A New Floating Piezoelectric Microphone for Fully Implantable Cochlear Implants in Middle Ear.

OBJECTIVE: Our team designed a long-lasting, well-sealed microphone, which uses laser welding and vacuum packaging technology. This study examined the sensitivity and effectiveness of this new floating piezoelectric microphone (NFPM) designed for totally implantable cochlear implants (TICIs) in animal experiments and intraoperative testing. METHODS: Different NFPM frequency responses from 0.25 to 10 kHz at 90 dB SPL were analyzed using in vivo testing of cats and human patients. The NFPM was tested in different positions that were clamped to the ossicular chains or placed in the tympanic cavity of cats and human patients. Two volunteers' long incus foot and four cats' malleus neck of the ossicular chain were clamped with the NSFM. The output electrical signals from different locations were recorded, analyzed, and compared. The NFPM was removed after the test without causing any damage to the middle-ear structure of the cats. Intraoperative tests of the NFPM were performed during the cochlear implant surgery and the cochlear implant surgery was completed after all tests. RESULTS: Compared with the results in the tympanic cavity, the NFPM could detect the vibration from the ossicular chain more sensitively in cat experiments and intraoperative testing. We also found that the signal output level of the NFPM decreased as the acoustic stimulation strength decreased in the intraoperative testing. CONCLUSION: The NFPM is effective in the intraoperative testing, making it feasible as an implantable middle-ear microphone for TICIs. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:937-944, 2024.

Are Meniere's disease patients with otolith organ impairment more likely to have balance dysfunction?

Background: Patients with Meniere's disease (MD) may present with peripheral vestibular end organ dysfunction and balance dysfunction. Objective: This study aimed to compare the results of vestibular evoked myogenic potential (VEMP) tests with those of the sensory organization test (SOT) in patients with MD to determine whether they are correlated. Material and methods: In total, 132 patients with unilateral MD were evaluated using an audiometric test, the SOT, a caloric test and VEMP tests. Results: Cervical VEMP and ocular VEMP tests were conducted in 132 patients with MD, and the response rates of the affected side were lower than those of the unaffected side. The composite score, C5ES, and C6ES of the SOT were significantly decreased in patients with no VEMP responses compared to those with VEMP responses. Conclusions and significance: MD patients with no VEMP responses are more likely to develop balance impairment than those with VEMP responses. MD patients with otolith organ impairment may therefore have balance disorders, and should exercise caution to prevent falls and subsequent injuries.

Contrasting results of tests of peripheral vestibular function in patients with bilateral large vestibular aqueduct syndrome.

OBJECTIVE: To analyze and summarize the effect of bilateral large vestibular aqueducts in peripheral vestibular organ function. METHODS: Eighteen patients with bilateral large vestibular aqueduct syndrome (LVAS; Study Group) and 18 healthy volunteers (Control Group) were investigated using audiometry, caloric test, sensory organization test (SOT), and vestibular-evoked myogenic potential (VEMP) tests. RESULTS: All 18 patients (36 ears) exhibited sensorineural hearing loss. For cervical VEMP (cVEMP), the Study Group showed lower thresholds (Study Group vs. CONTROL GROUP: 71.4vs. 75.3dBnHL; p=0.006), N1 latencies (24.1vs. 25.2ms; p=0.026) and shorter P1 (15.3vs. 16.6ms; p=0.003), and higher amplitudes (400.7vs. 247.2µV; p<0.001) than the Control Group. For ocular VEMP (oVEMP), the Study Group had lower thresholds (79.3vs. 81.8dBnHL; p=0.046) and higher amplitudes (40.6vs. 14.4µV; p<0.001) than the Control Group. Fourteen of 16 patients (87.5%) who completed caloric tests had abnormal results, and 10 of 18 patients (55.6%) exhibited abnormal results in SOTs. CONCLUSIONS: The hyperfunction of vestibular test in otolithic organs and the hypofunction of vestibular test in semicircular canals, as well as the dysfunction in the balance test were demonstrated in patients with LVAS. SIGNIFICANCE: Our findings can help clinicians gain a better understanding of the characteristics of vestibular organ function in patients with LVAS, which can facilitate optimal targeted treatment.

The potential dysfunction of otolith organs in patients after mumps infection.

OBJECTIVE: To investigate the relationship between mumps and the extent of hearing impairment and otolith organ damage. METHODS: A total of 27 patients with unilateral hearing impairment following mumps were enrolled. The degrees of hearing loss and otolith organ damage were confirmed by audiometric and vestibular evoked myogenic potential [VEMP] tests. All the results were compared and analyzed using Stata 13.0 software for Windows. RESULTS: The VEMP thresholds of the affected ears were significantly higher than those of the unaffected ears in both tests (cervical VEMP [cVEMP] test and ocular VEMP [oVEMP] test; p = 0.000 and 0.001, respectively). The mean cVEMP and oVEMP threshold values of the affected ears with hearing impairment for ≤10 years were significantly lower than those of affected ears with hearing impairment for >10 years [p = 0.009 and 0.004, respectively]. CONCLUSIONS: Deafness resulting from mumps is usually profound and permanent, which indicates severe damage to the cochlea due to the disease. The functions of otolith organs in the vestibular system are also impaired. Over time, the function of the otolith organs or their neural pathway may suffer secondary damage.

