Exploratory Analysis of Cortical-Vestibular Interaction: The Relation Between Caloric-Induced Changes in Electroencephalography Frequency Bands, the Vestibulo-Ocular Reflex, and Perception.

OBJECTIVES: Standardized assessments of vestibular function primarily focus on the structural integrity of brainstem reflexes. However, patients may report symptoms linked to disruptions in central vestibular processing and integration, mechanisms that remain poorly understood. Emerging evidence suggests that electroencephalography (EEG) can characterize the neural dynamics of central vestibular processing. This exploratory study examines the effects of caloric-induced vestibular stimulation on EEG rhythms to further elucidate neural dynamics and their relationship with lower-order (brainstem reflexes) and higher-order (perception) vestibular processes.

DESIGN: Ten healthy, right-handed participants underwent EEG recording during resting and caloric vestibular stimulation periods. Changes in spectral power were quantified using a measure that captured both desynchronization (suppression) and synchronization (enhancement) across frequency bands.

RESULTS: Results revealed a significant and widely distributed suppression of the alpha band. The individual changes in EEG frequency bands were not correlated with the degree of brainstem caloric responsiveness (peak slow phase velocity), while the changes in beta were significantly related to a measure of caloric-induced perception.

CONCLUSIONS: Although future studies should focus on the reproducibility and validity of vestibular-induced EEG responses, these findings support measurable cortical-vestibular interactions using EEG and highlight its potential to bridge gaps in knowledge between traditional assessment and cortical contributions to dizziness and imbalance.