Automatized ECAP Threshold Determination is a Reliable Replacement for Traditional Methods

Background

The evoked compound action potential (eCAP) is an objective measure that is often used for fitting and functional assessment of cochlear implants, and for the estimation of neural health.

The eCAP threshold refers to the stimulation current from which on valid eCAP responses are being detected. The traditional measurement method (StandART in MAESTRO 6 Software) provides a crude estimate of such threshold , but requires an adjustment through a specialist "by eye". A novel approach, termed FineGrain, uses a more sophisticated algorithm for automatic threshold determination, which is claimed to set thresholds as well as human specialists without the requirement for manual adjustments.

Objectives

The potential advantages of the FineGrain method are speed and allowing for more standarized way of eCAP threshold determination. However, in order to replace the traditional method, FineGrain and StandART have to be tested and compared on various populations of CI users. Here, we studied the two approaches in children.

Methods

We performed eCAP recordings using the traditional and the FineGrain approach in parallell, in a population of children and compared their outcomes. Also, we aligned the results with MCL and speech perception data.

Results

Our results demonstrate that the FineGrain recording approach delivers similar success rates and thresholds as StandART and that FineGrain eCAP thresholds even correlate slightly better with the MCLs.

Conclusions

We conclude that the FineGrain method is a more robust way of recording eCAPs than the traditional method, yet equally exact.