Band importance functions of listeners with cochlear implants using clinical maps

Area of Science:

• Audiology
• Speech Perception
• Cochlear Implants

Background:

• Band importance functions (BIFs) quantify the contribution of acoustic frequency bands to speech intelligibility.
• Previous research on BIFs in cochlear implant (CI) users often involved experimental stimulation methods.
• Understanding BIFs with clinical CI maps is crucial for optimizing hearing rehabilitation.

Purpose of the Study:

• To estimate BIFs using acoustic stimulation with clinical CI maps.
• To compare BIFs in CI users with those in normal-hearing listeners.
• To investigate factors influencing BIFs in CI users, including spread of excitation.

Main Methods:

• Acoustic stimulation was used to assess BIFs in CI users with their clinical speech processor maps.
• BIFs were measured in CI users and compared to a group of normal-hearing listeners.
• Normal-hearing listeners were tested with vocoded speech, with and without simulated spread of excitation.

Main Results:

• CI users exhibited BIFs that prioritized lower frequency bands compared to normal-hearing listeners.
• Significant inter-subject variability was observed in the BIFs of CI users, suggesting limitations of group averaging.
• No significant difference in BIFs was found between normal-hearing listeners tested with and without simulated spread of excitation.

Conclusions:

• Clinical CI map assessments reveal unique BIFs in CI users, emphasizing lower frequencies.
• High inter-subject variability in CI user BIFs challenges the meaningfulness of averaged functions.
• Spread of excitation alone does not fully explain altered BIFs in CI users, indicating other factors are involved.