A new floating piezoelectric microphone for the implantable middle ear microphone in experimental studies.

CONCLUSIONS: The new floating piezoelectric microphone is feasible for use as an implantable middle ear microphone in a totally implantable cochlear implant. OBJECTIVES: A piezoelectric sensor that is driven by the acoustic vibration of the ossicles is one possible design for a microphone for a totally implantable cochlear implant. Such a new floating piezoelectric microphone has been manufactured in the lab. The purpose of this article was to study the frequency response of the new floating piezoelectric microphone in the intact ossicular chain and to identify whether it is usable and implantable. METHODS: The frequency response of the new floating piezoelectric microphone was analyzed using in vitro testing of fresh cadaveric heads. The microphone, which was designed with an integrated unibody structure to ensure good biocompatibility and capsulation, was attached to the long process of the incus by a titanium clip, or placed in the tympanic cavity and stimulated with pure tones of different frequencies. RESULTS: The new floating piezoelectric microphone can pick up the vibration of the long process of the incus and convert it into electrical signals sensitively and flatly.

Objective and subjective evaluations of the Nurotron Venus cochlear implant system via animal experiments and clinical trials.

CONCLUSION: This study described objective and subjective evaluations of the Nurotron® Venus™ Cochlear Implant System and indicated that this system produced a satisfactory performance. OBJECTIVE: To observe the performance of the Nurotron® Venus™ cochlear implant (CI) system via electrophysiological and psychophysical evaluations. METHODS: A 26-electrode CI system was specially designed. The performance of MRI in animal and cadaveric head experiments, EABR in cats experiment, the correlation between ESRT and C level, and psychophysics evaluations in clinical trials were observed. RESULTS: In the animal and cadaveric head experiments, magnet dislocation could not be prevented in the 1.5 T MRI without removal of the internal magnet. The EABR was clearly elicited in cat experiment. In the clinical trial, the ESRT was strongly correlated with C level (p < 0.001). The human clinical trial involving 57 post-lingually deafened native Mandarin-speaking patients was performed. Residual hearing protection in the implanted ear at each audiometric frequency was observed in 27.5-46.3% patients post-operatively. A pitch ranking test revealed that place pitches were generally ordered from apical to basal electrodes. The recognitions of the perceptions of 301 disyllabic words, environment sounds, disyllabic words, and numerals were significantly better than the pre-operative performance and reached plateaus.

[Diagnosis and management of facial nerve neuromas].

OBJECTIVE: To provide the experience for early diagnosis and management of facial nerve neuromas, and to discuss the clinic and imaging feature of facial nerve schwannoma and facial nerve fibroma in 22 cases. METHODS: Twenty cases facial nerve schwannoma and two cases of facial nerve neurofibroma were diagnosed and reviewed retrospectively. Surgical removal were performed through the middle cranial fossa in 2 cases, through intratemporal approach in 8 cases, through intraparotid approach in 2 cases, and combined intra-temporal with out-temporal approaches in 10 cases. Seventeen cases underwent facial nerve graft for repairing a facial nerve defect. Great auricular nerve was used in 3 cases with intratemporal approach and 1 case with intratemporal combined intraparotid approach. Sural nerve graft was used in 5 cases with intratemporal approach and 8 cases with intra-temporal combined intraparotid approach. Two cases were employed two-stage facial muscle flap-plasty. RESULTS: Facial nerve neuromas were totally removed in 21 cases and subtotal neuroma removed in 1 case. In these cases, 20 patients were no recurrence and 1 patient was lost follow-up. One patient with subtotal neuroma removal received Gamma Knife treatment before and after surgery, and this case was no recurrence. The CT imaging of the temporal bone showed that schwannoma was separated "white mass" with smooth margin along the region of facial nerve without intact canal. But neurofibroma locate in enlarge fallopian with intact canal. Magnetic resonance imaging had the advantage of evaluating all segments of the facial nerve and showed continuity of intratemporal and intraparotid mass with the facial nerve. Pathological results indicated that 20 cases were diagnosed as facial nerve schwannoma and 2 cases were neurofibroma. CONCLUSIONS: Although tumors originating from the facial nerve are extremely rare, it is possible to make early diagnosis through finding clinical feature and imaging methods. Generally, systematic surgical approach for tumor removal and facial nerve reconstruction should be considered in the cases with facial neurinoma.