI) surgery by comparing differences between preoperative and immediate postoperative bone conduction thresholds.Prospective cohort study.Tertiary academic referral center.Sixteen patients with preoperative residual hearing and measurable (no-vibrotactile) bone conduction thresholds at 250 and/or 500 Hz who underwent cochlear implantation.Intraoperative ECochG and air and bone conduction thresholds.Nine patients showed no significant drop (30%) in ECochG amplitude during CI surgery with an average preoperative and immediate postoperative BC threshold of 46 and 39 dB HL, respectively, at 500 Hz. Seven patients with a decrease in ECochG amplitude of 30% or greater showed an average preoperative 500 Hz BC threshold of 32 dB HL and immediate postoperative threshold of 55 dB HL. Air and bone conduction thresholds measured approximately 1 month after CI surgery show delayed-onset of hearing loss across our study patients.A small decrease (30%) in difference response or cochlear microphonics amplitude correlates with no significant changes in immediate postoperative residual hearing, whereas patients who show larger changes (≥30%) in difference response or cochlear microphonics amplitude during intraoperative ECochG measurements show significant deterioration in BC thresholds. This study reveals the necessity of prompt postoperative bone conduction measurement to isolate the intraoperative cochlear trauma that may be detected during intraoperative ECochG measurements. Although delayed postoperative audiometrics represent longer-term functional hearing, it includes the sum of all postoperative changes during the recovery period, including subacute changes after implantation that may occur days or weeks later. Measuring air and bone conduction thresholds immediately postoperatively will better isolate factors influencing intraoperative, early postoperative, and delayed postoperative hearing loss. This will ultimately help refine surgical technique, device design, and highlight the use of intraoperative ECochG in monitoring cochlear trauma during CI surgery.

To evaluate the utility of intracochlear electrocochleography (ECochG) monitoring during cochlear implant (CI) surgery on postoperative hearing preservation.Prospective, randomized clinical trial.Ten high-volume, tertiary care CI centers.Adult patients with sensorineural hearing loss meeting the CI criteria who selected an Advanced Bionics CI.Patients were randomized to CI surgery either with audible ECochG monitoring available to the surgeon during electrode insertion or without ECochG monitoring. Hearing preservation was determined by comparing preoperative unaided low-frequency (125-, 250-, and 500-Hz) pure-tone average (LF-PTA) to postoperative LF-PTA at CI activation. Pre- and post-CI computed tomography was used to determine electrode scalar location and electrode translocation.Eighty-five adult CI candidates were enrolled. The mean (standard deviation [SD]) unaided preoperative LF-PTA across the sample was 54 (17) dB HL. For the whole sample, hearing preservation was "good" (i.e., LF-PTA change 0-15 dB) in 34.5%, "fair" (i.e., LF-PTA change15-29 dB) in 22.5%, and "poor" (i.e., LF-PTA change ≥30 dB) in 43%. For patients randomized to ECochG "on," mean (SD) LF-PTA change was 27 (20) dB compared with 27 (23) dB for patients randomized to ECochG "off" ( p = 0.89). Seven percent of patients, all of whom were randomized to ECochG off, showed electrode translocation from the scala tympani into the scala vestibuli.Although intracochlear ECochG during CI surgery has important prognostic utility, our data did not show significantly better hearing preservation in patients randomized to ECochG "on" compared with ECochG "off."

Impaired gamma oscillations found in a 40-Hz auditory steady-state response (ASSR) in patients with schizophrenia are the robust findings that can be used for future biomarker-based therapeutics. To apply these significant observations into the clinical practice, a clinical system for evoked response audiometry (ERA) may be available. In this study, the delayed 40-Hz ASSR, which was reported as a potent biomarker for schizophrenia, was examined using the ERA system in patients with schizophrenia and its clinical relevance was investigated. The phase of ASSR was significantly delayed in patients with schizophrenia compared with the healthy subjects. The delayed phase was associated with severity of the disease symptoms in the patients. A phase delay with aging was found in healthy subjects, but not in patients with schizophrenia. These findings show availability of the ERA system to identify the delayed 40-Hz ASSR and its clinical implication in patients with schizophrenia. Further applications of the ERA system in clinical psychiatry are warranted in developing biological assessments of schizophrenia with 40-Hz ASSR.

