Does Intraoperative Extracochlear Electrocochleography Correlate With Postoperative Audiometric Hearing Thresholds in Cochlear Implant Surgery? A Retrospective Analysis of Cochlear Monitoring.

In recent years, tools for early detection of irreversible trauma to the basilar membrane during hearing preservation cochlear implant (CI) surgery were established in several clinics. A link with the degree of postoperative hearing preservation in patients was investigated, but patient populations were usually small. Therefore, this study's aim was to analyze data from intraoperative extracochlear electrocochleography (ECochG) recordings for a larger group.During hearing preservation CI surgery, extracochlear recordings were made before, during, and after CI electrode insertion using a cotton wick electrode placed at the promontory. Before and after insertion, amplitudes and stimulus response thresholds were recorded at 250, 500, and 1000 Hz. During insertion, response amplitudes were recorded at one frequency and one stimulus level. Data from 121 patient ears were analyzed.The key benefit of extracochlear recordings is that they can be performed before, during, and after CI electrode insertion. However, extracochlear ECochG threshold changes before and after CI insertion were relatively small and did not independently correlate well with hearing preservation, although at 250 Hz they added some significant information. Some tendencies-although no significant relationships-were detected between amplitude behavior and hearing preservation. Rising amplitudes seem favorable and falling amplitudes disadvantageous, but constant amplitudes do not appear to allow stringent predictions.Extracochlear ECochG measurements seem to only partially realize expected benefits. The questions now are: do gains justify the effort, and do other procedures or possible combinations lead to greater benefits for patients?

The Hannover Coupler V2: Audiological outcomes of a round window coupler for the Vibrant Soundbridge.

Introduction: The Hannover Coupler version 2 (HC2) was designed to (1) adapt the coupler geometry to the round window (RW) niche (2) to stabilize the floating mass transducer, and (3) to control static coupling forces to the RW. First audiological outcomes with a custom-made HC2 are reported here. Material and Methods: Ten patients were enrolled in our site-initiated, prospective study. To assess audiological outcomes up to 6 months, preoperative and postoperative hearing thresholds, word recognition score (WRS) at 65 dB SPL and the speech recognition threshold in quiet and noise were performed. The effective gain (EG) and the coupling efficiency were calculated. Results: One revision surgery had to be performed during the study period and a significant, but clinically not relevant bone conduction thresholds change was observed at 4 and 6 kHz at 6-month follow-up. At 6 months, the median WRS (n = 10) improved significantly from 0% to 80%. The median speech reception threshold in noise improved significantly from 11.6 to -2.4 dB SNR, and in quiet significantly from 79.6 to 44.4 dB SPL. The average EG of -1.3 dB indicated a closure of the air bone gap. The determined average coupling efficiency of 23.3 dB was within the acceptance range suggested by the manufacturer. Conclusion: For patients with mixed hearing loss and multiple ear surgeries, the HC2 provided good and stable speech recognition results exceeding published results of RW coupling without a coupler or coupling with the RW soft coupler.

Inactivation of Fgf3 and Fgf4 within the Fgf3/Fgf4/Fgf15 gene cluster reveals their redundant requirement for mouse inner ear induction and embryonic survival.

BACKGROUND: Fibroblast growth factors (Fgfs) are required for survival and organ formation during embryogenesis. Fgfs often execute their functions redundantly. Previous analysis of Fgf3 mutants revealed effects on inner ear formation and embryonic survival with incomplete penetrance. RESULTS: Here, we show that presence of a neomycin resistance gene (neo) replacing the Fgf3 coding region leads to reduced survival during embryogenesis and an increased penetrance of inner ear defects. Fgf3neo/neo mutants showed reduced expression of Fgf4, which is positioned in close proximity to the Fgf3 locus in the mouse genome. Conditional inactivation of Fgf4 during inner ear development on a Fgf3 null background using Fgf3/4 cis mice revealed a redundant requirement between these Fgfs during otic placode induction. In contrast, inactivation of Fgf3 and Fgf4 in the pharyngeal region where both Fgfs are also co-expressed using a Foxg1-Cre driver did not affect development of the pharyngeal arches. However, these mutants showed reduced perinatal survival. CONCLUSIONS: These results highlight the importance of Fgf signaling during development. In particular, different members of the Fgf family act redundantly to guarantee inner ear formation and embryonic survival.

