Monitoring Neural Activity with ECAP Recordings at 34 Hz: Effects of Stimulation Intensity Growth Rates with Traditional and Novel FineGrain Approaches in Young CI Users

Background:

The ECAP is an objective measure used for fitting, functional evaluation of CIs and to assess neural health. The traditional method provides a crude estimate of the threshold and requires an adjustment through a specialist. FineGrain method is a novel recording approach with an improved algorithm. We hypothesize that is an improvement compared to the traditional one with regard to preciseness and noise reduction and should increase the success rate of ECAP recordings significantly.

Objective

FineGrain method has not been compared to the traditional method on a larger scale. We compared success rate and precision in ECAP threshold determination across the two methods. The results are aligned with EABR.

Method

We monitored the same subjects with the traditional and the novel ECAP recording approach and also performed eABR. To investigate effects of the fine-grain vs. the traditional approach, the frequency was fixed to 34Hz for both methods and the number of steps was set to 19 for the traditional approach to increase reproducibility.

To evaluate the overall performance and possible differences between fine-grain and traditional approach, EABR at 34Hz were included in the study.

Results and Conclusions

FineGrain and traditional ECAP measurement approaches were both highly successful (> 94%) while eABR success rate was a bit lower (73%). In one-on-one comparisons FineGrain ECAP thresholds appear more accurate and robust than traditional thresholds. No substantially differences were founded compared to eABR thresholds. eCAP recordings were in general much faster than eABR measurements with FineGrain being the quickest.