Detailed insight in intraoperative eABR measurements to assist auditory brainstem implantation in a patient with neurofibromatosis type 2

  • Magdalena LachowskaEmail author
  • Agnieszka Pastuszka
  • Lidia Mikołajewska
  • Przemysław Kunert
  • Kazimierz Niemczyk
Original article


Auditory brainstem implant (ABI) is used to provide auditory sensations in patients with neurofibromatosis type 2 who lost their hearing due to a surgical removal of the tumor. ABI surgery, implant activation and follow-up sessions present unique challenges including the exact placement of the electrode pad in the lateral recess of the IVth ventricle, identification of electrodes that trigger non-auditory sensation and their deactivation which lowers the number of electrodes responsible for hearing, changes of T- and C-levels across follow-up sessions. We present a complete procedure using an example case starting from the surgical part with the detailed description of intraoperative eABR measurement as a guidance for pad placement to the ABI activation and first fitting sessions with auditory sensation assessment. Since the first ABI electrode pad position presented non-satisfactory intraoperative eABR results it was decided to move the pad slightly which resulted in better eABR (more electrodes with auditory responses). The discussed patient demonstrated great auditory and speech perception results after the first ABI fitting (which included three sessions over 2 consecutive days). Repositioning of the ABI electrode pad during the surgery was carried out taking into account the intraoperative eABR results and this led to an overall positive outcome for the patient. The placement of ABI electrode pad is crucial for later auditory results. This study provides detailed insight in this very specialized procedure that is not performed in every clinic and adds to the knowledge of intraoperative navigation using eABR measurements during ABI surgery.


Hearing loss Evoked potentials Neurofibromatosis Cochlear nerve Cochlear nucleus Auditory brainstem implant 



We would like to thank Tomáš Tichý from Cochlear Company for his assistance with intraoperative measurements and ABI activation sessions.

Compliance with ethical standards

Conflict of interest

All authors declare that they have no conflict of interest.

Research involving human participants

All procedures performed in this study involving human participant were in accordance with the ethical standards of the institutional research committee (the local Institutional Ethics Committee Review Board, reference number AKBE/175/2018) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Informed consent

One patient participated in this study—the patient has given full written and informed consent, both for the participation and for the publication of the report.


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Copyright information

© Belgian Neurological Society 2019

Authors and Affiliations

  1. 1.Department of OtolaryngologyMedical University of WarsawWarsawPoland
  2. 2.Department of NeurosurgeryMedical University of WarsawWarsawPoland

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