A New Active Osseointegrated Implant System in Patients with Single-Sided Deafness.

OBJECTIVE: The Cochlear™ Osia® System (Osia) is an active transcutaneous bone conduction implant system intended for patients with conductive and mixed hearing loss but can also be used in cases of single-sided deafness (SSD) for the contralateral routing of signal (CROS). The Osia implant is placed subcutaneously under the intact skin behind the ear with the piezoelectric actuator connected to an osseointegrated BI300 implant - a titanium screw used for a 2-stage Baha surgery - on the mastoid. The external processor is magnetically attached to the subcutaneous implant receiver coil. As the Osia has recently been CE certified and is new on the market, with limited patient outcome data for SSD available, the objective of this study was the evaluation of surgical procedure, audiological results, and patient satisfaction for the Osia in SSD patients. STUDY DESIGN: In a prospective, monocentric clinical observation study, 6 patients (18 years of age or older) with SSD and bone conduction thresholds pure tone average 0.5, 1, 2, and 4 kHz ≤25 dB HL on the contralateral side were implanted with an Osia. Analysis of clinical outcome data with respect to surgical technique, adverse events, audiological measurement, and subjective benefit for SSD patients was conducted. Audiological measurements performed included hearing thresholds, sound field thresholds, word recognition scores (WRS; in %) in quiet, and speech recognition thresholds in noise (in dB SNR). All tests were performed unaided and aided with the Osia. The subjective benefit with the Osia was determined by using 2 questionnaires; the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Bern Benefit in Single-Sided Deafness (BBSSD). RESULTS: Preliminary results indicate a straightforward surgical procedure with a low rate of complications and an improvement in speech perception in quiet, listening performance in everyday situations and patient satisfaction. However, in one of 6 subjects, a revision surgery had to be performed. CONCLUSION: Provided that SSD patients are open for CROS hearing, they can benefit from the Osia by reduced head shadow effects and better speech recognition. Special caution should be given to the skin at the site of implantation to avoid complications.

Hearing Aid Treatment in Patients with Mixed Hearing Loss. Part I: Expected Benefit and Limitations after Stapes Surgery.

OBJECTIVE: The purpose of the present study was to determine the fraction of patients with mixed hearing loss who can or cannot expect benefit from power hearing aids (HAs) after stapes surgery. DESIGN: The audiological outcome of 374 stapes surgeries was used to calculate the patients' individual postoperative requirements in terms of gain and output of HAs. These requirements were compared to the available gain and output provided by state-of-the-art power HAs at 0.5, 1.0, 2.0, and 4.0 kHz. According to these comparisons, ears were divided into three groups. For G0, required gain and output lay within the corresponding technical limits of the HAs at all frequencies. In G1, one or both requirements could not be fulfilled at 1 frequency. G2 combined all ears where the requirements lay beyond the HA's technical limitations at 2 or more frequencies. RESULTS: Stapes surgery resulted in an improvement of air-bone gap (ABG) in 84.5% of the cases by 15.7 dB on average. Based on pure-tone average (0.5, 1.0, 2.0, 4.0 kHz), 40.6% of all cases showed an ABG ≤10 dB. 44.9% of all cases did no longer need a HA after stapes surgery. A power HA would fulfill both audiological criteria at all 4 frequencies in 81.6% of cases that needed a HA postoperatively. However, 18.4% would not be sufficiently treatable at 1 or more frequencies (15.0% in G1, 3.4% in G2). CONCLUSIONS: The present study identified a subset of patients with mixed hearing loss after stapes surgery that cannot be treated sufficiently with available power HAs. As the residual ABG is an important reason for this lack of treatment success, the advancement of alternative hearing devices that circumvent the middle ear, such as powerful active middle ear implants, is indicated.

Hearing Aid Treatment for Patients with Mixed Hearing Loss. Part II: Speech Recognition in Comparison to Direct Acoustic Cochlear Stimulation.