Introduction: The categorization of delayed endolymphatic hydrops (DEH) based on the ear which produces vertigo may sometimes cause misdiagnosis. Objectives: The aim of this study was investigating the vestibular-evoked myogenic potentials (VEMPs), electrocochleography (ECoG), and videonystagmography (VNG) in cases with DEH to determine the ear that originates symptoms. Methods: In this cross-sectional study, 34 patients – 20 males and 14 females – with profound unilateral sensorineural deafness and vertigo attacks were recruited and evaluated by the ECoG, VNG, and VEMPs tests. Results: The average age was around 43; the summating potential/action potential was abnormal in 29.4% of patients in their normal auditive ear. In 32.4, 17.6, and 50% of cases with a deaf ear, absent, normal, and abnormal VEMPs results were sequentially observed, respectively. In normal-hearing ears, absent, normal, and abnormal VEMPs were observed in 23.5, 50, and 26.5%, respectively. In the normal-hearing ear, the distribution of abnormal VEMPs was 26.5%, and in the deaf ear, this parameter was abnormal in 50% of the opposite ear (p value = 0.00021). In the VNG test, among patients with a normal-hearing ear, results in 27 and 7 patients were sequentially normal and hypofunction. Conclusion and Significance: The probability of a hypofunction VNG test in a normal-hearing ear might be greater when the VEMPs results of the contralateral deaf ear are normal. In patients with a normal-hearing ear, the distribution of abnormal VEMPs in the contralateral deaf ear is greater, although the intact side may also manifest abnormality in VEMPs tests. The initial evaluation should begin in a deaf ear as well as for the normal-hearing ear ere utilizing ablation surgery.

OBJECTIVES Electrocochleography (ECochG), obtained before the insertion of a cochlear implant (CI) array, provides a measure of residual cochlear function that accounts for a substantial portion of variability in postoperative speech perception outcomes in adults. It is postulated that subsequent surgical factors represent independent sources of variance in outcomes. Prior work has demonstrated a positive correlation between angular insertion depth (AID) of straight arrays and speech perception under the CI-alone condition, with an inverse relationship observed for precurved arrays. The purpose of the present study was to determine the combined effects of ECochG, AID, and array design on speech perception outcomes. DESIGN Participants were 50 postlingually deafened adult CI recipients who received one of three straight arrays (MED-EL Flex24, MED-EL Flex28, and MED-EL Standard) and two precurved arrays (Cochlear Contour Advance and Advanced Bionics HiFocus Mid-Scala). Residual cochlear function was determined by the intraoperative ECochG total response (TR) measured before array insertion, which is the sum of magnitudes of spectral components in response to tones of different stimulus frequencies across the speech spectrum. The AID was then determined with postoperative imaging. Multiple linear regression was used to predict consonant-nucleus-consonant (CNC) word recognition in the CI-alone condition at 6 months postactivation based on AID, TR, and array design. RESULTS Forty-one participants received a straight array and nine received a precurved array. The AID of the most apical electrode contact ranged from 341° to 696°. The TR measured by ECochG accounted for 43% of variance in speech perception outcomes (p < 0.001). A regression model predicting CNC word scores with the TR tended to underestimate the performance for precurved arrays and deeply inserted straight arrays, and to overestimate the performance for straight arrays with shallower insertions. When combined in a multivariate linear regression, the TR, AID, and array design accounted for 72% of variability in speech perception outcomes (p < 0.001). CONCLUSIONS A model of speech perception outcomes that incorporates TR, AID, and array design represents an improvement over a model based on TR alone. The success of this model shows that peripheral factors including cochlear health and electrode placement may play a predominant role in speech perception with CIs.

Introduction Meniere's disease is a clinical entity with no definitive objective testing. It has been hypothesized that underlying endolymphatic hydrops stiffens the basilar membrane leading to increased speed of the acoustic stimulus, therefore traveling wave velocity has been proposed as an objective test to aid in the diagnosis. The objective of this study is to compare electrocochleography frequency-specific action potential latency, basilar membrane traveling wave time, and summation to action potential (SP/AP) ratio in Meniere's and non-Meniere's patients. Methods Tympanic electrocochleography was performed with frequency-specific action potential latency time and SP/AP ratio recorded. Patient demographics, symptoms, audiogram data, AAO-HNS classification of Meniere's disease, management interventions, and follow-up were recorded. Statistical analysis was performed to compare outcome measures across patient groups, demographics, and clinical data. Results Ninety-one patients (182 ears) were included. There was a significant difference between a "definite" Meniere's diagnosis and an "unlikely" or "probable" diagnosis by an average of 13 dB HL for the pure-tone thresholds at 250 Hz on the affected side (p = 0.006). There was no significant difference in pure-tone thresholds at any other frequency, AP latency at any frequency, or AP/SP ratio between the different Meniere's classification groups. Conclusions Our study fails to show significance of the traveling wave velocity as an objective test for Meniere's disease. A significant correlation was found with low-frequency hearing loss between AAO-HNS Meniere's classification groups.

