A Site-Selection Strategy Based on Polarity Sensitivity for Cochlear Implants: Effects on Spectro-Temporal Resolution...

Area of Science:

• Audiology and Speech-Language Pathology
• Biomedical Engineering
• Neuroscience

Background:

• Cochlear implant (CI) performance varies significantly among users.
• The polarity effect (PE), differences in detection thresholds based on pulse polarity, is suggested to reflect neural health.
• PE may offer a basis for personalized CI programming strategies.

Purpose of the Study:

• To test if the polarity effect (PE) can guide site-selection strategies to enhance speech perception and spectro-temporal resolution in CI users.
• To investigate the relationship between PE, neural health indicators, and speech processing outcomes.

Main Methods:

• Measured detection thresholds for cathodic-dominant vs. anodic-dominant pulses in eight Advanced Bionics CI users.
• Created experimental programing maps (MAPs) by excluding electrodes with highest/lowest PE magnitudes.
• Assessed speech recognition (quiet/noise) and spectro-temporal processing (STRIPES, SMRT) with experimental and clinical MAPs.

Main Results:

• PE varied considerably across subjects and electrodes.
• No significant group-level improvements in speech or spectro-temporal measures were found with PE-based site-selection MAPs.
• Individual subject performance varied, with some benefiting from specific MAPs, and STRIPES predicted speech-in-noise outcomes.

Conclusions:

• PE-based site-selection strategies did not yield consistent group benefits for CI users.
• Individual variability in CI performance highlights the need for personalized approaches.
• PE correlates with subject age, deafness duration, and speech scores, suggesting its potential as a neural health biomarker for CI processing.