Listening Effort and Memory Effort in Cochlear Implant Users: A Pupillometry Study.

Area of Science:

• Auditory Neuroscience
• Cognitive Psychology
• Rehabilitation Engineering

Background:

• Conversational speech processing demands significant cognitive resources.
• Hearing impairment, especially in cochlear implant (CI) users, increases the cognitive load for speech processing and memory encoding.
• Understanding cognitive resource allocation in CI users is crucial for effective auditory rehabilitation.

Purpose of the Study:

• To investigate the cognitive effort (listening and memory) in CI users during an auditory dual task.
• To determine if pupil dilation can serve as an objective measure of cognitive effort allocation in CI users.
• To explore how CI users adapt their cognitive resources based on varying task demands.

Main Methods:

• Nineteen German-speaking CI users participated in a sentence final word identification and recall test.
• Pupil dilation was continuously monitored during sentence presentation in background noise.
• Participants completed tasks with varying list lengths (3 vs. 6 sentences) and recall requirements, with pupil size analyzed relative to sentence baselines.

Main Results:

• CI users demonstrated adaptive memory effort allocation, with significant changes observed across different list lengths and recall conditions.
• The slope of sentence baseline differed significantly between list lengths and halves, indicating altered cognitive processing.
• Sentence dilation, reflecting listening effort, did not significantly change, suggesting consistent auditory processing load.

Conclusions:

• CI users dynamically allocate memory effort according to task complexity.
• Listening effort in CI users appears to remain relatively stable during auditory tasks.
• Pupil dilation is a viable method for assessing cognitive effort in CI users during speech comprehension and memory tasks.