Objective: The efficiency of vibroplasty (coupler-floating mass transducer [FMT] assembly) can be monitored by direct stimulation of the inner ear through the active middle-ear implant system and comparison of the vibroplasty in vivo threshold and the postoperative bone-conduction pure-tone threshold. The aim of this study was to compare the vibroplasty in vivo threshold with the postoperative speech recognition in patients with a high preoperative maximum word recognition score. Study Design: Retrospective cohort study of German-speaking patients implanted with a vibrating ossicular prosthesis (VORP) 502 or VORP 503 and high preoperative maximum word recognition score between the years of 2011 and 2015. Setting: Multicenter study of four German centers. Patients: Twenty-three active middle-ear implant users. Intervention: Rehabilitative. Main Outcome Measures: Bone-conduction pure-tone and vibroplasty thresholds, postoperative aided word recognition score (WRS) at 65 dB SPL (sound pressure level) and preoperative maximum WRS with Freiburg monosyllabic words. Results: The mean postoperative aided WRS at 65 dB SPL was 82%. An increasing difference between vibroplasty thresholds and bone-conduction thresholds was associated with a higher discrepancy between the unaided maximum WRS and the postoperative aided WRS. Only if this difference was less than 20 dB, an articulation index of 0.5 (WRS = 75%) or more was achieved. Conclusions: Audiological outcome after vibroplasty depends on the coupling efficiency reflected by the vibroplasty threshold.

Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in preoperative diagnostics, intraoperative testing, and postoperative monitoring of auditory performance and success. The versatility of AEP's is essentially enhanced by their property to be evokable by acoustic as well as electric stimuli. Thus, the electric responses of the auditory system following acoustic stimulation and recorded by the conventional surface technique as well as by transtympanic derivation from the promontory (Electrocochleography [ECochG]) are used for the quantitative determination of hearing loss and, additionally, electrically evoked compound actions potentials (ECAP) can be recorded with the intracochlear electrodes of the implant just adjacent to the stimulation electrode to check the functional integrity of the device and its coupling to the auditory system. The profile of ECAP thresholds is used as basis for speech processor fitting, the spread of excitation (SOE) allows the identification of electrode mislocations such as array foldover, and recovery functions may serve to optimize stimulus pulse rate. These techniques as well as those relying on scalp surface activity originating in the brainstem or the auditory cortex accompany the CI recipient during its whole life span and they offer valuable insights into functioning and possible adverse effects of the CI for clinical and scientific purposes.

BACKGROUND: Intraoperative monitoring of brainstem auditory evoked potentials (BAEPs) has been implemented to reduce the risk of hearing impairment during microvascular decompression for hemifacial spasm. OBJECTIVE: To evaluate intraoperative monitoring of BAEPs during microvascular decompression in patients with hemifacial spasm for predicting the risk of hearing impairment after surgery. METHODS: This prospective study included 100 patients. BAEPs were recorded for all patients. We established a scoring system for the changes in wave I amplitude, I-III interpeak latency, and wave V amplitude and latency. For each change, total points were calculated, and a score out of 6 was assigned to every patient. We classified the patients based on the points scored into 3 risk groups: low-risk (0-3), medium-risk (4-5), and high-risk (6). Further, the correlation between the score and the hearing outcome was evaluated to detect the incidence and degree of hearing impairment. RESULTS: Eighty-seven patients scored 0 to 3, 10 scored 4 to 5, and 3 scored 6. The degree of hearing impairment was proportionate to the score recorded at the end of surgery, and patients in the low-risk group showed no impairment; medium-risk group, deterioration of maximum 2 grades according to World Health Organization classification of hearing impairment; and high-risk group, deterioration of 3 to 4 grades. CONCLUSION: Intraoperative monitoring of BAEPs evaluated through our scoring system was valuable in predicting hearing impairment after surgery.

Purpose: Evaluating the effectiveness of intraoperative auditory brainstem responses (ABRs) to stimulation by the Vibrant Soundbridge (VSB) active middle ear implant for quantifying the implant’s floating mass transducer (FMT) coupling quality. Methods: In a diagnostic multicentric study, patients (> 18 years) who received a VSB with different coupling modalities were included. Pre- and postoperative bone conduction thresholds, intraoperative VSB-evoked ABR thresholds (VSB-ABR) using a modified audio processor programmed to preoperative bone conduction thresholds, postoperative vibrogram thresholds, and postoperative VSB-ABR thresholds were measured. Coupling quality was calculated from the difference between the pure tone average at 1000, 2000, and 4000 Hz (3PTA) vibrogram and postoperative 3PTA bone conduction thresholds. Results: Twenty-three patients (13 males, 10 females, mean age 56.6 (± 12.5) years) were included in the study. Intraoperative VSB-ABR response thresholds could be obtained in all except one patient where the threshold was > 30 dB nHL. Postoperatively, an insufficient coupling of 36.7 dB was confirmed in this patient. In a Bland–Altman analysis of the intraoperative VSB-ABRs and coupling quality, the limits of agreement exceeded ± 10 dB, i.e., the maximum allowed difference considered as not clinically important but the variation was within the general precision of auditory brainstem responses to predict behavioral thresholds. Five outliers were identified. In two patients, the postoperative VSB-ABR thresholds were in agreement with the coupling quality, indicating a change of coupling before the postoperative testing. Conclusion: The response thresholds recorded in this set-up have the potential to predict the VSB coupling quality and optimize postoperative audiological results.

Objective: The objective of the study was to measure auditory brainstem responses elicited by stimulation via a semi-implantable active middle ear implant with an electromagnetically driven floating mass transducer to quantify the coupling efficacy (=vibroplasty in situ thresholds – bone conduction thresholds) in a patient during a revision surgery. Patients: One patient, reimplanted with an active middle ear implant in a revision surgery. Intervention(s): Diagnostic. Main Outcome Measure(s): Intraoperative auditory brainstem responses evoked by stimulation via an active middle ear implant in a calibrated set-up directly indicating the coupling efficacy magnitude (auditory brainstem response threshold = coupling efficacy), as well as pre- and postoperative bone conduction and vibroplasty in situ thresholds. Results: The intraoperative auditory brainstem response threshold was detected at 0 dB nHL, i.e., the magnitude of coupling efficacy was determined intraoperatively to be 0 dB. The actual postoperative coupling efficacy (=postoperative vibroplasty in situ – postoperative bone conduction thresholds) was –2.5 dB. Conclusions: The coupling efficacy determined intraoperatively was consistent with the postoperative coupling efficacy. The described method seems to be a promising tool to objectively quantify the magnitude of coupling efficacy in active middle ear implant surgeries.

In human cochlear implant (CI) recipients, the slope of the electrically evoked compound action potential (ECAP) amplitude growth function (AGF) is not very well investigated, in comparison to the ...