Objectives: (1) To correlate simultaneously recorded intra- and extracochlear electrocochleography (ECochG) signals during electrode insertion into the cochlea, (2) to track changes in the ECochG signal during insertion and removal of an electrode, and (3) to correlate the findings with the preoperative residual hearing. We hypothesized that intracochlear ECochG recordings show signal changes not reflected in simultaneous extracochlear ECochG recordings. Design: During cochlear implantation in human cochlear implant recipients, a short, slim, custom-made electrode was inserted and removed in a stepwise manner. At each step, ECochG recordings were simultaneously recorded by an extracochlear electrode near the round window and via the inserted electrode. The acoustic stimulus was a 500 Hz tone burst at 110 to 130 dB SPL. Results: The mean amplitude difference between intra- and extracochlear ongoing ECochG responses was 14 dB (range 9 to 24 dB; n = 10) at the beginning of insertion. Intracochlear ECochG responses were larger in all cases. Extracochlear ECochG responses remained stable while intracochlear recordings showed large variations regarding amplitude and phase during the electrode array insertion. Intracochlear signal changes during insertion were reversible with retraction of the electrode. There were only weak to moderate (rs = 0.006 to 0.4), nonsignificant correlations of residual preoperative hearing with maximum amplitudes and amplitude changes during electrode insertion and removal in intracochlear recordings. Conclusions: Signals in intracochlear ECochG recordings are reliably larger than ECochG signals recorded simultaneously from an extracochlear location. Intracochlear ECochG recordings show reversible amplitude and phase changes during insertion, not reflected in simultaneous extracochlear ECochG recordings. Such changes are most likely due to the movement of the recording electrode in relation to the signal generators. Residual high-frequency hearing is associated with larger ECochG signal amplitudes. Modeling of expected intracochlear ECochG changes during electrode insertions may allow detection of cochlear trauma in the future.

OBJECTIVES: To evaluate electrophysiological findings among patients with vestibular migraine (VM) and to compare them with those of patients suffering from definite Ménière disease (MD) without migraine. MATERIALS and METHODS: Twenty-one consecutive patients suffering from VM were enrolled; all subjects were selected according to the criteria proposed by the Bàràny Society for Neuro-otology. Each patient underwent a careful otological and neurotological examination. After completing a questionnaire regarding migraine and vertigo complaints, they were assessed by audiometric testing, video head impulse test (vHIT), and elec-trocochleography (EcochG). Data were compared with those of 21 patients who fulfilled the criteria for definite MD. RESULTS: 52.38% of the patients with VM suffered from at least two episodes of migraine per week, with 42.85% of the subjects complaining of migraines lasting ≥24 hours. 57.14% of the patients reported at least four episodes of vertigo per month, whereas 61.9% suffered from symptoms of chronic unsteadiness. No significant difference (p=0.76) resulted from the comparison of vHIT gain between patients with VM and MD. Eleven out of 21 patients (52.38%) with definite MD presented at least one ear with SP/AP >0.4, differently from patients with VM who exhibited SP/AP values suggestive of endolymphatic hydrops (EH) in only three cases (14.28%). CONCLUSION: The present study found a higher proportion of abnormal EcochG in MD than in VM (p=0.02) without any significant difference in the vHIT gain. On the basis of our findings, the identification of EH in some patients with VM cannot be definitely related to the same pathway that triggers MD symptoms. Future research may help in better understanding whether abnormal EcochG findings can predict the occurrence of MD among patients with VM.

Hearing loss caused by noise exposure, ototoxic drugs, or aging results from the loss of sensory cells, as reflected in audiometric threshold elevation. Animal studies show that loss of hair cells can be preceded by loss of auditory-nerve peripheral synapses, which likely degrades auditory processing. While this condition, known as cochlear synaptopathy, can be diagnosed in mice by a reduction of suprathreshold cochlear neural responses, its diagnosis in humans remains challenging. To look for evidence of cochlear nerve damage in normal hearing subjects, we measured their word recognition performance in difficult listening environments and compared it to cochlear function as assessed by otoacoustic emissions and click-evoked electrocochleography. Several electrocochleographic markers were correlated with word scores, whereas distortion product otoacoustic emissions were not. Specifically, the summating potential (SP) was larger and the cochlear nerve action potential (AP) was smaller in those with the worst word scores. Adding a forward masker or increasing stimulus rate reduced SP in the worst performers, suggesting that this potential includes postsynaptic components as well as hair cell receptor potentials. Results suggests that some of the variance in word scores among listeners with normal audiometric threshold arises from cochlear neural damage. NEW & NOTEWORTHY Recent animal studies suggest that millions of people may be at risk of permanent impairment from cochlear synaptopathy, the age-related and noise-induced degeneration of neural connections in the inner ear that “hides” behind a normal audiogram. This study examines electrophysiological responses to clicks in a large cohort of subjects with normal hearing sensitivity. The resultant correlations with word recognition performance are consistent with an important contribution cochlear neural damage to deficits in hearing in noise abilities.

