Comparing eSRT and eCAP measurements in pediatric MED-EL cochlear implant users

Area of Science:

• Audiology
• Biomedical Engineering
• Neuroscience

Background:

• Objective measurements like electrically evoked compound action potentials (eCAP) and electrically evoked stapedius reflexes (eSRT) are crucial for programming cochlear implant (CI) audio processors, especially in pediatric users who may have difficulty providing feedback.
• These objective measures aid in optimizing the audio processor settings for better hearing outcomes.

Purpose of the Study:

• To compare the electrically evoked stapedius reflex threshold (eSRT) with electrically evoked compound action potential (eCAP) thresholds and amplitude growth functions in pediatric CI users.
• To evaluate the time efficiency of eCAP and eSRT measurements for CI programming.

Main Methods:

• The study involved 52 pediatric CI users with MED-EL devices who had recordable eSRTs.
• eSRT fitting was used for programming, and eCAP thresholds and amplitude growth slopes were measured at apical, medial, and basal electrode contacts.
• Measurement durations for both eCAP and eSRT were recorded.

Main Results:

• A weak to medium correlation was found between eCAP thresholds and eSRTs, with eCAP thresholds generally requiring lower stimulation charge.
• The eCAP threshold profile did not correlate with the eSRT profile across electrodes.
• eSRT measurements were significantly faster, taking on average 4.2 times less time per electrode compared to eCAP measurements.

Conclusions:

• eSRTs are clinically more relevant than eCAPs for setting maximum comfort levels across the cochlear implant array in pediatric users.
• eSRT measurements are more time-efficient for CI programming compared to eCAP measurements, making them a more practical option for clinical settings.