Recurrence analysis of human postural sway during the sensory organization test.

The present study examined how the availability of and alterations in sensory information during the sensory organization test (SOT) influenced the amount, variability, and temporal structure of spontaneous postural sway in young, healthy adults. Findings indicated that postural sway tended to increase in amount and variability as the SOT condition became increasingly difficult (i.e. as the SOT condition moved from eyes open to eyes closed, to sway-referenced visual surround or support surface, and to sway-reference surface and visual surround). In addition, recurrence quantification analysis revealed that the temporal structure of postural sway tended to become increasingly regular as the SOT condition increased in difficulty. The functional utility of the observed changes in the temporal structure of postural sway across sensory conditions was discussed.