gms | German Medical Science

23. Jahrestagung der Deutschen Gesellschaft für Audiologie

Deutsche Gesellschaft für Audiologie e. V.

03.09. - 04.09.2020, Cologne (online conference)

Investigation of the facilitation effect using electrically evoked compound action potentials

Meeting Abstract

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  • presenting/speaker Sabrina Pieper - Universitätsklinikum Würzburg, Würzburg, Deutschland
  • David Herrmann - Universitätsklinikum Würzburg, Würzburg, Deutschland
  • Andreas Bahmer - Universitätsklinikum Würzburg, Würzburg, Deutschland

Deutsche Gesellschaft für Audiologie e.V.. 23. Jahrestagung der Deutschen Gesellschaft für Audiologie. Köln, 03.-04.09.2020. Düsseldorf: German Medical Science GMS Publishing House; 2020. Doc163

doi: 10.3205/20dga163, urn:nbn:de:0183-20dga1638

Published: September 3, 2020

© 2020 Pieper et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at



Neuronal responses to pulse trains with short interpulse intervals (IPIs) smaller than 300 µs are influenced by facilitation effects. These effects within the refractory period can be measured by electrically evoked compound action potentials (ECAPs) of the auditory nerve with cochlear implants (CI). In previous studies (e.g. [1]) intensive ECAP measurements with short IPIs were assessed with CI of the manufacturer Cochlear. The masker pulse level (relative to the probe pulse level) was varied and it was found, that the facilitation effect increased to its maximum for masker levels at or slightly below the ECAP threshold independent of the probe level. A further increase of the masker level revealed a decrease in facilitation.

Similar measurements were repeated in four subjects with CIs of the manufacturer Med-El to investigate if the described effects could be reproduced with a different setup. ECAP threshold were recorded using the manufacturers fitting software Maestro. Afterwards, ECAPs with short IPIs (15 µs) using a custom-made software were recorded with the artifact reduction method of Miller. The probe pulse level was fixed at ECAP threshold, while the masker pulse level varied from 0 CU (absolute value) up to 200 CU (relative to ECAP threshold).

The results of the original study could be confirmed using Med-El implants. As expected, the highest facilitation effect was at masker levels around ECAP threshold, with a steep decrease of ECAP amplitude after the maximum at higher masker levels. Increasing the probe level had no influence on the optimal masker level at the highest facilitation effect.


Hey M, Müller-Deile J, Hessel H, Killian M. Facilitation and refractoriness of the electrically evoked compound action potential. Hear Res. 2017;355:14-22. DOI: 10.1016/j.heares.2017.09.001 External link