Eye Movements and Frontal Cerebral Blood Flow during Dual-Task Performance in Young Adults: Basic Data to Identify the Mechanisms Underlying Falling in Older Adults

This study aimed to obtain basic data necessary for elucidating the mechanisms underlying falling in elderly people during walking. The participants, who were healthy young women (n=19; mean age, 23.1 ± 1.9 years), performed pseudo-walking foot-stepping motions according to the following three conditions: (1) foot-stepping at their usual walking speed (single task), (2) performing a foot-stepping motion at their usual walking speed while solving a mathematical problem (dual task), and (3) performing foot-stepping at their usual walking speed while looking carefully at an image in front of them (control task). Participants’ eyeball movements, number of steps, and blood flow rates in the frontal lobe were measured. We found that participants’ eyeball movements were significantly larger and faster during the dual task than during the single or control task (p<0.05). There were no significant differences in the number of footsteps among the single, dual, and control tasks. Blood flow rates in the frontal lobe were lower for the dual task than for the single task. Collectively, these findings imply that an increase in eye movements during thinking in young adults may suppress the input of visual information, and this may be more pronounced in older people with relatively poor frontal lobe function. The results of this study provide a baseline to compare the results of a similar study performed in older individuals.