Alterations in functional connectivity of the brain during postural balance maintenance with auditory stimuli: a stabilometry and electroencephalogram study

<i>Objectives.</i>In daily life, individuals continuously integrate motor and cognitive tasks, a process that is made possible by multisensory integration within the brain. Despite its importance, the neurophysiological mechanisms underlying the integration of stimuli from different sensory modalities remain unclear. The objective of this study was to investigate the characteristics of functional connectivity (FC) in healthy adults during a balance task with additional auditory stimuli.<i>Material</i>s<i>& Methods.</i>This study involved the simultaneous recording of stabilometry and electroencephalogram (EEG) in 17 healthy volunteers. The experimental design included two tasks. In the first task, participants were required to maintain their center of pressure on a stabilometric platform while receiving visual feedback on body position (VBF). In the second task, participants performed the same task but with the addition of auditory stimuli in the form of music (VBF+MUSIC). The FCs values of EEG signals were analyzed using the coherence method.<i>Results.</i>Analysis of the stabilometric data revealed that the most significant differences between the tasks were observed in the dynamic indicators related to the maintenance of the vertical body position. The values of the Quality of the balance function decreased with the expected increase in the cognitive load. EEG analysis showed that the value of functional connectivity (FC) was lower in VBF+MUSIC compared to VBF. Significant difference of FCs was detected between the right primary auditory cortex and associative auditory cortex involved in delta and theta rhythms that may reflect difference in auditory data processing, whereas differences in alpha and beta rhythms were found in the parietal region, which may reflect different level of attention.<i>Conclusion.</i>This study demonstrated that the presence of auditory stimuli leads to changes in postural balance indicators that specifically reflect oscillations in the sagittal plane. These findings suggest multiple neurophysiological levels of postural control in multisensory environments.