Speech performance in adults with cochlear implants using combined channel deactivation and dynamic current focusing

Area of Science:

• Audiology
• Neuroscience
• Biomedical Engineering

Background:

• Cochlear implants (CI) aim to restore hearing but face challenges in speech-in-noise understanding.
• Channel interactions in CI reduce signal accuracy, hindering complex auditory perception.
• Optimized CI programming strategies, like focused stimulation, can mitigate these issues.

Purpose of the Study:

• To investigate the combined effects of channel deactivation and focused dynamic tripolar stimulation in cochlear implant users.
• To evaluate speech perception in quiet and noise using different CI programming strategies.
• To assess the influence of individual factors on speech performance with optimized CI settings.

Main Methods:

• Developed three CI programs using an automatic channel selection algorithm based on focused detection thresholds.
• Programs varied in the proportion of channels using focused stimulation, monopolar, or dynamic focused modes.
• Tested 13 ears in 11 adult CI users (Advanced Bionics HiRes90k) on vowel and sentence recognition.

Main Results:

• Individual improvements in vowel and sentence perception were observed with focused stimulation compared to monopolar programming.
• Benefits of focused listening were more pronounced in CI users with less experience and poorer clinical performance.
• No significant group-level improvements were found, indicating substantial inter-individual variability.

Conclusions:

• Deactivating and focusing specific CI channels may enhance speech performance for certain individuals, especially those with lower baseline performance.
• Reduced channel interactions are a likely mechanism for observed improvements.
• Individual variability in CI performance necessitates personalized programming approaches.