Impact of cognition and noise reduction on speech perception in adults with unilateral cochlear implants.

Objectives: The purpose of this study was to investigate the impact of cognition and noise reduction (NR) technology in cochlear implants (CIs) on speech perception and listening effort.

Methods: Thirteen adults fitted with unilateral CIs (Nucleus 6, CP900) participated in this study. Participants performed: (I) cognitive tests of working memory and processing speed, (II) speech perception in noise tests, and (III) an auditory-visual dual-task paradigm to quantify listening effort, as a part of the three-phase experimental study. Both the participant and the tester, performing the outcome measures, were blinded to the NR settings (ON/OFF) of the CI for phases II and III.

Results: Speech intelligibility significantly improved with the NR activated, but was independent of individual differences in cognitive abilities. Listening effort did not significantly change with NR setting; however, there was a trend for participants with good working memory to have better speech perception scores with NR activated during the effortful listening task (dual-task paradigm).

Conclusion: Future studies are warranted to explore the interaction between cognition and CI NR algorithms during an effortful listening task.