TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Fröhlich, Laura
A1  - Müller, Alexander
A1  - Kropp, Miriam H.
A1  - Mir-Salim, Parwis
A1  - Dziemba, Oliver
A1  - Oberhoffner, Tobias
A1  - Plontke, Stefan K.
A1  - Rahne, Torsten
T1  - Active Middle Ear Implant Evoked Auditory Brainstem Response Intensity-Latency Characteristics
JF  - Frontiers in Neurology
N2  - Objective
To analyze intensity-latency functions of intraoperative auditory evoked brainstem responses (ABRs) to stimulation by the Vibrant Soundbridge (VSB) active middle ear implant with respect to coupling efficiency, VSB evoked ABR thresholds, and coupling modality [oval window (OW) placement vs. Incus placement and vs. round window (RW) placement].


Study Design
Exploratory study.


Setting
Bi-centric study at tertiary referral centers.


Patients
Twenty-four patients (10 female, 14 male, mean age: 58 years) who received a VSB.


Outcome Measures
Wave-V intensity-latency functions of intraoperative VSB evoked ABRs using a modified audio processor programmed to preoperative bone conduction thresholds for stimulation. Threshold level correction to coupling efficiency and ABR thresholds. Individual plots and exponential function fits.


Results
After ABR threshold level correction, the latency functions could be aligned. A large variance of latencies was observed at individual threshold level. Wave-V latency was longest in the Incus placement subgroup (9.73 ms, SD: 1.04) as compared to OW placement subgroup (9.47 ms, SD: 1.05), with the shortest latency in the RW placement subgroup (8.99 ms, SD: 0.68). For increasing stimulation levels, the variance decreased with intensity-latency function slopes converging toward a steady-state (saturation) latency caused by saturation of audio processor (stimulation) gain. Latency saturation was reached at a stimulation level of 50 dB nHL for the OW placement subgroup, 35 dB nHL for the Incus placement subgroup, and 30 dB nHL for the RW placement subgroup. The latency and saturation results indicated decreased dynamic range for RW placement, i.e., reverse stimulation.


Conclusions
VSB evoked ABR wave-V intensity-latency function slopes were similar to acoustic stimulation at high stimulation levels with a shift toward longer latencies caused by audio processor signal delay. Saturation of latencies occurred for higher stimulation levels due to saturation of audio processor gain. Thus, the analysis of VSB evoked intensity-latency functions appears to allow for the objective assessment of a patient's individual dynamic range. This can further improve diagnostics as well as intraoperative and postoperative quality control.
KW  - -
KW  - active middle ear implant
KW  - coupling efficiency
KW  - objective measures
KW  - auditory brainstem response
KW  - latency
UN  - https://nbn-resolving.org/urn:nbn:de:gbv:9-opus-59108
SN  - 1664-2295
SS  - 1664-2295
U6  - https://doi.org/10.3389/fneur.2021.739906
DO  - https://doi.org/10.3389/fneur.2021.739906
VL  - 12
SP  - 10
S1  - 10
PB  - Frontiers Media S.A.
CY  - Lausanne
ER  -