Evaluation of the Promontory Stimulation eABR in CI Candidates with the Med-El System

Background

In some patients the evaluation of presence and excitability of the auditory nerve before cochlear implantation cannot be fully performed by the standard audiological preoperative tests. Preoperative electrical auditory brainstem response (eABR) can be used in these cases to assess the response from the auditory pathway to electrical stimulation in CI candidates.

Objective

The goal of this work is to evaluate promontory eABR with the Med-El clinical system in CI candidates.

Methods

Promontory eABR recording was performed in 19 CI candidates. A trans-tympanic stimulating electrode with rounded-bent tip was placed on the promontory or round window niche. The electrical stimulation, with an increasing stimulating pattern, was generated by the Med-El Stimulator Box and operated by the clinical software. An external Evoked Potential (EP) recording device was used to collect eABR response. To this date, 13 of 19 subjects where implanted with CI and follow up was performed.

Results

The promontory eABR was recordable in 18 subjects. The statistical analysis of amplitude and latency of eIII and eV on the PromStim eABR and correlation with improvements using the CI are shown. Subjects implanted with the CI showed 43,3 dB as the average in the tone audiometry and benefit was also evaluated by the word speech test.

Conclusion

Promontory eABR with the Med-El clinical system an external EP recording device is easy to perform. The data suggests that this method can be valid in the selection process for CI implantation in any questionable CI candidate, also applicable in children.