Related Experiment Video
Updated: Feb 16, 2026

Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice
Published on: January 9, 2019
Evaluation of an artifact reduction strategy for electrically evoked auditory steady-state responses: Simulations and
Andreas Bahmer1, Sabrina Pieper1, Uwe Baumann2
1University of Würzburg, Clinic for Otolaryngology, Comprehensive Hearing Center, 97080 Würzburg, Germany.
Background:
Electrically evoked steady-state response (EASSR) recording is a measure of neuronal response strength after continuous electrical stimulation of the auditory system. In order to suppress the large electrical artifact generated by intracochlear electrical stimulation, a sophisticated artifact reduction processing strategy ("Hofmann procedure") has been proposed (Hofmann and Wouters, 2010). So far, EASSR recordings with artifact reduction procedures were reported only in cochlear implant (CI) users implanted with Cochlear devices (Macquarie, Australia).
New Method:
Here, we demonstrate the application of the Hofmann procedure in CI users implanted with MED-EL (Innsbruck, Austria) devices. To demonstrate potential limitations of the procedure, we calculated discrete time Fourier transformations (DTFT) of various pulse patterns which may be used for EASSR.
Results:
EASSR recordings were obtained in three subjects and processed with the Hofmann procedure. Neural response amplitude growth functions and phase for modulated and unmodulated pulse trains at various stimulation rates could be assessed. Simulations of three different interpolation methods aimed to suppress the electrical artifact show that the interpolation of a sinusoidal signal in a temporal window between 0 and 1 ms has demonstrated negligible impact on the spectral amplitude of the signal with a superior performance of a spline interpolation.
Comparison With Existing Method:
The Hofmann procedure, initially developed for recording EASSRs with CIs from the manufacturer Cochlear, was validated for MED-EL devices.
Conclusion:
It is feasible to record EASSRs with the described measurement setup and CIs from the manufacturer MED-EL.
Related Concept Videos
Transient and Steady-state Response
These test signals are integral in designing control systems to exhibit two key performance aspects: transient response and steady-state...
Steady State Concentration
Most drugs are administered in repeated doses at fixed intervals or through continuous...
Steady Flow of a Fluid Stream
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
Oxidation-Reduction Reactions
The Auditory Ossicles
The aptly named stapes look very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in...
Velocity and Acceleration in Steady and Unsteady Flow
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over...

