Acoustic Change Complex Recorded in Hybrid Cochlear Implant Users

Area of Science:

• Audiology
• Neuroscience
• Biomedical Engineering

Background:

• Cochlear implant (CI) candidacy is expanding, leading to more users with residual low-frequency hearing.
• Objective measures like cortical auditory-evoked potentials (CAEPs) can aid in optimizing listening modes for CI users.
• Hybrid CI users benefit from tailored recommendations based on objective physiological data.

Purpose of the Study:

• To investigate differences in CAEPs between acoustic alone (A-alone) and acoustic plus electric (A + E) listening modes in hybrid CI users.
• To determine if the acoustic change complex (ACC) can serve as an objective measure for evaluating hybrid CI benefit.
• To explore the potential of ACC in guiding clinical recommendations for individualized listening strategies.

Main Methods:

• Eight hybrid CI users participated in the study.
• Cortical auditory-evoked potentials (CAEPs), specifically P1-N1-P2 and ACC, were measured simultaneously.
• Responses were recorded in two listening modes: A-alone and A + E, using spectrally complex acoustic signals.

Main Results:

• ACC amplitudes were significantly larger in the A + E mode compared to the A-alone mode.
• The difference in ACC amplitude was most pronounced for stimuli involving low-to-high frequency changes.
• Stimulus type and listening mode significantly affected ACC amplitude and latency.

Conclusions:

• The ACC is a sensitive objective measure that varies with listening mode and stimulus type in hybrid CI users.
• ACC responses can potentially assist clinicians in making objective, individualized listening mode recommendations.
• Further research is warranted to validate ACC as a clinical tool for hybrid CI recipients and users with residual hearing.