BACKGROUND: The conventional therapy for severe mixed hearing loss is middle ear surgery combined with a power hearing aid. However, a substantial group of patients with severe mixed hearing loss cannot be treated adequately with today's state-of-the-art (SOTA) power hearing aids, as predicted by the accompanying part I of this publication, where we compared the available maximum power output (MPO) and gain from technical specifications to requirements for optimum benefit using a common fitting rule. Here, we intended to validate the theoretical assumptions from part I experimentally in a mixed hearing loss cohort fitted with SOTA power hearing aids. Additionally, we compared the results with an implantable hearing device that circumvents the impaired middle ear, directly stimulating the cochlea, as this might be a better option. OBJECTIVES: Speech recognition outcomes obtained from patients with severe mixed hearing loss supplied acutely with a SOTA hearing aid were studied to validate the outcome predictions as described in part I. Further, the results obtained with hearing aids were compared to those in direct acoustic cochlear implant (DACI) users. MATERIALS AND METHODS: Twenty patients (37 ears with mixed hearing loss) were provided and fitted with a SOTA power hearing aid. Before and after an acclimatization period of at least 4 weeks, word recognition scores (WRS) in quiet and in noise were studied, as well as the speech reception threshold in noise (SRT). The outcomes were compared retrospectively to a second group of 45 patients (47 ears) using the DACI device. Based on the severity of the mixed hearing loss and the available gain and MPO of the SOTA hearing aid, the hearing aid and DACI users were subdivided into groups with prediction of sufficient, partially insufficient, or very insufficient hearing aid performance. RESULTS: The patients with predicted adequate SOTA hearing aid performance indeed showed the best WRS in quiet and in noise when compared to patients with predicted inferior outcomes. Insufficient hearing aid performance at one or more frequencies led to a gradual decrease in hearing aid benefit, validating the criteria used here and in the accompanying paper. All DACI patients showed outcomes at the same level as the adequate hearing aid performance group, being significantly better than those of the groups with inadequate hearing aid performance. Whereas WRS in quiet and noise were sensitive to insufficient gain or output, showing significant differences between the SOTA hearing aid and DACI groups, the SRT in noise was less sensitive. CONCLUSIONS: Limitations of outcomes in mixed hearing loss individuals due to insufficient hearing aid performance can be accurately predicted by applying a commonly used fitting rule and the 35-dB dynamic range rule on the hearing aid specifications. Evidently, when outcomes in patients with mixed hearing loss using the most powerful hearing aids are insufficient, bypassing the middle ear with a powerful active middle ear implant or direct acoustic implant can be a promising alternative treatment.

Case Report of a New Coupler for Round Window Application of an Active Middle Ear Implant.

OBJECTIVES: To evaluate feasibility, surgical handling, audiological outcome, and coupling efficiency of a new coupler (custom-made device) for an active middle ear implant. PATIENT: Revision surgery after implantation of an active middle ear implant in a 66-year-old male patient with mixed hearing loss. INTERVENTION: Prosthetic hearing rehabilitation with a new coupler for round window application. MAIN OUTCOME AND RESULTS: The patient obtained good speech perception in quiet (word recognition scores 80%; Freiburg monosyllables) and noise (-3.3 dB SNR; Oldenburg Sentence Test). The effective gain with the Hannover coupler improved at frequencies > 0.5 kHz compared with the values reported for other round window (RW)-coupling modalities. CONCLUSION: The coupler provides a feasible option for the RW application of the middle ear implant actuator. The spring concept of the coupler needs to be improved to further standardize RW-coupling and improve coupling efficiency at low frequencies (0.5 kHz).

The Impact of Two-Stage Subtotal Petrosectomy and Round Window Vibroplasty on Bone Conduction Thresholds.

OBJECTIVE: To evaluate possible increases in bone conduction (BC) hearing thresholds in patients undergoing subtotal petrosectomy (SP) with fat obliteration and blind sac closure of the outer ear canal and subsequent round window vibroplasty. PATIENTS AND INTERVENTIONS: Between 1997 and 2013, 43 patients (45 ears) with combined hearing loss and recurrent chronic otitis or status post formation of a radical cavity underwent SP around 6 months prior to implantation of a Vibrant SoundbridgeTM. Pure tone audiograms (0.5, 1, 1.5, 2, 3, 4, and 6 kHz) prior to SP, after SP, prior to implantation, after implantation, and at first fitting around 5 weeks after implantation were collected and statistically analyzed. RESULTS: The comparison between BC thresholds before SP and at first fitting showed an overall decline during the two-step procedure between 2.8 and 6 dB that was significant (p < 0.05, Student t test) at 2, 3, 4, and 6 kHz. CONCLUSION: In some cases, SP is the only way to eradicate chronic otitis and to achieve a suitable environment for the implantation of active middle ear implants. The present data demonstrate a relatively small but significant decline in BC thresholds throughout the whole procedure. Knowledge of its extent is mandatory for a correct indication for later implantation of a Vibrant SoundbridgeTM.

