Extending pulse phase durations during ECAP recordings to optimise perceived loudness

Area of Science:

• Audiology
• Biomedical Engineering
• Neuroscience

Background:

• Cochlear implants (CI) use electrical compound action potentials (ECAPs) to assess neural response.
• Loudness sensitivity can limit ECAP measurement efficacy.
• Optimizing stimulation parameters like pulse phase duration (PD) may enhance user tolerance and data quality.

Purpose of the Study:

• To investigate the impact of varying pulse phase durations (PDs) on ECAP thresholds, loudness perception, and measurement success rates in CI users.
• To determine if adjusting PD can improve tolerance for ECAP measurements.

Main Methods:

• ECAP measurements were performed using AutoART software with PDs ranging from 30 to 100 µs.
• Loudness perception was evaluated alongside ECAP measurements.
• Twenty MED-EL CI users participated in the study.

Main Results:

• Longer PDs (80 & 100 µs) allowed higher maximum stimulation charges and were perceived as less loud.
• Both ECAP and perceptual thresholds increased with longer PDs.
• ECAP threshold determination rates remained consistent across tested PDs.

Conclusions:

• Increasing pulse phase duration in ECAP measurements can decrease loudness discomfort for CI users.
• This adjustment offers a potential benefit for sensitive CI users in clinical audiology settings.