Auditory neural entrainment: frequency-specific functional roles and emerging applications in neurological and...

Among sensory inputs, auditory information plays a significant role. Neural entrainment may establish a bridge for the brain's perception of rhythmic sound signals. It refers to the synchronization of ongoing neuronal activity with internal and external rhythmic stimuli, demonstrating the brain's plasticity and adaptive dynamics. Across canonical EEG bands, delta activity is associated with temporal prediction and hierarchical auditory processing over longer time scales; theta activity with speech parsing, audiovisual integration, and memory-related timing; alpha activity with cross-modal information processing; beta activity with predictive timing and auditory-motor coordination; and gamma-range responses with fine temporal encoding and steady-state activity. These associations overlap rather than represent one-to-one functional mappings. This mini review included studies based on speech, music, pure tones, and other natural or artificial auditory stimuli. We explored the functional roles of these oscillatory activities and their interactions. Finally, we prudently reviewed the emerging applications of auditory neural entrainment for brain diseases. These explorations have yielded some exciting results, but the evidence remains in its early stages and shows heterogeneity. It is also limited by small sample sizes and short study periods. Moreover, many music- and rhythm-based interventions have shown symptom improvement, but most provide only indirect evidence. Therefore, we emphasize that future studies should more deeply explore the relationship between neural entrainment and proven therapeutic benefits, while also attending to safety, individual differences, and the adequacy of control groups in sham interventions.