Spectral loudness summation for electrical stimulation in cochlear implant users

Area of Science:

• Auditory Neuroscience
• Biomedical Engineering
• Neuroscience

Background:

• Spectral loudness summation (SLS) is understood in acoustics.
• Its electrical equivalent in cochlear implant (CI) users is less understood.
• This study explores electrical SLS perception in CI users.

Purpose of the Study:

• To investigate electrical spectral loudness summation (SLS) in cochlear implant (CI) users.
• To define electrical SLS based on electrode separation at a fixed stimulation rate.
• To understand its perceptual impact on CI users.

Main Methods:

• Categorical loudness scaling (CLS) was performed at three stimulation rates.
• Single-electrode and multi-electrode stimuli were used.
• SLS was calculated by comparing current levels for equal loudness perception.

Main Results:

• Electrical SLS varied significantly among CI users.
• The number and location of stimulated electrodes influenced SLS.
• SLS was significantly greater than zero for a subset of participants.

Conclusions:

• Loudness models for CI users should incorporate nonlinear inter-electrode perceptual interactions.
• Electrical SLS needs consideration in CI fitting protocols, especially for a subpopulation.
• This impacts the clinical application of CLS data.