OBJECTIVE: A decrease in intracochlear electrocochleographic (ECochG) amplitude during cochlear implantation has been associated with poorer postoperative hearing preservation in several short-term studies. Here, we relate the stability of ECochG during surgery to hearing preservation at 3- and 12-months. METHODS: Patients with hearing ≤80-dB HL at 500 Hz were implanted with a slim-straight electrode array. ECochG responses to short, high-intensity, 500-Hz pure tones of alternating polarity were recorded continuously from the apical-most electrode during implantation. No feedback was provided to the surgeon. ECochG amplitude was derived from the difference response, and implantations classified by the presence ("ECochG drop") or absence ("no drop") of a ≥30% reduction in ECochG amplitude during insertion. Residual hearing (relative and absolute) was reported against the ECochG class. RESULTS: ECochG was recorded from 109 patients. Of these, interpretable ECochG signals were recorded from 95. Sixty-six of 95 patients had an ECochG drop during implantation. Patients with an ECochG drop had poorer preoperative hearing above 1000 Hz. Hearing preservation (in decibels, relative to preoperative levels and functionally) was significantly poorer at 250-, 500-, and 1000-Hz at 3 months in patients exhibiting an ECochG drop. Twelve-month outcomes were available from 85 patients, with significantly poorer functional hearing, and greater relative and absolute hearing loss from 250 to 1000 Hz, when an ECochG drop had been encountered. CONCLUSION: Patients exhibiting ECochG drops during implantation had significantly poorer hearing preservation 12 months later. These observational outcomes support the future development of surgical interventions responsive to real-time intracochlear ECochG. Early intervention to an ECochG drop could potentially lead to prolonged improvements in hearing preservation.

OBJECTIVES In adult cochlear implant patients, conventional audiometry is used to measure postoperative residual hearing which requires active listening and patient feedback. However, audiological measurements in pediatric cochlear implant patients are both challenging as well as time consuming. Intracochlear electrocochleography (ECOG) offers an objective and a time-efficient method to measure frequency-specific cochlear microphonic or difference thresholds (CM/DIF) thresholds that closely approximate auditory thresholds in adult cochlear implant patients. The correlation between CM/DIF and behavioral thresholds has not been established in pediatric cochlear implant patients. In the present study, CM/DIF thresholds were compared with audiometric thresholds in pediatric cochlear implant patients with postoperative residual hearing. DESIGN Thirteen (11 unilateral and 2 bilateral) pediatric cochlear implant patients (mean age = 9.2 years ± 5.1) participated in this study. Audiometric thresholds were estimated using conventional, condition play, or visual reinforcement audiometry. A warble tone stimulus was used to measure audiometric thresholds at 125, 250, 500, 1000, and 2000 Hz. ECOG waveforms were elicited using 50-msec acoustic tone-bursts. The most apical intracochlear electrode was used as the recording electrode with an extra-cochlear ground electrode. The ECOG waveforms were analyzed to determine CM/DIF thresholds that were compared with pediatric cochlear implant patients' audiometric thresholds. RESULTS The results show a significant correlation (r = 0.77, p < 0.01) between audiometric and CM/DIF thresholds over a frequency range of 125 to 2000 Hz in pediatric cochlear implant patients. Frequency-specific comparisons revealed a correlation of 0.82, 0.74, 0.69, 0.41, and 0.32 between the audiometric thresholds and CM/DIF thresholds measured at 125, 250, 500, 1000, and 2000 Hz, respectively. An average difference of 0.4 dB (±14 dB) was measured between the audiometric and CM/DIF thresholds. CONCLUSIONS Intracochlear ECOG can be used to measure CM/DIF thresholds in pediatric cochlear implant patients with residual hearing in the implanted ear. The CM/DIF thresholds are similar to the audiometric thresholds at lower test frequencies and offer an objective method to monitor residual hearing in difficult-to-test pediatric cochlear implant patients.