Abstract

Background: As the human population ages, there is an urgent need to find new fall prevention strategies that differ from the conventional strategy of  improving physical motor functions. Therefore, this study aimed to investigate the mechanism of falling during a dual task based on eye movements and frontal blood flow in the elderly.

Methods: Thirteen healthy elderly women participants performed the following tasks while walking on the spot: stepping at a normal walking speed (single task), stepping at a normal walking speed while solving mathematical problems (dual task), and stepping at a normal walking speed while looking carefully at an image in front of them (control task). Eye movements, stepping state (number of steps and toe height), and frontal blood flow of the participants were measured.

Results: The participants' eye movements were significantly greater during the dual task than during the single and control tasks. However, the number of  steps was not significantly different while performing the dual and single tasks. Toe height was significantly lower during the dual task than during the single task. Finally, frontal blood flow increased while performing the dual task compared with while the single task.

Conclusion: This study clarified the mechanism by which fall occurs in elderly participants. Eye movements increased during dual task walking; however, the additional task involving "thinking" required focus, the visual search became sparse, and the toe height was reduced. These factors increased the risk of "stumbling," which is considered the primary mechanism of falls.