Cortical response to balance perturbation is more sensitive in modern dancers than nondancers during biomechanically similar balance recovery

Motor skill expertise can facilitate more automatic movement, engaging less cortical activity while producing appropriate motor output. Accordingly, cortical-evoked error assessment responses to balance perturbations, assessed using electroencephalography (EEG), are smaller in young and older adults with better balance. However, the effect of balance expertise on cortical responses to balance perturbation has not been studied. Using professional modern dancers as balance experts, we compared cortical-evoked responses and biomechanics of the balance-correcting response between modern dancers and nondancers. We hypothesized that balance ability gained through long-term training facilitates more automatic balance control. We predicted modern dancers would have smaller cortical-evoked responses and better balance recovery at equivalent balance challenge. Support-surface perturbations were scaled to 60% and 140% of individuals' step threshold to account for individual challenge level, and N1 amplitude was assessed as an initial measure of cortical engagement relating to balance error assessment. In contrast to our prediction, dancers exhibited larger N1 responses compared to nondancers while demonstrating similar biomechanical responses, suggesting dancers have greater cortical sensitivity to balance perturbations. Further, in dancers, modulation of N1 responses across perturbation magnitudes scaled to differences in objective task difficulty. In contrast, nondancer N1 responses were modulated as a function of inter-subject differences in N1 amplitude, potentially reflecting individual balance challenge. Our findings suggest that modern dance training increases sensitivity of the initial, cortical N1 response to balance perturbation, supporting postural alignment to an objective reference. Differences in balance-error processing may thus be altered with specific long-term training, with implications for rehabilitation.