Retrospective Analysis of Hearing-Impaired Adult Patients Treated With an Active Transcutaneous Bone Conduction Implant.

OBJECTIVE: To determine the therapeutic success and safety of an active transcutaneous bone conduction implant (tBCI) in adult patients with conductive or mixed hearing loss. STUDY DESIGN: Retrospective case review. SETTING: Five university hospitals in Frankfurt, Hannover, Dresden, Würzburg, and Vienna. PATIENTS: Data were analyzed from 61 patients (31 women, 30 men) with a mean age of 50 years (min. 26, max. 80). Forty patients had mixed, and 21 conductive hearing loss. Typical etiologies were history of otitis media (n = 20) and cholesteatoma (n = 17). INTERVENTIONS: Implantation of the active tBCI. MAIN OUTCOME MEASURES: Data were analyzed for the following time points: up to 6 months postoperatively ("short-term"), 6 to 37 months postoperatively ("long-term"), and the last available measurement per patient ("most recent"). Pure-tone audiometry (air and bone conduction, AC and BC) and sound field thresholds with warble tones (WT), word recognition scores with Freiburger monosyllables (WRS), as well as speech reception thresholds (SRT) using the Oldenburg sentence test (OLSA) in quiet (SRT) and in noise (signal-to-noise ratio, SNR) were collected. RESULTS: No significant changes in air- and bone-conduction thresholds were observed after implantation. A mean WRS improvement of 54% using the active tBCI was shown at the short-term assessment, i.e., a mean score of 79% compared with 25% in the unaided condition. Results remained stable, with a mean score of 75% at the long-term assessment. SRT in noise improved by 3.6 dB SNR in the implanted ear at the short-term assessment. Overall six adverse events and four serious adverse events were reported, resulting in a rate of 9.84 and 6.56%, respectively. CONCLUSION: The tBCI clearly improves speech intelligibility in patients with conductive or mixed hearing loss, showing stable results up to 1 year post-implantation.

Subtotal petrosectomy and Codacs™: new possibilities in ears with chronic infection.

Subtotal petrosectomy combined with obliteration of the tympanomastoid is a standard procedure to treat temporal bones in patients with radical cavity and chronic infections. Currently, patients with profound-to-severe sensorineural hearing loss are often fitted with cochlear implants. In the case of profound mixed hearing loss, active middle ear implants have been used successfully. The new Codacs™ system provides an effective treatment for patients with severe-to-profound mixed hearing loss; however, only aerated middle ears have been treated with this device. The question arises whether the Codacs™ can be implanted in patients with radical cavity or ears with chronic otorrhea. Of the 41 patients who were implanted with the Codacs™ at the department, 4 received the device after subtotal petrosectomy and obliteration with abdominal fat. Clinical and audiological results were assessed. The device was implanted without any complications in the obliterated subtotal petrosectomy. The preliminary results of the first two patients showed stable bone conduction thresholds and indicated improved speech intelligibility in quiet and noise. Implanting the Codacs™ device after subtotal petrosectomy and obliteration with abdominal fat has been proven to be a feasible and suitable procedure for patients with radical cavity or chronic otorrhea. The speech intelligibility outcome directly after activation was comparable to patients with aerated middle ears.

Estrogen-related receptor gamma and hearing function: evidence of a role in humans and mice.

Since estrogen is thought to protect pre-menopausal women from age-related hearing loss, we investigated whether variation in estrogen-signalling genes is linked to hearing status in the 1958 British Birth Cohort. This analysis implicated the estrogen-related receptor gamma (ESRRG) gene in determining adult hearing function and was investigated further in a total of 6134 individuals in 3 independent cohorts: (i) the 1958 British Birth Cohort; (ii) a London ARHL case-control cohort; and (iii) a cohort from isolated populations of Italy and Silk Road countries. Evidence of an association between the minor allele of single nucleotide polymorphism (SNP) rs2818964 and hearing status was found in females, but not in males in 2 of these cohorts: p = 0.0058 (London ARHL) and p = 0.0065 (Carlantino, Italy). Furthermore, assessment of hearing in Esrrg knock-out mice revealed a mild 25-dB hearing loss at 5 weeks of age. At 12 weeks, average hearing thresholds in female mice((-/-)) were 15 dB worse than in males((-/-)). Together these data indicate ESRRG plays a role in maintenance of hearing in both humans and mice.

