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Systematic Hearing Performance Evaluation Process for Adolescents with Cochlear Implantation at Early Ages
Published on: March 24, 2023
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Loudness Perception and Dynamic Range Depending on Interphase Gaps of Biphasic Pulses in Cochlear Implants
Sabrina H Pieper1, Stefan Brill2, Andreas Bahmer1
1Clinic for Otolaryngology, Comprehensive Hearing Center, University of Würzburg, Würzburg, Germany.
Ear and Hearing
|January 24, 2020
Summary
Larger interphase gaps (IPGs) in cochlear implants (CIs) can reduce stimulus amplitude for a given loudness. However, increasing IPGs significantly decreases the dynamic range, impacting CI fitting strategies.
Area of Science:
- Audiology
- Biomedical Engineering
- Neuroscience
Background:
- Cochlear implants (CIs) use electrical stimulation of the auditory nerve with biphasic pulses.
- Interphase gaps (IPGs) between pulses influence electrically evoked compound action potential (ECAP) thresholds in animal models.
- ECAP thresholds may correlate with perceived loudness in CI users.
Purpose of the Study:
- To investigate the effect of varying interphase gaps (IPGs) on loudness perception and dynamic range in cochlear implant (CI) subjects.
- To determine if IPG adjustments can optimize loudness perception and reduce power consumption in CIs.
Main Methods:
- A loudness-matching procedure was employed using three IPGs (2.1, 10, 30 μs) and three pulse rates (200, 600, 1000 pps).
- An adaptive loudness-balancing test was conducted at 50% stimulus amplitude and most comfortable loudness level (MCL).
Main Results:
- Increasing IPG or pulse rate significantly decreased stimulus amplitude required for 50% level and MCL.
- The upper dynamic range (between MCL and 50% level) significantly decreased with increasing IPG (0.24–0.38 dB) across all tested pulse rates.
Conclusions:
- Larger IPGs allow for reduced stimulus amplitude for equivalent loudness perception in CIs.
- Increased IPGs lead to a reduction in the available dynamic range, a critical factor in CI programming.
- Findings aid in balancing battery conservation with adequate dynamic range during CI fitting.
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