Evaluation of objective test techniques in cochlear implant users with inner ear malformations

Area of Science:

• Otolaryngology
• Audiology
• Biomedical Engineering

Background:

• Inner ear malformations present unique challenges for cochlear implant (CI) fitting and evaluation.
• Objective test techniques are crucial for assessing auditory nerve function in CI users, especially those with complex inner ear anatomy.

Purpose of the Study:

• To compare the efficacy of objective electrophysiological tests, including electrically evoked compound action potentials (ECAPs), electrically evoked stapedius reflex thresholds (ESRTs), and electrically evoked auditory brainstem response (EABR) thresholds.
• To determine the most suitable objective test technique for evaluating and fitting cochlear implants in individuals with inner ear malformations.

Main Methods:

• A retrospective clinical study comparing CI users with inner ear malformations (n=20) to a control group with normal cochleae (n=15).
• Electrophysiological tests (ECAP, ESRT, EABR) were performed on 6 intracochlear electrodes after standard CI fitting.
• Statistical analysis included Mann-Whitney U test, Kruskal-Wallis analysis, and Dunn's Z test.

Main Results:

• Significantly lower percentages of acquired ECAP (25% vs. 74%) and ESRT (17.5% vs. 90%) thresholds were observed in the inner ear malformation group compared to the control group.
• Statistically significant differences were found in current levels and latencies of EABR wave V between the two groups.
• EABR demonstrated a higher applicability in the inner ear malformation group.

Conclusions:

• Electrically evoked auditory brainstem response (EABR) is a more applicable objective test technique for cochlear implant users with inner ear malformations than ECAP and ESRT.
• Findings suggest EABR should be prioritized for evaluation and fitting in this patient population.