Impact of Aging and the Electrode-to-Neural Interface on Temporal Processing Ability in Cochlear-Implant Users: Gap...

Area of Science:

• Auditory Neuroscience
• Neuroscience
• Speech Processing

Background:

• Accurate temporal processing is vital for speech comprehension in cochlear implant (CI) users.
• Age-related auditory temporal processing deficits may impact the growing population of older CI users.
• Understanding the interplay between aging and neural function is crucial for CI outcomes.

Purpose of the Study:

• To assess temporal processing in younger, middle-aged, and older CI users using a gap detection task.
• To investigate the influence of chronological age and peripheral neural status on temporal processing.
• To determine the predictive power of electrically evoked compound action potential (ECAP) slope on gap detection thresholds (GDTs).

Main Methods:

• Measured single-electrode GDTs across five electrode locations and three electrical stimulation rates.
• Assessed peripheral neural status via the slope of the ECAP amplitude growth function.
• Analyzed the relationship between ECAP slope, age, stimulation rate, and GDTs.

Main Results:

• ECAP slope was the strongest predictor of GDTs, with steeper slopes indicating better peripheral function and GDTs in younger CI users.
• ECAP slope interacted with stimulation rate and age, diminishing its predictive value for GDTs in middle-aged and older adults.
• Middle-aged and older CI users showed shallower ECAP slopes and reduced slope variability compared to younger users, complicating the isolation of aging effects.

Conclusions:

• Peripheral neural status, as indicated by ECAP slope, significantly influences temporal processing in younger CI users.
• The predictive relationship between ECAP slope and temporal processing is diminished in older CI users, particularly at certain stimulation rates.
• Age-related changes in peripheral neural function complicate the assessment of independent aging effects on temporal processing in CI users.