Cross-correlation between head acceleration and stabilograms in humans in orthostatic posture

This work aims at evaluating the role of the vestibular system in the postural sway control using the cross correlation function. A sample of 19 young, healthy male adults was monitored with a three axial accelerometer placed over the head during a stabilometric test, standing on a force platform during 3 min in four conditions: eyes closed and open, and feet apart and together. The normalized cross correlation (NCCF) function and the Monte Carlo simulation were used to correlate changes in body sway with head accelerations. Significant NCCF was rarely observed in conditions with opened eyes, and occurred in six subjects with eyes closed and reduced support basis. These results are inconclusive. As no delayed response was observed, the classical negative feedback appears to be absent, and either phasic displacements of the center of pressure and the head or anticipatory control could be occurring.