Audiobook familiarization is associated with theta-gamma power modulation and increased alpha-band phase synchronization

Understanding how repeated listening to naturalistic spoken narratives modulates neural oscillations is crucial for uncovering the connection between speech comprehension and memory. Prior studies have mainly focused on auditory evoked responses to phoneme or isolated-word repetitions. However, the temporal, spectral, and spatial dynamics of oscillatory activity remain largely underexplored. In this study, we investigated the impact of audiobook familiarization on oscillatory brain activity using electroencephalography (EEG). EEG responses were recorded from 17 participants as they familiarized themselves with 132 unfamiliar 10-second passages from audiobooks, each repeated three times. Time-frequency analyses revealed inhibition of theta- and gamma-band power during the first repetition, particularly over left temporal electrodes, with several effects most prominent in the comparison between the second and first repetitions. Repeated exposure was associated with reduced inhibition across subsequent repetitions. Functional connectivity analyses further revealed increased alpha-band phase synchronization between left frontal and right parietal electrodes across repetitions. Taken together, our results provide novel evidence that repeated listening to spoken narratives dynamically reshapes both power modulation and phase synchronization. These findings may reflect neural processes related to familiarization and be relevant to predictive-processing accounts of continuous speech comprehension.