Frequency following responses and rate change complexes in cochlear implant users
Robin Gransier1, Franҫois Guérit2, Robert P Carlyon2
1KU Leuven, Department of Neurosciences, ExpORL, Herestraat 49, Box 721, Leuven 3000, Belgium.
Hearing Research
|March 1, 2021
Summary
Measuring electrophysiological responses like the electrically-evoked frequency following response (eFFR) and auditory change complex (eACC) in cochlear implant (CI) users is feasible. These methods, free from stimulation artifacts, can reveal neural correlates for pitch and rate processing.
Area of Science:
- Auditory Neuroscience
- Cochlear Implant Technology
- Electrophysiology
Background:
- Cochlear implant (CI) users exhibit significant variability in rate-based pitch perception and discrimination.
- This variability may stem from biological limitations in temporal encoding within the electrically stimulated auditory pathway.
- Degenerative processes associated with hearing loss can also impact temporal encoding.
Purpose of the Study:
- To investigate the feasibility of measuring artifact-free electrically-evoked frequency following responses (eFFRs) and auditory change complexes (eACCs) in CI users.
- To assess the potential of these electrophysiological measures as neural correlates for temporal processing limitations.
- To explore these measures at stimulation rates up to 196 pulses per second (pps) and various pulse rate changes.
Main Methods:
- Five CI users were stimulated in a monopolar configuration.
- A high-sampling rate EEG system was employed to record electrophysiological responses.
- Linear interpolation was used to remove stimulation artifacts from the EEG data.
Main Results:
- Electrically-evoked frequency following responses (eFFRs) were successfully measured up to 162 pps.
- Auditory change complexes (eACCs) were measurable in response to tested pulse rate changes.
- The developed method allowed for artifact-free measurement of neural responses.
Conclusions:
- It is feasible to measure artifact-free electrophysiological responses in CI users using the described EEG approach.
- These artifact-free eFFRs and eACCs show promise as neural correlates for understanding rate and pitch processing.
- This technique could provide valuable insights into the temporal processing limitations in the electrically stimulated auditory pathway.
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