Extending pulse phase durations during ECAP recordings to optimise perceived loudness

In cochlear implants (CI), electrically evoked compound action potentials (ECAPs) are responses to pulses of increasing stimulation intensities.This can be limited by a user's loudness sensitivity. Adjusting pulse phase durations (PD) may improve user tolerance. This study compared hearing and ECAP thresholds, maximum stimulation chargesand ECAP threshold determination rates across different PDs. ECAP measurements (AutoART - MAESTRO software) were carried out with stimulation pulse PDs between 30 and 100 µs alongside loudness evaluation. Twenty MED-EL CI users (aged 19–77 years) participated in this study. Longer ECAP stimulation pulses (80 & 100 µs) enabled higher maximum stimulation charges and were perceived as less loud by CI users. Both, ECAP thresholds and perceptual thresholds increased with PD, while ECAP threshold determination rates and profiles over the electrode array remained consistent across PDs. Extending pulse phase duration during ECAP measurements can reduce loudness discomfort, potentially benefiting sensitive CI user in clinical settings.