Oval window membrane vibroplasty for direct acoustic cochlear stimulation: treating severe mixed hearing loss in challenging middle ears.

OBJECTIVE: To date, all the Vibrant Soundbridge (VSB) applications have managed to stimulate the inner ear indirectly. Our objective was to present a new VSB application for direct inner ear stimulation. STUDY DESIGN: Prospective cohort study. SETTINGS: Tertiary, referral center PATIENTS: Three patients with previous middle ear surgery and moderate-to-severe ipsilateral, mixed hearing loss. INTERVENTIONS: Oval window membrane vibroplasty (OWMV) for direct acoustic cochlear stimulation. A total ossicular replacement prosthesis (TORP) was attached to the floating mass transducer (FMT). Then, the stapes footplate was perforated, and the tip of the FMT-TORP assembly was advanced approximately 1 mm into the inner ear. A silicon ring was placed around the TORP's tip to prevent it from slipping deeper into the inner ear. MAIN OUTCOME MEASURE: Audiologic assessment involving pure-tone audiometry, aided and unaided free-field audiometry, Freiburg monosyllabic word test, and registration of any complications. RESULTS: OWMV resulted in an average functional hearing gain of 36.1 dB (range, 24.2-47.5 dB). Although the greatest amplification was observed in the higher frequencies, there also was a significant improvement in the lower frequencies. The surgery was not related to any difficulties; vertigo, inner ear trauma, or further complications did not occur. CONCLUSION: We present a new method for direct acoustic cochlear stimulation using an active middle ear implant. The preliminary results show that OWMV is a promising and safe option for treating moderate and severe hearing loss, even in challenging cases with previous middle ear operations or fixed stapes footplate.

Pathophysiology of the Eustachian tube--relevant new aspects for the head and neck surgeon.

OBJECTIVES: The impact of cranio-maxillofacial procedures upon Eustachian tube function is still largely unknown. The aim of this presentation is to depict new aspects of Eustachian tube function and to demonstrate its importance to cranio-maxillofacial surgery. METHODS: Two different groups of patients were examined both clinically and by MRI of the Eustachian tube region. One of these groups comprised 15 adult patients with a history of cleft palate; another consisted of 32 patients with a history of a so-called patulous Eustachian tube. RESULTS: Clinical and MRI-findings revealed that the problem of persistent chronic middle ear disease with cleft palate patients depends crucially on the integrity of the pterygoid hamulus and of the tensor veli palatini muscle after cleft palate repair. The masticatory muscles on the other hand also play an important role in Eustachian tube function in non-cleft patients. CONCLUSION: The maxillofacial surgeon should be aware that he holds a key position for preventing as well as treating Eustachian tube pathophysiology.

LIMP-2/LGP85 deficiency causes ureteric pelvic junction obstruction, deafness and peripheral neuropathy in mice.

In previous overexpression studies we revealed a role for the lysosomal membrane protein LIMP-2/LGP85 in lysosomal biogenesis. LIMP-2-deficient mice show an increased postnatal mortality which is associated with a development of a uni- or bilateral hydronephrosis caused by an obstruction of the ureteropelvic junction. An accumulation of lysosomes in epithelial cells of the ureter adjacent to the ureteral lumen and a disturbed apical expression of uroplakin was observed, suggesting an impairment of membrane transport processes. Serious hearing impairment in LIMP-2-deficient animals was indicated by deficits in acoustic startle responses, in brainstem evoked auditory potentials and a reduced endochondral potential. LIMP-2-deficient mice suffer from a massive decline of spiral ganglia in the cochlea concomitant with that of the inner and outer hair cells. These pathological changes begin at the age of 3 months and are probably secondary to a degeneration of the stria vascularis. LIMP-2-deficient mice are also characterized by a peripheral demyelinating neuropathy. Demyelinization was found to be associated with a massive loss of peripheral myelin proteins and an increased activity and expression of lysosomal proteins highlighting a hitherto unknown role of the lysosomal compartment in the development of this myelination disorder. The phenotype of LIMP-2-deficient mice stimulates the search for mutations in human disorders associated with degeneration of the stria vascularis and/or demyelinization of peripheral nerves.