Effect of Dual Task on Step Variability during Stepping in Place without Vision.

Stepping in place without vision is a spatial orientation task that is associated with unperceived foot displacements. This study was aimed at determining whether foot displacement variability is modified by a concurrent cognitive task. Fourteen young adults stepped for 50 steps with their vision blocked and performed a continuous mental counting task. 3-D Kinematic data from both feet (heel and big toe) was recorded. The variability of foot displacements was either unchanged or slightly lower in dual task, while the foot displacements were significantly shorter (p < 0.05) in dual task than without the cognitive task. The results suggest that the concurrent cognitive task might have allowed a better control of the repetitive lower limb movements.