Cortical oscillations predict auditory grouping in listeners with and without hearing loss

Area of Science:

• Neuroscience
• Auditory Perception
• Hearing Loss Research

Background:

• Auditory grouping enables forming coherent auditory objects from spectral and temporal information.
• Sensorineural hearing loss (SNHL) impairs spectral resolution, with effects varying by listening configuration.
• The impact of SNHL and different listening configurations on auditory grouping remains unclear.

Purpose of the Study:

• To investigate task performance and cortical activity during auditory object detection in individuals with SNHL using different listening configurations.
• To compare auditory grouping abilities between normal-hearing (NH) listeners and users of acoustic-only hearing aids (A-only), acoustic and electric cochlear implants (A+E), and electric-only cochlear implants (E-only).

Main Methods:

• Electroencephalography (EEG) was used to record cortical activity while participants performed a stochastic figure-ground task.
• The task involved detecting spectrally and temporally coherent tone pips within a background of random-frequency tone clouds.
• Four groups were studied: NH listeners, A-only users, A+E users, and E-only users.

Main Results:

• All groups achieved >80% accuracy, but cochlear implant (CI) groups performed worse than NH and A-only groups.
• Object-related evoked responses were weaker in A-only and absent in CI groups compared to NH listeners.
• Alpha and beta event-related desynchronization (ERD) was observed in all groups and predicted task accuracy, suggesting its role in auditory grouping.

Conclusions:

• Alpha and beta cortical activity reflects auditory grouping regardless of listening configuration.
• While SNHL and device type affect auditory object formation, alpha/beta ERD appears to be a robust neural correlate of auditory grouping.